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Branched-chain sugar nucleosides. Synthesis of structural analogues of puromycin Baker, Donald Arthur 1972

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BRANCHED-CHAIN SUGAR NUCLEOSIDES. SYNTHESIS OF STRUCTURAL ANALOGUES OF PUROMYCIN  BY  DONALD ARTHUR BAKER B.Sc,  The U n i v e r s i t y  o f B r i t i s h Columbia, 1968  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF  DOCTOR OF PHILOSOPHY  i n t h e Department of  CHEMISTRY  We a c c e p t t h i s required  t h e s i s as conforming t o t h e  standard  THE UNIVERSITY OF BRITISH COLUMBIA August, 1972  In p r e s e n t i n g  this  thesis  in p a r t i a l  fulfilment of  an advanced degree at the U n i v e r s i t y of the L i b r a r y I  further  for  this  freely  available  requirements  Columbia,  I agree  r e f e r e n c e and copying o f  this  for  that  study. thesis  purposes may be g r a n t e d by the Head of my Department or  representatives. thesis for  It  financial  i s understood that gain s h a l l  written permission.  Department  for  agree t h a t p e r m i s s i o n f o r e x t e n s i v e  scholarly  by h i s of  s h a l l make i t  British  the  of  The U n i v e r s i t y o f B r i t i s h Vancouver 8, Canada  Columbia  not  copying or  publication  be allowed without my  -i-  ABSTRACT Several new  routes to nitrogenous branched-chain  sugars have been  investigated and the preparation of several novel branched-chain sugar nucleosides having a s t r u c t u r a l relationship to puromycin has been described. The cyanomethyl branched-chain  sugars 3-C_-cyanomethyl^3-deoxy-  1,2:5,6-di-0_-isopropylidene-ct-D-allof uranose [LXXXVI], 3-C-cyanomethy13-deoxy-l,2:5,6-di-0-isopropylidene-a-D-gulofuranose  [LXVII], and  5-0_-benzyl-3-C_-cyanomethyl-3-deoxy-l,2-0-isopropylidene-a-p-ribofuranose [LXXVIII] were prepared by condensation of d i e t h y l cyanomethylphosphonate with 1,2 :5,6-di-0_-isopropylidene-a-D-r_ibo-hexofuranos-3-ulose 1,2;5,6-di-0-isopropylidene-q-D-xylo-hexofuranos-3-ulose  [XVIII],  [LXVII], and  5-0-benzyl-l,2-0-isopropylidene-q-g-erythro-pentofuranos-3-ulose [LXVIII], respectively, followed by stereoselective  hydrogenation  over palladium-on-charcoal of the intermediate unsaturated sugars. Reduction of the n i t r i l e group of LXXXVI and LXXXVIII gave the D-amino sugars, i s o l a t e d as their acetamido derivatives, 3-C_-(2'acetamidoethyl)-3-deoxy-l,2:5,6-di-O-isopropylidene-a-D-allofuranose [XCII] and 3-£-(2'-acetamidoethyl)-5-0-benzyl-3-deoxy-l,2-0_-isopropylidenea-D-ribofuranose  [XCIII].  Selective hydrolysis of the 5,6-0_-isopropylidene k e t a l of LXXXVII followed by sodium periodate degradation and sodium borohydride reduction afforded the L-cyanomethyl branched-chain  sugar 3-C_-cyanomethyl-3-  deoxy-l,2-0_-isopropylidene-6-L-lyxofuranose  [XCVI].  Reduction of the  n i t r i l e group of this compound gave the L-amino sugar characterized  -ii-  as i t s acetamido derivative 3-C_-(2'-acetamidoethyl)-3-deoxy-l,2-0_isopropylidene-8-L-lyxofuranose [XCVI]. The carbamoylmethyl branched-chain sugar  3-C_-carbamoylmethyl-3-  deoxy-l,2:5,6-di-0_-isopropylidene-a-D-allofuranose [C] was prepared v i a three d i f f e r e n t routes.  Hydrolysis of LXXXVI using a l k a l i n e  hydrogen peroxide afforded C i n 70 % y i e l d . also obtained by ammonolysis of  The same compound was  3-C-carbomethoxymethyl-3-deoxy-l,2:5,6-  di-O-isopropylidene-a-D-allofuranose [XXXIX] using l i q u i d ammonia and ammonium chloride and by the stereoselective photoaddition of formamide to the methylene branched-chain sugar  1,2:5,6-di-0-  isopropylidene-3-C-methylene-q-D-ribo-hexofuranose [XX]. A nitromethyl branched-chain sugar l,2:5,6-di-0-isopropylidene-3C-nitromethyl-a-D-glucofuranose [CV] was also prepared by condensing XVIII with nitromethane. The cyanomethyl branched-chain sugar LXXXVI was the key intermediate i n the synthesis of the branched-chain sugar nucleosides. Selective hydrolysis of LXXXVI to the 1,2-0-isopropylidene compound followed by benzoylation, hydrolysis of the 1,2-isopropylidene k e t a l and acetylation yielded 1,2-di-0_-acetyl-5,6-di-0-benzoyl-3-Ccyanomethyl-3-deoxy-B-D-allofuranose  [CX].  Fusion of CX with  6-chloropurine followed by reaction with methanolic-aqueous  dimethyl  amine gave the branched-chain sugar nucleoside 6-N,N-dimethylamino9-(3'-C-N,N-dimethylcarbamoylmethy1-3 -deoxy-g-D-allofuranosyl)-purine 1  [CXXI].  Sodium metaperiodate oxidation of CXXI followed by sodium  borohydride reduction gave the corresponding ribo nucleoside 6-N,N_-drmethylamino-9- (3' -C_-J},N-dimethylcarbaraoylmethyl-3'-deoxy-8-D~  -iii-  ribofuranosyl)-purine [CXXII]. In a separate procedure CXXII was obtained by fusion of 6-chloropurine with deoxy-g-D-ribofuranose  l,2-di-0-acetyl-5-0-benzoyl-3-C_-cyanomethyl-3[CXIII] prepared from LXXXVI by s e l e c t i v e  hydrolysis of the 5,6-isopropylidene group followed by sodium periodate degradation, sodium borohydride reduction of the aldehydo intermediate, benzoylation, hydrolysis of the 1,2-isopropylidene group and a c e t y l a t i o n ) , followed by reaction with methanolic aqueous dimethylamine. The corresponding unblocked cyanomethyl branched-chain  ribo sugar  nucleoside 6-N ,N-dimethylamino-9- (3' -C_-cyanomethy 1-3 -deoxy-g-D1  ribofuranosyl)-purine [CXXXI] was  obtained by fusion of CXIII with  6-chloropurine followed by reaction of the blocked nucleoside with anhydrous  dimethylamine.  Pyrolysis of the N.,N-dimethylcarbamoylmethyl ribonucleoside CXXII gave the novel lactone nucleoside 6-N,N_-dimethylamino-9-(3'C-carboxymethyl-2',3'-Y~lactone-3-deoxy-g-p-ribofuranosyl)-purine [CXXVIII].  Condensation  of this compound with ammonia afforded 6-N,N-  dimethylamino-9-( 3' -C_-carbamoylmethyl-3-deoxy-g-D-ribof uranosyl) -purine [CXXIX] and condensation of CVIII with ethyl glycinate gave the peptide nucleoside 6-N,N-dimethylamino-9-(3'-C-carbamoylmethyl-Nglycine e t h y l ester-3'-deoxy-g-D-ribofuranosyl)-purine [CXXX]. Reduction of cyanomethyl branched-chain afforded an amino branched-chain  ribo-nucleoside CXXXI  sugar nucleoside which was characterized  as i t s N-acetyl derivative 6-^,N_-dimethylamino-9-(3 -C-(2"-acetamido,  ethyl)-3'-deoxy-g-D-ribofuranosyl)-purine [CXXXIV].  -iv-  Compounds CX and CXIII were also converted into the corresponding blocked adenyl nucleosides 6-benzamido-9-(2'-0acetyl-5',6 -di-O-benzoyl-3'-C-cyanomethyl-3 -deoxy-g-D-allofuranosyl)1  1  purine [CXXXVI] and 6-benzamido-9-(2'-O-acety1-5'-0-benzoyl-3'-Ccyanomethyl-3'-deoxy-3-D-ribofuranosyl)-purine [CXXXXVII] by reaction with hydrogen bromide followed by condensation with chloromercuri-6benzamido purine.  -v-  TABLE OF CONTENTS  ABSTRACT  i  TABLE OF CONTENTS  v  LIST OF FIGURES  xi  ACKNOWLEDGEMENTS  xii  I.  OBJECTIVE  1  II.  INTRODUCTION  4  1.  Branched-chain sugars  4  1.1  6  Synthesis of branched-chain sugars  2.  Oxidations of secondary carbohydrate hydroxyl groups  3.  The Wittig reaction 3.1 3.2 3.3 3.4  8 10  A p p l i c a t i o n of the Wittig reaction to carbohydrates  11  The phosphonate modification of the Wittig reaction  14  Mechanism and stereochemistry of the phosphonate modification of the Wittig reaction  15  The modified Wittig reaction i n carbohydrate chemistry  17  4.  N i t r o p a r a f f i n addition to carbohydrates  19  5.  Photo-addition of formamide to o l e f i n s  23  5.1  25  6.  Photo-additions to carbohydrates  Nucleosides  27  6.1  Nucleoside synthesis  28  6.2  Synthesis of purine nucleosides  28  6.3  Branched-chain  32  6.4  B i o l o g i c a l a c t i v i t y of branched-chain nucleosides  sugar nucleosides sugar  32  -villi.  RESULTS AND DISCUSSION 1.  Synthesis of branched-chain cyanomethyl sugars by a Wittig reaction 1.1 1.2  1.3 1.4  2.  2.2  2.3  3.  4.  1,2:5,6-Di-0-isopropylidene-q-D-xylohexof uranos-3-ulose [LXVII]  36  5-0-Benzyl-l,2-0-isopropylidene-a-Il-erythropentofuranos-3-ulose [LXVIII]  38  3-C-Cyanomethyl-3-deoxy-l ,2:5, 6-di-0-isopropylidene-a-E-allofuranose [LXXXVI], 3-Ccyanomethyl-3-deoxy-l ,2:5, 6-di-0_-isopropylidene-a-g-gulofuranose [LXXXVII] and 5-0benzyl-3-C-cyanomethyl-3-deoxy-l, 2-0-isopropylidene-q-g-ribofuranose [LXXXVIII]  40  48  3-C-(2'-Acetamidoethyl)-3-deoxy-l,2:5,6-di-0isopropylidene-a-g-allofuranose [XCI]  49  3-C-(2'-Acetamidoethyl>5-0-benzyl-3-deoxy-l,2O-isopropylidene-a-Pj-ribofuranose [XCIII]...  51  3-C-Cyanomethyl-3-deoxy-l,2-0-isopropylideneB-L-lyxofuranose [XCV] and 3-C_-(2'-acetamidoethyl)-3-deoxy-l,2-0-isopropylidene-B-^-lyxofuranose [XCVI] 7  52  3-C-Carbamoylmethyl-3-deoxy-l,2:5,6-di-0isopropylidene-a-D-allofuranose [C]  55 56  Synthesis of nitrogenous branched-chain sugars having a s i n g l e carbon i n the branched-chain 60 4.1 4.2  5.  35  Synthesis of branched-chain carbamoylmethyl sugars 3.1  34  1,2:5,6-Di-O-isopropylidene-q-D-ribohexofuranos-3-ulose [XVIII]  Synthesis of branched-chain amino sugars by r e duction of branched-chain cyano sugars 2.1  34  Photoamidation of 4,6-di-0-acetyl-2,3-dideoxyct-D- ery thro-hex-2- enopyranos id e [CII]  60  Addition of nitromethane to 1,2:5,6-di-0isopropylidene-q-D-ribo-hexofuranos-3-ulose [X\'III] 7  63  Nucleoside synthesis  65  -vii5.1  Attempted a c e t o l y s i s of 3-C-(2'-acetamidoethyl) -5-0-benzyl-3-deoxy-l, 2-£-isopropylidene-a-Dribofuranose [XCIII] 66  5.2  Conversion of 3-C_-cyanomethyl-3-deoxy-l,2: 5,6-di-O-isopropylidene-a-D-allofuranose [LXXXVI] into 1,2-di-0-acetyl-5,6-di-0-benzoyl -3-£-cyanomethyl-3-deoxy-g-D-allofuranose [CX] and 1,2-di-£-acetyl-5-p_-benzoyl-3-C-cyanomethyl-3-deoxy-B-D^-ribof uranose [CXIII]  69  6-Chloro-9-(2'-0-acetyl-5',6'-di-0-benzoyl3' -C-cyanomethyl-3 '-deoxy-g-p_-allof uranosyl) purine [CXVI] and 6-chloro-9-(2'-0-acetyl5' -0-benzoyl-3' -C-cyanomethyl-3' -deoxy-g-Dribofuranosyl)-purine [CXVIII]  74  6-N_,N_-Dimethylamino-9- (3' -C-N ,N-dimethylcarbamoylmethyl-3'-deoxy-g-D-allofuranosyl)-purine [CXXI] and 6-N,N-dimethylamino-9-(3'-C-N,Ndiraethylamino-9-(3 '-C_-N_,N-dimethylcarbamoylmethyl-3 '-deoxy-g-D_-ribof uranosyl)-purine [CXXII]  77  6-N.,N-Dimethylamino-9-(3'-C_-carboxymethyl-2' , 3'-y-lactone-3-deoxy-g-D-ribofuranosyl)purine [CXXVIII]  86  Conversion of 6-N_,N_-dimethylamino-9-(3 -Ccarboxymethyl-2',3'-y-lactone-3-deoxy-g-Dribofuranosyl)-purine [CXXVIII] to 6-N,Ndimethylamino-9- (3' -C_-N.,N_-dimethylcarbamoylmethyl-3'-deoxy-g-D-ribofuranosyl)-purine [CXXII], and e-J^Nj-dimethylamino-g-(3'-Ccarbamoylmethyl-3' -deoxy-g-Dj-ribof uranosyl) purine [CXXIX] and 6-N,JS[-dimethylamino-9(3'-£-carbamoylmethyl-N-glycine ethyl ester3'-deoxy-g-D-ribofuranosyl)-purine [CXXX]...  88  6-N,N-Dimethylamino-9-(3'-C-cyanomethyl-3'deoxy-g-p -ribofuranosyl)-purine [CXXXI]  91  6-N,N.-Dimethylamino-9- (3' -C- (2"-acetamidoethyl) -3'-deoxy-g-D_-ribofuranosyl)-purine [CXXXIV]  92  5.9 6-Benzamido-9-(2'-0-acetyl-5',6'-di-0-benzoyl3 -C-cyanomethyl-3'-deoxy-g-D-allofuranosyl)purine [CXXXVI] and 6-benzamido-9-(2'-O-acetyl -5' -()-benzoyl-3 -£-cyanomethyl-3' -deoxy-g-Dr i b o f uranosyl)-purine [CXXXVI I]  94  5.3  5.4  5.5  5.6  5.7  1  =  5.8  1  1  5.10  9-(3/-£-Aminoethyl-3*-deoxy-g-D-allofuranosyl}adenine [CXXXIX]  97  -viii-  6.  Biological activity  evaluation of branched-chain  sugar nucleosides IV.  98  EXPERIMENTAL  99  1.  General methods  99  2.  Chromatography  99  2.1  Column  99  2.2  Thin layer chromatography  100  2.3  Paper chromatography  100  2.4  Gas l i q u i d chromatography  100  3.  Photolysis reactions  101  1,2:5,6-Di-0_-isopropylidene-a-g -glucofuranose =  [LXIX] .  101  5-0-Benzyl-l, 2-C^-isopropylidene-a-Dj-xylof uranose [LXXVII]  102  1, 2: 5, 6-Di-O-isopropylidene-ct-gj-gulofuranose [LXXIa] . . 1,2:5, 6-Di-O-isopropylidene-a-Dj-ribof uranos-3-ulose [XVIII] 1,2:5,6-Di-0-isopropylidene-a-D-xylo-furanos-3-ulose [LXVII] 5-0-Benzyl-l, 2-0-isopropylidene-ct-P_-erythro-pentofuranos-3-ulose [LXVIII]  103  103 104 105  3-C_-Cyanomethyl-3-deoxy-l ,2:5, 6-di-0-isopropylidenea-g-allof uranose [LXXXVI]  107  3-C_-Cyanomethyl-3-deoxy-l, 2: 5, 6-di-0-isopropylidenea-D-gulofuranose [LXXXVII]  108  5-£-Benzyl-3-C_-cyanomethyl-3-deoxy-l, 2-0-isopropylidene-a-D-ribofuranose [LXXXVIII]  109  3-C-(2'-Acetamidoethyl)-3-deoxy-l,2:5,6-d i-O-isopropylidene-a-D-allofuranose [XCII]  110  3-C_-(2'-Acetamidoethyl)-5-0-benzyl-3-deoxy-l, propylidene-a-D-ribof uranose [XCIII]  2-0-isoIll  -ix-  A c e t o l y s i s of 3-C_-(2'-acetamidoethyl)-5-0_-benzyl-3-deoxy1.2- 0_-isopropylidene-a-D-ribof uranose [XCIII] 112 3-C-Cyanomethyl-3-deoxy-l, 2-0-isopropylidene-B-L_-lyxofuranose [XCV]  112  3-C-(2'-Acetamidoethyl)-3-deoxy-l, 2-0-isopropylideneB-L-lyxof uranose [XCVI]  113  3-C-Carbamoylmethyl-3-deoxy-l,2:5,6-di-0_-isopropylidene-a-H-allofuranose [C]  114  Ethyl 4,6-di-0-acetyl-2,3-dideoxy-ct-D-erythro-hex-2enopyranoside [CII]  115  Photo-addition of formamide to ethyl 4,6-di-0-acetyl2.3- d ideoxy-ct-D-ery thro-hex-2-enopyranos id e [ C I I ] . . . .  116  1,2:5, 6-Di=0_-isopropylidene-3-C_-nitromethyl-a-Dglucof uranose [CV]  117  3-C-Cyanomethyl-3-deoxy-l, 2-()-isopropylidene-a-p allofuranose [CVIII]  118  5, 6-Di-0-benzoyl-3-C_-cyanomethyl-3-deoxy-l, pylidene-a-D^allof uranose [CIX]  119  =  5- C)-Benzoyl-3-C-cyanomethyl-3-deoxy-l, dene-cc-D-ribofuranose [CXII]  2-0-isopro-  2-0-isopropyli119  1,2-Di-0-acetyl-5, 6-di-0-benzoyl-3-C_-cyanomethyl-3deoxy-B-D-allof uranose [CX]  120  3-C-Cyanomethyl-3-deoxy-l, 2-0_-isopropylidene-ct-Dribofuranose [CXI]  121  1,2-Di-£-acetyl-5-0-benzoyl-3-C-cyanomethyl-3-deoxyB-D-ribofuranose [CXIII]  122  6- Chloro-9-(2'-O-acetyl-5',6'-di-0-benzoyl-3'-Ccyanomethyl-3'-deoxy-B-D-allofuranosyl)-purine [CXVI]  123  6-Chloro-9-(2'-0-acetyl-5'-0-benzoyl-3'-C-cyanomethyl3'-deoxy-3-D-ribofuranosyl)-purine [CXVIII]  124  6-H N.-Dimethylamino-9- (3' -C_-N,^-dimethylcarbamoylmethyl -3'-deoxy-8-g-allofuranosyl)-purine [CXXI]  124  6-N., N-Dimethylamino-9- (2 ,5' -di-0-acetyl-3 '-C-N.Ndimethylcarbamoylmethyl-3'-deoxy-B-D-ribofuranosyl)purine  125  s  1  -x-  6-N_,_N-Di!i!ethylamino-9- (3' -£-N ,tI-dimethylcarbamoylmethyl -3'-deoxy-S-g-ribofuranosyl)-purine [CXXII]  126  Preparation of 6-N_,_N-dimethylamino-9-(3-£-N_,N_-dimethylcarbamoylmethyl-3' -deoxy-S-D^-r ibof uranosyl) -purine [CXXII] from CXXXI  127  6-N,^-Dimethylamino-9-(3'-C_-carboxyraethyl-2 -3 -Ylactone-3-deoxy-S-D-ribofuranosyl)-purine [CXXVIII]..  128  6-N_,N_-Dimethylamino-9- (3' -C-carbamoylmethyl-3 -deoxye-D-ribofuranosyl)-purine [CXXIX]  128  6-JN,N-Dimethylamino-9-(3 -C-carbamoylmethyl-N-glycine ethyl ester-3'-deoxy-B-D-ribofuranosyl)-purine [CXXX]  129  6- N,_N_-Dimethyl;imino-9- (3' -£-cyanomethyl-3' -deoxy-B-Dribofuranosyl)-purine [CXXXI]  130  6-_N,N_-Dimethylamino-9-(3'-(2"-acetamidoethyl)-3 -deoxy -g-D-ribofuranosyl)-purine [CXXXIV]  130  Chloromercuri-6-benzamidopurine  131  6-Benzamido-9-(2'-£-acetyl-5' , 6'-di-£-benzoyl-3 '-£cyanomethyl-3'-deoxy-B-D -allofuranosyl)-purine [CXXXVI]  132  6-Benzamido-9-(2*-£-acetyl--5'-0-benzoyl-3' -C-cyanomethyl-3'-deoxy-B-D-ribofuranosyl)-purine [CXXXVII]..  134  9-(3'-£-Aminoethyl-3'-deoxy-g-D-allofuranosyl)-adenine [CXXXIX]  134  t  l  1  1  -  1  =  ADDENDA  136  -xi-  LIST OF FIGURES FIGURE 1.  2.  Proton magnetic resonance spectrum at 100 MHz i n deuteriochloroform of 3-C-cyanomethyl-3-deoxy-l,2: 5,6-di-O-isopropylidene-a-Dj-allofuranose [LXXXVI]  47  Proton magnetic resonance spectrum at 100 MHz i n dimethyl sulfoxide-d^ of 6-_N,N-dimethylamino-9(3 '-C_-li,N-dimethylcarbamoylmethyl-3' -deoxy-g-Dallofuranosyl)-purine [CXXI]  79  -xii-  ACKNOWLEDGEMENTS  The author wishes to express h i s sincere gratitude to Professor A. Rosenthal who suggested t h i s problem and provided s k i l l f u l guidance throughout the course of t h i s work. Professor G.G.S. Dutton and Dr. P. Legzdins are to be thanked for reading and commenting on t h i s manuscript. The encouragement and assistance of my wife during the preparat i o n of t h i s thesis was greatly appreciated. F i n a l l y , the f i n a n c i a l support of the H. R. MacMillan Family Fellowship (1971 - 1972) and the F. J . Nicholson Scholarship Fund (1969 - 1971) are g r a t e f u l l y acknowledged.  I.  OBJECTIVE:  I n r e c e n t y e a r s a wide v a r i e t y o f u n u s u a l n i t r o g e n c o n t a i n i n g c a r b o h y d r a t e d e r i v a t i v e s has been i s o l a t e d from a n t i b i o t i c s ( 1 ) . T h i s has l e d t o a g r e a t i n t e r e s t t h i s t y p e as not o n l y has  i n the s y n t h e s i s of compounds o f  t h e r e been the m o t i v a t i o n of p r e p a r i n g  m a t e r i a l s h a v i n g i n t e r e s t i n g b i o l o g i c a l a c t i v i t i e s but  also,  because of the h i g h d e n s i t y of d i v e r s e f u n c t i o n a l groups p r e s e n t , t h e i r p r e p a r a t i o n has p r e s e n t e d to the s y n t h e t i c o r g a n i c chemist intriguing challenges. The  first  o b j e c t i v e o f t h i s work was  t o e x p l o r e ways o f p r e p a r -  i n g c a r b o h y d r a t e d e r i v a t i v e s c o n t a i n i n g deoxy-nitrogenous chains.  A l t h o u g h no c a r b o h y d r a t e s h a v i n g a n i t r o g e n o u s  c h a i n have as y e t been encountered two of  amino (9,11) b r a n c h e d - c h a i n  i n n a t u r e , one n i t r o  sugars have been found  branchedbranched-  (10)  to be  and components  antibiotics. To a t t a i n the above o b j e c t i v e t h r e e new  nitrogenous branched-chains,  methods o f i n t r o d u c i n g  t h e a d d i t i o n of the W i t t i g  reagent  d i e t h y l cyanomethylphosphonate t o s e v e r a l 3-ketoses,  the  of n i t r o m e t h a n e  of unsaturated  w i t h k e t o s e s and  s u g a r s , were examined.  D u r i n g the c o m p l e t i o n of t h i s work t h e  d e n s a t i o n of n i t r o m e t h a n e n i t r o methyl groups  and  w i t h c a r b o h y d r a t e s to g i v e  amino methyl  (20,79,80).  the p h o t o - a m i d a t i o n  condensation  sugars was  con-  branched-chain  r e p o r t e d by s e v e r a l o t h e r  -2-  The second o b j e c t i v e of t h i s work was  t o c o n v e r t some o f t h e  3-deoxy b r a n c h e d - c h a i n s u g a r s p r e p a r e d v i a t h e above W i t t i g  reaction  i n t o hexo- and, i n p a r t i c u l a r , p e n t o - f u r a n o s y l b r a n c h e d - c h a i n  sugar  nucleosides. The C-3' m o d i f i e d n u c l e o s i d e s p r e p a r e d were m a i n l y d i m e t h y l aminopurine d e r i v a t i v e s .  D i m e t h y l a m i n o p u r i n e was  chosen t o be t h e  h e t e r o c y c l i c b a s e i n t h e s e compounds i n o r d e r t h a t t h e s e b r a n c h e d c h a i n sugar n u c l e o s i d e s would be s t r u c t u r a l a n a l o g s of t h e a n t i b i o t i c puromycin  [I] (2a).  The b i o l o g i c a l a c t i v i t y of puromycin and i t s  a n a l o g s i s known t o be v e r y dependent on t h e C-3'  substituent.  For  example, t h e d i m e t h y l a m i n o p u r i n e n u c l e o s i d e I I , h a v i n g a h y d r o x y l group a t t h e 3' p o s i t i o n , has been shown to be c o m p l e t e l y i n a c t i v e (2b) w h i l e t h e c o r r e s p o n d i n g £-3 -amino-C-3-deoxy-dimethylaminopurine 1  n u c l e o s i d e III (3) and v a r i o u s C-3'  secondary amino n u c l e o s i d e s IV  (4) show a range o f a n t i m e t a b o l i c a c t i v i t y  (3,4).  t h a t d i m e t h y l a m i n o p u r i n e n u c l e o s i d e s h a v i n g C-3'  T h i s suggests branched-chains  b e a r i n g n i t r o g e n s u b s t i t u e n t s c o u l d be p o t e n t i a l t h e r a p e u t i c a g e n t s .  [I]  -3-  I n o r d e r to p r o v i d e a p e r s p e c t i v e f o r subsequent d i s c u s s i o n , methods o f s y n t h e s i s o f b r a n c h e d - c h a i n nitroparaffin and  condensations,  sugars, W i t t i g r e a c t i o n s ,  p h o t o - a d d i t i o n s o f formamide t o o l e f i n s  photo-additions to carbohydrates  w i l l a l l be b r i e f l y  reviewed.  In a d d i t i o n , some comments on methods of n u c l e o s i d e s y n t h e s i s and the b i o l o g i c a l a c t i v i t i e s of branched-chain be made.  sugar n u c l e o s i d e s  will  II. 1.  Branched-chain  INTRODUCTION:  sugars  A b r a n c h e d - c h a i n sugar i s a c a r b o h y d r a t e i n which a hydrogen or h y d r o x y l group i s r e p l a c e d by a c a r b o n so as to l e a d to b r a n c h i n g of the carbon s k e l e t o n .  Over t h e y e a r s t h e s e m o d i f i e d sugars have  been i s o l a t e d from a number of n a t u r a l p r o d u c t s ( 5 ) .  However, i t  has been the r e l a t i v e l y r e c e n t d i s c o v e r y t h a t t h e s e u n u s u a l sugars a r e components o f some important a n t i b i o t i c s t h a t has l e d t o a heightened i n t e r e s t  i n the p r e p a r a t i o n and p r o p e r t i e s o f t h e s e  compounds. In T a b l e I a r e shown some r e p r e s e n t a t i v e b r a n c h e d - c h a i n sugars i s o l a t e d from n a t u r a l l y o c c u r r i n g a n t i b i o t i c s . seen t h a t t h e r e e x i s t s a v a r i e t y o f branched-chains and sugars.  I t can be unusual  Of p a r t i c u l a r i n t e r e s t here a r e the b r a n c h e d - c h a i n sugars  garosamine [ V I I I ] and e v e r n i t r o s e  [IX] as t h e s e compounds a r e  examples o f n i t r o g e n c o n t a i n i n g b r a n c h e d - c h a i n s u g a r s .  Very  r e c e n t l y another amino b r a n c h e d - c h a i n sugar, s i b i r o s a m i n e (11), so f a r o n l y i d e n t i f i e d as a 4,6-dideoxy-3-C-methyl-4-methylaminohexopyranose, has been i s o l a t e d G r i s e b a c h and Schmid  from the a n t i b i o t i c  sibiromycin.  (12) have l a t e l y reviewed the c h e m i s t r y and  biochemistry of these unusual sugars.  -5-  TABLE I B r a n c h e d - c h a i n Sugars  Structure  I s o l a t e d from A n t i b i o t i c s  Reference  Structure HO/  6  0  LlMe V Me"  OH  10  Me  3  [VI]  [IX]  Me  \  OH [VII]  9  [VIII]  7  A  H  OH  [V]  MeO  °  /  OH  CH  Reference  8  -6-  1.1  S y n t h e s i s of b r a n c h e d - c h a i n There a r e two  sugars  p o s s i b l e ways b r a n c h e d - c h a i n sugars can  prepared.  One  condensing  t o g e t h e r s m a l l non-carbohydrate  be  can e i t h e r c o n s t r u c t the d e s i r e d sugar i n s t a g e s by u n i t s , or one  i n t r o d u c e a b r a n c h - c h a i n i n t o an a l r e a d y pre-formed  can  carbohydrate.  Because i n the former method racemic m i x t u r e s r e s u l t whenever asymmetric  c e n t e r s a r e produced,  a h i g h d e n s i t y o f asymmetric approach  and c a r b o h y d r a t e s g e n e r a l l y have  c e n t e r s , t h i s has not been a p o p u l a r  f o r t h e p r e p a r a t i o n of b r a n c h e d - c h a i n s u g a r s .  e x c e p t i o n , however, was and coworkers  (13).  One  notable  i n t h e s y n t h e s i s o f mycarose [VI] by Lemal  As a t t h e time t h e r e was  f o r t h e r e l a t i v e c o n f i g u r a t i o n a t C-3,  C-4  no c l e a r  and C-5  evidence  they d e v i s e d a  scheme whereby t h e f o u r p o s s i b l e racemic mycarose isomers c o u l d be prepared.  T h i s was  done by condensing  the keto a c e t a l X w i t h the  G r i g n a r d r e a g e n t 1-propynylmagnesium bromide f o l l o w e d by h y d r o g e n a t i o n and c i s h y d r o x y l a t i o n .  partial  T h i s gave a m i x t u r e of  triols  which were c y c l i z e d and s e p a r a t e d as t h e i r methyl g l y c o s i d e s . t h i s way  they were a b l e t o s y n t h e s i z e racemic mycarose and i t s  3-epimer.  CH, 3 [VI]  [X]  In  -7-  Methods used t o d a t e to i n t r o d u c e skeleton  of a pre-formed  branching i n t o the carbon  sugar a r e summarized i n T a b l e I I .  a wide v a r i e t y o f r e a c t i o n s  Although  has been employed i n the m a j o r i t y  cases the b r a n c h e d - c h a i n s o b t a i n e d a r e f o r m a l l y  produced  of  by  TABLE I I Methods f o r I n t r o d u c t i o n  o f Branched--chains i n t o Sugars  Method  1.  From C a r b o h y d r a t e (a) (b) (c) (d) (e) (f) (g) (h)  2.  (a) (b) 3.  4.  