@prefix vivo: . @prefix edm: . @prefix ns0: . @prefix dcterms: . @prefix skos: . vivo:departmentOrSchool "Science, Faculty of"@en, "Chemistry, Department of"@en ; edm:dataProvider "DSpace"@en ; ns0:degreeCampus "UBCV"@en ; dcterms:creator "Webster, Godfrey Robin Barrie"@en ; dcterms:issued "2011-09-20T21:44:12Z"@en, "1965"@en ; vivo:relatedDegree "Master of Science - MSc"@en ; ns0:degreeGrantor "University of British Columbia"@en ; dcterms:description """Since 1893, acetate has been regarded as a very important precursor of naturally occurring phenolic compounds. Although intensive work has been directed at the complete elucidation of this biogenetic pathway, a satisfactory method has yet to be devised for the synthesis of the polyketide chains proposed as intermediates in the acetate scheme. Labelling studies with such compounds would provide information regarding their intermediate role in the acetate route to aromatic compounds. Efforts to date to synthesize these extended poly-β-ketone chains have been unsuccessful. Polypyrones, containing potential polyketide chains, appeared to offer a feasible solution. Synthesis of these compounds by fusing successive C₃ units to triacetic lactone proved successful, and by this method, bis-, tris-, and tetrapyrone systems were constructed. Basic hydrolysis of these fused pyrone systems, followed by intramolecular aldol condensation, demonstrated that naturally occurring phenolic compounds could be synthesized by the cyclization of a polyketide intermediate."""@en ; edm:aggregatedCHO "https://circle.library.ubc.ca/rest/handle/2429/37513?expand=metadata"@en ; skos:note "AN ASPECT OP PIRONE CHEMISTRY by GODFREY ROBIN BARRIE WEBSTER ' B . S c Univers i ty of B r i t i s h Columbia 1963 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OP SCIENCE i n the Department of Chemistry We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September 1965 In presenting th i s thes i s in p a r t i a l f u l f i lmen t of the requirements for an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary sha l l make i t f r ee l y ava i l ab l e fo r reference and study, I fur ther agree that per-mission for extensive copying of t h i s thes i s for scho lar ly purposes may be granted by the Head of my Department or by his representatives,, It i s understood that copying or p u b l i -cat ion of t h i s thes i s for f i n a n c i a l gain sha l l not be allowed without my wr i t ten permiss ion. Department of C f j g M I JT^X The Un ivers i ty of B r i t i s h Columbia Vancouver 8, Canada Date Je^t&**U^ f^bi' i i . ABSTRACT Since 1893, acetate has been regarded as a very important precursor of n a t u r a l l y occurring phenolic compounds. Although intensive work has been directed at the complete e luc idat ion of th is biogenetic pathway, a sa t i s fac tory method has yet to be devised for the synthesis of the polyketide chains proposed as intermediates i n the acetate scheme. Labe l l ing studies with such compounds would provide information regarding the ir intermediate role i n the acetate route to aromatic compounds. Ef for t s to date to synthesize these extended poly-|3-ketone chains have been un-successful . Polypyrones, containing potent ia l polyketide chains, appeared to offer a feas ible so lut ion . Synthesis of these compounds by fusing successive C^ units to t r i a c e t i c lactone proved successful , and by th i s method,, b i s - , t r i s - , and tetrapyrone systems were constructed. Basic hydrolys is of these fused pyrone systems, followed by intramolecular a ldo l condensation, demonstrated that na tura l ly occurring phenolic compounds could be synthesized by the c y c l i z a t i o n of a polyketide intermediate. i i i . TABLE OF CONTENTS Introduction . . . . . . 1 Discussion . . . . . 21 Experimental 53 Bibliography . . . . . . . . •» 77 i v . LIST OP TABLES Table I Attempts to Synthesize Bispyrone . . . . 34 Table II Attempts to Synthesize Trispyrone . . . 38 Table III Spectral Tables 74 LIST OP FIGURES Figure II 7 FxgUI*© XXX* • e « «• • • e e o 0 c . « « o • • 3 Figure IV 11 Figure V 13 Figure VI . . . . . 16 Figure VII 19 Figure VIII 24 Figure IX . . . . . . . . 25 Figure X 28 Figure XII . 44 Figure XIII 46 F i Figure XV 50 v i . A CKN 0 ¥LEDGMEN T I would l i k e to express my g r a t i t u d e to Dr. T. Money and P r o f e s s o r A. I. Scott f o r continued guidance, forbearance and i n s p i r a t i o n during the course of t h i s work. Thanks are a l s o due to Mr. H. Hanni f o r t e c h n i c a l a s s i s t a n c e . \" The attempt to a r t i f i c i a l l y produce natura l ly occurring substances and to imitate in the laboratory some of the many processes which are perpetual ly being carr ied on around us i n nature, has always been one of the chief aims of the organic chemist . . . \" J . Norman C o l l i e , 1893. INTRODUCTION In recent years, intensive investigation has been directed at the elucidation of biosynthetic pathways to natural products,, This work has led to the discovery that many classes of naturally occurring compounds are derived from simple structural units. Prom thi s discovery, several biogenetic rules have been formulated which considerably simplify the task of the natural product chemists they indicate previously undetected relationships between classes of substances; they l i m i t the number of possible formulas i n struct-u r a l studies; they very often serve as a guide to elegant labora-tory syntheses; and they as s i s t the biochemical approach by pointing to l i k e l y l i n e s of investigation. Long before i t became possible to follow biosynthetic processes with precision, attempts were made to determine something of their nature purely from structural r e g u l a r i t i e s within, and resemblances between, groups of natural products. Such consider-ations led Ruzicka^\" to propose the isoprene rule stating that t e r -penoids are formed by head-to-tail condensation of isoprene units. 2 The hypothesis, which was enlarged by Robinson , has stimulated a great deal of research i n this f i e l d . The discovery of the s i g n i f -icance of the acetate derived mevalonic acid ( l ) marked a milestone i n the history of the terpenoid f i e l d . . Mevalonic acid has only one 3 biochemical role, that of terpenoid precursor.. Phosphorylation converts i t to the A - isopentenyl pyrophosphate (2) intermediate (the active synthetic u n i t ) , which forms, by the appropriate number of head-to-tail condensations, a series of families of terpenoids (C-J^ Q, ^159 ^209 ^309 4^0' E^ C°)« 2. 3 CH3COOH OH CH-C CH o C H k 0 H J i z z CH 2 C 0 0 H CH, C = CH CH 20 PP T E R P E N O I D S R o b i n s o n i n t r o d u c e d a n o t h e r u s e f u l c o n c e p t , t h e c a r b o h y d r a t e o r s h i k i m i c a c i d ( 3 ) p a t h w a y , l e a d i n g t o t h e f o r m a t i o n o f c o m p o u n d s s u c h a s a r o m a t i c a m i n o a c i d s ( e . g . 4 ) , i n d o l e a l k a l o i d s ( e . g . 5 ) , f l a v o n o i d s ( e . g . 6 ) , a n t h o c y a n i n s ( e . g . 7 ) , c o u m a r i n s ( e . g . 8 ) , s s t i l b e n e s ( e . g . 9 ) , l i g n a n e s ( e . g . 1 0 ) , a n d l i g n i n ^ , a r o u t e r e i n -f o r c e d b y e l e g a n t b i o c h e m i c a l i n v e s t i g a t i o n s u c h a s t h a t o f D a v i s 5 a n d S p r i n s o n a n d t h e i r c o l l a b o r a t o r s . C O O H HO' OH ( 3 ) s h i k i m i c a c i d C M , C H C O O H M H ( 4 ) p h e n y l a l a n i n e 1 H CH.CH C O O H ( 5 ) t r y p t a m i n e O O H (6) 5 , 7 - d i h y d r o x y f l a v o n e 3. O G , H „ 0 5 OC f cHA (7) cyanin (8) coumarin O H (9) p i n o s y l v i n w O H C H 3 O -a O H OCH-(lO) p i n o r e s i n o l 4. Aromatic compounds derived from shikimic acid are eas i ly d i s t i n -guishable from those derived from polyacetate condensation because of the oxygen subst i tut ion pattern on the r i n g . Just as terpenoids can be considered to be constructed by h e a d - t o - t a i l l inkages between isoprene uni t s , so can many phenolic compounds be shown to resu l t from l i n k i n g between acetate units ranged i n a chain and subsequently modified by reactions such as r i n g c losure, reduct ion, C-acy la t ion , dehydration, methylation, and oxidat ion. C o l l i e ^ ' ^ was the f i r s t to suggest that the head-t o - t a i l condensation of acetate units was involved i n the biosyn-thesis of many n a t u r a l l y occurring phenolic compounds. He studied the cyc l i za t ions and condensations of synthetic poly-P-ketones, and was struck by the resemblance of some of the products to certa in natural products. Thus, as early as 1893, C o l l i e made the rather astounding proposal that i t might be possible to explain b i o -chemical reactions on the basis of laboratory analogies. C o l l i e ' s acetate hypothesis lay dormant for almost f i f t y years . I t was not u n t i l several years after Birch had. proposed an e s sent ia l ly i d e n t i c a l hypothesis that C o l l i e ' s work was again 5 brought to l i g h t . , g Birch considered what might happen i n a fa t ty ac id type synthesis , proceeding v i a h e a d - t o - t a i l l inkage of acetate uni t s , i f the (3-oxygen atoms, the residues of the acet ic ac id carboxyl groups, were not s e r i a l l y reduced out. He and his colleagues had not iced that the oxygen subst i tut ion pattern i n many na tura l ly occurring phenolic compounds corresponded to that expected i f these 5. compounds were derived i n such a fashion. Acetic acid units had already been established as building units i n f a t t y acids and steroids. Poly-p-ketones can be shown to lead to many naturally occur-rin g compounds. Figure I shows a schematic representation of condensations of these poly -P-ketones leading to phloroglucinols, orcinols, and pyrones, which form the basis of a large number of natural products. Thus, we see that, given a poly-P-ketone;. chain ( l l ) , condensation, proceeding through C-alkylation or O-alkylation , leads v i a path (a), a Claisen-type condensation, to acylphloroglucinols (12); v i a path (b) to a-pyrones (13); v i a path (c), an aldol condensation, to compounds of the o r s e l l i n i c acid family (14); and v i a path (d) (with terminal decarboxylation) to Y-pyrones (15). If one of the carbonyl groups not involved i n c y c l i z a t i o n were reduced to a hydroxyl group, ring closure through C-alkylation would be accompanied by dehydration. The products from poly -3-ketone modified i n this way, following paths (a) and (c) above, would lead to compounds of the acylresorcinol type (16) and the 6-methyl s a l i c y l i c acid type (17) respectively, Figure I I . It i s known that these types of condensations occur i n nature; indeed, two or more co-occur i n some instances. For example many pine heartwoods contain, i n association, compounds such as pino-s y l v i n (9) and 5,7-dihydroxyf lavone((6). The basic carbon skeleton of each could be constructed (Figure III) from the same precursor (18)** i f the poly -P-ketone chain started from cinnamic acid (presum-ably as the coenzyme-A ester). The involvement of cinnamic acid i n the F i g u r e I F i g u r e I I (c) / / / / (a)' / • O H (c) \\ o (17) 8. Figure III 9 o biosynthesis of these compounds has been confirmed by tracer - experiments. Tangonin ( 1 9 ) and i t s analogues could be derived i n a s imi lar fashion by a v a r i a t i o n of the flavone