14 15 16 17 18 19 20 21,  Epoxides  A d d i t i o n of c a r b a n i o n s Methyl l i t h i u m a d d i t i o n  From U n s a t u r a t e d (a) (b)  Ketoses  Acetonitrile addition Cyanohydrin r e a c t i o n Diazomethane a d d i t i o n Enamine a l k y l a t i o n Grignard a d d i t i o n Methyl l i t h i u m a d d i t i o n Nitromethane a d d i t i o n Wittig reaction  From C a r b o h y d r a t e  Reference  23 24  Carbohydrates  Oxo r e a c t i o n Photoamidation  25 26  M i s c e l l a n e o u s Approaches (a) (b) (c) (d)  D i m e r i z a t i o n to b r a n c h e d - c h a i n sugars Nitromethane a d d i t i o n t o sugar d i a l d e h y d e s R e d u c t i o n o f a l a c t o n e to a branched-c h a i n sugar Ring c o n t r a c t i o n to a branched--chain sugar  27 28 29 30  22  -8-  s u b s t i t u t i n g a b r a n c h - c h a i n f o r a hydrogen s k e l e t o n of t h e sugar. (deoxy b r a n c h e d - c h a i n  atom i n the carbon  The o t h e r type o f b r a n c h e d - c h a i n s u g a r s ) , where a h y d r o x y l group  by a b r a n c h - c h a i n , a r e l e s s r e a d i l y a v a i l a b l e .  Three  sugars  i s replaced reactions:  W i t t i g a d d i t i o n s , n i t r o p a r a f f i n a d d i t i o n s and p h o t o - a d d i t i o n s , which do l e a d t o deoxy b r a n c h e d - c h a i n greater d e t a i l .  But f i r s t ,  because  s u g a r s , w i l l be d i s c u s s e d i n  the s y n t h e s i s o f many  branched-  c h a i n sugars i s dependent on the p r e p a r a t i o n o f c a r b o h y d r a t e k e t o s e s (see T a b l e I I ) , methods o f o x i d a t i o n o f secondary h y d r o x y l groups o f sugars w i l l be  2.  reviewed.  O x i d a t i o n s o f secondary c a r b o h y d r a t e h y d r o x y l P r i o r t o about 1963  t h e means g e n e r a l l y a v a i l a b l e f o r o x i d a t i o n  of secondary c a r b o h y d r a t e h y d r o x y l groups were: oxygen ( 3 1 ) , l e a d pyridine low and  (33).  tetracetate-pyridine  Y i e l d s o f ketones  trioxide-  i n b l o c k e d d e r i v a t i v e s were o f t e n  t h e n however, the a d d i t i o n o f two new (DMSO) and ruthenium  p l a t i n u m o x i d e and  (32) and chromium  i n some cases the r e a c t i o n f a i l e d  sulfoxide  groups  completely (34).  o x i d i z i n g agents, dimethyl  tetroxide  (RuO^) and  the o l d e r p r o c e d u r e s have made a v a i l a b l e many new  improvements i n  carbonyl carbohydrates.  The a p p l i c a t i o n o f a l l t h e s e r e a g e n t s to c a r b o h y d r a t e s has reviewed RuO.) 4  been  (35) and o n l y those r e a g e n t s employed i n t h i s work (DMSO and  w i l l be c o n s i d e r e d f u r t h e r .  D i m e t h y l s u l f o x i d e has proved t o be a v e r y p o w e r f u l agent  Since  f o r c a r b o h y d r a t e h y d r o x y l groups  secondary a l c o h o l i s o x i d i z e d  (36).  oxidizing  Using t h i s reagent a  to a c a r b o n y l and  the DMSO i s reduced  -9-  to d i m e t h y l s u l f i d e .  Although  some a l c o h o l s have been s u c c e s s f u l l y  o x i d i z e d u s i n g DMSO a l o n e .(37) , f o r sugar d e r i v a t i v e s the b e s t y i e l d s a r e o b t a i n e d by u s i n g combinations  o f DMSO and some " a c t i v a t -  i n g " agent such a s N, N - d i c y c l o h e x y l c a r b o d i i m i d e (39) o r phosphorus p e n t o x i d e  (40).  (38), a c e t i c  These e l e c t r o p h i l i c  anhydride  "activating"  agents (E) ( E q u a t i o n 1) r e a c t w i t h DMSO (36) t o form an i n t e r m e d i a t e which i s s u b s e q u e n t l y  a t t a c k e d by the a l c o h o l r e s u l t i n g  i n displace-  ment o f t h e " a c t i v a t i n g " agent and f o r m a t i o n o f a d i m e t h y l a l k o x y sulfonium s a l t . transfer (DMS).  R e a c t i o n w i t h base f o l l o w e d by i n t r a m o l e c u l a r hydrogen  (41) then g i v e s t h e c a r b o n y l p r o d u c t and d i m e t h y l The most common b y - p r o d u c t s  methyl ethers  sulfide  of this oxidation are methylthio-  (42, 4 3 ) .  + (CH  ) S=0  +  E  (CH ) S-O-E + J  R-CH-R' OH (1)  P  DMS  +  + R (CH_)„S-0-CH  ,  0=0^, • *  2 2 S  -  R.'  O x i d a t i o n w i t h ruthenium t e t r o x i d e i s a method whereby carbohydrate  secondary  h y d r o x y l groups can b e o x i d i z e d t o ketones under  r e l a t i v e l y mild conditions.  T h i s reagent  c a n e i t h e r be prepared  s e p a r a t e l y and added t o a s o l u t i o n o f t h e a l c o h o l t o be o x i d i z e d (44) (at l e a s t one e q u i v a l e n t o f ruthenium t e t r o x i d e f o r each h y d r o x y l group t o be o x i d i z e d ) , o r generated and  sodium o r potassium  jLn s i t u  p e r i o d a t e (45).  from ruthenium d i o x i d e  The i n s i t u p r e p a r a t i o n o f  -10-  ruthenium t e t r o x i d e i s g e n e r a l l y p r e f e r r e d as i t i s s i m p l e r  and  o n l y t r a c e amounts ( about-20 mg  ruthenium  per g s u b s t r a t e ) o f c o s t l y  d i o x i d e a r e used. The s o u r c e o f s u p p l y o f ruthenium d i o x i d e used i s v e r y important (46).  i n this  oxidation  Commercial ruthenium d i o x i d e i s p r e p a r e d i n  one of two ways, e i t h e r by d i r e c t c o m b i n a t i o n of ruthenium w i t h m o l e c u l a r oxygen, o r from ruthenium t r i c h l o r i d e v i a t h e p r e c i p i t a t i o n process (47).  U s i n g aqueous p e r i o d a t e s o l u t i o n s i t i s o n l y  p o s s i b l e to p r e p a r e ruthenium t e t r o x i d e from ruthenium  dioxide  p r e p a r e d v i a the p r e c i p i t a t i o n p r o c e s s . S i d e p r o d u c t s i n ruthenium t e t r o x i d e o x i d a t i o n s u s u a l l y from o v e r - o x i d a t i o n  3.  The W i t t i g  (48) r e s u l t i n g  aldehydes or ketones.  (49) i s a method f o r p r e p a r i n g o l e f i n s  from  This r e a c t i o n involves a condensation e l i m i n -  a t i o n between a phosphonium y l i d  and the c a r b o x y l group o f an a l d e h y d e  ketone to form an o l e f i n and a phosphine o x i d e ( E q u a t i o n 2 ) .  + -  9  (R) P-CHY 3  Y=H  i n lactone formation.  reaction  The W i t t i g r e a c t i o n  or  result  +  R -d-R  or e l e c t r o n withdrawing  »>  RjR^CHY  +  (R) P0  (2)  3  group  As t h i s r e a c t i o n i s w i d e l y used by o r g a n i c c h e m i s t s , g e n e r a l r e v i e w s (50) and d e t a i l e d d i s c u s s i o n s of the mechanism and chemistry  stereo-  (51) a r e a v a i l a b l e i n the l i t e r a t u r e and t h e r e f o r e t h e s e  features w i l l  not be reviewed h e r e .  The a p p l i c a t i o n o f t h i s  reaction  -11-  to carbohydrates w i l l be examined, however. 3.1  A p p l i c a t i o n of the Wittig reaction to carbohydrates The f i r s t a p p l i c a t i o n of the Wittig reaction i n carbohydrate  chemistry was reported i n 1963 by Kochetkov et a l . (52). workers had undertaken  These  to develop a general route to higher aldoses.  The unsaturated aldonic esters obtained v i a a Wittig reaction (Equation 3) were key intermediates i n their program.  By means of  CO. Et I 2 CH  CHO I (CHOAc)n | CH OAc  +  II  (C H ) PCHC0 Et 6 5 3 2 c  o  CH i (CHOAc)n CH OAc  o  2  (3)  2  d i f f e r e n t Wittig reagents others have used the same strategy to obtain unsaturated higher ketoses (53), aldonic acids (54), deoxy sugars (55) and C_ glycosides (56) . The Wittig reaction has also been used to extend the carbon skeletons at the opposite end of the sugar chain.  Condensation of  the aldehyde XI (57) with either n-pentadecyltriphenyl phosphonium bromide or ethoxycarbonylmethylene  triphenylphosphorane gave the  expected unsaturated compounds XII and XIII respectively.  R=CH  OCH 1  i Ph  J  [XI]  R  = 0  [XII]  R = CH(CH ) CH  [XIII]  R = CHC0 Et  2  2  n  3  -12-  N u c l e o s i d e s h a v i n g a 5' aldehydo with W i t t i g reagents.  group have a l s o been  condensed  When p y r i m i d i n e n u c l e o s i d e XIV (58) was r e a c t e d  w i t h t h e phosphorane y l i d ,  g e n e r a t e d i n s i t u by t h e a c t i o n o f sodium  e t h o x i d e on ( e t h o x y c a r b o n y l m e t h y l ) t r i p h e n y l p h o s p h o n i u m bromide, a rapid reaction identified  ensued  which gave f i v e p r o d u c t s .  These were s u b s e q u e n t l y  as u r a c i l , u n s a t u r a t e d a c i d s XV and XVI and t h e e t h y l  e s t e r s of these  acids. B  B R=CH-  [XIV] [XV]  R r= 0  [XVI] R = CHC0 H 2  R -• CHCQ H 2  B = uracil  In t h i s laboratory  t h e W i t t i g r e a c t i o n has been employed t o  p r e p a r e deoxy b r a n c h e d - c h a i n  sugars.  Thus c o n d e n s a t i o n o f t h e b a s i c  W i t t i g reagent methyltriphenylphosphonium  bromide w i t h c a r b o h y d r a t e  k e t o s e s XVII and X V I I I has been used by R o s e n t h a l and S p r i n z l t o obtain  t h e 2-C-2-deoxy- XIX (59) and 3-C-3-deoxy- XX (21)  methylene branched  chain sugars.  exocyclic  Compound XX has a l s o been  p r e p a r e d under s l i g h t l y d i f f e r e . . t c o n d i t i o n s  by Jones e t  al.  (60).  Other b r a n c h e d - c h a i n sugars p r e p a r e d v i a a W i t t i g r e a c t i o n have included  t h e u n s a t u r a t e d cyano sugars XXI (61).  were p r e p a r e d by c o n d e n s a t i o n o f k e t o s e XX w i t h t r i p h e n y l phosphorane.  These compounds cyanomethylene-  -13-  Me 0. OMe  0  Me'  o - j — Me  •Me  0  Me  Me  Me [XVII] [XIX]  [XVIII]  R = 0 R =  CH  [XX]  2  R = 0  R =  CH  [XXI]  2  In a l l of the above examples the carbohydrates have served only as the carbonyl components of the W i t t i g r e a c t i o n .  However,  Zhdanov and Polenov (62) have reversed t h i s approach and prepared a W i t t i g reagent from a carbohydrate.  This carbohydrate phosphorane  XXII was found to react with activated aldehydes to give both c i s and trans o l e f i n i c ketones. For example, r e a c t i o n with p-nitrobenzaldehyde gave the c i s and trans isomers of ketone XXIII.  R=CH  Me Me [XXII] [XXIII]  R = P(Ph)  3  R = CH(C H )N0 -p 6  4  2  -14-  3.2  The phosphonate m o d i f i c a t i o n As mentioned p r e v i o u s l y  tion  of the W i t t i g  reaction  the W i t t i g r e a c t i o n i n v o l v e s  e l i m i n a t i o n between a phosphonium  I t has been shown (63) t h a t y l i d s  ylid  a condensa-  and an aldehyde or ketone.  can be o b t a i n e d from any  phosphorus  system h a v i n g a hydrogen atom a d j a c e n t t o a phosphorus atom b e a r i n g a r e a s o n a b l e degree o f p o s i t i v e c h a r g e . One phosphorus system which meets the above c r i t e r i a phosphonates XXIV and t h e c o n d e n s a t i o n o f y l i d s  i s the  p r e p a r e d from t h e s e  compounds w i t h a l d e h y d e s and k e t o n e s i s r e f e r r e d t o as t h e phosphonate modification  of t h e W i t t i g  reaction.  0 II  (RO) P-CHR'R" 2  [XXIV] The f i r s t  r e p o r t e d r e a c t i o n of t h i s  coworkers (64) who  obtained triphenylethylene  by c o n d e n s i n g benzophenone phosphonate.  t y p e was  with the y l i d  due t o Horner and  i n quantitative  p r e p a r e d from  yield  diethylbenzyl-  The use o f phosphonates i n W i t t i g - t y p e r e a c t i o n s  thoroughly i n v e s t i g a t e d i n g e n e r a l compared  by Wadsworth and Emmons (65) who  t o phosphonium  more r e a c t i v e , and gave b e t t e r  ylids,  that  t h e phosphonates were  y i e l d s of o l e f i n .  phosphonates a r e cheaper than phosphonium  found  was  salts.  In a d d i t i o n , Also,  t h e phosphorus  b y - p r o d u c t from phosphonates i s a water s o l u b l e phosphate  ester  which i s e a s i e r t o s e p a r a t e from the o l e f i n than t r i p h e n y l p h o s p h i n e o x i d e , t h e u s u a l b y - p r o d u c t from t h e s t a n d a r d W i t t i g  reaction.  -15-  3.3  Mechanism and  stereochemistry of the phosphonate modification  of the Wittig reaction The Wittig o l e f i n synthesis  i s usually considered to proceed  as shown below (Equation 4) (51) with the erythro-betaine to the c i s o l e f i n and  XXVI leading  the threo-betaine XXVII leading to the  For s t a b i l i z e d y l i d s (XXV,  trans.  R = electron withdrawing group) reaction  with aldehydes gave predominately trans o l e f i n s while non-stabilized y l i d s (XXV,  R = a l k y l ) gave the c i s isomers, p a r t i c u l a r l y i n s a l t -  free non-polar solvents  (66). 0 (Ph) P  R  1  0  -  /\R' R H (Ph)o J  0  p  l_  R  H  II  . R'  <$r  H  [XXVIII]  /  (Ph) P 3| C ' \  /  C  \  R'  H  CIS  L C 1  /  H  [XXVI]  0  ^ [XXV]  erythro  —  H  \  R  H /  \ \ ,  *"  /\H R' R H threo [XXVII]  C=C  /  \  H  R* trans  The reaction of phosphonate carbanions with aldehydes and  ketones  i s also presumed to proceed as shown above for the phosphoranes. Although the stereochemistry of the products has not been as  extensive-  l y studied as the products from the standard Wittig reaction, i t would appear that i n most instances  both s t a b i l i z e d and non-stabilized anions  give a predominance of the trans o l e f i n (67).  Fortuitously,  the  condensation of d i e t h y l cyanomethylphosphonate anion with aldehydes and ketones has been the subject of two  recent studies  i s the modified Wittig reaction used i n t h i s work.  (68, 69).  This  ^16-  In t h e e a r l i e r  investigation  (68) the p r o d u c t s a r i s i n g  from the  r e a c t i o n of a l k y l p h e n y l ketones w i t h the c a r b a n i o n g e n e r a t e d from d i e t h y l cyanomethylphosphonate and sodium h y d r i d e ( E q u a t i o n 5) were examined.  I t was  found t h a t when the p h e n y l group  t e d i n t h e o r t h o - p o s i t i o n and the a l k y l group predominance of t r a n s o l e f i n  isomer were formed  2  w  a  s  unsubstitu-  unbranched, a  ( c i s / t r a n s r a t i o 0.1 - 0.2)  However, i f t h e a l k y l group was cis  (R )  (R^) was  resulted.  secondary, s u b s t a n t i a l amounts o f  ( c i s / t r a n s r a t i o 0.5 - 0.7), and i f  t e r t i a r y a l k y l group t h e c i s o l e f i n was  w  t h e major p r o d u c t .  a  s  a  Ortho  s u b s t i t u t i o n i n the phenyl r i n g a l s o increased the p r o p o r t i o n of c i s isomer, whereas meta and p a r a s u b s t i t u t i o n d i d not a p p r e c i a b l y  affect  the p r o d u c t c o m p o s i t i o n .  R^ NC  ^  P(0)(0Et)  erythro  /  R  2  [XXXI]  C=C  CN / \ H  2  cis  [XXXIII]  0  / R  C=0  +  I-.-  (EtO)_P-CHCN  (5)  2 [XXIX]  [XXX]  H  U  P(0)(0Et)  > R  threo  [XXXII]  R, = s u b s t i t u t e d o r u n s u b s t i t u t e d p h e n y l Ro = a l k y l o r H  =  c  x  2  2  trans  CN [XXXIV]  -17-  I n the l a t e r study  (69) the e r y t h r o XXXV and  t h r e o XXXVI  diethyl-l-cyano-2-hydroxy-2-phenylethylphosphonates and  separated.  By s t u d y i n g the d e c o m p o s i t i o n  i n b a s i c media,  R  2  (a)  aldehyde,  without  the f o l l o w i n g c o n c l u s i o n s were  I n t h i s b a s i c medium a n i o n s XXXI and XXXII (R^ = p h e n y l ,  = H) p a r t l y r e v e r t e d t o benzaldehyde  interconverted d i r e c t l y  ( i e . XXXI  i n t e r m e d i a t e s XXIX and XXX. ( c i s / t r a n s about was  of t h e s e compounds  (sodium h y d r i d e i n t e t r a h y d r o f u r a n ) , w i t h and  the p r e s e n c e o f competing reached:  were prepared  0.18)  (b)  and a n i o n XXX.  partly  the f o r m a t i o n of  The c i s - t r a n s r a t i o o f c i n n a m o n i t r i l e s t r a n s XXXIV, R^^ = p h e n y l , R  i f t h e r e a c t i o n was  u s i n g XXXV o r XXXVI, w i t h or w i t h o u t competing u s i n g benzaldehyde  and  XXXII) w i t h o u t  ( c i s XXXIII,  v e r y n e a r l y the same no matter  and a n i o n XXX  carried  aldehyde,  or  T h i s i n d i c a t e d t h a t the  2  =  out  directly cis-trans  r a t i o depended m a i n l y on the r e l a t i v e r a t e s o f o l e f i n f o r m a t i o n from oxyanions  XXXI and  XXXII.  [XXXV]  3.4  [XXXVI]  The m o d i f i e d W i t t i g r e a c t i o n i n c a r b o h y d r a t e The  first  chemistry  a p p l i c a t i o n o f the phosphonate m o d i f i c a t i o n of the  W i t t i g r e a c t i o n to a c a r b o h y d r a t e k e t o s e was and Nguyen (22) i n 1967.  r e p o r t e d by  Here t h e k e t o s e XVIII was  the c a r b a n i o n p r e p a r e d by the a c t i o n o f potassium  Rosenthal  condensed w i t h  t - b u t o x i d e on  H)  -18-  trimethylphosphonoacetate.  This procedure gave as the major prod-  ucts a mixture of c i s and trans unsaturated esters (XXXVII and XXXVIII).  Hydrogenation of either isomer gave as the only product  the same 3-deoxy a l i o branched-chain sugar XXXIX.  A p p l i c a t i o n of  the same r e a c t i o n to the 2-deoxy keto sugar XL afforded, a f t e r s t e r e o s e l e c t i v e hydrogenation, the 2,3-dideoxy branched-chain ribo sugar XLI (70).  [XVIII]  R = 0  [XXXVII]  R =  [XXXIX]  H  X  C0 CH 2  [XL]  3  [XLI]  -19-  P r o t e c t e d 5'-aldehyde- n u c l e o s i d e s X L I I and X L I I I have a l s o been condensed w i t h phosphonate W i t t i g r e a g e n t s  (71) .  Thus X L I I  when condensed w i t h t h e c a r b a n i o n from d i p h e n y l t r i p h e n y l p h o s p h o r onylidine-methylphosphonate  [XLIV] gave t h e  p h o s p h i n y l m e t h y l ) - n u c l e o s i d e XLV.  5*-deoxy-5'-(dihydroxy-  N u c l e o s i d e X L I I I condensed w i t h  t h e same r e a g e n t gave t h e c o r r e s p o n d i n g u r i d i n e compound XLVI.  [XLII] B = adenine [XLV] B = a d e n i n e  R = 0 R = CHPO(OPh)  [XLIII] B = u r a c i l [XLVI] B = u r a c i l  4  N i t r o p a r a f f i n a d d i t i o n to  R = 0 R = CHPO(OPh)  carbohydrates  N i t r o p a r a f f i n condensation been e x t e n s i v e l y s t u d i e d ( 7 2 ) .  r e a c t i o n s with carbohydrates H i s t o r i c a l l y these  (Equation 6),  the i n i t i a l a l k y l n i t r o condensation products being converted aldehydes  o r k e t o n e s by t h e Nef r e a c t i o n ( 7 3 ) .  have  condensations  were u s e d as a r o u t e t o h i g h e r c a r b o n a l d o s e s o r k e t o s e s  to  A m o d i f i c a t i o n of  t h i s r e a c t i o n ( E q u a t i o n 7) has p r o v i d e d a g e n e r a l r o u t e t o t h e 2-deoxy a l d o s e s .  Thus a c e t y l a t i o n o f t h e i n i t i a l  aldose condensation  nitromethane-  p r o d u c t s f o l l o w e d by a S c h m i d t - R u t z r e a c t i o n  (74) y i e l d s u n s a t u r a t e d n i t r o c a r b o h y d r a t e s .  Reduction of  these  compounds f o l l o w e d by a Nef r e a c t i o n on t h e n i t r o - s u g a r y i e l d s 2-deoxy a l d o s e s .  2  the  2  -20-  CH N0  HC=0  2  I  CH N0 3  R  2  HC=0  2  1. OH  CHOH  I  I  2. H 0+  R  3  CH„OH I R 2  CH.OH I  2  (6)  CH NO CHJDH I 2 CHNO„ I 2 CHOH  CH„OH I 2  1. OH  c=o  I CHOH  2. H 0 3  I  I  R  R  CH N0 2  2  CHOH I R  1.  CHNO.  (Ac) 0  I  2  2  CH I  2. NaHCO„  1. H  HC=0 r  CH  2. OH 3. H 0  R  2  (7)  R  3  As w e l l as t h e s e above r e a c t i o n s which s e r v e t o extend t h e sugar c h a i n , n i t r o p a r a f f i n c o n d e n s a t i o n s have been used t o p r e p a r e deoxyamino sugars (75), b r a n c h e d - c h a i n d e o x y n i t r o sugars (28, 76) and d i d e o x y b r a n c h e d - c h a i n d i n i t r o  sugar d e r i v a t i v e s  (77).  The  m a j o r i t y o f t h e s e r e a c t i o n s were developed by H. H. Baer and coworkers a t t h e U n i v e r s i t y o f Ottawa. with nitromethane  The c o n d e n s a t i o n o f sugar d i a l d e h y d e s  (75) ( E q u a t i o n 8) i s p a r t i c u l a r l y  interesting.  Under t h e r e a c t i o n c o n d i t i o n s c y c l i z a t i o n o c c u r r e d and r e d u c t i o n o f the a c i n i t r o compound a f f o r d e d deoxyamino s u g a r s .  By s u b s t i t u t i n g  n i t r o e t h a n e f o r n i t r o m e t h a n e i n t h i s r e a c t i o n d e o x y n i t r o branchedc h a i n sugars have been p r e p a r e d  0  0CH„  (28, 7 6 ) .  0. 0CH„ CH N0 3  2  OCH, KHSO  NaOCH ' NH  2  OH  -21-  Despite this considerable body of work done on the addition of n i t r o p a r a f f i n s to carbohydrates, u n t i l very recently no attempt had been made to condense nitromethane with carbohydrate ketoses i n order to obtain branched-chain sugars.  This s i t u a t i o n changed,  however, i n 1969 when two groups (78, 79) independently reported the addition of nitromethane to keto sugars. In the report from our laboratory (78) the 2-deoxy-3-ketohexo-pyranose XLVII was condensed with nitromethane to afford the 2-deoxy-3-C-nitromethyl-D-rlbo-hexopyranose  XLVIII.  [XLVII]  [XLVIII]  The second study dealt with the addition of nitromethane to the 3-keto furanoses XLIX (79) .  By t h i s means the 3-C-nitromethyl-D-  ribofuranose branched-chain sugar L was obtained.  Me [XLIX] R = t r i t y l or tosylate  Me [L]  -22-  Shortly a f t e r these i n i t i a l investigations appeared, et a l .  Overend  (20) published an extensive study on the addition of nitromethane  to methyl glycopyranosiduloses, and Albrecht and Moffat (80) announced the condensation of nitromethane with 3-keto-furanose XVIII to obtain the 3-Cj-nitromethyl-E-ribofuranose L I .  This compound was  converted by a Schmidt-Rutz reaction (74) followed by reduction to the deoxy nitromethyl branched-chain sugar LII from which were obtained 3-C_-nitromethyl L U I a and 3-C-amino methyl L U I b branchedchain sugar nucleosides.  Me.  / 0 \  Me  v  ,0>^  Me [XVIII]  [LII]  Me [LI]  [LUIa]  R =  N0  2  [LUIb]  R =  NH  2  -23-  5.  Photo-addition of formamide to o l e f i n s The photo-addition of formamide (81-84) to o l e f i n s was devel-  oped by Elad and Rokach as a general process for converting o l e f i n s to amides.  I t was found that i n the absence of ketones the photo-  addition of formamide required long i r r a d i a t i o n periods and gave low y i e l d s .  However, i n the presence of ketones such as acetone,  i r r a d i a t i o n (X > 300) of formamide solutions of o l e f i n s gave good (50-80%) y i e l d s of amides. For terminal o l e f i n s (81) the photo-products were found to be mainly the 1:1 adducts r e s u l t i n g from anti-Markovnikov addition of formamide to the double bond (Equation 9).  RCH=CH  2  +  HC0NH  2  Minor side products  — — -  RCH CH CONH 2  2  2  (9)  included non-terminal 1:1 formamide o l e f i n adducts, acetone addition products and teleomeric material.  Non-terminal o l e f i n s i n t h i s  r e a c t i o n were found to give primarily a mixture of 1:1 formamide o l e f i n adducts.  Reaction of a,B-unsaturated esters afforded mainly  products where formamide addition had taken place at the B carbon (84). Of p a r t i c u l a r interest i n this reaction i s the s e n s i t i v i t y of the addition to s t e r i c features of the o l e f i n .  As well as the  nearly exclusive anti-Markovnikov addition discussed above for terminal o l e f i n s , i t was found that the photo-condensation of formamide with norbornene exo-carboxyamide  [LIV] (82) gave only the single amide, norbornane-2[LV].  -24-  CONH,  [LIV]  [LV]  The mechanism postulated by Elad and Rokach (82) f o r the acetone i n i t i a t e d photo-addition of formamide was as follows (Equation 10). They hypothesized that the carbamoyl r a d i c a l s are generated either from the collapse of the photo-activated formamide molecule or through hydrogen atom abstraction from formamide by the excited t r i p l e t of acetone.  The o l e f i n then serves as a scavenger f o r the  carbamoyl r a d i c a l s thereby forming the formamide addition products. Chain propagation can continue as shown i n equation 10 d-f. hv  acetone HC0NH  2  +  R C H = CH  [acetone]  RCHCH CONH  2  RCHCH C0NH 2  2  (a)  (n -*Tr*) o  •CONH,  (n^*)  • CONH,  +  2  2  [acetone]  Termination  (b) (c)  RCHCH C0NH 2  +  HC0NH  +  RCH=CH  2  RCH„CH„C0NH  2  1  1  2  +  o  RCHCH„C0NH  2  I  2  2  «C0NH,  i  (d) (e)  o  CH -CHR RCHCH-CONH. , 2 2  +  HC0NH„ 2  CH -CHR  2  •CONH,  +  2  RCHCH CONH 2  o  +  •CONH,  (f)  CH CH R  2  RCH = CH  RCHCH C0NH„  2  +  2  RCHCONH CH « 2  'C0NH  2  (g)  2  RCHCH C0NH I  2  o  C0NH„  2  o  (h)  (10)  -25-  of the chain may occur i n many d i f f e r e n t ways, as f o r example i n equation lOh.  Products r e s u l t i n g from the side reactions  (10 e-h) were isolated i n some instances (82,83). The exact r o l e of acetone i n this reaction was recently (85).  clarified  For a d i r e c t energy transfer between the n "•IT* t r i p l e t of  acetone and the n-nr* f i r s t t r i p l e t of formamide to occur, the t r i p l e t energy of acetone (3.5 ev) (86) would have to be higher than that of formamide.  When the energy of the n "Hr* f i r s t t r i p l e t of formamide  was calculated i t was found to be 4.2 ev.  