condensation CW30-( 1 9 ) which leads to c y c l i z a t i o n to oxygen, since there are i n s u f f i c i e n t carbon atoms to complete an ordinary carbon 6-membered r i n g . The f i r s t s t r i k i n g confirmation of the correctness of the 9 r 1 4 i acetate hypothesis was B i r c h ' s work demonstrating that [ 1 - CJ acet ic ac id was incorporated by P e n i c i l l i u m griseofulyum Dierckx into 6-methyl s a l i c y l i c acid to give the d i s t r i b u t i o n of labe l shown i n ( 2 0 ) . KL C M 3 C O O H COOH l O o I t has since been shown, u s i n g t r a c e r methods, t h a t a number of r a t h e r d i v e r s e s t r u c t u r e s a r i s e by t h i s route i n c l u d i n g g r i s e o f u l v i n ( 2 1 ) ? a l t e r n a r i o l (22), and c i t r o m y c e t i n (23). O O C H 3 Ci (21) HO-\\ — / (22) X HOOC C l CH: (23) r 1 4 i G r i s e o f u l v i n , which i s formed from seven [ 1 - CJ acetate u n i t s was the subject of one of the f i n e s t examples of acetate b i o s y n -t h e t i c i n v e s t i g a t i o n . The method of degradation given i n F i g u r e IV i s a general method f o r i d e n t i f y i n g l a b e l l e d atoms i n phenolic n u c l e i \" ^ . In the diagram, the r a d i o a c t i v i t y of g r i s e o f u l v i n i s assumed to represent the expected t o t a l of seven l a b e l l e d carbon atoms, and on t h i s b a s i s , the corresponding a c t i v i t i e s of the degradation products c l o s e l y f o l l o w the p r e d i c t e d v a l u e s . Rickards r 14 i has r e c e n t l y confirmed t h i s work by using [2 - CJ acetate. 11. Figure IV 7 CH3COOH C H 3 O o 9CI^ =0 (21) C H 3 O C 0 2 v BaC0 3 1.04\" OH\" I OCM, -COOH ^ 0 u cs 4.05' O C H , ' 3 I 2.94° N O , 3BaC03< 3C02-*~ 3Br 3CN0 2 0.01* ( c 2 + c 4 + c 6 ) - O H HNO, 2.93' NO, H O ^ ,L .Ol-• N O , C H 3 NaOBr 2C0, ( c 3 + c 5 ) 2BrC0, 0.97' 12. From the beginning, of work on the acetate hypothesis, i t was necessary to assume that almost any organic ac id found i n Nature (presumably as i t s coenzyme-A ester) might conceivably i n i t i a t e a polyacetate chain by condensing with the methyl end of an acetyl coenzyme-A u n i t . Among such acids are various fat ty ac ids , branched chain acids , cinnamic acid (as mentioned above), 5 n i c o t i n i c ac id , and poss ibly glutamic ac id . The number of acet ic acid units which w i l l condense head-t o - t a i l i n such a chain varies from one to eight or more, but with the exception of propionic ac id , there i s no clear evidence that other acids can be involved i n chain bu i ld ing as d i s t i n c t from , chain i n i t i a t i o n . I t has been shown, however, that the acet ic acid un i t involved i n chain bu i ld ing i s f i r s t converted to malonyl coenzyme-A, by carboxylation of acetyl coenzyme-A.^\"!' The construction of poly-P-ketone chains may then be summarized as shown i n Figure V. Several ract ions are ava i lable whereby the end products are modified from simple poly-p-ketone c y c l i z a t i o n . The reduction of a carbonyl i s a poly-P-ketone intermediate leads to^the removal (24) (25) 1 3 . of the oxygen from the ring on aromatization by dehydration. The li k e l i h o o d that such routes are correct i s increased by the natural occurrence of compounds such as flavoskyrin (24) . This',- or the anthrone 'precursor,;, could very l i k e l y 1 aromatize. to -' chrysophanol (25). Figure V CQ2 CH3COSCoA > CH2C0SCoA b i o t i n etc. C02H H-0. H-0 R - CO f CH - CO ^ CH - CO CsCoA R» CsCoA R» SCoA R» R' B' I l I > R - CO - CH - CO - CH - CO - CH . . . C02H 59- phenolic compounds, pyrones, macrolide a n t i b i o t i c s R = CH3, CH CH2-, NH2COCH2, PhCH = CH; R» = H, CH 3 only. 14. The introduct ion of oxygen into organic molecules i s a well known process, and operates i n phenolic compounds by i n t r o -duction of oxygen at ortho or para posi t ions on the. 'ring. Several oxidative cleavage reactions of rings are also becoming apparent and i t i s known that p e n i c i l l i c ac id (26) comes from o r s e l l i n i c ac id (27) and that patu l in (28) i s derived from 6-methyl s a l i c y l i c ac id (29). Structure analysis shows that and C,_ units are i n t r o -duced by d i r e c t biochemical attachment at carbon i n .'addition to the well known reactions on oxygen, nitrogen, and sulfur;, That the biochemical precursors of these groups are methionine,(or other members of the C-^ pool) and the terpenoid precursors has been proved by tracer experiments. Further work has shown that these carbon groups are most l i k e l y added at the poly-{3-ketone 5 intermediate stage. C o l l i e was the f i r s t to propose the biochemical s i g n i f i -7 12 cance of poly-P-ketone chains. He discovered that dehydro-13 acet ic acid (30) , which he recognized as a condensed poly-j3-ketone (although he did not assign i t the correct s tructure) , formed the n a t u r a l l y occurring compound orc ino l (31') on treatment with weak base. In a s imi lar experiment, he found that heptane 2 ,4 ,6 - tr ione (d iacety l acetone) (32), a well known poly-P-ketone, which he had prepared from dehydroacetic acid (30), condensed with a second molecule of (32) to form a naphthalene der ivat ive (33). This react ion also y ie lded a small quantity of o r c i n o l . (See Figure VI) -O OCH 5 (26) 16. Figure VI Birch and his co-workers re-examined 14 C o l l i e ' s work, and along with Bethe l l and Maitland p o s i t i v e l y i d e n t i f i e d the condensation products. They agreed with C o l l i e ' s structure for the naphthalene compound ( 33), but disagree with his proposed mono-r ing intermediate. C o l l i e held the benzenoid intermediate to be (34). The modern workers pointed out the improbabi l i ty of this structure because i t would involve react ion of a carbonyl group with the anion from -CO-CH^ i n preference to the equally a v a i l -able but more r e a d i l y formed 1anion from -CO-CH^-CO-. They counter with structure (35) which condenses to (33) and present chemical and spectral evidence to prove i t . d i f f e r s from those which f i t into the biogenetic scheme leading to phenols i n that both ends of the chain are \"blocked\" by methyl groups; i . e . , both ends are \"start ing ends\" for a chain. A poly-p-ketone chain of the type useful as a biosynthetic intermediate must have one end free to form a coenzyme-A ester. S t i l l , C o l l i e had obtained a l imi t ed y i e l d of orc ino l (3l) from condensation of heptane 2 ,4 ,6 - tr ione (32). Although heptane 2 ,4 ,6 - tr ione i s a poly--|3-ketone, i t B i r c h ' s attempted biogenetic type synthesis of p inosy lv in (9) 14 i s the only attempt in recent times to synthesize a natural product using a polyketide chain. O H \\ OH (9) 1 8 , By Knoevenagel condensation of benzaldehyde with dehydroacetic ac id (30);, he obtained the benzil idene der ivat ive (36). Acid a l ine hydrolys is of each of these compounds (36, 37, 38) gave react ion mixtures i n which paper chromatography revealed no ind ica t ion of p inosy lv in . B irch then attempted to condense the hydrogenated trione (39) under a lka l ine conditions to obtain dihydropinosylvin (40) i n a closer analogy to C o l l i e ' s conversion of heptane 2 ,4 ,6 - tr ione (32) to orc ino l ( 3 l ) . Both the tr ione (39) and the corresponding pyrone cyc l i zed to dihydropinosylvin (40). A second component, was also i so la ted and i d e n t i f i e d as (4 l ) , produced by the a l t e r -native intramolecular a ldol condensation. A t h i r d component, detected by paper chromatography, was tentat ive ly i d e n t i f i e d as a naphthalene der ivat ive analogous to (42). This work i s summarized i n Figure VII . The highest members of the poly-P-ketone series known at th is time were diformyl acetone (43), heptane 2 ,4 ,6 - tr ione (32), formyl acetone (44), and 3,5-dioxohexanoic ac id (45). hydrolys is followed by decarboxylation y ie lded the pyrone (37) which y ie lded the tr ione (38) by way of i t s barium s a l t . A l k -o o o o o o (43) (32) 0 o o o o ( 4 4 ) (45) Figure V I I 20, 16 B irch and his col leagues , '\" thus, set out to synthesize poly-|3-ketones longer than these. He had already shown that ozonolysis of cyclohexa-1,4-dienes led to (3-diketones. To th is method he added the ozonolysis of 4,7-dihydroindan-2-one der ivat ives . The products produced by these pathways were red o i l s which decomposed soon after i s o l a t i o n . Attempts to prepare c r y s t a l l i n e derivat ives from the pentaketone (46) f a i l e d although the keta l (47) was i s o l a t e d . o o o o o (46) (47) Thus, u n t i l the beginning of our work poly-P-ketone chains containing greater than three carbonyl groups had not been synthe-s ized , and the longest polyketide chain known with a terminal carboxyl group was 3,5-dioxohexanoic a c i d , ^ 2 1 . DISCUSSION The study of the s tructure , synthesis, biosynthesis , and chemical properties of natural products has resul ted i n important and far-reaching contributions to the development of organic chemistry. Natural products are also of immense importance i n the pharmaceutical industry and are extensively used as chemotherapeutic agents. Various biosynthet ic proposals have been made to account for the formation of a wide var ie ty of natural products, and i n many cases, experimental confirmation of these biosynthet ic routes has been obtained. The e f f i c iency and essential s i m p l i c i t y of the biosynthesis of s t r u c t u r a l l y complex natural products has resulted i n attempts to duplicate these processes i n the laboratory. The term \"biogenetic-type synthesis\" has thus been applied to those syntheses which follow c lose ly the presumed or known biosynthetic route, Robinson's celebrated tropinone synthesis may be quoted as the f i r s t successful appl i ca t ion of biosynthetic ideas to the laboratory synthesis of complex natural products. Since that time, and espec ia l ly within the past decade, many syntheses have i been announced which are equally s t r i k i n g and have provided simple synthetic routes to complex natural products. For a more complete account of recent work i n this f i e l d , see the review by Van Tamelen. In this work, we have set out to develop a new biogenet ic-type synthesis of n a t u r a l l y occurring phenolic compounds. I t can be seen from information presented i n the introduct ion that present 22. evidence supports the acetate o r i g i n of many phenolic natural products and strongly indicates the intermediacy of a poly-|3-ketoacid der ivat ive i n the biogenetic pathway. As yet , however, there i s no d i r e c t proof of the existence of such an intermediate. E f f o r t s to synthesize poly-P-ketoacid chains i n v i t r o have so far 18 f a i l e d except for the work of Witter and Stotz who synthesized 3 s5-dioxohexanoic ac id ( t r i a c e t i c acid) (45). This compound and heptane 2 ,4 ,6 - tr ione (32) were the longest polyketide chains known at that time.\"1\"^ 6 An examination of work done over seventy years ago by C o l l i e ' provided a clue to the solut ion of th is problem. When C o l l i e synthesized orc ino l (31) from dehydroacetic acid (30), HO. O H (30) (31) he showed that a n a t u r a l l y occurring phenol could be sythesized from 7 an a-pyrone e During his work, C o l l i e recognized i n dehydroacetic ac id a cyc l i zed polyacetate chain and postulated that his synthesis of orc ino l somewhat resembled the pathway followed i n Nature. He perceived that a polyacetate chain could be cyc l i zed to an a-pyrone, then hydrolyzed, regenerating an act ive polyacetate chain which could subsequently undergo a ldol condensation to y i e l d a natura l ly occurring phenol. 