Therefore d i r e c t  energy  transfer to formamide from an acetone t r i p l e t i s not possible and consequently the carbamoyl r a d i c a l s i n t h i s photolysis must be produced by extraction of a formyl hydrogen from ground state formamide by a photo-activated acetone molecule.  5.1  Photo-additions to carbohydrates Although photo-degradation reactions of sugars have been well  studied (87), there i s only a limited number of instances of photoadditions to carbohydrates reported i n the l i t e r a t u r e . In 1966 Horton and Turner (88), while studying carbohydrates having heteroatoms other than oxygen i n the r i n g , prepared the thioacetate LVI by photo-addition of t h i o a c e t i c acid to the unsaturated sugar LVII.  Other sulfur-containing sugar derivatives have been  prepared (89) by the addition of t h i o a c e t i c acid and benzyl mercaptan to the unsaturated sugar LVIII. Various other reagents photo-condensed  with unsaturated sugar  LVII have included phosphine and phenylphosphine dioxalan (91).  (90) and  1,3  With the exocyclic "ene" sugar XX photo-addition of  -26-  OMe  0  Me  0  Me [LVI]  •C7  •Me  0 Me-^  Me [LVII]  0 ^Me  [LVIII]  dioxalan afforded the 3-deoxy-allo-branched-chain sugar LIX as the only product.  More recently reports of photo-condensations of  acetone with t r i a c e t y l - D - g l u c a l [LX] (92), and 2,3 dimethylbut-2ene with hexenopyranoses  [XX]  (93) have appeared.  [LIX]  In t h i s laboratory photo-amidation has been examined as a route to deoxy branched-chain amido and amino sugars.  I t was found that  the acetone s e n s i t i z e d photo-addition of formamide to t r i a c e t y l - g g l u c a l [LX] (26) gave the mixture of amides depicted i n equation 11 as w e l l as trace amounts of acetone addition products.  The same  r e a c t i o n applied to compound [LXI] (94) afforded the carbamoyl  -27-  [LXII]  I — CK  X X  Me  [LXIII]  branched-chain sugars LXII and LXIII along with some products r e s u l t ing from the photo-addition of acetone.  6.  Nucleosides The term nucleoside i s used to denote compounds containing a  nitrogen heterocycle (purine or pyrimidine and t h e i r close analogs) i n g l y c o s i d i c linkage with a carbohydrate moiety.  For naturally  -28-  occurring nucleosides the heterocyclic bases are attached v i a 8 glycosyl linkages, with the most commonly occuring bases being the purines adenine and guanine and the pyrimidines cytosine, u r a c i l and thymine. The carbohydrate portion i s usually D-ribose or "2-deoxy-D-ribose" i n the furanose form. 6.1  Nucleoside synthesis Rapid advances i n nucleic acid chemistry have resulted i n the  development of many new methods of nucleoside syntheses.  A complete  review of the a v a i l a b l e methods i s beyond the scope of this thesis; therefore only those methods of purine nucleoside synthesis used i n t h i s work w i l l be discussed.  For more complete surveys of the  synthetic methods a v a i l a b l e see references (95) and 6.2  (96).  Synthesis of purine nucleosides Fischer and H e l f e r i c h prepared the f i r s t purine glycosides  (purine nucleosides) by condensing  s i l v e r s a l t s of some purine  derivatives with acetylated glycosyl halides (97).  Subsequent  modifications of t h i s procedure resulted i n the replacement  of the  purine s i l v e r s a l t s with chloromercuri derivatives (98) and the i n s i t u generation of the glycosyl halide from the ester with titanium t e t r a c h l o r i d e (99) [Equation 12]. For sugars having at C-2 an ester hydroxyl protecting group, the anomeric (C-l') configurations of the nucleosides obtained by the above condensations are predicted by Baker's trans rule (100):  "condensations  of a heavy metal s a l t of a purine or pyrimidine with an acylated glycosyl halide w i l l form a nucleoside with a C - l ' , C-2'  trans  -29-  configuration i n the sugar moiety regardless of the o r i g i n a l configurat i o n of C - l , C-2."  The mechanistic  considerations underlying t h i s  observation have been reviewed (101) and although some exceptions  are  known (102), i n the vast majority of cases the C - l ' , C-2' c i s configuration i s not observed, or observed only i n minor proportions. Experimentally the anomeric configuration of glycofuranosyl purine nucleosides have been determined from the sign of t h e i r e f f e c t (103); the 9-B-P_-glycofuranosyl  Cotton  d e r i v a t i v e s give negative  Cotton e f f e c t s (104) and the 9-a-Dj-compounds show p o s i t i v e Cotton effects.  RO  Although i n equation 12 the N-9 as being the only product cases the N-7  OR  substituted nucleoside i s depicted  formed, as i t i s i n most instances, i n some  isomer i s produced, occasionally to the complete  -30-  exclusion of the N-9 form.  A case i n point occurred i n the preparation  of the puromycin analog LXIV.  When ct-bromoacetoglucose  was condensed  with the chloromercuri d e r i v a t i v e of 6-dimethylamino purine (105) only the N-7 nucleoside LXIV was i s o l a t e d .  Fortunately, i n the case of  puromycin d e r i v a t i v e s , the N-7 and N-9 isomers are e a s i l y d i f f e r e n t i a t e d on the basis of their u l t r a v i o l e t spectra, N-9 isomers at pH-7 having a X maximum at about 275 nm and N-7 isomers having a X maximum at about 295 nm (105).  At present there i s s t i l l no completely  s a t i s f a c t o r y r u l e f o r predicting whether the N-9 or N-7 isomer w i l l be formed i n t h i s r e a c t i o n .  2 AcO OAc [LXIV]  A more recently developed method for purine nucleoside synthesis i s the fusion procedure  (106,107).  Here the acetylated sugar, with  or without an acid c a t a l y s t , i s simply fused under reduced with a purine d e r i v a t i v e .  pressure  The resultant nucleosides are usually the  N-9 substituted isomers having anomeric configurations consistent with that which would be predicted by Baker's r u l e . Aside from s i m p l i c i t y , the fusion procedure has the a d d i t i o n a l advantages that the r e l a t i v e l y unstable glycosyl halide i s not necessary as an intermediate and that the purine may be substituted with amino, oxo, or thio f u n c t i o n a l i t i e s which need not be protected  -31-  during the reaction.  Also t h i s procedure r e s u l t s i n nucleosides  free of mercury contamination which i s sometimes not possible using the above halo-mercuri method.  This i s important i n cases where the  b i o l o g i c a l a c t i v i t y of a nucleoside i s to be evaluated as i t has been —8 shown (108) that mercuric ion concentration as low as 10  molar  can lead to erroneous interpretations of b i o l o g i c a l a c t i v i t y . 6.3  Branched-chain sugar nucleosides As branched-chain sugars had been isolated from a number of  important a n t i b i o t i c s , i n the middle years of the l a s t decade a number of research groups independently began programs leading to the synthesis of nucleosides containing branched-chain sugars instead of the normal D_-ribo furnoses i n order that their p o t e n t i a l as therapeutic agents could be evaluated. The f i r s t report of a synthesis of a branched-chain sugar nucleoside came i n 1966 from Walton et a l . (109) working i n the research laboratories of Merck, Sharp and Dohme.  These workers  reported the preparation of the 2'-C-methyl-Dj-ribofuranose LXV and 3'-C-methyl-D-ribofuranose LXVI analogs of adenosine.  NH  [LXV] [LXVI] OH  OH  R = H R = CH  R' = CH 3  3  R' = H  -32-  Since then, i n addition to the  3'-deoxy-3'-C-hydroxyethyl  (110) , 3'-deoxy-3'-C-methyl (22) and 3'-deoxy-3'-C_-hydroxymethyl (111) ribo and a l i o furanosyl adenine nucleosides prepared i n t h i s laboratory, numerous other branched-chain nucleosides (Table I I I ) have been synthesized.  The continuing interest of both academic  and i n d u s t r i a l research groups i n the chemistry of these compounds has made t h i s a very a c t i v e area of research.  6.4  B i o l o g i c a l a c t i v i t y of branched-chain sugar nucleosides Although no studies have been published concerning the b i o l o g i c a l  a c t i v i t y of a l l these modified nucleosides i n a single system, the fragmentary reports which do exist i n the l i t e r a t u r e indicate that some of these compounds might be developed into useful therapeutic agents.  For example, the methyl branched-chain sugar nucleo-  sides have been shown to i n h i b i t the growth of KB c e l l s i n culture (112) and to be e f f e c t i v e anti-neurovaccinia agents i n mice (113). In addition, the 3'-amino-3'-hydroxymethyl derivative of adenosine has been shown to exhibit weak i n h i b i t i o n against v a c c i n i a Dairen (118). It should be noted that where compounds have been assayed b i o l o g i c a l l y those having branches at the 3' p o s i t i o n (eg. LXVI) showed the greatest a c t i v i t y .  -33-  TABLE I I I S y n t h e s i s o f B r a n c h e d - c h a i n Sugar N u c l e o s i d e s  HOCH  (114)  HOCH  2  Q  DMP  >  2  Q  o r NH  (80)  C o r FC  >  (115)  HOCH  OH  2  2  HOCH  (114)  CH R R = N0  C o r FC  2  NH 2  2  OH  R = H o r Me  B = A, DMP, G, C, U  (116)  (117)  A = a d e n i n e ; C = c y t o s i n e ; CP = 6 - c h l o r o p u r i n e ; DMP = FC = 5 - f l u o r o u r a c i l ; G = guanine; P = p u r i n e .  6-dimethylaminopurine  The numbers i n p a r e n t h e s e s a r e t h e r e f e r e n c e s f o r t h e s e compounds.  III. 1.  RESULTS AND DISCUSSION  Synthesis of branched-chain cyanomethyl sugars by a Wittig reaction In  the objective i t was indicated that the f i r s t goal of the work  described here was to explore various means f o r introducing deoxynitrogenous branched-chains into carbohydrates.  As a modified Wittig  reaction had been shown i n this laboratory to be a u s e f u l way of preparing carbomethoxymethyl branched-chain sugars (22), i t was decided to attempt the condensation of the phosphonate Wittig reagent d i e t h y l cyanomethylphosphonate (68,69) with the carbohydrate 3-keto furanoses  1,2:5,6-di-O-isopropylidene-q-D-ribo-hexofuranos-3-ulose  [XVIII], 1,2:5,6-di-0-isopropylidene-D-q-xylo-hexofuranos-3-ulose [LXVII] and 5-0-benzyl-l,2-0-isopropylidene-q-D-erythro-pentofuranos-3ulose [LXVIII]. This p a r t i c u l a r Wittig reagent was chosen because i t was f e l t that a f t e r reduction of the i n i t i a l cyanovinyl addition products to cyanomethyl deoxy branched-chain sugars, these cyanomethyl compounds could be converted into various other nitrogenous branched-chain sug'ars such as aminomethyl and car bamoy line thy 1 d e r i v a t i v e s .  As the  second objective was to use these branched-chain compounds to prepare branched-chain sugar nucleosides and to examine the b i o l o g i c a l a c t i v i t y  -35-  of these modified nucleosides, i t was decided to use 3-keto-furanoses as the carbonyl component of t h i s W i t t i g reaction.  In t h i s  way  the branched-chain sugars prepared would be i n the furanose conf i g u r a t i o n (the carbohydrate configuration present i n most n a t u r a l l y occurring nucleosides) and the branched-chain nucleosides prepared from these sugars would have 3'-branched-chains.  As was pointed  out i n the Introduction (p.32 ) branching at t h i s p o s i t i o n appears to confer the greatest degree of b i o l o g i c a l a c t i v i t y .  Me Me  v  ,0 .CK.  0  [XVIII]  PhCH OCH 2  2  ^  Q  [LXVIII]  1.1 1,2:5,6-Di-O-isopropyl idene-ct-D-ribo-hexofuranos-3-ulose [XVIII] This compound was prepared from D-glucose by known procedures. Condensation of acetone with D-glucose i n the presence of an acid c a t a l y s t (118) afforded  1,2:5,6-di-O-isopropylidene-a-D-glucofuranose  -36-  [LXIX].  The secondary hydroxyl group of this compound was then oxidized  to the hydrated 3-keto compound LXX (Equation 13) using sodium periodate and a "cataly tic'-' amount of ruthenium dioxide (119) . The water of hydration was removed from LXX by azeotroping with toluene to afford ketose XVIII. A point of technique frequently omitted i n the discussion of the above oxidation i s the neccessity f o r c a r e f u l l y controlled addition of the periodate s o l u t i o n , p a r t i c u l a r l y at the beginning of the reaction.  Too rapid addition of periodate generally r e s u l t s i n  p r e c i p i t a t i o n of the ruthenium catalyst as an insoluble complex on the walls of the reaction f l a s k .  The best y i e l d s of ketose were obtained  by i n i t i a t i n g the reaction by adding only a few drops of periodate solution.  A f t e r several small additions of oxidant, i t was added i n  larger portions (1-2 ml) were observed.  a n  d the colour changes i n the reaction mixture  The presence of the actual oxidant, ruthenium  tetroxide was indicated by the reaction mixture taking on a green-black colour; when only ruthenium dioxide was present the solution appeared black.  Additions of periodate were made only when a l l the ruthenium  tetroxide generated by the previous addition of periodate had been consumed.  1.2  1,2:5,6-Di-O-isopropylidene-q-D-xylo-hexofuranos-3-ulose  [LXVII]  This ketose was prepared from hydrated ketose LXX following the procedure of Slessor and Tracey (119) (Equation 13).  Thus compound  LXX was acetylated to afford the enol acetate LXXI which a f t e r hydrogenation over palladium-on-charcoal followed by removal of the  -37-  -38-  3 - a c e t a t e u s i n g sodium methoxide and o x i d a t i o n ( w i t h  ruthenium  t e t r o x i d e as b e f o r e ) gave the r e q u i r e d 3-keto compound A p o i n t to note here  LXVII.  f o r f u t u r e d i s c u s s i o n i s the s t e r i c  e x e r t e d by t h e 1 , 2 - 0 - i s o p r o p y l i d e n e Because o f the d i r e c t i v e e f f e c t  control  group o f e n o l a c e t a t e LXXI.  e x h i b i t e d by t h i s group,  hydrogenation  of LXXI was s t e r e o s e l e c t i v e and r e s u l t e d i n f o r m a t i o n o f o n l y one product  1.3  [LXXIa].  5-0-Benzyl-l,2-0-isopropylidene-q-D-erythro-pentofuranos-3-ulose [LXVIIIJ T h i s compound was o b t a i n e d by a r a t h e r l e n g t h y procedure  14) s t a r t i n g from D - x y l o s e  [LXXIII].  The d i - O - i s o p r o p y l i d e n e compound  LXXIV was p r e p a r e d by the a c i d c a t a l y z e d c o n d e n s a t i o n D-xylose  (120).  (Equation  o f acetone  The 3 , 5 - i s o p r o p y l i d e n e group o f LXXIV was  s e l e c t i v e l y cleaved with d i l u t e acid to afford  the  with  then  mono-isopropylidene  compound LXXV (120).  T o s y l a t i o n o f the 5 - h y d r o x y l  f o l l o w e d by treatment  of the t o s y l a t e w i t h sodium methoxide, gave the  3,5-anhydro sugar LXXVI (121).  Opening o f the 3,5-anhydro r i n g w i t h  b e n z y l a l c o h o l and sodium a f f o r d e d xylo-furanose monobenzylation  [LXXVII] (122).  5-0_-benzyl-l,2-0_-isopropylidene-a-D-  P r e p a r a t i o n o f t h i s compound by d i r e c t  o f LXXV was n o t s u c c e s s f u l .  Two methods f o r the o x i d a t i o n o f the secondary a l c o h o l LXXVII were examined.  ( 4 0 ) . T h i s procedure  h y d r o x y l group o f  I n the f i r s t method the o x i d a n t was  d i m e t h y l s u l f o x i d e w i t h phosphorus p e n t o x i d e agent  group of LXXV (121)  s e r v i n g as the " a c t i v a t i n g "  a f f o r d e d a 65% y i e l d  isopropylidene-q-D-erythro-pentofuranos-3-ulose  o f 5—0—benzyl—1,2—0— [LXVIII] as a homogeneous  -39-  HOCH  OCH ^ , Dr x y l o s e  acetone • *H 0  2  H 0 3  /° OH  Me Me  3  -Me [LXXIV]  •Me  Me  [LXXV]  Me  1. TsCl 2. Na/MeOH  ROCH  2 ^0  RuO.  CH  ROCH. I  4  ROH  2  2^0  46  DMSO/P 0 2  5  0  0  Me  Me  Me [LXVIII]  •Me  • Me  •Me  [LXXVI]  [LXXVII]  R = benzyl  syrup  (R^ 0.76, benzene:methanol 4:1) h a v i n g no h y d r o x y l a b s o r p t i o n and  a s t r o n g c a r b o n y l a b s o r p t i o n a t 1760 cm  Attempted  chromatography  of t h i s k e t o s e (on s i l i c a g e l ) l e d t o d e c o m p o s i t i o n so i t was t h e r e f o r e c h a r a c t e r i z e d as i t s 2 , 4 - d i n i t r o p h e n y l h y d r a z o n e d e r i v a t i v e . I n t h e second method t h e o x i d a t i o n o f LXXVII was a c c o m p l i s h e d u s i n g r u t h e n i u m t e t r o x i d e g e n e r a t e d as i n t h e p r e v i o u s two o x i d a t i o n s from r u t h e n i u m d i o x i d e and sodium p e r i o d a t e ( 1 1 9 ) . v e r y good y i e l d s  This procedure  gave  ( c a . 90%) o f k e t o s e L X V I I I i d e n t i c a l by t i c , i r and  nmr w i t h t h e p r o d u c t from t h e DMSO o x i d a t i o n .  Although t h i s  oxidation  -40-  required about twenty hours to complete, the y i e l d of ketose was very good and none of the r i n g i n s e r t i o n lactone product was detected.  In  the oxidation of the related compound LXXIX with ruthenium tetroxide (123) (the ruthenium tetroxide being generated externally and added to a s o l u t i o n of alcohol LXXIX ) the 3-ketose LXXX was i s o l a t e d i n about a 50% y i e l d a f t e r a three hour reaction time.  Longer reaction periods  were found to give s u b s t a n t i a l amounts of the lactone side product LXXXI.  [LXXIX]  1.4  [LXXX]  [LXXXI]  3-C-Cyanomethyl-3-deoxy-l, 2:5,6-di-0_-isopropylidene-a-B-allof uranose [LXXXVI], 3-C-cyanomethyl-3-deoxy-l,2:5 ,6-di-0-isopropylidene-ctD-gulofuranose [LXXXVII] and  5-0_-benzyl-3-C_-cyanomethyl-3-deoxy-  1,2-0-isopropylidene-a-D-ribofuranose  [LXXXVIII]  Having obtained the 3-ketoses j u s t described the next step was to condense these compounds with the carbanion prepared from d i e t h y l cyanomethylphosphonate  and sodium hydride.  The method followed here  was e s s e n t i a l l y that u t i l i z e d by Jones and Maisey (68) i n the preparation of a,B-unsaturated n i t r i l e s from a l k y l phenyl ketones.  The only  modifications to t h e i r procedure were that the reaction mixture was held  -41-  at 0° during addition of the ketose to the solution (this was  found  to eliminate the formation of side products) and that the i n i t i a l l y produced a,^-unsaturated n i t r i l e s were hydrogenated  (at atmospheric  pressure using palladium on charcoal) without p r i o r p u r i f i c a t i o n to afford  the 3-C_-cyanomethyl-3-deoxy branched-chain sugars.  Thus, the above reactions applied to l,2:5,6-di-0-isopropylidenect-D-ribo-hexof uranos-3-ulose  [XVTII] afforded 3-C-cyanomethyl-3-deoxy-  1,2:5,6-di-0-isopropylidene-ct-D-allofuranose [LXVII] i n 78% y i e l d ; 1,2:5,6-di-0-isopropylidene-q-D-xylo-hexofuranos-3-ulose afforded  [LXVIII]  3-C-cyanomethyl-3-deoxy-l,2:5,6-di-0-isopropylidene-a-I)-  gulofuranose [LXXXVI] i n 79% y i e l d , and 5-0-benzyl-l,2-0-isopropylideneot-g-erythro-pentofuranos-3-ulose [LXXXVII] afforded cyanomethyl-3-deoxy-a-D-ribofuranose  5-0-benzyl-3-C-  [LXXXVIII] i n 93% y i e l d (Equation  15). Although the intermediate a, 3-unsaturated n i t r i l e sugars XXI, LXXXIV and LXXXV were not characterized, i t i s presumed these were the i n i t i a l condensation products as they are the expected reaction products and hydrogenation of these compounds gave the cyanomethyl sugars as would be expected. contained c h a r a c t e r i s t i c  branched-chain  Furthermore, i n each case the i r spectra  stretching absorptions f o r carbon-nitrogen  t r i p l e bonds (ca. 2250 cm ^) and the nmr spectra showed the presence of an o l e f i n i c proton (chemical s h i f t about T 4.1). The palladium-on-charcoal atmospheric pressure hydrogenation of the o l e f i n i c bond proceeded smoothly  i n each instance, the uptake of hydrogen  stopping spontaneously after absorption of about one equivalent. s t a b i l i t y of the 5-0-benzyl group of compound LXXXVIII i n t h i s  The  [LXVIII]  -43-  hydrogenation i s somewhat s u r p r i s i n g as these hydroxyl protecting groups are known to be hydrogenolyzed under mild conditions (124a); however, cases are known where hydrogenolysis of this group has required both heat and pressure (124b). That this series of reactions d i d indeed lead to the cyanomethyl branched-chain sugars was c l e a r l y shown by the i r and nmr spectra. The presence of the n i t r i l e group was confirmed by the c h a r a c t e r i s t i c C=N stretching absorption (ca. 2250 cm "*") i n the i r spectra and the presence of the methylene protons adjacent to the cyano group was confirmed by finding a two proton multiplet i n the region 7.0-7.5  T.  In each instance the product a f t e r hydrogenation was judged homogeneous (by  t i c and nmr).  cyanomethyl  No trace of isomeric compounds having a C-3  configuration epimeric with those shown i n equation 15 was  ever detected. The configuration at C-3 of these cyanomethyl  branched-chain  sugars was determined by nmr spectroscopy i n the following manner. It has been shown by H a l l and coworkers  (125) that f o r 1,2-0-  isopropylidene-a-D-glucofuranose and of 1,2-0-isopropylidene-g-Lidofuranose compound i n a l l cases the twist conformation LXXXIX i s adopted.  That i s , C-2 l i e s below and C-3 above the plane formed by C - l ,  0 and C-4.  Assuming this conformation was adopted by the above 3-C-  cyanomethyl branched-chain sugars and assuming a f i r s t order Karplus r e l a t i o n s h i p (126), holds f o r H-l, H-2 and H-3, i t i s possible to make the following predictions: (a)  If the C-3 cyanomethyl  substituent projects above the plane  (opposite to the configuration shown i n equation 15) the H-2 nmr signal  -44-  Me [LXXXIX]  should appear as a doublet ( J ^ ^ ~ 3-4 ^ z , (b)  3 < 0.5  Hz).  I f the C-3 substituent i s as shown i n equation 15 the  resonance should appear as a t r i p l e t or quartet (J- _ - 3-4 J  2  3  =  3 - 6  H z )  H-2  Hz,  *  In Table IV are l i s t e d the H-2  chemical s h i f t s  and coupling  constants f o r compounds LXXXVI, LXXXVII and LXXXVIII plus the same values for some representative 1,2-0-isopropylidene-furanoses. from this Table, the H-2,  H-3  the cyanomethyl branched-chain  coupling constant values indicate that sugars have assumed the configurations  depicted ( i . e . the cyanomethyl branched isopropylidene group).  As can be seen  chain i s c i s to the  1,2-  -45-  TABLE IV H-2 C h e m i c a l S h i f t s and C o u p l i n g C o n s t a n t s f o r Some 1 , 2 - 0 _ - I s o p r o p y l i d e n e ~ f u r a n o s e s Compound  H-2 C h e m i c a l  [LXXXVI]  5.23 x  C D C 1  3  3.6  3.6  [LXXXVII]  5.27  C D C 1  3  4.0  5.0  [LXXXVIII]  , CDC1. 5.34 x 3  3.6  3.9  [LXIX]  5.60 x  3.9  [LXIXa]  x  x  Shift  4 (146)  rn 5.53  [LXXXVII]  T  4 (146)  J  l,2  J  2,3  =0  3.9  5.0  [LXXXVIII]  -46-  To i l l u s t r a t e the t y p i c a l H - l , H-2 coupling pattern of these 3-C-cyanomethyl-3-deoxy-l,2-0-isopropylidene  branched-chain sugars the  100 MHz spectrum of compound LXXXVI i s reproduced i n Figure I.  The  hydrogen assignments f o r LXXXVI were made i n the following way: 1.  i r r a d i a t i o n of the doublet at 4.13 T (H-l) collapsed the  t r i p l e t at 5.23 2.  T  to a doublet i n d i c a t i n g this was the H-2  resonance,  i r r a d i a t i o n of the t r i p l e t at 5.23 r collapsed the doublet at  4.13 T to a s i n g l e t , confirming the previous assignment and altered the multiplet 7.6-7.8 x i n d i c a t i n g this was H-3 resonance. Another factor corroborating the C-3 configurational assignment i s the known d i r e c t i v e e f f e c t of the 1,2-0-isopropylidene furanoses.  As  was previously noted (p. 38 ), the hydrogenation of enol acetate LXXI gave only one product LXXII.  There i s a generally observed trend that  for compounds of this sort the bulky isopropylidene group blocking the C - l , C-2 hydroxyls i n t e r f e r e s with the approach of reagents from the underside ( c i s to the 1,2-0-isopropylidene group) of the r i n g  (80,123).  Therefore, i t was to be expected that c a t a l y t i c hydrogenation of the unsaturated bond, took place v i a c i s addition from the topside of the ring, thereby r e s u l t i n g i n compounds having the proposed C-3 configuration. Some time a f t e r our i n i t i a l report on the preparation of cyanomethyl branched-chain sugars v i a the above modified Wittig reaction (127), Tronchet et a l . (61) reported the synthesis of branched-chain unsaturated cyano sugars by reaction of the Wittig reagent cyanomethylene triphenylphosphorane with keto sugars.  