23. An cx-pyrone r ing system such as that i n dehydroacetic acid (30) and i n t r i a c e t i c lactone (48) provides a cyc l i zed form of the two longest s tra ight chain polyketides known, 3,5-dioxohexanoic ac id (45) and heptane 2 ,4 ,6- tr ione (32) mentioned above,, O O O OH ( 4 5 ) (48) O O O C H ^ ^ - ^ C ^ (32) These s tra ight chain compounds are r e l a t i v e l y easy to prepare and are r e l a t i v e l y stable fol lowing i s o l a t i o n . D i f f i c u l t i e s encountered by previous workers, and theore t i ca l considerations forced us to conclude that longer poly-P-ketone chains would be exceedingly d i f f i c u l t to prepare and i s o l a t e . The expansion of an cx-pyrone system offered a possible so lut ion to the d i f f i c u l t i e s involved i n synthesizing and i s o l a t i n g these more complex polyacetate systems. One way i n which this could be achieved was considered! i t was thought that construction of the bispyrone (49) would present us with a potent ia l C R polyketide chain (see Figure V I I I ) . H O O 2> (30) 24. Figure VIII o O H (49) 0 -COOH CHC^O This would require fusion of a second pyrone r ing to t r i a c e t i c lactone (48). The synthesis of polypyrones through fusion of addi t ional a-pyrone rings to an i n i t i a l a-pyrone requires the condensation of the a-pyrone with a sui table species such as a der ivat ive of malonic a c i d . Each malonate unit added to the i n i t i a l r ing rep-resents an a d d i t i o n a l acetate uni t i n the potent ia l polyketide chain so constructed, and i s incorporated as part of a new a-pyrone r i n g . By simple extension, this approach could be used for the synthesis of potent ia l polyketides of varying length. Polypyrones had been already synthesized by at least two 19 methods. Zieg ler and his coworkers formed members of an aromatic based polypyrone series (Figure IX) i n an es sent ia l ly uncontrol led manner, by condensing 4-hydroxycoumarin (50) with carbon suboxide(C-0 9 ) . 25. Figure IX 26. This work provided a route to polypyrones, but involved d i f f i c u l t i e s i n the preparation of carbon suboxide (pyrolys is of d i a c e t y l t a r t a r i c -20 0 anhydride at 600 ), In addi t ion , carbon suboxide bo i l s at 7 and i s therefore a gas at room temperature. These facts coupled with the observation by Zieg ler that the react ion could not be control led eas i ly to y i e l d discrete polypyrones, caused this pathway to poly-pyrones to be regarded with reserved enthusiasm. 21 Yoods et a l . developed, i n contrast to the work of Z ieg ler , a method whereby discrete malonate units could be fused to the cx-pyrone r ing of 4-hydroxycoumarin. They synthesized the aromatic bispyrone (5l) by react ing 4-hydroxycoumarin (-50) with cyanoacetic ac id in t r i f l u o r o a c e t i c ac id (TFA). (50) (51) 27. Both cyanoacetic acid and t r i f l u o r o a c e t i c acid are commercially ava i lable and can be used conveniently i n the laboratory without special equipment. That polypyrone systems can be synthesized with an a l i -phatic group at C-6 on the i n i t i a l a-pyrone r ing was demonstrated 19 by Zieg ler when he synthesized the polypyrone series based on the tetrahydrocoumarin (52) by react ion of cyclohexanone with carbon suboxide. OH (52) As before, he was not able to control the react ion s u f f i c i e n t l y to obtain discrete polypyrones i n his react ion product. However, since t r i a c e t i c lactone (48) had a methyl group (a l iphat i c ) at C-6, Z i e g l e r ' s work provided a stepping stone between the work of Woods 2 et a l . , i n which aromatic substituted polypyrones were synthesized, and the purely polyketide derived polypyrones l i k e bispyrone (49) and higher members of th is ser ies . To complete our proposed biogenetic pathway to phenolic com-pounds, the polypyrones must be hydrolyzed to s tra ight chain i n t e r -mediates (Figure X) which can undergo intramolecular a ldo l conden-22 sat ion . Edwards et a l . hydrolyzed the s t y r y l pyrone t r i -O-methy l -28a Figure X o cr H O o o o CH^\"\" ' \" ' O M h i s p i d i n (52) with N ethanolic potassium hydroxide, and obtained potassium sa l t of the s tyry l poly-p-ketoacid (53). An approach of th i s sort was considered to provide a method for the opening of our polypyrones. C y c l i z a t i o n to form phenolic compounds might then proceed spontan-r eously, since the conditions used to hydrolyze the polypyrone r ing systems are also those which would promote intramolecular a ldol condensation. 2 9 c I t must be p o i n t e d out t h a t , a l t h o u g h p o l y p y r o n e s p r o v i d e a r a t h e r i n g e n i o u s s o l u t i o n to the problem of i s o l a t i o n s t a b l e p o l y -ketideSj, they do not r e t a i n the s t r i c t b i o g e n e t i c c h a r a c t e r of a poly - | 3 - k e t o a c i d c h a i n , T r i a c e t i c l a c t o n e (48) i s formed from t h r e e a c e t a t e u n i t s which c y c l i z e w i t h o u t d e s t r o y i n g the b i o g e n e t i c c h a r -a c t e r of the p o l y a c e t a t e c h a i n . F u r t h e r pyrone r i n g s a re b u i l t up, j u s t as p o l y - P - k e t o a c i d c h a i n s a re b u i l t up, by adding s u c c e s s i v e malonate u n i t s , but i n the case of p o l y p y r o n e s , the second c a r b o x y l group of each malonate group must be r e t a i n e d to form each s u c c e s s i v e pyrone r i n g . 