The unsaturated cyano sugars were c i s -  dihydroxylated (KMnO^) to y i e l d aldehydo branched-chain sugars (e.g. equation 16). This procedure gave compounds having the same branched-chain  l 1 IT | I I I I' "lI l Il  TV  Figure 1.  T T T  TV  I I I  r i i I i ii i I TT  r i' i I  I ' l l l l'  I I 'I I I > I I ' I I I II T T I I I 7  II I  i ii i  I I II I  9  Proton magnetic resonance spectrum at 100 MHz i n deuteriochloroform of 3-Ccyanomethyl-3-deoxy-l,2:5,6-di-0-isopropylidene-a-D-allofuranose [LXXXVI].  II I I | M  T T  I  10  -48-  OH  OH [V]  which occurs i n the branched-chain sugar streptose [V].  2.  Synthesis of branched-chain amino sugars by reduction of branchedchain cyano sugars As i t was  desired to prepare branched-chain sugars having a v a r i e t y  of nitrogenous f u n c t i o n a l i t i e s , the reduction of the previously described branched-chain cyanomethyl compounds to the corresponding aminoethyl branched-chain sugars. Although a l k y l cyanides provide useful intermediates f o r the synthesis of a l k y l amines, the cyano group being reduced by metal hydrides (128), by c a t a l y t i c hydrogenation (129), or by diborane (130); there have been very few reports of successful conversion of carbohydrate cyanides into carbohydrate amines.  Coxon and Fletcher (131) have  reported the l i t h i u m aluminum hydride reduction of a galactopyranosyl cyanide to an amino h e p t i t o l and i n t e r e s t i n g l y , the branched-chain cyano sugar XC (132) has reportedly been hydrogenated  (no d e t a i l s given)  to the corresponding amino sugar i s o l a t e d as the t r i - a c e t a l derivative XCI.  -49-  2.1  3-C_-(2'- Acetamidoethyl)-3-deoxy-l, 2:5 ,6-di-O-isopropylidene-a-D— allofuranose [XCI] As a successful c a t a l y t i c reduction of a n i t r i l e branched-chain  sugar had been reported (see above) i t was decided to attempt the reduction of 3-C- cyanomethyl-3-deoxy-l,2:5,6-di-j3-isopropylidene-a-Dallofuranose [LXXXVI] by c a t a l y t i c hydrogenation.  C a t a l y t i c hydro-  genation of n i t r i l e s to amines has been assumed to proceed through an imine intermediate (128) (Equation 17a).  R-CHN  H -=—*• RCH=NH  RCH=NH  +  RCH NH 2  H —  > RCH NH 2  (a)  2  RCH (NH )NHCH R  2  2  (b)  2  H RCH(NH )NHCH R 2  RCH=NH  • (RCH^NH  2  +  RCH=NCH R  RCH NH 2  +  H  +  NH^  RCH=NCH R  2  2  •  (RCH ) NH  +  (c) NH^  (d)  (e)  (17)  -50-  Complications i n this reaction occur when the primary amine couples with the intermediate imine, (Equation 17b) giving a product from which a secondary amine may be formed by hydrogenolysis (Equation 17c) or by elimination of ammonia (Equation 17d) followed by hydrogenation (Equation 17e) of the resultant imine.  Variations on t h i s general  scheme have been used to account f o r the formation of other observed side products (128). The above coupling reactions have been prevented by e i t h e r forming a derivative of the primary amine as soon as i t was produced,  this  being done by hydrogenation i n the presence of mineral acid (133) or a c e t i c anhydride (134), or by hydrogenation i n an ammonia saturated s o l u t i o n (135) which reverses the equilibrium i n equation 17d.  As  n i t r i l e branched-chain sugar LXXXVI contains the very acid l a b i l e 5,6-O-isopropylidene group, i t was decided to hydrogenate LXXXVI i n ethanol saturated with ammonia. Accordingly LXXXVI i n ethanol saturated with ammonia at 0° was hydrogenated at 60 p s i f o r twenty hours at room temperature over 5% rhodium-on-alumina.  Because of the presence of ammonia i t was impossible  to monitor the hydrogen uptake; however, the reaction was continued u n t i l no s t a r t i n g material remained  (as evidenced by t i c ) .  This  procedure gave the expected aminoethyl branched-chain sugar characterized as i t s N-acetyl derivative  3-C-(2'-acetamidoethyl)-3-deoxy-l,2:5,6-di-0-  isopropylidene-ct-D-allofuranose [XCII] i n 80% y i e l d . of this compound contained no C=N at 3300 cm"  1  The i r spectrum  absorption but did show an N-H  and a carbonyl absorption at 1640 cm" . 1  The nmr  stretch  spectrum  -51-  showed the presence of the N-H proton as a broad t r i p l e t at 3.27 x and the N-acetate as a 3 proton s i n g l e t at 8.03  2.2  x.  3-C-(2 -Ace tamidoe thy l)-5-0j-benzyl-3-deoxy-l,2-0-isop ropy lidene1  a-D-ribofuranose [XCIII] To reduce the n i t r i l e group of the 5-0-benzyl  cyanomethyl  branched-chain sugar LXXXVIII c a t a l y t i c hydrogenation procedures were judged to be i n a p p l i c a b l e as the rather vigorous conditions involved would i n a l l l i k e l i h o o d have hydrogenolyzed the 5-0-benzyl hydroxyl protecting group.  Had t h i s happened i t would have then been necessary  to reblock the 5-hydroxyl group to use this compound i n nucleoside syntheses. In view of this i t was decided to attempt the reduction of the cyano group of LXXXVIII using l i t h i u m aluminum hydride i n ether. Reduction to the pentose amino sugar proceeded smoothly with the product being characterized as before as the N-acetyl derivative 3-C-(2'-  -52-  acetamidoe thy l ) - 5 - 0 _ - b e n z y l - 3 - d e o x y - l , 2 - 0 - i s o p ropy l i d e n e - a - D - r i b o f uranose [XCIII].  That  the p r o d u c t o f t h i s r e d u c t i o n was the e x p e c t e d  e t h y l branched-chain  sugar was c o n f i r m e d by the NH and c a r b o n y l  a b s o r p t i o n s found i n the i r spectrum respectively  acetamido-  a t 3300 cm ^ and 1650 cm ^  and by t h e b r o a d NH s i g n a l and t h e N - a c e t y l s i g n a l found i n  the nmr spectrum  PhCH OCH 2  a t 4-4.4 T and 8.1 T r e s p e c t i v e l y .  2  PhCHOCH  0  -Me  | 2 H  CN  •Me  f2 H  Me  Me HNAc [XCIII]  [LXXXVIII]  2.3  3-C_-Cyanomethyl-3-deoxy-l,2-0_-isopropylidene-g-L-lyxof uranose [XCV]  and 3 - C - ( 2 ' - a c e t a m i d o e t h y l ) - 3 - d e o x y - l , 2 - 0 - i s o p r o p y l i d e n e -  B-L-lyxofuranose  [XCVI].  As v a r i o u s L-amino sugars a r e known t o e x i s t i n Nature was d e c i d e d t o undertake  the s y n t h e s i s o f t h e above cyanomethyl and  acetamidoethyl branched-chain done i s i l l u s t r a t e d  (136) i t  sugars.  i n e q u a t i o n 18.  The manner i n which t h i s was  -53-  (18)  [XCVI]  [XCV]  The f i r s t step i n t h i s sequence i s the s e l e c t i v e h y d r o l y s i s of the 5,6-isopropylidene group of LXXXVII.  I t has been widely  observed that f o r 1,2:5,6-di-0-isopropylidene furanose d e r i v a t i v e s the 5,6-isopropylidene k e t a l i s hydrolyzed much more r a p i d l y than the 1,2 isopropylidene moiety (137).  The h y d r o l y s i s of 1,2,5:6-  di-O-isopropylidene-a-D-glucofuranose  [LXIX] provides an excellent  example of the s e l e c t i v i t y of t h i s r e a c t i o n .  In t h i s instance  the 5,6-isopropylidene group i s cleaved with d i l u t e hydrochloric acid  -54-  some eighty times faster than the 1,2-isopropylidene (138).  The  5,6-  isopropylidene group has been s e l e c t i v e l y hydrolyzed using a variety of a c i d i c conditions (138,139,140). In the present work this group  was  removed using an aqueous methanol solution containing s u l f u r i c acid as i n the case of the preparation of 1,2-0-isopropylidene glucose (140). The hydrolysis was  conducted at room temperature for 7 hours to afford  the mono-isopropylidene compound XCIV as a syrup i n 88% y i e l d .  The  nmr spectrum of this compound showed the presence of two hydroxyl groups and only two methyl groups (at 8.40 and 8.64  T) belonging to  the 1,2-isopropylidene group. The L sugar  3-C_-cyanomethyl-3-deoxy-l,2-0_-isopropylidene-(3-L-  lyxofuranose [XCVI] was obtained from mono-isopropylidene compound XCIV by sodium periodate oxidative cleavage to the 5-aldehydo followed by sodium borohydride reduction of the 5-aldehydo  compound  group (21).  This series of reactions i s very frequently used i n carbohydrate chemistry to prepare sugars having one carbon less than the s t a r t i n g compound.  The best y i e l d s are usually obtained by reducing the  intermediate aldehydo compound without i s o l a t i o n , as was instance.  done i n this  That the cyanomethyl branched-chain of XCVI had survived  the above operations was  confirmed by the i r spectrum  (C=N  2245 cm "*").  Reduction of the cyanomethyl branched-chain sugar XCV to the corresponding acetamidoethyl compound XCVI was accomplished by c a t a l y t i c hydrogenation.  As hydrogenation i s t e c h n i c a l l y simpler than  l i t h i u m aluminum hydride reduction, where possible i t i s the method of choice f o r reduction of the cyano moiety.  In t h i s instance the  hydrogenation medium chosen was an acetic anhydride-ethanol 1:1 mixture.  -55-  As the 1,2-isopropylidene group i s comparatively acid stable, there was no danger of hydrolysis i n this weakly acid medium.  In the  presence of a c e t i c anhydride the N-acetyl derivative i s formed i n s i t u preventing the previously discussed coupling reactions.  Accordingly  XCV was hydrogenated at 60 p s i over platinum oxide f o r four and a h a l f hours.  A t i c examination of the reaction mixture a f t e r this time  indicated that no s t a r t i n g material remained and showed the presence of only one product.  Spectral data (nmr 3.8-4.3  T , broad N-H, 8.02 T  s i n g l e t , N acetyl) confirmed the reduction had taken the expected course to afford c r y s t a l l i n e  3-C-(2'-acetamidoethyl)-3-deoxy-l,2-0-  isopropylidene-g-L-lyxofuranose [XCVI] i n 93% y i e l d .  3.  Synthesis of branched-chain carbamoylmethyl sugars In order that the variety of nitrogenous deoxy branched-chain  sugars available might be increased, the preparation of carbamoyl branched-chain sugars was also examined.  Although no branched-chain  carbamoyl sugars have been reported as yet, the nucleoside a n t i b i o t i c gougerotin fXCVII] (141a) i s known to contain a C-6' carbamoyl and 5'-carboxyamide  group  adenosine analogs are used i n the treatment  of c i r c u l a t i o n disorders (141b).  [XCVI]  -56-  3.1  3-C-Carbamoylmethyl-3-deoxy-l ,2:5,  6-di-O-isopropylidene-a-D-  allofuranose [C] One method which has been u t i l i z e d i n carbohydrate  chemistry f o r  the preparation of amides involves ammonolysis of an ester by reacting i t with l i q u i d ammonia i n the presence of ammonium c h l o r i d e .  Heynes  and Baltes (142) had used t h i s procedure to convert the C-6 methyl ester of compound XCVIII to the C-6 amide XCIX.  Fortunately a 3-C-  carbomethoxymethyl sugar XXXIX (22) had already been prepared laboratory (p. 18 ) so therefore i t was only necessary  i n this  to apply the  above ammonolysis to t h i s compound to obtain the desired carbamoylmethyl branched-chain sugar 3-C_-carbamoylmethyl-3-deoxy-l,2:5,6-di-CJisopropylidene-a-35-allofuranose  [C] .  S u r p r i s i n g l y under the conditions used by Heynes and Baltes  (heat-  ing i n a sealed tube at 50° for 6 hr i n l i q u i d ammonia containing ammonium chloride) only about 10% conversion XXXIX to C occurred. was necessary  (as evidenced  by t i c ) of  I t was found that to obtain s a t i s f a c t o r y y i e l d s i t  to allow the r e a c t i o n to proceed at 60° f o r 24 hr.  these conditions XXXIX was converted  to C i n 76% y i e l d  Under  (Equation 19).  As an a l t e r n a t e route to carbamoylmethyl branched-chain sugars  MeO  MeO  0  •Me  0  Me [XCVIII]  Me Me  [XCIX]  -57-  -58-  the  base catalyzed reaction of cyanomethyl branched-chain sugar LXXXVI  with hydrogen peroxide was examined.  Although this reaction has been  known f o r sometime (143) as a means of converting n i t r i l e s  to the  corresponding amides, to the best of our knowledge this reaction has not  been previously applied to a carbohydrate n i t r i l e . When an ethanol solution of n i t r i l e LXXXVI was reacted with  hydrogen peroxide and 6 N sodium hydroxide at 50° for 6 hr, i t was smoothly hydrolyzed to the carbamoylmethyl sugar C (70% y i e l d ) (Equation 19) i d e n t i c a l (by nmr, i r , mixed m.p.) to the compound prepared v i a ammonolysis of ester XXXIX. As w e l l as providing two routes to the carbamoyl methyl sugars, the  above procedures provide a means of i n t e r r e l a t i n g the products of  two d i f f e r e n t W i t t i g reactions (Equation 19).  As both LXXVI and XXXIX  give the same amide both these compounds must have the same r e l a t i v e configuration.  Since i n connection with another problem an x-ray  study of a derivative of compound XXXIX i s underway, i t was desireable to have a way of chemically r e l a t i n g the two Wittig products LXXXVII and XXXIX As a t h i r d route to these carbamoylmethyl branched-chain sugars the  photoaddition of formamide to the exocyclic unsaturated sugar XX  was undertaken.  The preparation of compound XX and the mechanism of  this photoamidation have already been dealt with i n the Introduction (p.  12  and p. 24 r e s p e c t i v e l y ) .  When compound XX was i r r a d i a t e d (X > 300) for seven hours i n an oxygen-free mixture of formamide, t e r t i a r y butanol and acetone products were i s o l a t e d from the reaction mixture (Equation 20). The major product (50% y i e l d ) proved to be the carbamoylmethyl branched-chain  -59-  [CI]  sugar C i d e n t i c a l the  last  ( i r , nmr, mixed m.p.)  two r e a c t i o n s .  to the product  In view o f the f a c t  isolated  from  that photoaddition of  formamide t o t e r m i n a l o l e f i n s i s known t o take p l a c e i n an a n t i M a r k o v n i k o v manner by s t e r i c  ( 8 1 ) , and as t h i s r e a c t i o n i s known t o be i n f l u e n c e d  f e a t u r e s o f the o l e f i n  (82) (p. 23 ) , i t i s n o t t o o s u r p r i s i n g  t h a t the a d d i t i o n o f formamide t o XX takes manner t o g i v e o n l y  the a l i o  place i n a stereoselective  carbamoylmethyl a d d i t i o n p r o d u c t  o f XX.  - 6 0 -  Th e minor product CI (11%) was not characterized but was  tentatively  assigned the structure CI on the basis of nmr evidence:  H-2  as a t r i p l e t i n d i c a t i n g an a l i o configuration, there i s one  appears exchangeable  proton present i n the molecule i n d i c a t i n g the l i k e l y presence of a hydroxyl group, and there are s i x methyl signals, four belonging to the isopropylidene groups and presumably branched-chain.  two for the methyl groups i n the  The formation of acetone addition i n this reaction has  been noted previously (81).  4.  Synthesis of nitrogenous branched-chain sugars having a single carbon i n the branched-chain Concommitant with the program to develop routes to nitrogenous  branched-chain sugars having two carbons i n the branched-chain, the preparation of analogous compounds having only a single carbon i n the branched-chain was  attempted.  4.1  4,6-di-0-acetyl-2,3-dideoxy-a-D-erythro-hex-2-  Photoamidation of enopyranoside  [CII]  As the photoaddition of formamide to the exocyclic methylene sugar C j u s t described had been r e l a t i v e l y successful, i t was decided to apply the same reaction to  the unsaturated sugar 4,6-di-0_-acetyl-2,3-  dideoxy-ct-D-erythro-hex-2-enopyranoside  [CII] .  This compound was  prepared from t r i a c e t y l - D - g l u c a l by the method of F e r r i e r and Prasad (144). It was anticipated that the photoaddition of formamide to this compound would r e s u l t i n 2- and/or 3-C-carbamoyl-2,3-dideoxy pyranosides  -61-  (Equation 21) which could hopefully be d i f f e r e n t i a t e d on the basis of t h e i r nmr  spectra.  Accordingly o l e f i n CII dissolved i n a de-oxygenated  (21)  mixture of formamide, t_-butanol and acetone was f o r 9 hr.  A f t e r this time t i c examination  i r r a d i a t e d (X >  300)  showed that no s t a r t i n g  material remained and that there were two product spots.  These two  components were separated by chromatography on s i l i c a - g e l and examined. The minor component (about 12% of the t o t a l product) was on the basis of i t s nmr  judged  spectra to be a mixture of acetone addition  products and was not further i n v e s t i g a t e d . The major component, a syrup amounting to about 88% of the t o t a l product mixture had the following c h a r a c t e r i s t i c s : (a)  The i r spectrum contained i n addition to the usual  absorptions an absorption at 3400 cm 1660  1  C-H  and a strong absorption at  cm" . 1  (b) at 3.47  The nmr  spectrum showed a broad  T and a t o t a l of 21 protons  low f i e l d 2 proton absorption  present.  -62-  (c)  The e l e m e n t a l a n a l y s i s was c o n s i s t e n t w i t h t h a t e x p e c t e d  f o r t h e a d d i t i o n o f the elements o f formamide t o o l e f i n C I I . From t h e above d a t a i t was c o n c l u d e d t h a t t h i s p r o d u c t was a 1:1 f o r m a m i d e : o l e f i n adduct. superimposed  triplets  However, as t h e nmr spectrum showed s e v e r a l  f o r t h e m e t h y l peaks o f the e t h y l  glycoside,  i t was assumed t h a t t h i s p r o d u c t was a m i x t u r e o f i s o m e r s . t h i s p r o d u c t was a m i x t u r e was f u r t h e r s u b s t a n t i a t e d de-acetylated derivatives  ( m e t h a n o l i c sodium methoxide)  That  by f i n d i n g t h a t the  trimethylsilylated  (145) showed t h e p r e s e n c e o f f o u r components i n about  e q u a l amounts when examined r e p e a t e d chromatography  by gas l i q u i d  chromatography.  Despite  no s i n g l e isomer c o u l d be s e p a r a t e d i n a pure  form. From t h e above i t would  appear t h a t  t h e major p r o d u c t o f t h e p h o t o -  a m i d a t i o n o f C I I i s a m i x t u r e o f a l l f o u r p o s s i b l e formamide a d d i t i o n products C i l i a ,  C H I b , CIVa, and CIVb.  As i t was apparent t h a t i t  R' [Cilia]  R = CONH , R' = H  [CIVa]  R = CONH , R' = H  [CHIb]  R' = H, R = CONH  [CIVb]  R' = H, R = CONH  2  2  2  2  -63-  would be very d i f f i c u l t  to prepare useful amounts of a s i n g l e pure  carbamoyl branched-chain sugar by t h i s method, work along these l i n e s was discontinued.  In contrast to these r e s u l t s as indicated i n the  Introduction (p. 21 ) other workers i n t h i s laboratory have been able to apply t h i s r e a c t i o n with some success to the unsaturated sugars LX LXI.  I t i s evident that photoaddition of formamide to carbohydrate  Me [LX]  [LXI]  o l e f i n s i s most u s e f u l when s t e r i c features of the o l e f i n r e s u l t i n the p r e f e r e n t i a l formation of a single product as was the case with compound XX.  4.2  Addition of nitromethane to 1,2;5,6-di-0-isopropylidene-ct-g-ribohexofuranos-3-ulose  [XVIII]  A second route investigated leading to nitrogenous branched-chain sugars having a single carbon i n the branched-chain was the addition of nitromethane  to carbohydrate ketoses.  As was mentioned i n the  Introduction (p. 21 ) although the addition of n i t r o p a r a f f i n s to  -64-  c a r b o h y d r a t e s had been e x t e n s i v e l y i n v e s t i g a t e d , when t h i s work was begun t h e r e had been o n l y two r e p o r t s (78,79) (one o f which from  t h i s l a b o r a t o r y ) on the a d d i t i o n o f n i t r o m e t h a n e  ketoses  to a f f o r d branched-chain  (78) was  to carbohydrate  sugars.  The manner i n which t h i s r e a c t i o n was used i s i l l u s t r a t e d i n e q u a t i o n 22.  Condensation  o f k e t o s e XVIII w i t h the c a r b a n i o n p r e p a r e d  R = N0  o  o r NH  -65-  from nitromethane and sodium methoxide afforded the branched-chain n i t r o sugar 1,2:5 ,6-di-C_-isopropylidene-3-C_-nitromethyl-a-D-glucof uranose [CV]. (by  I t was planned to use t h i s compound to prepare deoxy nitromethyl a c e t y l a t i o n of the 3° hydroxyl group followed by a Schmidt-Rutz  reaction (74) and reduction of the n i t r o - o l e f i n double bond) and deoxy aminomethyl branched-chain sugars (Equation 23).  However, shortly  a f t e r the preliminary r e s u l t s concerning the addition of nitromethane to XVTII were published (148), a b r i e f communication from Albrecht and Moffatt (80) reported t h e i r r e s u l t s on condensing nitromethane with the  same ketose XVIII, the conversion of the i n i t i a l nitromethane  condensation product into deoxy nitromethyl and aminomethyl branchedchain sugars, and the conversion of these compounds into branched-chain sugar nucleosides.  In view of t h i s , further work here along these  l i n e s was discontinued and no further attempts were made to prepare branched-chain sugars of t h i s type.  5.  Nucleoside synthesis Having synthesized the 3-deoxy, two carbon nitrogenous branched-  chain sugars j u s t described, the next step was  to use these compounds  to prepare the corresponding branched-chain sugar nucleoside derivatives. In  order to u t i l i z e these compounds i n standard nucleoside syntheses,  i t was necessary to convert them f i r s t into t h e i r l,2-di-0-acetyl derivatives.  As the procedures for preparation of amino sugar  nucleosides had been extensively investigated (149), i t was decided to attempt f i r s t the preparation of an amino branched-chain sugar nucleoside using the acetamidoethyl branched-chain sugar XCIII.  - 6 6 -  5.1  Attempted a c e t o l y s i s of 3-£-(2'-acetamidoethyl)-5-0-benzyl-3-deoxyl,2-0_-isopropylidene-a-D-ribofuranose  [XCIII]  The preparation of the blocked branched-chain  sugar 3-C-(2'-  acetamidoethyl)-l,2-di-0_-acetyl-5-0-benzyl-3-deoxy-ribofuranose was  f i r s t attempted.  procedure  I t was  [CVI]  hoped that a c e t o l y s i s by the normal  (150) using a c e t i c a c i d , a c e t i c anhydride, and s u l f u r i c acid,  would convert the 1,2-isopropylidene compound XCIII i n t o the ing 1,2-di-acetyl d e r i v a t i v e CVI  correspond-  (Equation 24).  (24)  [XCIII]  [CVI]  Unfortunately, under these a c e t o l y s i s conditions the C-5 ether group was  cleaved.  This was  evidenced by the nmr  benzyl  spectrum of  the major product which indicated that no aromatic protons were present i n the molecule.  Cleavage of the benzyl ether moiety was  desirable as t h i s would allow the branched-chain  not  sugar to revert to  the unwanted but more stable pyranose configuration. That the benzyl ether was  unstable to these a c e t o l y s i s conditions was  not e n t i r e l y  unexpected i n view of the findings of A l l e r t o n and Fletcher (151) that  -67-  b e n z y l e t h e r s are r e a d i l y removed i n a c e t o l y s i s media. trials,  on the model compound LXXVII, i n which the p e r c e n t a g e  s u l f u r i c a c i d i n the r e a c t i o n medium was primary as  b e n z y l group of LXXVII was  the 1 , 2 - i s o p r o p y l i d e n e  procedure. hydrolyze  First  decided  X C I I I was  to prepare  r e a c t e d w i t h 90%  the i s o p r o p y l i d e n e k e t a l  (152),  n i t r o g e n h e t e r o c y c l e CVII.  no NH  b e n z y l and  t y p i c a l of 3° amides. product groups.  and  then  was  tentatively identified based on the  compound c o n t a i n e d s i g n a l s  nmr  CVI would be expected  This  mixture. as  the  observations  corresponding  t h a t the i r spectrum showed  a low w a v e l e n g t h c a r b o n y l a b s o r p t i o n The  to  the r e a c t i o n p r o d u c t  and p y r i d i n e ( E q u a t i o n 25).  f o u r a c e t a t e groups and  a b s o r p t i o n , and  C-5  a two-step  trifluoroacetic acid  T h i s c o n c l u s i o n was  the nmr spectrum of t h i s  t o one  CVI by  r e s u l t e d i n the f o r m a t i o n of a complex p r o d u c t  A major component of t h i s m i x t u r e  that  v a r i e d , r e v e a l e d t h a t the  a c e t o l y z e d a t about the same r a t e  a c e t y l a t e d with a c e t i c anhydride  procedure  of  ketal.  In v i e w of t h i s i t was  was  Acetolysis  spectrum of the d e s i r e d to show the presence  (1640  cm  ^)  1,2-0-acetyl  of o n l y t h r e e a c e t y l  -68-  The formation of the nitrogen heterocycle CVIII was by postulating that a f t e r hydrolysis an equilibrium was  rationalized set up between  [CVII]  the oxygen and the nitrogen h e t e r o c y c l i c compounds; subsequent a c e t y l a t i o n of t h i s mixture lead to compounds having both nitrogen and oxygen as the ring heteroatom (Equation 25). of C-4  and C-5  The  rearrangement  amino and amido monosaccharides to nitrogen hetero-  cycles has been w e l l studied (153).  