3 CH3COOH OH C H ^ C r ' ^ o (48) 30. In the acetate theory, polyacetate chains are b u i l t up by the condensation of acetyl coenzyme-A with successive units of raal-onyl coenzyme-A, themselves formed by carboxylation of acetyl co-enzyme-A. Each malonyl group loses this added C0 2 uni t after condensation i s complete (see Figure V ) , a fact born out by feeding 3 14 experiments with l abe l l ed carbonate. No C i s retained by the phenolic product so synthesized. Opened polypyrones re ta in the ir terminal carboxyl (corresponding to a l abe l l ed carboxyl above) on condensation to phenolic compounds. In spite of th i s inconsistency with the acetate hypothesis, polypyrones as described herein provide an elegant vehic le for biogenetic-type synthesis of acetogenins. As mentioned previously , the goal i n th is work was to prepare polypyrones of appropriate s ize and to study the ir possible use i n the synthesis of phenolic compounds. Only the f i r s t member of the proposed ser ies , t r i a c e t i c lactone (48), had previously been pre-23 pared., and was considered a convenient s tart ing material for the synthesis of the desired polypyrone structures . T r i a c e t i c lactone was prepared i n the laboratory by the deacetylation of dehydroacetic ac id (30), synthesized from ethylacetoacetate^, or obtained commercially. (30) (48) 31. The react ion of t r i a c e t i c lactone with an equimolar amount 21 of cyanoacetic acid y ie lded only s tar t ing mater ia l . Longer react ion times made no difference to the r e s u l t s . Further work led to the discovery that the react ion of an excess of cyanoacetic acid with t r i a c e t i c lactone resulted i n the formation of a new product, mp. 2 9 9 - 2 3 2 ° , i n i t i a l l y dist inquished from s tar t ing material by TLC„ The u l t r a v i o l e t spectrum (328,269 mjx) of the product provided evidence for a longer chromophoric system than that of t r i a c e t i c lactone (283 m\\i). The NMR spectrin showed a r i n g methyl at 7.44T, and two aromatic hydrogens at 4.02T and 3.30T5, respect ive ly , and was e s sent ia l ly the same as that of t r i a c e t i c lactone (7.53, 3.79, 3 .48T ) . This data, combined with mass spectro™ metric analysis and microanalysis , was consistent with the fused bispyrone structure (49). A pos i t ive f e r r i c chloride test confirmed the presence of an enolizable |3-diketone. (48) (49) Simultaneously, a l ternate routes to bispyrone were examined. 25 Voods et a l . discovered that t r i a c e t i c lactone with equimolar amounts of acetyl ch lor ide , benzoyl ch lor ide , phenylacetyl ch lor ide , and p-nitrobenzoyl ch lor ide , respect ive ly , acylated the pyrone r ing 32. at C-3 i n every case. Based on these observations, - t r i a c e t i c lactone was reacted with ethylchloroformylacetate under s imi lar condit ions. Examination of the react ion product by TLC indicated the presence of a new compound. Mixed TLC with the product from the successful cyanoacetic acid react ion showed that the two products were i d e n t i c a l . (48) (49). This new method, being a one step react ion provided a higher y i e l d of bispyrone (49) than did the two step cyanoacetic acid method. The r e l a t i v e inconvenience involved i n the preparation of ethylchloroformylacetate coupled with the success of Elvidge et a l . i n his heterocycl ic synthesis involv ing malonyl chloride and enolic ketones and diketones, led to invest igat ions with commercially ava i lable malonyl ch lor ide . Although a two-fold excess of malonyl chlor ide was necessary, the product of th i s react ion was again i d e n t i c a l with the bispyrone i so la ted above. This provided an i n t e r -25 esting contrast to the f indings of Woods et a l . : i n the ir work, react ion of t r i a c e t i c lactone with a two-fold excess of the acid 3 3 c chloride resulted i n each case i n the formation of the 3 , 5 - d i a c y l -ated product ( 5 4 ) . For a summary of these and other attempts towards the syn-thesis of bispyrone, see Table I . Having achieved a sat i s factory synthesis of the fused b i s -pyrone ( 4 9 ) we could now proceed with the construction of other sui table pyrone structures . A simple extension of the potent ia l poly- |3-ketone chain could be v i s u a l i z e d as occurring by the conden-sation of bispyrone with acetyl ch lor ide . ( 5 4 ) o o o ( 4 9 ) ( 5 5 ) 34 c Table I ATTEMPTS TO SYNTHESIZE BISPYRONE un i t react ion medium resu l t cyanoacetic ac id cyanoacetic acid ethylcyanoacetate 1:1 2:1 1:1 TFA TPA TPA s tar t ing material bispyrone s tar t ing material e thylchloroformyl- 1.3:1 acetate TPA 25 bispyrone malonyl chloride d ie thy l malonate 2:1 TPA 1:1 EtOH/HCl 25 b i spyrone t r i a c e t i c lactone methyl ether monoethylmalonate 1:1 TFA s tar t ing material e thylchloroformyl-ac etate 1:1 pyridine 27 tar cyanoacetic ac id 28 1:1 ZnCl„/HCl s tar t ing material 35„ Examination of the react ion product from the condensation of equimolar portions of bispyrone and acetyl chloride by TLC revealed a new material (mp, 2 4 5 - 2 5 2 ° ) , showing intense fluorescence under u l t r a v i o l e t l i g h t . This new compound did not react with f e r r i c chlor ide and had an u l t r a v i o l e t spectrum which indicated a chromo-phoric system longer than that i n bispyrone, and with a d i f ferent pattern of i n t e n s i t i e s (347 mu. (€ =.14,300), 261 mu,.(€ = 6400), 225 mu. (€ = .12,800) ; cf. b i spyrone: 328 mu. (6 = 6800), 269 mu. (€ = 1 0 , 4 0 0 ) ) » The NMR spectrum showed, in addit ion to the expected methyl protons at 7.48T, and the r ing proton at 3.45T? (corresp-onding c lose ly to s imi lar protons i n bispyrone), an a d d i t i o n a l methyl group at 7 ,17T . Examination by mass spectrometry showed that the molecular weight was 236. This evidence was consistent with the expected product, acetyl bispyrone (55), and the elemental analysis confirmed th is conclusion. I n i t i a l attempts to synthesize a fused tr ispyrone structure, the next higher member of the fused p y r 3 n e ser ies , using conditions s imi lar to those above were surpr i s ing ly unsuccessful . Thus, bispyrone (49) was reacted with a two-fold excess of malonyl chloride i n t r i f l u o r o a c e t i c ac id y i e l d i n g a product which resembled i n every way the product obtained by the react ion of bispyrone with acety l ch lor ide; that i s , acetyl bispyrone (55). I t was evident that the malonyl chloride was, indeed, condensing with the bispyrone, but was undergoing decarboxylation before c y c l i z a t i o n could take place to y i e l d a t h i r d pyrone r i n g . However the react ion of bispyrone with an e ight - fo ld excess i n t r i f l u o r o a c e t i c acid y ie lded a yellow c r y s t a l l i n e product (mp. 2 5 5 - 2 5 7 ° ) which gave a pos i t ive f e r r i c chloride tes t , TLC showed a new material at Rf = 0 . 3 36. (cf . bispyrone Rf = O . 75 acetylbispyrone Rf = 0.65). The u l t r a -v i o l e t spectrum (373, 282, 255 mjj,) revealed an extended bispyrone-type chromophore at a wavelength reasonable for the lengthening of the pyrone system by an addi t ional fused pyrone r i n g „ The NMR spectrum was s imi lar to that for bispyrone, and exhibited bands at 7.42, 3.96, 3.30T„ Mass spectrometry showed the molecular weight to be 262, which, combined with the microanalyt ica l data, was consistent with the conclusion that th is new compound was tr ispyrone (56). O H (49) O O H (56) P u r i f i c a t i o n of tr ispyrone involved repeated r e c r y s t a l l i z a t i o n and charcoal treatments. Only after column chromatography was used was f i n a l p u r i f i c a t i o n effected and s ingle-spot material obtained (TLC examination). TLC revealed, before p u r i f i c a t i o n of the pro-duct, a series of spots at Rf values lower than that of trispyrone and consistent with those expected for extended polypyrones and acet-ylpolypyrones i f they followed the pattern apparent i n the behav-i o r of bispyrone, acetylbispyrone and tr i spyrone . 37. A number of addi t ional attempts were made to synthesize tr i spyrone , but y ie lded inconclusive r e s u l t s . For a summary of these and the above react ions , see Table I I . Because of TLC evidence for the existence of higher poly-pyrones and acetylpolypyrones i n the react ion product of the tr ispyrone react ion , attempts were made to synthesize higher members of the polypyrone ser ies . Thus, treatment of trispyrone with a s i x - f o l d excess of acetyl chloride i n the manner previously described for the synthesis of acetylbispyrone y ie lded the desired product, acety l tr i spyrone (57). I t may be noted that the d i f f i -cul ty of obtaining acety l tr ispyrone i n th i s way indicates a r e -duced r e a c t i v i t y at the act ive methylene pos i t ion at C-3. This was also confirmed by the d i f f i c u l t i e s encountered during the synthesis of the tetrapyrone (58). (58) Thus, react ion of tr ispyrone with an e ight - fo ld excess of malonyl chloride y ie lded acety l tr i spyrone , A twelve-fold excess of malonyl ch lor ide was required before a compound having properties i n d i c -ative of a t e t r a c y c l i c polypyrone was formed. The new product was extremely d i f f i c u l t to p u r i f y , and ef forts to th i s end reduced the y i e l d considerably. Further work 38 o Table II ATTEMPTS TO SYNTHESIZE TRISPYRONE u n i t r e a c t i o n medium r e s u l t malonyl c h l o r i d e 2:1 TP A' a c e t y l b i s p y r o n e malonyl c h l o r i d e 2:1 r e f l u x i n g TPA a c e t y l b i s p y r o n e malonyl c h l o r i d e 8:1 e t h y l c h l o r o f o r m y l - 7:1 acetate TPA 25 TPA t r i spyrone s t a r t i n g m a t e r i a l e t h y l c h l o r o f o r m y l - 7:1 acetate TFA (120°) a c e t y l b i spyrone, s t a r t i n g m a t e r i a l , and a t r a c e of t r i s p y r o n e e t h y l c h l o r o f o r m y l - 5:1 p y r i d i n e acetate 27 s t a r t i n g m a t e r i a l e t h y l c h l o r o f o r m y l - 2:1 DMP/pyridine acetate s t a r t i n g m a t e r i a l 39. i s i n progress to obtain a sa t i s fac tory y i e l d of the desired t e t r a -pyrone (58). Having achieved the synthesis of some of the desired pyrone s tructures , we were now i n a pos i t ion to invest igate the ir usefulness i n the production of phenolic compounds. I t can readi ly be seen that the pyrone structures so far constructed are i n fact disguised polyacetate chains of varying length. (See page 40.) Basic hydrolysis of the fused pyrone systems was therefore carr i ed out with the hope that r ing opening would occur, followed by intramolecular a ldol condensation of the po ly -P -ketoac id chain so produced. Bispyrone was hydrolyzed with N methanolic potassium hydroxide and y ie lded three compounds. Compound A prec ip i ta ted from solut ion at pH 6. It gave a negative sodium bicarbonate test , a pos i t ive f e r r i c chloride test , and melted at 1 1 2 ° . This new material was, therefore, not an a c i d , but possessed an enolized (3-dicarbonyl system. The u l t r a v i o l e t spectrum (315, 260 sh, 247 sh, 232 m[x) dis t inguished compound A from the expected o r s e l -l i n i c ac id (27) (300, 260 mu) and indicated i t s s i m i l a r i t y to the phenolic t r i e s t e r 3,5-dihydroxy-2,4 - dicarboxyphenylacetic ac id / \\ 29 tr imethylester (59) which has u l t r a v