Normally where there i s a competi-  t i o n for ring formation between a hydroxyl group and an acetamido group the oxygen heterocycle i s formed predominantely even i f i t has  the  -69-  thermodynamically less favoured f i v e membered ring structure (153). Thus i t had been anticipated that CVII would not be a major constituent of the product mixture.  Since this was not so, further attempts to  prepare CVI were abandoned.  5.2  Conversion of  3-C_-cyanomethyl-3-deoxy-l,2:5,6-di-0_-isopropylidene-  a-g-allofuranose [LXXXVI] into l,2-di-0_-acetyl-5,6-di-0benzoyl-3-C_-cyanomethyl-3-deoxy-8-D-allofuranose  [CX] and 1,2-di-  O-acetyl-5-0-benzoyl-3-C-cyanomethyl-3-deoxy-8-D-ribofuranose  [CXIII]  Since the preparation of amino branched-chain sugar derivatives suitable for nucleoside synthesis had been unsuccessful, i t was decided to prepare an appropriate derivative from the branched-chain sugar LXXXVI.  cyanomethyl  To prepare the hexose derivative required  the following steps: (1)  s e l e c t i v e hydrolysis of the 5,6-isopropylidene group;  (2)  blocking of the free 5,6-hydroxyl groups as the benzoate esters;  (3)  hydrolysis of the 1,2-isopropylidene group;  (4)  acetylation of the 1,2-hydroxyl  groups.  To prepare the pentose derivative required a modifiction of this procedure i n that a f t e r step (1) a sodium periodate oxidative cleavage followed by sodium borohydride reduction was to remove the C-6 hydroxymethyl group.  carried out  The resultant pentose compound  was then benzoylated and subjected to steps (3) and (4).  The  reaction scheme representing these steps i s shown i n equation 26.  -70-  1. 10. 4  [CXI]  [CXII]  [CXIII]  -71-  The s e l e c t i v e hydrolysis of a 5,6 isopropylidene ketal and the removal of a C-6 hydroxymethyl  group by oxidative cleavage, followed  by reduction, were discussed previously i n the preparation of compound XCVI and w i l l not be considered i n d e t a i l again.  Suffice i t  to say that treatment of LXXXVI with an aqueous methanol s o l u t i o n containing a small amount of s u l f u r i c acid s e l e c t i v e l y hydrolyzed the 5,6-isopropylidene group of LXXXVI to afford CVIII as a syrup i n nearly quantitative y i e l d .  Compound CXI was obtained as a c r y s t a l l i n e s o l i d  i n 90% y i e l d by cleavage of the 5,6-hydroxyl groups of CVIII with sodium periodate followed by reduction of the 5-aldehydo group with sodium borohydride (21). The hydroxyl groups of compounds CVIII and CXI were benzoylated using the method of Molau (154).  In this procedure the compound to  be benzoylated i s dissolved i n anhydrous benzene to which i s added only a s l i g h t excess of the amount of benzoyl chloride necessary f o r e s t e r i f i c a t i o n and two equivalents of pyridine.  Work up consists of  f i l t e r i n g the reaction mixture through a short column of grade II alumina (a r a t i o of about 5:1 alumina to compound was used), evaporation of the f i l t r a t e and removal of traces of pyridine by azeotroping with toluene.  Applying this procedure to compound CVIII afforded a 90%  y i e l d of c r y s t a l l i n e benzoate CIX and a 93% y i e l d of c r y s t a l l i n e benzoate CXII from CXI.  The chief advantage of this procedure l i e s i n  the fact that no opportunity f o r benzoic anhydride contamination of the product a r i s e s .  Standard benzoylation procedures i n carbohydrate  chemistry sometimes r e s u l t i n the contamination of the benzoylated product with benzoic anhydride produced during the addition of water during work up (155).  -72-  Attempted a c e t o l y s i s (150) of the 1,2-isopropylidene k e t a l of CIX using a mixture of a c e t i c acid, acetic anhydride and s u l f u r i c acid for  twenty four hours at room temperature led to a complex mixture of  products.  The major component of this mixture (about 30% based on  s t a r t i n g material) was i s o l a t e d by column chromatography  on s i l i c a .  Elemental analysis of t h i s material showed that i t contained no nitrogen, i n d i c a t i n g that the n i t r i l e group on the branched-chain was apparently unstable to these conditions. It was therefore decided to proceed as before and use a two-step procedure; f i r s t hydrolysis of the isopropylidene k e t a l with t r i f l u o r o a c e t i c acid followed by acetylation with acetic anhydride i n pyridine. Several exploratory runs using d i f f e r e n t acid concentrations were performed i n order that the optimal conditions for hydrolysis might be found.  For compound CIX reaction with 80% aqueous t r i f l u o r o a c e t i c  acid f o r 45 minutes at room temperature was found to give the best y i e l d ; f o r compound CXII i t was found to be more advantageous  to use  a greater percentage of acid (90%) and run the hydrolysis f o r a shorter time (22 minutes). A c e t y l a t i o n , using acetic anhydride and pyridine, of the hydrolysis product from CIX gave a f t e r chromatography  on s i l i c a gel l,2-di-0-  acetyl-5,6-di-0-benzoy1-3-C-cyanomethy1-3-deoxy-g-D-allofuranose  [CX]  as a c r y s t a l l i n e s o l i d i n 69% y i e l d . The anomeric (H-l) hydrogen of this compound appeared i n the nmr spectrum as a singlet at 3.77-r .  As there was no measurable coupling  between H-l and H-2 i t was concluded that a trans  relationship existed  between these two protons and that therefore CX had a 8 anomeric  -73-  configuration. systems  Because of the conformational mobility of furanose  (125a) i t i s not generally possible to d e f i n i t e l y assign  anomeric configurations on the basis of H-l, H-2 alone.  coupling constants  However, i n instances where there i s no appreciable coupling  between two neighbouring protons i t can be f a i r l y safely assumed that a trans relationship exists between them (156). Acetylation of the hydrolysis product from CXII, using the same conditions as above, gave a f t e r column chromatography  on s i l i c a gel  two components. The major component i s o l a t e d as a c r y s t a l l i n e s o l i d i n 69% y i e l d proved to be the expected acetylated cyanomethyl branched-chain sugar 1,2-di-0-ace tyl-5-0-benzoyl-3-C_-cyanome thy 1-3-deoxy-g-g-ribof uranose [CXIII], the  The g-configuration was t e n t a t i v e l y assigned as before from  nmr spectrum (H-l appeared as a s i n g l e t at 3.80 T ) . The minor product, i s o l a t e d i n about 5% y i e l d as a c r y s t a l l i n e  s o l i d , gave the following data upon examination: (1) the nmr spectrum indicated that only one benzoate and one acetate ester were present; (2) the i n f r a r e d spectrum showed no n i t r i l e absorption and three carbonyl absorptions. From the above i t was  concluded that this compound was  the lactone  l-0-acetyl-5-0_-benzoyl-3-C_-carboxymethyl-2,3-Y-lactone-3-deoxy-g-Dribofuranose [CXV].  The elemental analysis of this compound was  to be in agreement with the proposed structure.  The  B-anomeric  configuration was again assigned on the basis of the nmr (H-l was observed as a s i n g l e t at 3.6 T ) .  spectrum  found  -74-  I t i s probable that the above side product arose as i s i l l u s t r a t e d i n equation 27.  During the t r i f l u o r o a c e t i c acid h y d r o l y s i s of compound  CXII the n i t r i l e group i n the branched-chain underwent p a r t i a l h y d r o l y s i s to the carboxylic acid which lactonized to afford compound CXIV. A c e t y l a t i o n of this m a t e r i a l would then lead to CXV.  0 [CXII]  5.3  0  [CXIV]  6-Chloro-9-(2'-0-acetyl-5',  [CXV]  6'-di-O-benzoyl-3'-C-cyanomethyl-3 1  deoxy-B-D-allofuranosyl)-purine [CXVI] and 6-chloro-9-(2'-0acetyl-5'-0-benzoy1-3 -C-cyanomethyl-3'-deoxy-B-D-ribofuranosyl)1  purine  [CXVIII]  As i t was desired to obtain 6-^,N_-dimethylaminopurine derivatives of the previously described cyanomethyl  nucleoside  branched-chain  sugars, the methods used f o r the preparation of dimethylaminopurine nucleosides were examined.  B.R.  c l a s s i c synthesis of puromycin,  Baker and coworkers formed  (157), i n their  the carbon nitrogen g l y c o s i d i c  bond by condensation of the titanium-amino sugar complex with  -75-  chloromercuri-2-methylmercapto-6-dimethylaminopurine.  Raney n i c k e l  d e s u l f u r i z a t i o n of the purine then gave the 6-dimethylaminopurine nucleoside (Equation 28). was  While a 6-dimethylaminopurine nucleoside  obtained by t h i s method several steps were required and the y i e l d  i n the d e s u l f u r i z a t i o n was  AcNH  only f a i r .  OBz  AcNH  OBz  An alternate route to these nucleosides has been devised by R.K.  Robins (158).  .Here a 6-mercaptopurine nucleoside (159)  f i r s t prepared and then this compound was  reacted with dry chlorine  gas to afford the 6-chloropurine nucleoside. nucleoside was  was  This chloropurine  then converted to the 6-dimethylaminopurine nucleoside  with aqueous dimethylamine.  The chief disadvantage  i s the number of manipulations  of this procedure  of the base required to obtain the  -76-  6-dimethylaminopurine  compound.  This disadvantage has been overcome by the r e l a t i v e l y recently developed fusion procedure  (106).  Using this method the 6-chloro-  purine nucleosides were prepared d i r e c t l y by fusion of a C - l acetylated sugar with 6-chloropurine. was  The 6-dimethylamino f u n c t i o n a l i t y  then introduced as above, by reacting the 6-chloropurine  nucleoside with aqueous dimethylamine.  In view of i t s s i m p l i c i t y ,  and the fact that the nucleosides prepared are free of mercury contamination, t h i s procedure was dimethylaminopurine  selected for the preparation of  nucleosides from the cyanomethyl branched-chain  sugars. Accordingly CX was  fused with 6-chloropurine at 155-160° under  reduced pressure f o r 45 minutes.  Chromatography on s i l i c a gel  afforded as the only nucleoside product 6-chloro-9-(2 -0_-acetyl-5' ,6'1  di-0_-benzoyl-3' -C-cyanomethyl-3' -deoxy-g-D-allofuranosyl) -purine [CXVI] i n 69% y i e l d .  S i m i l a r l y fusion of CXIII with 6-chloropurine  under the same conditions gave 6-chloro-9-(2'-0_-acetyl-5'-0_-benzoyl3'-C-cyanomethy1-3'-deoxy-g-D-ribofuranosyl)-purine The 0-anomeric configuration was  t e n t a t i v e l y assigned to these  nucleosides on the basis of t h e i r small H - l ' , H-2' (CXVI J ,  , = 2 Hz; CXVIII J , 1  , =1  [CXVIII] i n 66% y i e l d .  Hz).  coupling constants  This assignment was  l a t e r confirmed by the c i r c u l a r dichroism (cd) spectra of the unblocked nucleosides.  A thorough examination of a l l the reaction products did  not reveal the presence of any other nucleoside i n d i c a t i n g as expected that there was no appreciable formation of the a-anomer.  -77-  Cl  [CXIII]  5.4  R = H  [CXVIII]  R = H  6-N, N-Dimethylamino-9-(3' -C-N,_N-dimethylcarbamoylmethyl-3' deoxy-g-D-allof uranosyl)-purine [CXXI] and 6-N^,N-dimethylamino9-(3!-£-N,N-dimethylamino-9-(3 -£-N,N-dimethylcarbamoylmethyl,  3'-deoxy-g-D-ribofuranosyl)-purine  [CXXII]  The second step i n the preparation of the nucleosides was  6-dimethylaminopurine  the reaction of the above 6-chloropurine blocked  nucleosides with aqueous dimethylamine.  This procedure was  intended  to remove the ester hydroxyl protecting groups and replace the 6-chloro group by a dimethylamino f u n c t i o n a l i t y thereby r e s u l t i n g i n the formation of the cyanomethyl branched-chain nucleosides CXIX and CXX. chloropurine nucleoside CXVI was  When the  reacted for four hours with an aqueous  methanol solution of dimethylamine  and the products were separated  by chromatography on s i l i c a g e l a single c r y s t a l l i n e nucleoside was i s o l a t e d i n 78% y i e l d .  -78-  Th e nmr spectrum In dimethyl sulfoxide-d^ of t h i s nucleoside i s reproduced i n Figure 2. interpreted:  Some features of this spectrum were r e a d i l y  the two low f i e l d s i n g l e t s at 1.69 and 1.88 T were  assigned to the H-2 and H-8 protons of the h e t e r o c y c l i c base; the doublet at A.08 T i s the H - l ' s i g n a l ; the two doublets at A.28 and A.6A T which disappeared on addition of deuterium oxide were assigned to the secondary hydroxyl groups of C-2' and C-5', not necessarily r e s p e c t i v e l y ; a t h i r d hydroxyl group i s superimposed on the C-2' s i g n a l at 5.A8 x; the large s i n g l e t at 6.7A x was assigned to the s i x protons of the N,N-dimethyl group of the h e t e r o c y c l i c base, a small water peak was superimposed on t h i s s i g n a l .  However, the  two s i n g l e t s at 7.02 x and 7.20 x which integrate f o r three protons each were not consistent with the expected nmr spectrum of the cyanomethyl branched-chain sugar nucleoside CXIX.  N(Me)  CH„  I  OH  2  CN [CXIX ] R = CH 0H 2  [CXX]  R = H  TT 2  I i ' I I Ii I i i I I I i I I I I 1 I  i ii  I  , iI  i i i i I i ii i Ii i i i I i ii iI i i i i | i i i 1 r ; i i i' i r i i i ii r i i i II i i 1  i  i  I I  i |i  i i  i |i i i  i i i ' i i, n  I  I I I I  I"  N(Me), HO—CH NMe  NMe  purine -N(Me), H-8 DMSO H-2 I  [CXXI]  H-l'  \J  i iiii iiiiI 'iii i i!iiI it i iI i iI i i l . : : 1 I ' l l ! I i ' i I ii'il :iii I Proton magnetic resonance spectrum at 100 MHz i n dimethyl s u l f o x i d e - d of 6-N,N-dimethylaniino9_(3'_C-N,N-climethylcarbamoylmethyl-3'-deoxy-3-D-allofuranosyl)-purine [CXXI].  '  Figure 2.  \*J Vu»  1  ''i 1  I ' l l !  I  1  1  I  I  i iii iI i  1  1  6  -80-  A point to note here was signals i n t h i s spectrum.  the method of assigning the hydroxyl  In dimethyl sulfoxide i t i s possible to  d i f f e r e n t i a t e between primary, secondary and t e r t i a r y hydroxyl groups on the basis of their couplings with adjacent protons.  Primary  hydroxyl groups generally appear as a t r i p l e t because of coupling to the two adjacently methylene protons; secondary hydroxyl groups appear as a doublet, and t e r t i a r y hydroxyl groups appear as a s i n g l e t . simple method of d i f f e r e n t i a t i n g hydroxyl groups was  This  frequently used  i n this work. Further i n v e s t i g a t i o n of the above nucleoside provided the following information:  the u l t r a v i o l e t absorption (A v  = 275 nm)  indicated  max  that the p o s i t i o n of attachment of the base to the sugar was  at N-9  (105); the c i r c u l a r dichroism (cd) spectrum showed a negative Cotton e f f e c t confirming that this nucleoside had the expected g-anomeric configuration (104); the i r spectrum but did show an unexpected nmr  spectrum  contained no n i t r i l e absorption  carbonyl absorption (1610 cm  ; the  i n deuterochloroform showed the molecule contained about  26 hydrogens; the mass spectrum gave a value of m/e  = 394 for the  highest non-isotopic fragment, and no fragment at m/e  = 348, which  would correspond to the molecular ion of CXIXa was found. of the above data i t was  concluded that this compound was  carbamoylmethyl branched-chain  On the basis the dimethyl-  sugar nucleoside 6-N,N_-dimethylamino-9-  (3' -C_-N,N_-dime thylcarbamoylme thy 1-3 '-deoxy-g-D-allof uranosyl) -purine [CXXI]. That this structure for CXXI was i s readily apparent.  i n agreement with the observed data  The two singlets at 6.78  and 6.86  to the N,N-dimethyl moiety i n the branched-chain;  T were assigned  the carbonyl absorption  -81-  at 1610 cm  i s t y p i c a l of t e r t i a r y amides and the mass s p e c t r a l m/e  value of 394 was consistent with the molecular formula C.-,H. ,N,0,_ 17 26 6 5 obtained from this structure. Reaction of the pentose chloropurine nucleoside CXVIII with the same methanol aqueous dimethylamine mixture afforded the analogous pentose nucleoside  6-N,N-dimethylamino-9-(3'-C_-N,N-dimethylcarbamoyl  methyl-3'-deoxy-i3-D-ribofuranosyl)-purine as a syrup i n 72% y i e l d after chromatography on s i l i c a gel.  Although CXXII appeared homogeneous  [CXXI]  R = CH 0H  [CXXII]  R = H  2  by nmr, t i c and paper chromatography, i t could not be obtained c r y s t a l l i n e , nor  could a s a t i s f a c t o r y  elemental analysis be obtained.  Consequently  this compound was characterized as i t s 2',5'-di-O-acetyl derivative. To further v e r i f y the structure of nucleoside CXXII, the previously described sodium periodate, oxidative cleavage sodium borohydride reduction (59) was used to remove the C-6'-hydroxymethyl group from  -82-  nucleoside yield  CXXI.  T h i s procedure a f f o r d e d  a homogeneous syrup i n 69%  i d e n t i c a l by i r and nmr w i t h the p r o d u c t o b t a i n e d  of aqueous dimethylamine w i t h c h l o r o p u r i n e To  account f o r the f o r m a t i o n  i n i t i a l l y postulated  nucleoside  from the r e a c t i o n  CXVTII.  of the above n u c l e o s i d e s  i t was  t h a t i n the b a s i c aqueous dimethylamine medium  the n i t r i l e group on the b r a n c h e d - c h a i n underwent h y d r o l y s i s t o g i v e the  carboxylic a c i d , followed  dimethylamine t o t h e l a c t o n e  ? 2 C=N H  by l a c t o n i z a t i o n and a d d i t i o n o f (Equation  29).  The h y d r o l y s i s o f n i t r i l e s  OH  V2  OH  H  C0 H 2  f  *0H  -H 0  (29)  2  f«2 0=C \ N(Me),  OH ||*-NH(Me), 0  to c a r b o x y l i c a c i d s i s known t o be c a t a l y z e d by b o t h a c i d s and b a s e s ; however, as a r u l e h y d r o l y s i s proceeds f a s t e r i n a c i d i c media It  should  (160).  be r e c a l l e d here t h a t i n the t r i f l u o r o a c e t i c a c i d h y d r o l y s i s  of t h e 1 , 2 - i s o p r o p y l i d e n e s m a l l amount o f l a c t o n e  k e t a l of CXII, t h a t a f t e r a c e t y l a t i o n a CXV was  recovered.  -83-  BzOCH  BzOCH  Me Me  OAc  0  C  /  0  II  0 [CXV]  [CXII]  In order to examine the r e a c t i v i t y of the n i t r i l e group i n these branched-chain sugars towards aqueous dimethylamine, compounds LXXXVI CVIII and XCIV were subjected to the same hydrolysis conditions as the above chloro nucleosides.  In each instance there was  no  detectable hydrolysis (even after twenty-four hours) and the s t a r t i n g materials were recovered unchanged.  Furthermore, i t was found that  the n i t r i l e group of the chloro-nucleoside CXXIII (161) under the same conditions was not hydrolyzed and only the branched-chain nucleoside CXXIV was obtained.  cyanomethyl  Obviously, therefore, the hydrolysis  of the n i t r i l e moiety i n branched-chain nucleosides CXXI and CXXII was unusually f a c i l e . Although the a l k a l i n e hydrolysis of n i t r i l e s having adjacent hydroxyl groups has not been extensively studied some example which could have a bearing on these r e s u l t s were found i n the l i t e r a t u r e . For example, the addition of hydrogen cyanide (usually v i a aqueous sodium cyanide) to reducing sugars ( K i l i a n i syntheses (162), equation 30) i s a c l a s s i c a l method for extending sugar chains.  A f t e r addition of the  -84-  hydrogen  cyanide the a l k a l i n e solution of n i t r i l e was heated to 60-100°  to effect hydrolysis.  It has been found, however, that for some  sugars (e.g. 2-deoxy-ribose and ribose  (163) ) hydrolysis of the n i t r i l e  proceeded spontaneously under very mild conditions a carbonate buffered s o l u t i o n ) .  (room temperature i n  -85-  H  \  ' I  0 HCN  R  OH  C=N l  C0 H  (30)  2  CHOH I R  CHOH R  Another pertinent instance of n i t r i l e hydrolysis was found i n the addition of cyanide to epoxide CXXV heated to 100° i n aqueous potassium  (164).  When t h i s epoxide was  cyanide solution no cyano addition  products  (e.g. CXXVI) were i s o l a t e d , but rather only the lactone  CXXVII.  In r a t i o n a l i z i n g this r e s u l t the authors postulated that the  intermediate n i t r i l e addition product CXXVI underwent intramolecular hydrolysis by attack of the C-5 alkoxide anion on the C-3 cyano group (Equation 31).  [CXXV]  [CXXVI]  [CXXVII]  If i t i s assumed that intramolecular hydroxyl group p a r t i c i p a t i o n can aid i n the hydrolysis of a n i t r i l e group i t i s possible to r a t i o n a l i z e the f a c i l e hydrolysis of the n i t r i l e group i n nucleosides CXVI and CXVIII as the C-2 hydroxyl ion formed a f t e r acetate cleavage, i s i n a p o s i t i o n to p a r t i c i p a t e i n hydrolysis of the nitrile  (Equation 32).  However, this theory does not account for the  -86-  resistance of the n i t r i l e group compounds XCIV and CXXIV to h y d r o l y s i s , as i t would be expected that intramolecular hydroxyl group p a r t i c i p a t i o n leading to hydrolysis of the n i t r i l e moiety would be possible with these compounds also.  Apparently there  are other factors involved here and the f u l l explanation awaits further i n v e s t i g a t i o n .  [CXVI]  R - CH OBz  [CXVIII]  5.5  2  R = H  6-N,N-Dimethylamino-9-(3'-C-carboxymethyl-2 ,3'-y-lactone-31  deoxy-B-D.-ribofuranosyl)-purine In an attempted CXXII i t was  [CXXVIII]  p u r i f i c a t i o n of the branched-chain nucleoside  sublimed at 200-205° and 0.1 mm.  a c r y s t a l l i n e nucleoside i n 73% y i e l d .  It was  This procedure afforded immediately  obvious,  however, that during sublimation nucleoside CXXII had undergone decomposition as the i r spectrum of the sublimed nucleoside had a  -87-  d i s t i n c t l y d i f f e r e n t carbonyl absorption (1770 vs. 1610 and the nmr  spectrum i n DMSO-d^ indicated that there was  cm now  for CXXII) only a  single (primary) hydroxyl group present and that the molecule no longer contained the N.,N_-dimethyl group on the branched-chain. nucleoside CXXII had undergone deamination was  That  further substantiated  by the finding that the highest nonisotopic fragment i n the mass spectrum occurred at m/e  319.  This implied that the new  nucleoside  had a molecular weight 45 units less than CXXII corresponding loss of dimethylamine from CXXII. i t was  determined that this new  to the  On the basis of the above information  compound was  the novel lactone  nucleoside 6-.N ,N-dimethylamino-9- (3' -C_-carboxymethyl-2 ', 3'-y-lactone3-deoxy-g-D-ribofuranosyl)-purine  [CXXVIII].  The deamination of CXXII under these conditions was not s u r p r i s i n g , as amides having a neighboring hydroxyl group which can p a r t i c i p a t e i n the displacement  of an amine from an amide have been shown to be  e a s i l y deaminated (165) i n a c i d i c , n e u t r a l , or basic media. the C-2'  Presumably,  hydroxyl group of branched-chain t e r t i a r y amide nucleoside  CXXVIII (Equation 33) a s s i s t s i n displacement lactone CXXVIII.  of dimethylamine to give  It i s also possible that this reaction was  further  f a c i l i t a t e d by intermolecular c a t a l y s i s by the h e t e r o c y c l i c base of the nucleoside.  -88-  5.6  Conversion of 6-N,N-dimethylamino-9-(3'-C-carboxymethyl-2 ,3'-y1  lactone-3-deoxy-B-D-ribofuranosyl)-purine  [CXXVIH] to 6-N,N-  dimethylamino-9- (3* -C_-21,N-dimethylcarbamoylmethyl-3 '-deoxy-B-Dr i b o f uranosyl)-purine [CXXII], and 6-N,N_-dimethylamino-9- (3'-Ccarbamoylmethyl-3'-deoxy-B-D-ribofuranosyl)-purine  [CXXIX] and 6-N,N-  dimethylamino-9-(3 -C_-carbamoylmethyl-N-glycine ethyl ester-3'1  deoxy-g-D-ribofuranosyl)-purine  [CXXX]  The lactone nucleoside CXXVIII proved for preparing amido branched-chain  to be a very useful compound  sugar nucleosides.  The reaction of  this nucleoside with a variety of amines i s i l l u s t r a t e d i n equation 34.  -89-  (34)  CH  OH  2  0=C NHCH CO Et %  DMP = 6-N,N-dimethylaminopurine  [CXXX]  Reaction of CXXVIII with dimethylamine f o r four hours at zero degrees centigrade  afforded the N,N-dimethylcarbamoylmethyl  nucleoside CXXII as a syrup i n q u a n t i t a t i v e y i e l d .  branched-chain This compound  was i d e n t i c a l by nmr and i r with the compound prepared by reaction of  dimethylamine with chloropurine nucleoside CXVIII.  Using ammonia  (166) i n place of dimethylamine afforded the carbamoylmethyl nucleoside CXXIX as a c r y s t a l l i n e s o l i d i n 95% y i e l d . As the above condensation  of lactone nucleoside CXXVIII with ammonia  -90-  and dimethylamine were successful i t was  decided to undertake the  preparation of a peptide nucleoside using this compound.  Lately  i n t e r e s t has increased i n nucleosides containing non-hydroxyl peptides.  This has come about p a r t l y because commercially  linked  important  a n t i b i o t i c s such as the polyoxins (167), gougerotin (141), b l a s t i c i d i n S (168), and puromycin (2a) have been shown to be nucleoside peptide derivatives with the aminoacyl moiety attached through an amino group of the sugar, and p a r t l y because amino acids which are not removed by the usual deproteinization procedures have been found i n highly p u r i f i e d samples of ribonucleic acid (169) and deoxy r i b o n u c l e i c acid (170) .  The group of investigators led by R.K.  Robins at the ICN  Nucleic Acid Research I n s t i t u t e have been at the forefront i n the preparation of these nucleoside peptides.  These workers have made  use of the active ester (171) and N_,N'-dicyclohexylcarbodiimide  (172)  methods of peptide synthesis to prepare various 5'-N-aminoacyl-5'amino-ribofuranosyl purine nucleosides (173). The method chosen here to prepare a peptide nucleoside, analogous with the above reactions of the lactone nucleoside with amines, was to simply condense glycine ethyl ester (174) with lactone nucleoside CXXVIII (Equation 34).  Thus a mixture of glycine ethyl ester and  nucleoside CXXVIII i n dimethylformamide were s t i r r e d at room temperature for 30 hours.  After removal of the solvent and chromatography on  s i l i c a g e l the peptide nucleoside 6-N_,N-dimethylamino-9-(3'-Ccarbamoylmethyl-N-glycine [CXXX] was  ethyl  ester-3 -deoxy-g-D-ribofuranosyl)-purine 1  i s o l a t e d as a c r y s t a l l i n e s o l i d i n 72% y i e l d .  condensation had taken place as expected was  That the  e a s i l y v e r i f i e d by the  -91-  i r spectrum which showed the c h a r a c t e r i s t i c amide carbonyl absorption at 1650  5.7  cm  1  as w e l l as an, ester carbonyl absorption at 1780  cm  \  6-N,N-Dimethylamino-9- (3' -C_-cyanomethyl-3'-deoxy-g-D-ribof uranosyl)purine [CXXXI] In order to prepare the cyanomethyl branched-chain  i t was necessary to prevent  the previously discussed hydrolysis of the  n i t r i l e moiety i n the branched-chain of  nucleoside CXXXI  which occurred during reaction  the blocked chloropurine nucleosides with aqueous dimethylamine.  Although  the f i n e points of the mechanism f o r the above hydrolysis  had not been d e f i n i t e l y elucidated, by simply comparing the reactants and products i t was of  apparent that i n anhydrous dimethylamine conversion  the n i t r i l e f u n c t i o n a l i t y to the t e r t i a r y amide was not possible. Consequently the chloropurine branched-chain  sugar nucleoside CXVIII  was  dissolved i n anhydrous dimethylamine and allowed to stand at -10°  for  twenty days.  Upon removal of the solvent and t r i t u r a t i o n of the  reaction mixture with ether, a portion of the desired cyanomethyl branched-chain  sugar nucleoside CXXXI c r y s t a l l i z e d out.  Chromatography  of the remaining material gave a further portion of nucleoside CXXXI ( t o t a l y i e l d 78%).  That this compound was  the desired nucleoside  6-N,N-dimethylamino-9-(3'-C-cyanomethyl-3 -deoxy-g-D-ribofuranosyl)1  purine [CXXXI] was  confirmed by s p e c t r a l data.  The i r spectrum  contained hydroxyl and n i t r i l e absorptions at 3200-3400 cm 2230 cm \  1  and  r e s p e c t i v e l y , and no carbonyl absorptions, i n d i c a t i n g that  no hydrolysis of the n i t r i l e had taken place and that the ester hydroxyl protecting groups had been completely removed.  The  nmr  -92-  CH_ 0=CN(Me)  OH 2  [CXXII]  spectrum and elemental composition were also consistent with the above structure. It i s i n t e r e s t i n g to note that when t h i s compound was dissolved i n an aqueous dimethylamine-methanol  mixture hydrolysis to the amide  branched-chain sugar nucleoside CXXII took place but proceeded at a much slower rate (12 hr f o r complete hydrolysis) than the hydrolysis of chloropurine nucleoside CXVIII to CXXII.  5.8  6-N,N-Dimethylamino-9-(3*-C-(2"-acetamidoethy1)-3'-deoxy-g-Dr i b o f uranosyl) -purine [CXXXIV] The preparation of an aminoethyl branched-chain sugar nucleoside  was i n i t i a l l y attempted by reduction of the amido branched-chain nucleoside CXXIX with l i t h i u m aluminum hydride i n pyridine (175). Pyridine was chosen as the reaction solvent because of the n e g l i g i b l e  -93-  s o l u b i l i t y of nucleoside CXXI  i n ethers.  Unfortunately using these  conditions no appreciable reduction took place and the s t a r t i n g material was  recovered unchanged.  An alternate approach to the desired aminoethyl nucleoside through reduction of the n i t r i l e moiety of nucleoside CXXXI was investigated.  Hydrogenation  then  at room temperature and 60 p s i of this  compound over platinum oxide i n a 1:1 mixture of a c e t i c  anhydride  and ethanol gave a f t e r four hours two products  and 0.10  (R^ 0.18  on  s i l i c a gel with dichloromethane:ethyl acetate:ethanol as developer). These were separated by column chromatography on s i l i c a gel and t h e i r nmr  spectra i n dimethyl sulfoxide-d^ were examined.  The spectra of  both compounds exhibited a single low f i e l d broad t r i p l e t the f a s t e r moving component and 2.22 c h a r a c t e r i s t i c of a N-H  (2.14 x f o r  x f o r the slower moving  acetamido proton.  reduction of the n i t r i l e had taken place.  one)  This indicated that However, s u r p r i s i n g l y the  f a s t e r moving component CXXXII had no hydroxyl absorptions and 3 methyl s i n g l e t s (7.85 x, 8.04  x, 8.20  x); the slower moving component  CXXIII on the otherhand, showed one hydroxyl absorption (a doublet at 4.18  x i n d i c a t i n g a secondary hydroxyl group) and two methyl  s i n g l e t s (7.98 x and 8.17  x).  From this i t was  concluded that as w e l l  as reduction of the n i t r i l e group acetylation of some of the hydroxyl groups had taken place to give as the reduction products an  approximately  50:50 mixture of compounds CXXXII and CXXXIII (Equation 35). Presumably i t i s the h e t e r o c y c l i c base of the nucleoside which catalyzes the acetylation of the hydroxyl groups i n the nucleoside. This i s somewhat remarkable i n view of the low concentration of base present i n the reaction mixture.  -94-  HOCH 2 ^0  DMP  R'OCH  DMP (35)  (Ac) 0 2  EtOH  [CXXXI]  [CXXXII] [CXXXIII] N(Me),  [CXXXIV]  R = R' = Ac R* = Ac, R = H R = R' = H  DMP = / /  These two compounds were de-O-acetylated by reaction with aqueous dimethylamine to give the same acetamidoethyl branched-chain sugar nucleoside  6-N,N-dimethylamino-9-(3'-C-(2"-acetamidoethyl)-3'-deoxy-  g-D-ribof uranosyl) -purine [CXXXIV] as a c r y s t a l l i n e  5.9  solid.  6-Benzamido-9-(2 -0-acetyl-5',6'-di-O-benzoyl-3'-C-cyanomethyl-3'1  deoxy-g-D-allofuranosyl)-purine [CXXXVI] and 6-benzamido-9-(2'-0acetyl-5 '-0-benzoyl-3'-C-cyanomethyl-3'-deoxy-g-D-ribofuranosyl)purine [CXXXVII] In order to extend the u t i l i t y of cyanomethyl branched-chain sugars i n nucleoside synthesis the preparation of nucleosides using the standard glycosyl halide, chloromercuri purine method (98,99) was b r i e f l y examined.  When the titanium tetrachloride,  chloromercuri-6-benzamido-  purine method (176) was used with CX (Equation 36) no appreciable y i e l d  -95-  (36)  CHI 2 CN  NHBz  OAc  [CXXXVI]  CMP =  of nucleoside was obtained.  The main product of t h i s r e a c t i o n  appeared from s p e c t r a l data to be the C - l hydrolysis product CXXXV, i n d i c a t i n g that the g l y c o s y l h a l i d e had been formed but that i t had not undergone condensation with the base, but rather had been hydrolysized to CXXXV probably during workup. In view of the above r e s u l t i t was decided to prepare the more reactive g l y c o s y l bromo derivative and to condense this compound with chloromercuri-6-benzamido  purine.  Thus the g l y c o s y l bromide of CX  was synthesized by reacting this compound with a saturated s o l u t i o n of  -96-  h y d r o g e n bromide i n d i c h l o r o m e t h a n e  (177).  The u n s t a b l e bromo-  g l y c o s i d e o b t a i n e d a f t e r e v a p o r a t i o n o f the s o l v e n t was  immediately  added t o a s u s p e n s i o n o f c h l o r o m e r c u r i 6-benzamido p u r i n e i n t o l u e n e a t 65°  (176).  A f t e r the u s u a l work up and chromatography on  g e l t h i s procedure  silica  a f f o r d e d the b l o c k e d a d e n y l n u c l e o s i d e 6-benzamido-  9-(2 -0-acety-5 ,6 -di-0-benzoyl-3'-C-cyanomethyl-3'-deoxy-B-D1  1  r  allofuranosyl)-purine of  [CXXXVI] as a s y r u p i n 60% y i e l d .  t h e g - c o n f i g u r a t i o n t o t h i s compound was  rule  (100) and t h e s m a l l H - l ' , H-2'  The  b a s e d on B a k e r ' s  coupling constant ( J ^ , '  assignment trans =  1  H z  2  ^•  A p p l i c a t i o n o f t h e above p r o c e d u r e t o C X I I I gave the c o r r e s p o n d i n g p e n t o s e n u c l e o s i d e 6-benzamido-9- (2' - 0 - a c e t y l - 5 ' - 0 - b e n z o y l - 3 ' - C _ cyanomethyl-3'-deoxy-B-D-ribofuranosyl)-purine c o n f i g u r a t i o n was  [CXXXVII].  The  anomeric  deduced as b e f o r e from B a k e r ' s r u l e and the f a c t  t h a t the anomeric p r o t o n appeared  as a s i n g l e t a t 3.95  T.  -97-  5.10  9-(3*-C-Aminoethyl-3'-deoxy-B-D-allofuranosyl)-adenine In order to reduce the n i t r i l e  [CXXXIX]  group i n the branched-chain of  the blocked adenyl nucleoside CXXXVI c a t a l y t i c hydrogenation at 60 p s i i n a c e t i c anhydride with platinum oxide catalyst was attempted.  However under these conditions no detectable reduction took  place a f t e r 24 hours at room temperature. reduce this compound using lithium (131).  initially  I t was  therefore decided to  aluminum hydride i n tetrahydrofuran  Using t h i s procedure the desired aminoethyl nucleoside  was obtained as a c r y s t a l l i n e s o l i d a l b e i t i n low (20%) y i e l d .  CXXXIX Although  the compound was p u r i f i e d by passage through an ion exchange r e s i n (Dowex 50W-X2 (NH^  +  form)) and c r y s t a l l i z e d several times from methanol,  the product always remained contaminated with a trace of inorganic material.  This tendency of nucleosides to complex with metals was  noted before (108).  Wherever p o s s i b l e , reaction conditions which  could introduce such contamination should be avoided, e s p e c i a l l y i f the compounds are to undergo b i o l o g i c a l  testing.  NHBz  [CXXXVII]  [CXXXIX]  -98-  6.  B i o l o g i c a l a c t i v i t y evaluation of branched-chain  sugar nucleosides  A l l the nucleosides whose preparation i s described herein (with the exception of the l a s t mentioned compound CXXXIX) are currently undergoing b i o l o g i c a l testing at the United States National Cancer Institute,  Bethesda, Maryland.  The means being used to evaluate the  a c t i v i t y of these nucleosides i s the Leukemia L 1210 system, as this type of compound generally shows i t s greatest a c t i v i t y i n this system  (178).  IV. 1.  EXPERIMENTAL:  General Methods Unless otherwise s p e c i f i e d a l l solvent evaporations were done  i n vacuo at p r e v a i l i n g aspirator pressure and a bath temperature  less  than 50°. C i r c u l a r dichroism (cd) spectra were recorded on a Jasco ORD/UV-5 spectropolarimeter or a Jasco J-20 automatic recording spectropolarimeter.  O p t i c a l rotations were measured with a Perkin  Elmer model 141 polarimeter.  Infrared ( i r ) spectra were recorded on  a Perkin Elmer model 137 spectrophotometer. magnetic resonance  Sixty MHz nuclear  (nmr) spectra were measured on a Varian T-60  spectrometer; 100 MHz spectra were recorded on a Varian HA-100 or XL-100 spectrometer.  Absorptions are given i n x units with  tetramethylsilane as i n t e r n a l standard ( set at x 10). The following abbreviations are used:  (b) = broad, (d) = doublet(s), (s) = s i n g l e t ( s ) ,  (t) = t r i p l e t ( s ) , (p) = proton(s). A. E. I. MS 9 spectrometer.  Mass spectra were recorded on an  Elemental analyses were performed by  Mr. Peter Borda at the University of B r i t i s h Columbia.  2. Chromatography 2.1  Column S i l i c a g e l column chromatography was accomplished using either  s i l i c a g e l 60-200 mesh, Davidson commercial grade H, indicated i n the  -100-  e x p e r i m e n t a l as " s i l i c a  gel",  Ltd.,  silica  indicated  as " t i c  or s i l i c a gel."  gel for t i cD 0  For s i l i c a  Mondray  g e l column  chroma-  tography t h e r a t i o of m a t e r i a l to absorbent was about 1 t o 70. II For  activity  Grade  i n d i c a t e s t h a t 10% o f water has been added to the a b s o r b e n t .  ticsilica  g e l column chromatography the r a t i o of m a t e r i a l to  a b s o r b e n t was about 1 to 200 and columns were r u n under a p o s i t i v e pressure of 2 to 7 p s i .  Alumina column chromatography was done u s i n g  aluminum o x i d e Woelm n e u t r a l , t h e d e s i r e d a c t i v i t y grade b e i n g  pre-  pared a c c o r d i n g to the d i r e c t i o n s on the c o n t a i n e r .  2.2  Thin Layer All  gel  Chromatography  t h i n l a y e r chromatography ( t i c )  was performed u s i n g  silica  f o r t i c D 5 Mondray L t d . c o n t a i n i n g 1% e l e c t r o n i c phosphor.  Compounds were d e t e c t e d e i t h e r by u l t r a v i o l e t a b s o r b t i o n or by s p r a y i n g w i t h c a . 20% s u l f u r i c a c i d  2.3  f o l l o w e d by h e a t i n g on a hot p l a t e .  Paper Chromatography Paper chromatograms were developed on Whatman No. 1 paper.  N u c l e o s i d e s were d e t e c t e d w i t h u l t r a v i o l e t  2.4  Gas L i q u i d  light.  Chromatography  Gas l i q u i d p a r t i t i o n c h r o m a t o g r a p h i c s e p a r a t i o n s  ( g l c ) were  performed u s i n g a V a r i a n a e r o g r a p h model 1525 w i t h the f o l l o w i n g columns:  column A i s a s t a i n l e s s s t e e l column (10' x 3/8")  packed  w i t h 5% butane d i o l s u c c i n a t e on Chromosorb W-AW-DMCS 60-80 mesh; column B i s a s t a i n l e s s s t e e l column (8' x 1/4")  packed w i t h  8.5%  -101-  SF 96 on Chromosorb W.  3.  Photolysis Reactions The l i g h t s o u r c e i n t h e s e r e a c t i o n s was a Hanovia 450 w t y p e L  lamp.  L a r g e s c a l e ( i n t e r n a l ) p h o t o l y s e s were c a r r i e d out by p l a c i n g  t h e lamp, and f i l t e r i f r e q u i r e d , i n s i d e a water c o o l e d q u a r t z immersion w e l l a p p a r a t u s w h i c h was p l a c e d i n s i d e a 3-necked p y r e x vessel  ( c a p a c i t y w i t h lamp about 300 ml ) .  Small s c a l e  (external)  p h o t o l y s e s were performed by p l a c i n g t h e s o l u t i o n t o be p h o t o l y s e d i n a p y r e x tube ( c a p a c i t y about 80 m l ) and c l a m p i n g t h i s tube t o t h e o u t s i d e o f t h e q u a r t z immersion w e l l .  The immersion w e l l and p h o t o l y s i s  tube t h e n were p l a c e d i n a water b a t h i n o r d e r t h a t t h e s o l u t i o n b e i n g p h o t o l y s e d would r e m a i n a t room t e m p e r a t u r e .  I n b o t h o f t h e above  p r o c e d u r e s i n o r d e r t o p r e v e n t a c c i d e n t a l exposure t o u l t r a v i o l e t r a d i a t i o n and t o make t h e most e f f i c i e n t u s e o f t h e r a d i a t i o n s o u r c e , t h e whole p h o t o l y s i s a p p a r a t u s was wrapped i n aluminum f o i l . A l l p h o t o l y s i s s o l v e n t s were r e a g e n t g r a d e , d i s t i l l e d and d r i e d b e f o r e u s e . P h o t o l y s i s s o l u t i o n s were deoxygenated  w i t h Matheson p r e p u r i f i e d  nitrogen.  1,2:5, 6 - D i - 0 _ - i s o p r o p y l i d e n e - a - D - g l u c o f u r a n o s e [LXIX] To an e f f i c i e n t l y s t i r r e d s u s p e n s i o n o f a-D-glucose i n a b s o l u t e a c e t o n e (21) was added p u l v e r i z e d anhydrous (280 g) and 85 % p h o s p h o r i c a c i d ( 15 g ) . shake a t room t e m p e r a t u r e f o r two days. was  (300 g) zinc chloride  The m i x t u r e was a l l o w e d t o The u n r e a c t e d sugar (108 g)  removed by f i l t r a t i o n and t h e f i l t r a t e was made s l i g h t l y a l k a l i n e  -102-  with sodium hydroxide (170 g i n 170 ml of water).  The  insoluble  inorganic material was removed by f i l t r a t i o n and washed with acetone. The f i l t r a t e and washings were concentrated under reduced pressure. The residue was dissolved i n water (300 ml) and extracted with chloroform (300 ml x 3).  The combined chloroform extracts were  washed again with water, then dried over sodium s u l f a t e .  Evaporation  of the solvent yielded a s o l i d residue, which was r e c r y s t a l l i z e d  from  cyclohexane to afford c r y s t a l l i n g LXIX (220 g, 80% y i e l d based on IDglucose consumed), m.p.  109°.  Reported  (179): m.p.  5-0-Benzyl-l,2-0-isopropylidene-a-D-xylofuranose This compound was  110-111°.  [LXXVII]  synthesized following known procedures.  Starting with 100 g of D-xylose  [LXXIII], diacetone xylose [LXXIV]  was prepared following a procedure given by Baker and Schaub (120); y i e l d 104 g (73%) b.p. 97 - 98° (0.25 mm).  Reported  (0.2 mm).  then hydrolyzed to  The diacetone xylose (104 g) was  (120):  90 - 92°  monoacetone xylose (120) by d i l u t e s u l f u r i c acid; y i e l d 95 g (95%). The monoacetone xylose [LXXIV] (75 g) was  converted to 1,2-0-  isopropylidene-5-0_-tosyl-a-D xylofuranose; y i e l d 71 g (52%), 135 - 136°.  Reported  (121): m.p.  133 - 134°.  m.p.  Treatment of the  tosylate (60 g) with sodium methoxide converted i t to 1,2-0isopropylidene-3,5 anhydro-a-D-xylofuranose (83%) b.p. 48 - 50° (about 0.05 mm). (0.1 mm).  [LXXVI]; y i e l d 24.5 g  Reported  (121):  63 - 65°  F i n a l l y the anhydro sugar LXXVI (23 g) was allowed to  react with benzyl alcohol and sodium (122) to afford  5-0-benzyl-  -103-  1,2-0-isopropylidene-ct-D-xylof uranose 64°.  Reported  (122):  m.p.  [LXVIII] (32.5 g, 87%), m.p. 63-  63-65°.  1,2:5,6-Di-0-isopropylidene-a-D-gulofuranose  [LXXIa]  This compound was prepared by known procedures  (119) from the  hydrate of 1,2:5,6-di-0-isopropylidene-q-g-ribo-hexofuranos-3-ulose [LXX]. The hydrate of LXX (6.5 g) was reacted with a c e t i c anhydride and pyridine to afford 3-0-acetyl-1,2:5,6-di-0-isopropylidene-ct-D-erythrohex-3-enofuranose 62°.  [LXXI] (3.1 g) , m.p. 56-57°. Reported  (119): m.p.  Hydrogenation of LXXI (3 g) over 5% palladium-on-charcoal (1 g)  gave 3-0-acetyl-l,2:5,6-di-0-isopropylidene-ct-D-gulofuranose [LXXII] (2.4 g).  De-acetylation of this material with  methanolic sodium  methoxide afforded the t i t l e compound (2.01 g, 33% y i e l d based on LXX), m.p. 105°. Reported  (119):  105-106°.  1,2:5,6-Di-0-isopropylidene-a-D-ribofuranos-3-ulose  [XVIII]  To a solution of 1,2:5,6-di-0-isopropylidene-a-D-glucofuranose [LXIX] (5 g) i n carbon tetrachloride (80 ml) was added water (15 ml), sodium bicarbonate (1 g) and f i n e l y powdered ruthenium dioxide (80 mg). this solution was added with vigorous s t i r r i n g a few drops of 10% sodium periodate solution.  A f t e r approximately 5 min another small  addition of periodate was made.  This process was then repeated several  times while gradually increasing the volume of periodate s o l u t i o n added.  Addition was discontinued when the solution appeared a greenish-  black, which indicated the presence of ruthenium  tetroxide, and was  -104-  restarted when the solution appeared black, which indicated only ruthenium dioxide was present.  The reaction was stopped when t i c  examination indicated that no more s t a r t i n g material remained (the t o t a l volume of periodate solution added was about 50 ml).  Any  r e s i d u a l ruthenium tetroxide was then destroyed by addition of isopropyl alcohol (0.5 ml) and the ruthenium dioxide removed by filtration.  The carbon tetrachloride layer was separated and the water  layer extracted with chloroform (10 x 20 ml).  The combined organic  extracts were dried over sodium s u l f a t e and the solvent evaporated to y i e l d the ketose hydrate LXX (4.8 g, 97%) m.p. 109-110°. (119):  m.p. 109-111°.  Reported  The hydrate was suspended i n dry toluene  (200 ml) and 50 ml was d i s t i l l e d o f f at atmospheric pressure.' The remaining toluene was then removed by f l a s h evaporation using a rotary evaporator connected to an o i l pump.  The crude ketose was then  d i s t i l l e d , i n a n apparatus having a very short d i s t i l l a t i o n path (bulbto-bulb), (150°, 0.1 mm) to afford XVIII (4.5 g, 90%) as a syrup. The i r spectrum showed a carbonyl absorption at 1760 cm  1  and no  hydroxyl absorption.  1,2:5,6-Di-O-isopropylidene-q-g-xylo-furanos-3-ulose 1,2 :5,6-Di-O-isopropylidene-a-D-gulofuranose  [LXVII]  (5 g) was oxidized  with sodium periodate and ruthenium dioxide as previously described f o r compound [XVIII].  Only f i v e extractions with chloroform were  necessary to remove the ketose from the water layer. crystallized  The product  from petroleum ether (65-110°) to give the ketose LXVII  (3.9 g, 78%), m.p. 75°. Reported  (119): m.p.  76-77°.  -105-  5-O-Benzyl-l,2-0-isopropylidene-g-D-erythro-pentofuranos-3-ulose [LXVIII] Method A: A solution of 5-0-benzy 1-1,2-0-isopropylidene-ct-D-xylofuranose [LXXVII]  (10 g i n anhydrous dimethyl sulfoxide (60 ml)) was  an i c e bath u n t i l frozen.  Phosphorus  pentoxide (4 g) was  and a f t e r one hour at 0° the mixture was room temperature.  cooled i n then added  slowly allowed to come to  A f t e r twenty-four hours t i c examination of the  reaction mixture indicated that a l l the s t a r t i n g material had been consumed (R  f  LXVIII 0.76;  The reaction mixture was  R  f  LXXVII 0.47,  benzene methanol (4:1)).  then added with s t i r r i n g to a cold saturated  sodium bicarbonate solution (100 ml) and a f t e r f i l t r a t i o n , was extracted with chloroform (7 x 50 ml).  the f i l t r a t e  The chloroform extract  was washed once with sodium bicarbonate solution (10 ml) and once with water and dried over magnesium s u l f a t e . The majority of the solvent was  then removed by evaporation and the residue dried by d i s s o l v i n g  i t i n anhydrous benzene (50 ml) and d i s t i l l i n g o f f 25 ml at atmospheric pressure.  The remainder of the benzene and r e s i d u a l DMSO was removed  by evaporation on a rotary evaporator connected to a vacuum pump (pressure about 1 mm) yellow o i l .  leaving 6.5 g of ketose LXVIII as a viscous  The i r spectrum of this material showed no hydroxyl  absorbtion and a strong carbonyl absorbtion at 1760 compound was  cm \  This  characterized as i t s 2,4-dinitrophenylhydrazone derivative 22  which was  c r y s t a l l i z e d from acetone water, m.p.  (c 2, i n chloroform).  143-144°,  [ a ] ^ +140°  -106-  Anal. Calcd. for C H 0 N . : o1  no  o  C, 55.02; H, 4.84; N, 12.22.  Found:  C, 55.25; H, 5.03; N, 12.08. Method B: To a solution of 5-0-benzyl-l,2-0_-isopropylidene-a-D-xylofuranose [LXXVII] (5 g) i n carbon tetrachloride (80 ml) was added ruthenium dioxide (80 mg), water (10 ml), and sodium bicarbonate (1 g).  While  the mixture was being vigorously s t i r r e d about 0.25 ml of 10% sodium metaperiodate solution was added dropwise.  A f t e r 5 minutes another 0.5  ml of 10% sodium metaperiodate solution was added and a f t e r a further 5 minutes more periodate solution was added u n t i l the solution was observed to turn a green-black colour (indicating the presence of ruthenium  tetroxide).  Addition of periodate s o l u t i o n was then continued  at i n t e r v a l s whenever the solution turned black (indicating only ruthenium dioxide was present).  When t i c examination indicated that  a l l the s t a r t i n g material had been oxidized (this required about 1.3 equivalents of sodium periodate) a few drops of isopropyl alcohol were added to the reaction mixture to decompose any unreacted ruthenium tetroxide and the ruthenium dioxide was f i l t e r e d o f f . The carbon tetrachloride layer was then separated and the aqueous layer extracted with chloroform (3 x 75 ml).  The combined organic extracts  were then dried over magnesium s u l f a t e and the solvent evaporated. A f t e r drying with benzene as previously described there remained 4.8 g of ketose LXVII (90% of theoretical) i d e n t i c a l by nmr and i r to the product from the DMSO oxidation.  -107-  3-C-Cyanomethyl-3-deoxy-l, 2:5,6-di-0-isopropylidene-a-D-allof uranose [LXXXVI] 1,2:5,6-Di-0-isopropylidene-a-D-ribofuranos-3-ulose  [XVIII]  (14.7 g, 0.057 mole) dissolved i n 1,2-dimethoxy ethane (DME) was  (250 ml)  added dropwise with s t i r r i n g to a solution (kept at 0°) of  d i e t h y l cyanomethylphosphonate carbanion (prepared as i n the synthesis of LXXXVIII from sodium hydride (1.64 g, 0.0685 mole) and d i e t h y l cyanomethylphosphonate (12.1 g, 0.0685 mole)) i n DME addition was  (50 ml).  After  complete the reaction mixture was allowed to come to  room temperature  and after 4 hr i t was  d i l u t e d with i c e water (100 ml)  and the product extracted with ether (3 x 200 ml).  The combined  ether extracts were washed with water (3 x 20 ml), dried (sodium and evaporated.  The residue a f t e r evaporation of the solvent was  bulb-to-bulb d i s t i l l e d syrup (R  f  0.68,  sulfate)  (190°, 0.1 mm)  to afford 13.6  g of a colourless  benzene:methanol (19:1)); i r (film) 2250 cm  (CEN);  -1  CDC1 T  3  3.9-4.1 (m, 2p, H-l and o l e f i n i c proton).  Hydrogenation  of this material i n ethanol (150 ml) at ambient  pressure and temperature  over 5% palladium-on-charcoal (4 g)  (1.01  equivalents of hydrogen absorbed) gave, a f t e r removal of the catalyst by f i l t r a t i o n and evaporation of the solvent, 13.6  g of syrup.  C r y s t a l l i z a t i o n of t h i s material from ether-petroleum ether 30-60°, afforded the branched-chain [a]  2?  4.18  +91°  sugar LXXXVI (12.6 g, 78%), m.p. 109°, —1 rnn (c 2, i n chloroform); i r (nujol) 2270 cm (C=N); 3 T  (d, l p , H-l, J  ±  2  = 3.6  Hz), 5.23  ( t , l p , H-2,  ^  I r r a d i a t i o n of LXXXVI at the H-l signal collapsed H-2  2  3  = 3.6 Hz).  into a doublet.  -108-  Anal. Calcd. for C^H C, 59.26; H, 7.35;  N,  $  N 0: 5  C, 59.3; H, 7.47;  N, 4.94.  Found:  4.81.  3-C-Cyanomethyl-3-deoxy-l ,2:5,6-di-0_-isopropylidene-a-D-gulof uranose [LXXXVII] 1,2: 5 ,6-Di-0_-isopropylidene-a-D-xylohexafuranos-3-ulose (290 mg)  dissolved i n DME  (20 ml) was  [LXVII]  added dropwise with s t i r r i n g to  a solution (kept at 0°) of d i e t h y l cyanomethylphosphonate carbanion (prepared as i n the synthesis of LXXXVIII from sodium hydride (30 and diethylcyanomethyl phosphonate (220 mg) addition was  i n DME  complete the reaction mixture was  room temperature  and a f t e r 4 hours i t was  (15 ml).  mg))  After  allowed to come to  d i l u t e d with i c e water (20 ml)  and the product was extracted with ether (3 x 25 ml) as previously described. 260 mg  C r y s t a l l i z a t i o n from ether-pet. ether 30-60° afforded  (80%) of the unsaturated cyano branched-chain  sugars  3-C-  cyanovinyl-3-deoxy-l,2:5,6-di-0-isopropylidene-a-D-xylofuranose  -l [LXXXIV], m.p.  98°; i r (nujol) 2260 cm  rnn (C=N);• T  3  4.06-4.33  (m, 2p, H-l and o l e f i n i c proton). Hydrogenation  of LXXXIV (260 mg i n 10 ml ethanol) at ambient  pressure and temperature  over 5% palladium-on-charcoal (100  (1 equivalent of hydrogen absorbed) gave the t i t l e sugar LXXXVII (260 mg, ether 30-60°, m.p. —l 2280 cm t, l p , H-2, doublet.  79%) which was  112°, [a]*  5  mg)  branched-chain  c r y s t a l l i z e d from  ether-petroleum  -28.6° (c 2.3, i n chloroform); i r (nujol)  rnn (C=N); T J  3  4.17  _ = 5.0 Hz).  (d, l p , H - l , J  = 4.0 Hz), 5.27  I r r a d i a t i o n of H-l collapsed H-2  (broad  to a  -109-  Anal. Calcd. for C, 59.33; H, 7.63;  N,  C  H 1 4  N 2 1  °5  :  c  >  59.35; H, 7.47;  N, 4.94.  Found:  4.69.  5-0-Benzyl-3-C_-cyanomethyl-3-deoxy-l, 2-0-isopropylidene-a-Dribofuranose [LXXXVIII] To a suspension of sodium hydride (NaH) anhydrous 1,2-dimethoxyethane (DME)  (0.36 g, 15 mg) i n  (20 ml) was  added a solution of  d i e t h y l cyanomethylphosphonate (2.7 g, 15 mmole) i n DME evolution of hydrogen had ceased the mixture was above operations were performed  filtered  To t h i s  [LXVIII] (2.8 g, 10.1 mmole) i n DME  When the addition was  complete the reaction mixture  allowed to come to room temperature was  ( a l l the  then added dropwise 5-0_-benzyl-l,2-0-isopropylidene-a-D-  erythro-pentofuranos-3-ulose (60 ml).  When  i n a dry box under nitrogen atmosphere)  and the solution of phosphonate carbanion cooled to 0°. solution was  (20 ml).  was  and a f t e r four hours the solution  d i l u t e d with i c e water (75 ml) and extracted with ether (3 x 50 ml),  The combined ether extracts were washed with water ( 3 x 5 (magnesium sulfate) and evaporated.  ml), dried  The remaining residue was  dissolved i n benzene (50 ml) and decolourized with charcoal. Evaporation of the solvent gave 3 g of syrup.  Hydrogenation  of t h i s  syrup i n ethanol (25 ml) at ambient pressure and temperature  over  10% palladium-on-charcoal (1 g) (1.05 equivalents of hydrogen absorbed) gave a f t e r removal of the c a t a l y s t and evaporation of the solvent 23 the t i t l e compound LXXXVIII as a homogeneous syrup (3 g, 93%); [a]p -1 CT)C\ +50° (c_ 3, i n chloroform); i r (nujol) 2270 cm (d, l p , H-l, J  = 3.6 Hz), 5.34  ( t , l p , H-2,  (C=N) ; T J  3  = 3.9 Hz).  4.2  -110-  I r r a d i a t i o n of the H-l s i g n a l of LXXXVIII collapsed H-2 into a doublet. Anal. Calcd. for C^H^NO^:  C, 67.31; H, 6.98; N, 4.62. Found:  C, 67.45; H, 7.20; N, 4.78.  3-C-(2'-Acetamidoethyl)-3-deoxy-l,2:5,6-di-O-isopropylidene-a-Dallofuranose [XCII] The 3-C_-cyanomethyl-3-deoxy-l, 2:5 ,6-di-0_-isopropylidene-a-Dallofuranose [LXXXV] (1 g) dissolved i n absolute ethanol (70 ml) saturated with ammonia was hydrogenated over 5% rhodium-on-alumina (200 mg) at room temperature and 60 p s i for 20 hr.  The catalyst was  then removed by f i l t r a t i o n and the solvent evaporated.  The r e s u l t i n g  syrup was acetylated with a mixture of a c e t i c anhydride (3.5 ml) and pyridine (3.5 ml) for 24 hr at room temperature.  The mixture was  then d i l u t e d with i c e water (20 ml) and the product extracted with dichloromethane  (3 x 20 ml), washed with water ( 2 x 5  over sodium s u l f a t e .  ml) and dried  Evaporation of the solvent afforded 0.92 g (80%)  23 of the above amide XCII as a syrup; [ a ] ^ +41° (c 1, i n chloroform); —1 -1 m n i r (film) 3300 cm (N-H), 1640 cm (N-C=0); x 3 3.27 (broad t , l p , H-N 8.03  ), 4.30 (d, l p , H-l  J  ±  2  =  4.0 Hz), 5.30 ( t , l p , H-2),  (s, 3p, Ac).  Anal. Calcd. for C^H.^N.O,: 16 II l b C, 58.27; H, 8.44; N, 4.00.  C, 58.34; H, 8.20; N, 4.25.  Found:  -111-  3-C- (2' -Acetamidoethyl)- 5-0-benzyl-3-deoxy-l, 2-0-isopropylidene-a-Dribofuranose [XCIII] A solution of  5-0_-benzyl-3-C-cyanomethyl-3-deoxy-l,2-0-  isopropylidene-a-D-ribofuranose [LXXXVIII]  (7 g i n anhydrous ether  (50 ml)) was added dropwise to a suspension of lithium aluminum hydride (LAH)  (2.03 g) i n anhydrous ether (100 ml).  After two hours  unreacted LAH was decomposed by the slow addition of e t h y l acetate (35 ml) i n ether (50 ml) followed by water (2 ml). then f i l t e r e d and the f i l t r a t e was evaporated.  The solution was  The residue was  taken up i n chloroform (100 ml) and the chloroform s o l u t i o n was washed with water (3 x 10 ml), dried (sodium sulfate) and evaporated.  The  remaining material was acetylated by treatment with a mixture of a c e t i c anhydride (10 ml) and anhydrous methanol (19 ml) for 3 hours. The mixture was  then poured i n t o i c e water (50 ml) and the product  extracted with chloroform (3 x 75 ml).  The combined chloroform  extracts were washed with 5% sodium bicarbonate s o l u t i o n (2 x 10 ml) and water (2 x 10 ml) and dried  (sodium s u l f a t e ) .  Evaporation of  the f i l t r a t e gave 6.6 g of syrup which was chromatographed on s i l i c a gel using benzene:ethyl acetate (2:1) as developer to afford amide XCIII as a syrup (5.5 g, 68.5% from LXXXVIII]; [a] , +39° (c 0 -i n rnn 2  2  3, i n chloroform);  D  ir (b,  (film) 3300 (N-H), 1650 cm l p , N-H),  8.1  (-C-N); x  4.2  (d, l p , H - l ) , 4-4.4  (s, 3p, N-Ac).  Anal. Calcd. f o r C^H^N^O : C, 65.60; H, 8.02;  3  N,  3.87.  C, 65.31; H, 7.79; N, 4.01.  Found:  -112-  Acetolysis of 3-C-(2'-acetamidoethyl) -5-0-benzyl-3-deoxy-l, 2-0isopropylidene-a-D-ribofuranose [XCIII] Concentrated s u l f u r i c acid (0.25 ml) was added dropwise to a cooled (0°) solution of 3-C-(2'-acetamidoethyl)-3-deoxy-l,2-0-isopropylidenect-D-ribofuranose (500 mg) acetic acid (5 ml). was  i n acetic anhydride (0.5 ml) and g l a c i a l  A f t e r addition was  complete  allowed to come to room temperature  Workup was  the reaction mixture  and l e t stand for one  day.  accomplished by pouring the reaction mixture into i c e  water (30 ml) and extracting the product with chloroform (3 x 25 ml). A t i c examination of the chloroform extract showed the presence of f i v e products (R^ 0.0,  0.1, 0.45,  0.61  and 0.75, benzenermethanol (9:1))  i n about equal amounts.  3-£-Cyanomethyl-3-deoxy-l,2-£-isopropylidene-8-L-lyxofuranose To a s o l u t i o n of a-D-gulofuranose  [XCV]  3-C-cyanomethyl-3-deoxy-l,2:5,6-di-0-isopropylidene-  [LXXXVII] (160 mg i n 9 ml methanol) was  added 0.7 M  s u l f u r i c acid (1.5 ml) and the mixture l e f t to stand for 7 hours. The hydrolysis mixture was  then neutralized with s o l i d sodium  bicarbonate and extracted with chloroform (4 x 15 ml). chloroform extracts were dried afford  (sodium sulfate) and evaporated to  3-C-cyanomethyl-3-deoxy-l,2-0_-isopropylidene-a-D-gulofuranose  [XCIV] (121 mg, t, lp H-2), (2s,  The combined  88%) as a syrup; x  3  7.0-7.5 (m, 5p, CH C N, H-3, 2  6p, l p ) . Upon addition of D 0  7.0-7.5 disappeared.  2  4.07  (d, l p , H - l ) , 5.23  (broad  C-5  OH, C-6 OH),  8.64  8.40,  two absorbtions i n the region  The above d i o l XCIV (121 mg) was  x  reacted with  sodium periodate and sodium borohydride as described for the preparation  -113-  of XCI to afford the t i t l e branched-chain based on LXXXVII) which was  sugar XCV  (105 mg,  24 81°, [a]^  c r y s t a l l i z e d from ether, m.p.  +10.4° (c_1.6, i n chloroform); i r (nujol) 3500 (OH,  87%  (CEN);  2245 cm"  1  rnn 3  T  4.10  (d, l p , H-l, J  4.5 Hz), 8.43,  8.67  1  2  = 4 Hz), 5.23  ( t , l p , H-2,  J  2  3 =  (2 s, 6p, l p ) .  Anal. Calcd. for C, H, ..N-O. : 10 15 1 4 C, 56.22; H, 7.05; N , 6.50.  N , 6.57.  C, 56.33; H, 7.09;  rt  Found:  3-C-(2'-Acetamidoethyl)-3-deoxy-l,2-O-isopropylidene-B-L-lyxofuranose [XCVI] A solution of 3-C_-cyanomethyl-3-deoxy-l, 2-0-isopropylidene-B-Llyxofuranose  [XCV]  (18 mg)  dissolved i n acetic anhydride  (2 ml)  ethanol (2 ml) and containing platinum oxide (19 mg) was at  room temperature and 60 p s i for 4.5 hrs.  time indicated that the reaction was 0.05, was  dichloromethane:ethyl  R^ XCVI  The  catalyst  then removed by f i l t r a t i o n and the solvent evaporated  (R, 0.59 t  1.6, N-H),  i n chloroform); i r (KBr) 1630 (d, l p , H-l, J  1  cm  133°  (C-N);  = 4 Hz), 5.35  2  to afford  (92%) which c r y s t a l l i z e d on standing  dichloromethane:methanol 9:1); m.p. 0 -l n  4.17  at this  0.47,  acetate:ethanol (5:5:1)).  the t i t l e compound XCVI (20 mg)  8.0  hydrogenated  A t i c examination  complete (R^ XCV  and  [a] , +1.50° (c_ D rnn 2  5  3  T  3.8-4.3 (b, l p ,  ( t , l p , H-2,  J  2  3  = 5 Hz),  (s, 3p, N-Ac). Anal. Calcd. for  C, 55.72; H, 8.27;  N,  C  H 1 2  21 1°5 N  5.10.  :  C  '  5 5 , 5 8  » » H  8  - 5 16  N  >  5.40.  Found:  -114-  3-C_-Carbamoylmethyl-3-deoxy-l ,2:5,6-di-O-isopropylidene-a-D-allofuranose [C] To a s o l u t i o n of  3-C_-cyanomethyl-3-deoxy-l,2:5,6-di-0-isopropylidene-  a-D-allofuranose [LXXXVI] (0.566 g i n 6 ml ethanol) was  added 30% hydrogen  peroxide (0.8 ml) and 6 N sodium hydroxide.  The mixture was  then s t i r r e d at 50° for 6 hrs.  (0.8 ml).  Any unreacted hydrogen peroxide was  then  decomposed by the addition of a few milligrams of platinum oxide, and the solution was  f i l t e r e d and evaporated to dryness.  evaporation, was extracted with dichloromethane  The residue a f t e r  (40 ml) and the  dichloromethane extract washed with water (5 ml) and dried over sodium sulfate.  Evaporation of the solvent gave a s o l i d which was  r e c r y s t a l l i z e d from ether to afford the t i t l e compound C (0.40 g, 70%), m.p.  138°; [ a ] J +81° 4  1650 cm  —1  (C=0);  T  (c_2, i n chloroform); i r (nujol) 3490, 3250 (NH),  fnn  3  3.8-4.4 (b, 2p,  Anal. Calcd. f o r O, .H„-N-0,: 14 23 1 6 C, 55.7; H, 7.91; N, 4.57.  NH ). 2  C, 55.8: H, 7.69; N, 4.47.  Found:  Preparation of C from XXIX 3-C_- (Carbomethoxymethyl) -3-deoxy-l ,2:5,6-di-0-isopropy lidene-a-Dallofuranose [XXIX] (150 mg)  and ammonium chloride (15 mg) were dissolved  i n l i q u i d ammonia (3 ml) and heated i n a sealed s t a i n l e s s s t e e l tube at 60° for 24 hrs.  The ammonia was  dissolved i n ether.  then evaporated and the residue  Insoluble material was removed by f i l t r a t i o n and  the f i l t r a t e was evaporated.  The remaining material was  minimum amount of ether and stored at 0° for 24 hrs. t i t l e amide C (90 mg)  taken up i n a  A portion of the  c r y s t a l l i z e d from this solution and was removed by  -115-  filtration;  a further 18 mg of C ( t o t a l y i e l d 76%) was obtained by  concentrating the mother liquor and allowing i t to stand at 0° f o r a further 24 hrs.  The amide prepared by this procedure was i d e n t i c a l  ( i r , nmr, melting point, and mixed melting point) with the amide prepared from LXXXVI.  Preparation of C from XX A de-oxygenated solution of l,2:5,6-di-0_-isopropylidene-3-Cmethylene-q-g-ribo-hexofuranose (20 ml) and acetone for  7 hrs.  [XX] i n formamide (40 ml), t-butanol  (5 ml) was photolyzed externally i n a pyrex vessel  The v o l a t i l e solvents were then evaporated and the remaining  s o l u t i o n d i l u t e d with saturated sodium chloride solution. of this solution with dichloromethane  Extraction  (3 x 35 ml) afforded (after  drying over sodium s u l f a t e and evaporation of the solvent) 300 mg syrup. Column chromatography of t h i s material on t i c s i l i c a gel using benzene:ethyl acetate:ethanol (5:5:1) as developer gave amide C (152 mg, 50%) i d e n t i c a l (by i r , nmr, and mixed m.p.) to the product prepared from LXXXVI and some uncharacterized acetone addition product (35 mg, 11%).  The nmr spectrum of the acetone addition product contained the  rnn following signals:  x  3  4.23 (d, l p , H - l ) , 5.27 ( t , l p , H-2),  8.0 (s, l p , OH), 8.5-8.8 (m, 18p, 6Me). Upon addition of D 0 the 2  s i n g l e t at x 8.0 was removed. Ethyl 4,6-di-0-acetyl-2,3-dideoxy-a-D-erythro-hex-2-enopyranoside  [CII](144)  Tri-O-acetyl-D-glucal (5 g) was dissolved i n anhydrous benzene (20 ml, dried over molecular sieves) and d i s t i l l e d anhydrous ethanol  -116-  (1.8 ml).  Boron t r i f l u o r i d e - e t h e r (1 ml) was added to the mixture  under anhydrous conditions.  Vigorous s t i r r i n g was maintained at room  temperature f o r twenty-five minutes, carbonate (5 g) was quickly added.  a f t e r which time anhydrous  sodium  S t i r r i n g was then continued  for a further f i f t e e n minutes so as to ensure the complete n e u t r a l i z a t i o n of any excess boron t r i f l u o r i d e . removed by f i l t r a t i o n .  The s o l i d sodium carbonate was  Upon evaporation of the solvents, the  r e s u l t i n g syrupy residue c r y s t a l l i z e d spontaneously.  Recrystallization  from ether-petroleum ether afforded CII (4 g, 80%), m.p. Reported (144): . . m  p  78-79°.  78-79°.  Photo-addition of formamide to ethyl-4, 6-di-0-acetyl-2,3-dideoxy-ct-Djerythro-hex-2-enopyranoside [CII] Ethyl 4,6-di-0-acetyl-2,3-dideoxy-a-p-erythro-hex-2-enopyranoside [CII] (0.500 g) was dissolved i n a mixture of freshly d i s t i l l e d formamide (190 ml), t-butanol (70 ml) and acetone (17 ml) and the s o l u t i o n purged with oxygen-free nitrogen for ten hrs. (pyrex f i l t e r A >300) was  then commenced.  Irradiation  After 1 1/2 hr a further  2.5 g of CII i n oxygen-free t-butanol (20 ml) and acetone (3 ml) was added dropwise over a three hour period.  Examination of the reaction  mixture by t i c (95:5 benzene :methanol R^ CII 0.50, R^. products  -0 and  0.1) indicated that after 9 hrs no more s t a r t i n g material remained. The v o l a t i l e solventswere then removed by evaporation and the remainder of the solution diluted with saturated sodium chloride solution (200 ml) and extracted with chloroform (4 x 100 ml).  The combined chloroform  -117-  extracts were washed with water (3 x 20 ml), dried over sodium s u l f a t e and evaporated to y i e l d 3.1 g of syrup.  Column chromatography of  this material on s i l i c a gel grade II (benzene:ethyl acetate:ethanol 10:10:1) gave two components:  0.33 g of the f i r s t eluted  and 2.1 g of the second eluted  component  component.  The f i r s t eluted component  proved to be a mixture of acetone  rnn addition products:  x  3  7.66  (s, l p , OH), 7.94  ( t , 3p, CH^ of ethyl glycoside) 8.80 addition branched-chain).  (s, 6p, 2 methyl peaks of acetone  Glc column A:  retention time 24-26 min at 200°.  (s, 6p, 2Ac), 8.80  2 unresolved peaks,  Column B:  2 unresolved peaks,  retention time 15 1/2-18 1/2 min at 210°. Anal. Calcd. f o r C. H„-0-,:  C, 56.59: H, 8.23.  c  lb  H,  ir  Found:  C, 56.31;  /  8.00. The second component proved to be the amide addition product 0 -l - i - i ii rnn (film) 3400 cm (NH.), 1740 cm (C=0), 1660 cm (C-N; x 3 0  3.47  1  (b, 2p, C-NH ), 7.90 (s, 6p, Ac), 8.74 2  ( t , 3p, methyl peak of  e t h y l glycoside). Anal. Calcd. f o r  c  H 1 3  2i i°7 N  :  c  » 51.47; H, 6.97; N, 4.61.  Found:  C, 51.93; H, 6.67; N, 4.20.  I, 2:5,6-Di-0-isopropylidene-3-£-nitromethy1-a-D-glucofuranose  [CV]  A solution of one M sodium methoxide i n methanol (1.95 ml, 1.95 mmoles) was added dropwise with s t i r r i n g to a solution of 1,2:5,6di-O-isopropylidene-q-D-ribo-hexofuranos-3-ulose [XVIII] (0.5 g, 1.95 mmoles) i n 5 ml of nitromethane. The reaction mixture was s t i r r e d f o r 16 hr at room temperature and then deionized, and the f i l t r a t e then  -118-  evaporated to a syrup.  C r y s t a l l i z a t i o n from petroleum ether (b.p.  60-110°) gave 0.430 g (71% of pure, c r y s t a l l i n e n i t r o derivative m.p.  138-140°,  [a]  2 2  (N0 ); 2  system, J  (c 2, chloroform);  i r (CC1 ) 3650 (s) (OH) 4  rnn  -1 1560 cm  +31°  CV,  x  3  4.05  (d, H-l,  2  3.5 Hz), 5.13  (an AB  , 12.5 Hz, methylene protons a and b on C - l ' ) , 5.38  (d,  3. y D  H-2,  3  8.62  and 8.66  1  2  3.5 Hz), 5.5-6.3 (m), 6.50  (OH), 8.40,  8.55  (2s, 6p, lp)  (2s, 6p, l p ) .  Anal. Calcd. for C H „ . N 0 :  N, 4.39.  Found:  3-C-Cyanomethyl-3-deoxy-l,2-0-isopropylidene-a-D-allofuranose  [CVIII]  10  C, 48.73; H, 6.49;  N,  To a solution of  0  C, 48.89; H, 6.63;  4.54.  3-C_-cyanomethyl-3-deoxy-l,2:5,6-di-0_-isopropylidene-  ct-D-allofuranose [LXXXVI] (6.5 g) i n methanol (300 ml) was s u l f u r i c acid (30 ml).  The hydrolysis mixture was  added 1 N  l e f t to stand at  room temperature u n t i l t i c indicated that a l l the s t a r t i n g material was gone (about 4 h r ) , then neutralized with s o l i d sodium bicarbonate and extracted with chloroform (3 x 200 ml).  The combined chloroform  extracts a f t e r drying (over sodium sulfate) were evaporated to afford 25 compound CVIII (5.5 g) as a syrup i n nearly quantitative y i e l d : +99.4° (£1.67, i n chloroform); i r (film) 3500 cm"  1  x  C D C 1  3  8.17,  8.33  [ l a  (OH), 2280 cm"  1  n  (CHN) ;  (2s, 6p,Ip).  Anal. Calcd. f o r C ^ ^ N ^ : C, 54.01; H, 7.21; N,  5.56.  C, 54.31; H, 7.04; N, 5.76.  Found:  -119-  5,6-Di-0_-benzoyl-3-C_-cyanomethyl-3-deoxy-l,2-0_-isopropylidene-a-Dallofuranose [CIX] To a solution of 3-Cj-cyanomethyl-3-deoxy-l, 2-0-isopropylidene-aD-allofuranose [CVIII] (6.0 g i n anhydrous benzene (30 ml)) was added dropwise a mixture of benzoyl chloride (3.2 ml) and pyridine (4.5 ml). After 14 hrs at room temperature the reaction mixture was f i l t e r e d through a short column of grade I I alumina (25 g) and the column washed with benzene (150 ml).  Evaporation of the combined eluents  gave the t i t l e ester CIX which was c r y s t a l l i z e d  from ether-petroleum  ether 30-60° to give 10.0 g (90%) of product; m.p. 71-72°, [ a ]  2 4  +48.2° (c 1.3, i n chloroform). Anal. Calcd. f o r C ^ H ^ N ^ :  C, 66.6; H, 5.57; N, 3.10.  Found:  C, 66.33; H, 5.54; N, 2.95.  5-0-Benzoyl-3-C_-cyanomethyl-3-deoxy-l, 2-0-isopropylidene- o-D-ribofuranose [CXII] To a s o l u t i o n of 3-C_-cyanomethyl-3-deoxy-l,2-0-isopropylidene-a-Dribofuranose [CXI] (4.75 g, 22.3 mmole i n anhydrous benzene (25 ml)) was added dropwise a mixture of benzoyl chloride (2.9 ml, 24.8 mmole) and pyridine (4 ml).  After 20 hr at room temperature the reaction  mixture was f i l t e r e d through a short column of grade II alumina (20 g) and the column was washed with benzene (100 ml).  Evaporation of the  solvent from the eluent gave the t i t l e ester CXII which was c r y s t a l l i z e d from ether-petroleum-ether 30-60°: (6.55 g, 93%), m.p. 110°, +59° (c_ 1.8, i n chloroform).  [a]  2 2  -120-  Anal. Calcd. for C C, 61.11, H, 5.93;  N,  H^N^:  C, 64.34; H, 6.03;  N, 4.45.  Found:  4.31.  Attempted a c e t o l y s i s of CIX 5,6-Di-0-benzoyl-3-C-cyanomethyl-3-deoxy-l,2-0-isopropylidene-aD-allofuranose CXII (350 mg) was  dissolved i n a mixture of acetic  acid (4 ml) and acetic anhydride  (0.4 ml).  added dropwise concentrated s u l f u r i c acid reaction mixture was  (0.4 ml).  After 24 hr the  T i c examination of the chloroform extract  showed three products; (R^ 0.65  major, 0.3,  The chloroform extract was  evaporated to a syrup which was  and 0.1, benzene:methanol  dried (over sodium sulfate) and  chromatographed on a column of grade  I I s i l i c a g e l using benzene:ethyl acetate (4:1) as developer. major component was  was  diluted with i c e water (20 ml) and extracted  with chloroform (3 x 15 -ml).  (9:1)).  To t h i s solution  recovered (100 mg).  The  Elemental analysis of this  product showed that i t contained no nitrogen. Found:  C, 64.40; H,  5.03.  1,2-Di-0_-acetyl-5 ,6-di-0_-benzoyl-3-£-cyanomethyl-3-deoxy-g-D-allof uranose [CX] 5,6-Di-0_-benzoyl-3-C_-cyanomethyl-3-deoxy-l, 2-0-isopropylidene-aD - a l l o f uranose [CIX] (4.5 g) was  allowed to react with an 80% s o l u t i o n  of t r i f l u o r o a c e t i c acid (60 ml) at room temperature The reaction mixture was  then neutralized with s o l i d sodium bicarbonate,  f i l t e r e d , and the f i l t r a t e was (6 x 50 ml).  for 45 minutes.  extracted with methylene chloride  Evaporation of the combined methylene chloride extracts  -121-  afforded a syrup (4.1 g) which was acetylated with acetic anhydride (15 ml) and pyridine (15 ml).  After 20 hrs the reaction mixture  was poured into ice water (100 ml) and worked up i n the usual way obtain 4.4 g of syrup.  to  Column chromatography of this material on  grade II s i l i c a gel using benzene-ethyl acetate (3:1) as developer yielded after c r y s t a l l i z a t i o n from ether 3.3 g (69%) of acetate CX, m.p. C D C 1 T  110°, [ a ] 3  2 3  -31° (c 2, i n chloroform); i r (KBr) 2230 cm"  1  1.8-2.8 (m, 10p, 2 Bz), 3.77  (s, l p , H - l ) , 7.87,  7.97  (C=N); (2s,6p,  2 Ac). Anal. Calcd. for C , H - N 0 „ : zo zi> i y C, 63.00; H, 4.97; N, 2.65. o  c  n  C, 63.00: H, 5.08; N, 2.81.  3-C-Cyanomethyl-3-deoxy-l,2-0_-isopropylidene-a-D-ribofuranose To a s o l u t i o n of JD-allof uranose  Found:  [CXI]  3-C-cyanomethyl-3-deoxy-l,2-0-isopropylidene-a-  [CVIII] (1.5 g, 6.2 mmole, i n ethanol (40 ml)) was  added with s t i r r i n g saturated sodium bicarbonate solution (2 ml) and sodium periodate (1.32 g, 6.2 mmole, dissolved i n water (70 ml)). After the solution was  l e f t stand for 3 hr i n the dark at room  temperature a few drops of ethylene g l y c o l were added to destroy any unreacted periodate.  Sodium borohydride (120 mg) was  then added  followed after 4 hr by acetone (0.5 ml) and the mixture s t i r r e d for an a d d i t i o n a l 0.5 hr.  A f t e r f i l t r a t i o n the solution was extracted  with methylene chloride (4 x 100 ml) and-; the organic extracts were combined and dried over sodium s u l f a t e . gave a syrup which was m.p.  Evaporation of the solvent  c r y s t a l l i z e d from ether to afford CXI ( l g , 90%),  70°, [a] ) +97° (c 1.1, i n chloroform); i r (nujol) 3500 (OH), 2  2250 cm"  1  3  (C=N).  -122-  Anal. Calcd. for C, 56.6; H, 6.99;  N,  C  H 1 0  N 1 5  1  °4  :  c  >  56.4; H, 7.05;  N, 6.57.  Found:  6.67.  1,2-Di-0-acetyl-5-0_-benzoyl-3-C-cyanome  thy 1-3-deoxy-S-D-ribof uranose  [CXIII] 5-0_-Benzoyl-3-C-cyanomethyl-3-deoxy-l,2-0-isopropylidene-a-Dribofuranose [CXII] (7 g) was dissolved i n 90% t r i f l u o r o a c e t i c acid (42 ml) and l e t stand at room temperature f o r 22 minutes. mixture was  The reaction  then d i l u t e d with toluene (100 ml) and the solvent  evaporated under vacuum (about 1 mm).  The l a s t traces of acid were  removed by a second d i s t i l l a t i o n of toluene from the product and the remaining material (6.1 g) was  then acetylated with a c e t i c anhydride  (20 ml) and pyridine (20 ml) f o r 24 hr at room temperature.  The  a c e t y l a t i o n mixture was poured into i c e water and worked up as described f o r compound CX.  The syrupy product (7 g) was  dissolved i n  ethanol and allowed to stand at 0° overnight during which time some of the t i t l e acetate CXIII (3.5 g, 44% based on CXII) c r y s t a l l i z e d . The mother l i q u o r was  concentratedto a syrup and chromatographed  on a s i l i c a gel column using benzene:ethyl acetate (3:1) as developer to  afford an a d d i t i o n a l 2 g of acetate CXII (25%) and a s l i g h t l y  moving component (0.4 g).  The main component was  faster  c r y s t a l l i z e d from  ethanol to afford 1,2-di-0_-acetyl-5-£-benzoyl-3-C-cyanomethyl-3-deoxy24 g-D-ribofuranose [CXII], m.p. ir  (nujol) 2260 cm  117°; [a]  (C=N) ; ^ 3 T  (d, l p , H-2), 5.46  ±  1.8-2.7 (m, 5p, Bz), 3.80  H-l),  4.66  7.2-8  (m, 3p, CH -C^N and H-3), 8.43, 2  -21.9° (c_1.5, i n chloroform); (s, l p ,  (d, 2p, C-5 CH ), 5.6-6.0 (m, l p , H-4), 8.63  (2s, 6p, 2 Ac).  -123-  Anal. Calcd. f o r C ^ H ^ N ^ :  C, 59.82; H, 5.31; N, 3.81.  Found:  C, 59.56; H, 5.17; N, 3.53. The minor component was c r y s t a l l i z e d from ethanol to give 1-0acetyl-5-0_-benzoyl-3-C_-carboxymethyl-2  ,3-Y-lactone-3-deoxy-3-D-  2A ribofuranose [CXV], m.p. 137°, [ c J ^ -95.7° (c 1.6, i n chloroform);  rnn  -i ir (s,  (nujol) 1700-1780 cm  (C=0); x  3  1.9-2.7 (m, 5p, Bz), 3.6  l p , H - l ) , 5.0 (d, l p , H-2), 5.5-5.9 (m, 3p, C-5CH and H-4), 2  6.7-7.5 (m, -CH -C-0 and H-3), 8.0 (s, 3p, Ac). 2  Anal. Calcd. for C.^H.,,0-,: ID  ID  C, 60.00; H, 5.04.  Found:  C, 59.80;  /  H, 5.18. 6-Chloro-9-(2'-0-acetyl-5',6'-di-0-benzoyl-3'-C-cyanomethyl-3'-deoxyg-D-allof uranosyl)-purine [CXVI] A thoroughly dried, f i n e l y powdered intimate mixture of 1,2-di0-acety1-5,6-di-0-benzoyl-3-C-cyanomethy1-3-deoxy-g-D-allofuranose  [CX]  (1 g) and 6-chloropurine (350 mg) was heated i n an o i l bath at 160° and 30 mm pressure f o r 5 minutes, followed by further heating at 160° and 0.1 mm f o r an a d d i t i o n a l 40 minutes.  The melt was then cooled  to room temperature and extracted with dichloromethane (50 ml). F i l t r a t i o n and evaporation of the dichloromethane extract gave a yellow foam which was chromatographed gel  on a column of grade I I s i l i c a  using benzene:ethyl acetate (1:1) as developer to afford two  fractions.  The f i r s t eluted component proved to be unreacted s t a r t i n g  material (150 mg) and the second component was the t i t l e nucleoside CXVI (700 mg, 69% y i e l d ) .  This nucleoside remained as an amorphous  foam and could not be c r y s t a l l i z e d :  22 [ ° t ] -13° (c 1.7, i n chloroform); n  -124-  rnn  -i ir (d,  (film) 2230 cm lp, H-l , J  (C=N); ^ 3  1  l  1.42, 1.74 (2s, H-2, H-8), 3.9  U<J±  T  t2  , = 2 Hz), 7.2 (d, 2p, CH C=N). 2  Anal. Calcd. f o r C H .C1 N 0^: 29 24 1 5 7 Found : C, 59.46; H, 4.35; N, 11.47. on  0  1  C  C, 59.19; H, 4.10; N, 11.87.  6-Chloro-9-(2'-0_-acetyl-5 -0-benzoyl-3'-C_-cyanomethyl-3'-deoxy-6-D,  ribofuranosyl)-purine  [CXVIII]  A thoroughly dried mixture of 1, 2-di-0J-acetyl-5-0-benzoyl-3-Ccyanomethyl-3-deoxy-B-p-ribof uranose [CXIII] (722 mg) and 6-chloropurine (325rag)was fused as described f o r compound CXVI.  Chromatography of  the material i s o l a t e d a f t e r fusion on a column of t i c s i l i c a gel using benzene:ethyl acetate:ethanol (10:10:1) as developer afforded the t i t l e nucleoside CXVIII (600 mg, 66%) a f t e r c r y s t a l l i z a t i o n  from  23 ethanol, m.p. 136.5-137°; [ c t ]  (d, l p , H-l', J  l  (C=N); T  x  t  2  3  , = 1 Hz),  Anal. Calcd. f o r Found:  +15.5° (c 1.5, i n chloroform); i r  rnn  -i (nujol) 2250 cm  D  O  1.5, 1.74 (2s, 2p, H-2, H-8), 3.96  7.2  (d, 2p, C H C H N ) ,  N 0 Cl: c  c  2  7.78  (s, 3p, Ac).  C, 55.33; H, 3.98; N , 15.35.  C, 55.00; H, 3.6; N , 15.14.  6-N,N-Dimethylamino-9-(3'-C-N,N-dimethylcarbamoylmethyl-3'-deoxy-B-Dallofuranosyl)-purine [CXXI] To a s o l u t i o n of 6-chloro-9'- (2' -0-acetyl-5' , 6' -di-0-benzoyl-3'-Ccyanomethyl-3'-deoxy-B-p allofuranosyl)-purine _  [CXVI] (450 mg i n 20  ml methanol) was added dropwise 25% aqueous dimethylamine and the mixture l e f t to stand at room temperature  solution (10 ml)  f o r four hrs.  After  -125-  evaporation of the solvent the remaining syrup was  chromatographed  on a column of t i c s i l i c a gel using dichloromethanemethanol  (93:7)  as developer to afford the t i t l e nucleoside (240 mg,  78% y i e l d ) which  was  184-185°,  c r y s t a l l i z e d from a methanol-ether mixture, m.p.  23 [a]_ -66° (c 1.8, i n methanol); uv X 275 nm D — * max cd X max (0=0); 6.93,  275 nm  rnn 3  T  7.04  C-5'0H).  (e 20,000 i n methanol);  (6 -11,000, c 0.0047, i n methanol); i r (KBr) 1630 ' ' ' ' 2.0, 2.17  (2s, 2p, H-2,  (2s, 6 , 0CN(Me) ); p  D M S 0 _ d  2  T  Molecular weight Calcd:  H-8), 6.57  6  394.  4.28,  cm"  1  (s, 6p, N(Me) ), 2  4.64  (2d, 2p, C-2'0H,  Found by mass spectrometry:  394. Anal. Calcd. f o r C.-,H_,0 N,: 17 26 5 6 C, 51.69; H, 6.71; N, 21.28. C  C, 51.79; H, 6.64;  N, 21.31.  6-N,N-Dimethylamino-9- (3' -C_-N,N-dimethylcarbamoylmethyl-3' ribofuranosyl)-purine To a solution of  Found:  -deoxy- g-D-  [CXXII] 6-chloro-9-(2'-0-acetyl-5'-O-benzoyl-3'-C-  cyanomethyl-3'-deoxy-g-D-ribofuranosyl)-purine  [CXVIII] (102 mg i n  methanol (7 ml)) was added dropwise a 25% aqueous solution of dimethylamine (2 ml).  After 4 hr the solvent was evaporated and the residue  chromatographed on a column of t i c s i l i c a gel using dichloromethane: methanol (93:7) as developer to afford the t i t l e amide nucleoside CXXII (64 mg,  72% y i e l d ) as a syrup.  This compound was homogeneous by  chromatography on paper (R^ 0.68 butanol:ethanol:water, 40:19:11), CDC1 and on s i l i c a gel (R^ 0.42 (s, 2p, H-2,  dichloromethane:methanol  and H-8), 6.10  C-2'0H), 5.2-6.5 (m, 4p, H-2,  (d, l p , H - l ' ) , 6.43 H-4,  9:1); x  (b, 2p, C-5'0H and  and C-5'CH ), 6.53 2  1.80  (s, 6p, N(Me )), 2  -1260 (i  6.97,  7.08 (2s, 6p, C N ^ l e ^ ) .  This compound could not be induced to  25 [a]„ -31.2° (c 1.37, i n water); uv X 275 nm (e 14,300, D — max i n water) i r (film) 3200-3500 cm" (OH), 1640 cm" (C=0). crystallize;  1  Anal. Calcd. for C-.H-.N-O.: 16 24 6 4 C, 50.86; H, 6.43; N, 22.40  6-N,N-Dimethylamino-9-(2* ,5  1  C, 52.74; H, 6.65; N, 23.06.  Found:  '-di-0--acetyl-3'-Cj-N,N-dimethylcarbamoylmethyl-  3'-deoxy-g-D-ribofuranosyl)-purine A solution of CXXII (50 mg) i n pyridine (0.5 ml) and acetic anhydride  (0.5 ml) was stored at room temperature  f o r 20 hrs.  After  this time the reaction mixture was d i l u t e d with i c e water (10 ml) and extracted with chloroform (3 x 20 ml).  The chloroform extracts  were dried over sodium sulfate and evaporated.  The material remaining  a f t e r evaporation was chromatographed on a column of t i c s i l i c a to 25 y i e l d 55 mg (40%) of the t i t l e nucleoside as a syrup;  f  a  ]  D  -25.2°  (c 1, i n chloroform). Anal. Calcd. f o r Found:  c  o 28 6°6 H  2  C, 53.90; H, 6.31;  N  :  C  '  5 3  -  6 4 ;  H  > - 5 » 18.74. 6  2 9  N  N, 18.65.  Preparation of 6-N,N-Dimethylamino-9-(3'-C_-N,N_-dimethylcarbamoylmethyl3'-deoxy-g-D-ribofuranosyl)-purine  [CXXII] from CXXVIII  6-N, .N-Dimethylamino-9-(3'-C-carboxymethy1-2',3'-y-lactone-3'deoxy-g-D-ribofuranosyl)-purine [CXXVIII] (30 mg) was dissolved i n dimethylamine (3 ml) and allowed to stand at 0° for 4 hr.  After  evaporation of the dimethylamine from the reaction mixture, the branched-chain  N_,N_-dimethylcarbamoylmethyl nucleoside CXXII (34 mg,  -127-  quantitative y i e l d ) was recovered, having i r and nmr spectra i d e n t i c a l to those of the product obtained by treatment of CXVIII with aqueous dime thylamine.  Preparation of CXXII from CXXI Sodium periodate (152 mg) was added to a solution of 6-N,Ndimethylamino-9-(3'-C_-N,N-dimethylcarbamoylmethyl-3'-deoxy-g-Da l l o f uranosyl) -purine [CXXI] (275 mg i n 21 ml water, 14 ml ethanol and 0.5 ml saturated sodium bicarbonate solution) and the mixture was s t i r r e d i n the dark f o r 2.5 hrs. added and the reaction mixture was  Sodium borohydride (212 mg) was  then  s t i r r e d for an a d d i t i o n a l 3 hrs.  Unreacted borohydride was destroyed by the addition of a few drops of g l a c i a l acetic acid and the solvent was residue was  then evaporated.  The  taken up i n methanol, refluxed f o r five minutes and the  methanol evaporated.  The remaining material was dissolved i n  dichloromethane and inorganic material removed by f i l t r a t i o n . material remaining a f t e r evaporation of the f i l t r a t e was  The  chromatographed  on a column of t i c s i l i c a gel using dichloromethane:methanol  (93:7) as  developer to afford the pentose amide nucleoside CXXI (170 mg,  68%  y i e l d ) as a syrup i d e n t i c a l by nmr and i r with the product obtained by treatment of CXVIII with  dimethylamine.  Preparation of 6-N,N-dimethylamino-9-(3 -C_-N,N-dimethylcarbamoy Diethyl1  s'-deoxy-g-D-ribof uranosyl)-purine [CXXII] from CXXXI 6-N,N-Dimethylamino-9-(3'-C-cyanome thy1-3'-deoxy-g-D-ribofuranosyl)purine [CXXXI] (20 mg) was dissolved i n a mixture of methanol (4 ml)  -128-  and 25% aqueous dimethylamine (2 ml).  After the reaction mixture had  stood at room temperature for 12 hrs the solvent was evaporated to y i e l d CXXII (23 mg, quantitative y i e l d ) as a syrup i d e n t i c a l by i r and nmr with the product obtained by treatment of CXVIII with aqueous dimethylamine.  6-N,N-Dimethylamino-9-(3'-C_-carboxymethyl-2',3'-y-lactone-3-deoxy-B-Dribofuranosyl)-purine [CXXVIII] Sublimation of  6-N,N_-dimethylamino-9-(3'-C_-N,N-dimethylcarbamoyl-  methyl-3'-deoxy-B-D-ribofuranosyl)-purine [CXXII] (30 mg) at 210° and 0.1 mm afforded, a f t e r c r y s t a l l i z a t i o n from ethyl acetate, the t i t l e lactone nucleoside CXXVIII (19 mg,  73%); m.p.  198-199° (with  22 [ a ] ^ -57.5° (c 1.1, i n chloroform); uv X 274 nm D — max  sublimation);  (e 14,500, i n methanol); cd X 274 nm (e -10,000, c 0.004 i n methanol); max ir  (KBr) 1770 cm  (s, 6p, N(Me) ); 2  (C=0) ; ' ' 3 K  uy  1. 73, 2.23  x  T  D M S 0 _ d T  6  4.93  ( , l p , C-5'OH). t  absorption disappeared on addition of B^O. 319.  (2s, 2p, H-2, H-8),  6.48  The hydroxyl  Molecular weight Calcd:  Found by mass spectrometry: 319.  Anal. Calcd. f o r C, .H., _,N0. : 14 17 5 4 C, 52.43; H, 5.54; N, 21.83. C  C, 52.65; H, 5.37; N, 21.93.  Found:  6-N_,N_-Dimethylamino-9- (3* -C-carbamoylmethyl-3 -deoxy-g-D-ribof uranosyl) 1  purine  [CXXIX]  6-N,N-Dimethylamino-9-(3'-C-carboxymethyl-2',3'-y-lactone-3-deoxyg-D-ribofuranosyl)-purine [CXXVIII] (30 mg) was dissolved i n l i q u i d ammonia (3 ml) and the ammonia was allowed to evaporated slowly during  -129-  a period of s i x hrs.  The resultant residue was c r y s t a l l i z e d from  ethanol to afford the t i t l e nucleoside CXXIX (30 mg, 95%), m.p. [a] D  2 3  -29.9° (c 0.5, i n water); i r (nujol) 1650 cm" — 0  1  (C=0);  207°,  D M S 0 - d T  6  II  2.60, 3.13 (b, 2p, -C-NH ), 4.08 (d, l p , C-2'0H), 4.83 ( t , l p , C-5'0H); 2  uv X max  275 nm (e 14,100 i n water); cd X  max  275 nm (6  -6,000,  c 0.0057, i n water). Anal. Calcd. f o r C .H N,0.: 14 20 6 4 C, 49.59; H, 5.94; N, 24.72. 1  on  C, 49.99; H, 5.99; N, 24.98.  Found:  6-N,N-Dimethylamino-9-(3'-C-carbamoylmethy1-N-glycine ethyl ester-3'deoxy-8-D-ribofuranosyl)-purine  CXXX]  6-N, N-Dimethylamino-9-(3 '-C_-carboxymethyl-2 ,3' -y-lactone-3-deoxy1  8-D-ribofuranosyl)-purine  [CXXVII] (40.mg) was dissolved i n a mixture  of N»N_-dimethylformamide (0.75 ml) and e t h y l glycinate (0.25 ml) and s t i r r e d at room temperature for 30 hr. by d i s t i l l a t i o n  V o l a t i l e material was removed  (50°, 0.1 mm) and the remaining residue column  chromatographed on t i c s i l i c a g e l using dichloromethane:methanol (9:1) as developer to a f f o r d , a f t e r c r y s t a l l i z a t i o n from ethyl acetate, the t i t l e nucleoside CXXX (38 mg, 72%), m.p. 155-7°, [ c t ]  2 5  -48.8°  (c 1.3, i n chloroform); uv X 275 nm (e 14,600, i n water); — ' max ' ' 275 nm (6 1650 cm  -i  -8,550, c 0.0043, i n water); i r (KBr) 1730 (C=0 e s t e r ) , (C=0 amide);  rnn  3  x  1.83, 2.00 (2s, 2p, H-2, H-8); 1.8  (b, l p , NH), 4.10 (d, l p , H - l ) , 8.70 ( t , 3p, CH Anal. Calcd. for C. H N,0-: o  o£  3  of e t h y l e s t e r ) .  C, 51.1; H, 6.21; N, 19.89.  lO ZD 0 O Found:  cd X  C, 50.92; H, 6.19; N, 19.61.  max  -130-  6-f£,N-DInethylamino-9-(3 '-C-cyanomethyl-3' -deoxj'-g-D-ribof uranosyl) purine fCXXXI] 6-Chloro-9-(2'-0-acetyl-5 '-O-benzoyl-3 -C-cyanomethyl-3' -deoxy-81  D-ribofuranosyl)-purine [CXVIII] (268 mg) was dissolved i n anhydrous dimethylamine  (30 ml) and stored at -10° for twenty days.  The  dimethylamine was then evaporated and the residue t r i t u r a t e d with ether (5 ml).  The material remaining a f t e r the ether was  decanted  was taken up i n ethanol and allowed to stand at 0° for twenty four hrs. out  A portion of the t i t l e nucleoside (94 mg) c r y s t a l l i z e d d i r e c t l y of this solution and a further 60 mg  obtained by chromatography  ( t o t a l y i e l d 78%)  was  of the mother liquor on a column of t i c  s i l i c a g e l using dichloromethane:ethanol (93:7) as developer. Nucleoside CXXXI was c r y s t a l l i z e d from ethanol, m.p.  206° with  25 sublimation, [a]_ -39.4° (c 0.6, i n ethanol); uv X 275 nm D max i n water); cd X max 2230 cm"  1  (CEN);  H - l ' ) , 6.80  275 nm (6 -6,100, c 0.0048, i n water); i r (KBr)  D M S 0 T  (s, 6p,  (e 15,800,  ~ 6 1.70,  1.76  d  (2s, sp, H-2, H-8), 3.98  (d, l p ,  N(Me) ). £  Anal. Calcd. for C, ,H., N,0 : C, 52.82; H, 5.70; N, 26.40. 14 l o o j Found: C, 52.64; H, 5.64; N, 26.42. o  o  6-N,N-Dimethylamino-9-(3'-(2"-acetamidoethyl)-3'-deoxy-g-D-ribofuranosyl)purine [CXXXIV] 6-N,Nj-Dimethylamino-9-(3'-C-cyanomethy1-3'-deoxy-g-D-ribofuranosyl)purine [CXXXI] (32 mg) was dissolved i n a mixture of a c e t i c anhydride (2 ml) and absolute ethanol (2 ml) and hydrogenated over platinum oxide  -131-  (20 mg) at 60 p s i f o r four hrs. The catalyst was then removed by f i l t r a t i o n and the solvent evaporated to afford 40 mg of syrup. Examination of this product by t i c showed that i t contained two components (R  f  0.18 and 0.10, R  acetate:ethanol 5:5:1).  f  CXXI 0.62 i n dichloromethane:ethyl  These-two components were separated by column  chromatography on t i c s i l i c a g e l using the above developer, to afford 17 mg of the faster component,  D M X  ^° 6 d  2.14 (broad t, l p , N-H), 7.85,  8.04, 8.20 (3s, 9p, 3Ac), no hydroxyl signals and 19 mg of the slower component, 7.98, 8.17  D M S 0 _ d T  6  2.22 (broad t, l p , N-H), 4.18 (d, l p , C-2'0H),  (2s, 6p, 2Ac).  The slower moving component was dissolved i n 25% aqueous dimethylamine solution f o r 3 hrs. A f t e r evaporation of the solvent the remaining material c r y s t a l l i z e d on t r i t u r a t i o n with  dichloromethane.  Reaction of the faster moving component under the same conditions afforded the i d e n t i c a l product.  The above two products were combined  and r e c r y s t a l l i z e d from an isopropanol water mixture to y i e l d CXXIV (23 mg, 63%) which c r y s t a l l i z e d as the hemi-hydrate, m.p. 193-194°, 25 [aU 1.0 (c 0.9, i n ethanol); uv \ 274 nm (e =23,900 water); D — max x  D M S 0  " 6 d  1.56, 1.76 (2s, 2p, H-2, H-8), 2.19 ( t , l p , N-H), 4.0 (s, l p ,  H - l ' ) , 8.23 (s, 3p, N-Ac). Anal. Calcd. for C. ,H-.N.0 •1/2H.0: 16 24 6 4 2 Found: C, 51.38; H, 6.39; N, 22.07.  C, 51.47; H, 6.74; N, 22.47.  Chloromercuri-6-benzamidopurine To a s t i r r e d solution of 7.8 g (0.028 mole) of mercuric  chloride  i n 100 ml of 50% aqueous ethanol was added 6.8 g (0.028 mole) of 6-benzamidopurine.  To the r e s u l t i n g suspension, 10.3 ml of 10% aqueous  -132-  sodium hydroxide (0.028 mole) was added dropwise with s t i r r i n g .  The  yellow mixture was s t i r r e d 1 hr and then allowed to stand at room temperature for a period of 20 hr.  The white s o l i d was f i l t e r e d ,  washed with 25 ml of cold 50% aqueous ethanol and dried i n vacuo over phosphorus  pentoxide:  y i e l d , 13g (96%).  Reported (176):  y i e l d 96%.  6-Benzamido-9-(2'-0-acetyl-5 ,6'-di-0-benzoyl-3'-C-cyanomethyl-3'1  deoxy-B-D-allofuranosyl)-purine [CXXXVT] Hydrogen bromide was bubbled into a s o l u t i o n of l , 2 ' d i - 0 - a c e t y l 5,6-di-0_-benzoyl-3-C_-cyanomethy  1-3-deoxy-g-D-allofuranose  [CX] (1 g,  2.02 mmole) i n anhydrous dichloromethane (50 ml) at 0° f o r f i f t e e n minutes.  A f t e r the reaction mixture was l e f t to stand at 0° f o r 1 hr  and then at room temperature f o r 15 minutes, the s o l u t i o n was evaporated to a syrup and the l a s t traces of hydrogen bromide were removed by co-evaporation with dry toluene. dry  The syrup, dissolved i n  toluene (40 ml), was immediately added to a suspension of  chloromercuri-6-benzamidopurine (960 mg, 2.02 mmole) and C e l i t e (300 mg) i n dry toluene (30 ml). hot  A f t e r refluxing f o r 45 minutes the  solution was f i l t e r e d and evaporated.  The residue a f t e r evaporation  was taken up i n dichloromethane (120 ml) and washed successively with aqueous potassium iodide (30%, 2 x 20 ml) and water (2 x 20 ml).  The  dried (sodium sulfate) solution was evaporated and the resultant material chromatographed  on s i l i c a g e l (60 g, benzene:ethyl acetate  (1:1) as developer) to give the t i t l e nucleoside CXXXVI (900 mg, 60% 22 y i e l d ) as aa amorphous foam; [ a ] -37° (c 1.5, i n chloroform); i r f i l m n  -i 2230 cm  rnn (CEN); x  3  0.8 (b, l p , NH), 1.38 (s, l p , H-2), 1.9-2.8  -133-  (m, 16p, 3 Bz and H-8), 7.25  (d,2p, CH^C^N) .  Anal. Calcd. for C„,H„ N,0 : n  JO  C, 63.76; H, 4.72;  Attempted  JU  o  D  C, 64.07; H, 4.45;  N, 12.47.  Found:  O  N, 12.08.  preparation of CXXXVI using titanium tetrachloride  chloromercuri-6-benzamido-purine method A mixture of CX (100 mg), C e l i t e (100 mg)  (176)  chloromercuri-6-benzamidopurine  (105 mg),  and anhydrous xylene (15 ml) was dried by d i s t i l l i n g  o f f the xylene under reduced pressure (about 50 mm)•  To the r e s u l t i n g  residue was added anhydrous ethylene chloride (25 ml) and 15 ml of the solvent was d i s t i l l e d . titanium tetrachloride was  The mixture was then cooled to 30° and (30 y l ) added and the reaction mixture was  heated under reflux for 16 hrs.  The cooled reaction mixture was  poured i n t o saturated sodium bicarbonate solution and s t i r r e d vigorously f o r 30 min. and then f i l t e r e d . withdichloromethane  The f i l t e r cake was washed  (10 ml) and the combined organic extracts were  washed with 30% aqueous potassium iodide solution (5 ml) and water (3x5  ml).  The organic extract was  the solvent evaporated.  then dried over sodium sulfate and  The remaining residue was chromatographed on  a column of s i l i c a gel to y i e l d 50 mg of a homogeneous syrup; CDC1 T  3  1.8-2.8 (m, lOp, 2 Bz), 7.80  contain a purine moiety.  (s, 3p, Ac).  The compound did not  -134-  6-Benzamido-9- (2' -O-acetyl-5 '-O-benzoyl-3 -C-cyanomethyl-3' -deoxy1  g-D-ribof uranosyl) -purine [CXXXVII] Hydrogen bromide was bubbled into a solution of 1,2-di-0-acetyl5-0_-benzoyl-3-£-cyanomethyl-3-deoxy-g-D-ribofuranose [CXIII] (500 i n anhydrous dichloromethane  (25 ml) at 0° for 15 minutes.  mg)  After  being kept at 0° for 1 hr and at room temperature for 15 minutes, the s o l u t i o n was  evaporated to a syrup and the l a s t traces of hydrogen  bromide were removed by co-evaporation with dry toluene. syrup was  The resultant  redissolved i n toluene (10 ml) and added to a suspension of  chloromercuri-6-benzamidopurine toluene (50 ml) at 65°.  (658 mg)  and C e l i t e (500 mg) i n  (The above C e l i t e ,  chloromercuri-6-benzamido-  purine mixture had been previously dried by d i s t i l l i n g o f f 20 ml of toluene from the mixture.)  When addition was  completed  the mixture  was  refluxed f o r one hr and then worked up as previously described  for  compound CXXXVII.  (508 mg) was  The material r e s u l t i n g from this procedure  chromatographed on s i l i c a gel using benzene:ethyl  acetate:ethanol (5:5:1) as developer to a f f o r d nucleoside CXXXVII (298 mg,  25 40% y i e l d ) as an amorphous foam; [ a ] +3.1° n  chloroform); i r (film) 2250 cm 1.46  (s, l p , H-2  or H-8), 7.26  (C=N); x  3  0.75-1.00 (b, l p , N H )  (d, 2p, - C H ~ C E N ) , 7.83  Anal. Calcd. for C „ H N , 0 , :  (c 1.2, i n  CT)C~\  -1  2  (s,3p, Ac).  C, 62.22; H, 4.48;  N , 15.55.  9-(3'-C-Aminoethy1-3'-deoxy-g-D-allofuranosyl)-adenine  [CXXXIX]  o  C,  61.99; H, 4.80;  O/  N , 15.50.  To a suspension of LAH (150 ml) was  Found:  (210 mg,  5.5 mmole) i n tetrahydrofuran  added dropwise a s o l u t i o n of 6-benzamido-9-(2' -O-acetyl-  -135-  5',6'-di-O-benzoy1-3'-C-cyanomethy1-3'-deoxy-g-D-allofuranosyl)-purine [CXXXVI] (826 mg, 1.23 mmole) i n THF. After 0.5 hr at room temperature and 2 hr reflux the excess reagent was destroyed by slow addition of water (10 ml), ethanol (10 ml), and 5 N NH^OH (10 ml).  The r e s u l t i n g  p r e c i p i t a t e was removed by f i l t r a t i o n and washed with ethanol (50 ml). The residue obtained by evaporation of the combined  f i l t r a t e and  washings was p a r t i t i o n e d between dichloromethane (10 ml) and water (75 ml).  Examination of the dichloromethane extract showed that i t  contained no nucleoside, nor any material giving a p o s i t i v e test with ninhydrin.  The water extract was evaporated to dryness and the  remaining material (700 mg)taken  up i n ethanol and l e f t at 0° overnight.  From this solution was obtained 200 mg of c r y s t a l l i n e product having an u l t r a v i o l e t spectrum s i m i l a r to that of adenosine.  The u l t r a v i o l e t  spectrum of the mother liquor indicated that i t contained a n e g l i g i b l e amount of nucleoside. The above c r y s t a l l i n e material was dissolved i n 2% a c e t i c acid (2 ml) and chromatographed resin.  on 5 ml of Dowex 50 W-X2 (NH^ form) +  The column was f i r s t washed with 100 ml water and then with  5% ammonium hydroxide to afford a f t e r c r y s t a l l i z a t i o n of the main component from methanol nucleoside CXXXIX (80 mg, 20%), m.p. 170-171°, 25 [a]_ -59.1°  (c 1.2, i n water); uv X  u  ^DMSO-dg  , 261 nm (e 15,000, i n water);  in 3.x  1  %  6  6  t  1  >  8  2  (  2p, H-2, H-8), 2.70 (b, 2p, NH ), 4.10 (d,  2 S j  l p , H - l ' ) , 4.2-4.6 (b, 2p, NH ) , 5.28 ( t , l p , H-2'). Anal. Calcd. for C H N,0,: C, 48.14; H, 6.62; N, 25.91. 13 20 6 4 1o  OA  C, 44.45; H, 5.41; N, 21.69.  The sample contained some inorganic  material which could not be removed.  Found:  -136-  ADDENDA An i n t e r e s t i n g rearrangement  of cyanovinyl sugar LXXXIV was  discovered too l a t e to be included i n the body of t h i s thesis and i s therefore added as a b r i e f note here. When a sample of LXXXIV (1 g, R  f  0.49 benzene:methanol 9:1)  was hydrogenated at ambient pressure and temperature over 5% palladiumon-charcoal (500 mg), i t was observed that reduction was very slow (0.19 equivalents of hydrogen absorbed i n 24 hours).  Apparently i n  this case the catalyst had been inadvertently poisoned as normally t h i s hydrogenation was completed of  i n about two hours.  A t i c examination  the hydrogenation mixture a f t e r 24 hours indicated the presence of  three components (R^ 0.57 major, R^ 0.49 and R^ 0.35 benzene:methanol 9:1).  The catalyst was then removed by f i l t r a t i o n , the solvent was  evaporated and the remaining material was chromatographed on t i c s i l i c a gel  (with benzene:ethyl acetate 4:1 as developer).  This procedure  afforded three compounds. Two of these products were r e a d i l y i d e n t i f i e d , one being the unreduced  s t a r t i n g material LXXXIV (170 mg,  0.49) and the other  being the expected reduction product LXXXVII (140 mg, R^ 0.35). Surprisingly the t h i r d component was i d e n t i f i e d on the basis of CDC1 nmr evidence as the unsaturated sugar CXL (x J  3, 3.97 (d, l p , H-l,  „ = 5 Hz), 4.71 (broad d, l p , H-2), 5.28 (broad t, l p , H-5),  5.6 - 6.2 (m, 2p, C-6 methylene), 6.55 (d, 2p, CH CN). 2  These nmr  values should be compared with those obtained from enol acetate LXXI rnn (x  3 3.97 (d, l p , H - l ) , 4.60 (d, l p , H-2), 5.30 ( t , l p , H-5),  -137-  5.97  (d, 2p, C-6 methylene).  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