i o l e t spectrum 314, 260 sh, 30 2 5 0 , 228 mu.. The NMR spectrum of compound A showed a r ing methyl group at 7.53T, two carbomethoxy groups at 5.91T and 5.85T, and only one aromatic proton. The t r i e s t e r (59) had an i d e n t i c a l NMB spectrum with the exception that a t h i r d carbomethoxy group was present. Examination by mass spectrometry showing that the molecular (58) 41 0 H O . C O O H OH (27) C O O C M 5 HQ-C H 3 O O C •COOCH3 O H (59) weight was 240, coupled with microanalysis confirmed that compound A was d imethyl -2 ,4 -orc inol dicarboxylate (60), The i s o l a t i o n of the diester (60) from the hydrolys is react ion of bispyrone indicated that both pyrone rings were attacked by methoxide ion 0 (See page 42,) Extract ion of the mother l iquors from compound A with chloroform yie lded compound B (mp. 1 3 8 - 1 4 0 ° ) whose spectral char-a c t e r i s t i c s and chromatographic behavior indicated that i t was methyl o r s e l l i n a t e (61). Comparison of these properties with those 31 of an authentic sample of methyl or se l l ina te confirmed th i s conclusion. ' Here again, the bispyrone was i n i t i a l l y attacked by meth-oxide, but only i n one r i n g . The other carboxyl group (non-terminal) was l o s t through decarboxylation. The mother l iquors were adjusted to pH2 and re-extracted with chloroform, y i e l d i n g compound C (mp, 1 5 7 - 1 6 7 ° ) which gave both a pos i t ive sodium bicarbonate test and a pos i t ive f e r r i c chloride test . 42. This compound therefore contained a free ac id and an enolized P -d icarbonyl system,, Its u l t r a v i o l e t spectrum was an o r s e l l i n i c ac id spectrum and the NMR spectrum showed a r ing methyl at 7 c 43T,an ether methyl at 6 0 I 6 T , and two aromatic protons at 3 „ 6 4T 0 Mass spectrometric analysis showed the molecular weight to be 182, TLC dist inguished compound C from methyl o r s e l l i n a t e ( 6 1 ) , o r s e l l i n i c : ac id (27) and dimethyl-2,4~orcinol dicarboxylate (60) o Prom the above evidence i t was concluded that compound C was p-0-methyl o r s e l l i n i c ac id (everninic acid) ( 6 2 ) „ The formation of an o r s e l l i n i c acid methyl ether from the hydrolys i s of bispyrone indicated attack on the polyketide chain by methoxide fol lowing hydrolys is and preceding r ing c losure. For a summary of the hydrolysis of bispyrone i n methanolic potassium hydroxide see Figure XI , 32 The work of Caldin and Long provides a very interes ing and quite simple explanation of the predominance of methoxide i n the methanolic hydrolys is media as evidenced by the production of methyl esters and methyl ethers. Caldin and Long showed that , i n solutions made by d i s so lv ing sodium hydroxide i n ethanol, much of the hydroxide ion i s replaced by ethoxide, the equi l ibrium 0H~ + EtOH 0Et~ + H 20 l y i n g well to the r i g h t . Even with 2 ° / o water i n the ethanol, 9 4 ° / o of the basic species were ethoxide. I t i s not s u r p r i s i n g , then, that methyl esters and methyl ethers were produced from the hydrolys is of bispyrone i n both methanolic and 10 percent aqueous methanolic potassium hydroxide. 43o Figure XI Compound C 44. The most a t t rac t ive goal i n the hydrolys is of bispyrone was the synthesis of o r s e l l i n i c acid i t s e l f . O r s e l l i n i c ac id (27) i s a common mould metabolite, produced for instance by P e n i c i l l i u m 33 madrit i and was the most obvious product expected from the react ion of bispyrone with d i l u t e base. In an attempt to increase the concentration of hydroxide ions, the react ion medium was changed from N methanolic potassium hydroxide to N 1 0 ° / o aqueous methanolic potassium hydroxide. Hydrolysis of bispyrone i n th i s new basic medium y ie lded two compounds. (See Figure XII . ) (61) (62) Figure XII 45. The f i r s t prec ip i ta ted from solut ion at pH 2 and was shown by U . V . , I . R . , N . M . R . , mass spectrometry, mixed melting point and mixed TLC to be i d e n t i c a l with compound C i so la ted above; that i s , p~0-methyl o r s e l l i n i c acid (62). Extract ion of the mother l iquors with chloroform yie lded the second product which was shown by U.V. , I . R . , N . M . R . , mixed melting point and mixed T„C to be i d e n t i c a l with compound B i so la ted above; that i s , methyl or se l l ina te (6 l ) . C l e a r l y , i f o r s e l l i n i c acid were to be produced, the concentration of hydroxide ion must be d r a s t i c a l l y increased. The react ion medium was therefore changed to totally aqueous N potassium hydroxide. Bispyrone (49) 9 hydrolyzed i n th is new medium, y ie lded no product through p r e c i p i t a t i o n at pH 2. Extract ion of the pH 2 so lut ion with chloroform yie lded only a trace amount of brown tar , which nevertheless contained a very minor amount of material r e -sembling o r s e l l i n i c acid (27) on TLC. Freeze drying of . the aqueous so lut ion , however, y ie lded a new product (mp. 1 8 0 - 1 8 8 ° ) (see Figure XII l ) which gave a pos i t ive sodium bicarbonate test and a pos i t ive f e r r i c chloride tes t . The new compound therefore contained a free carboxyl group and was presumably phenol ic , The u l t r a v i o l e t spectrum was i d e n t i c a l to that of o r s e l l i n i c acid (300, 260 mu.). The NMR spectrum revealed only a r ing methyl at 7 . 4 7 T and two aromatic prtotons at 3.73T. Mixed melting point and mixed TLC 4 6 c 3 4 with authentic o r s e l l i n i c acid confirmed our c o n c l u s i o n Accompanying the o r s e l l i n i c ac id i n th i s product was a small quantity of orc ino l ( 3 l ) which was detected and characterized by TLC., C O O H T II (27) ( 3 1 ) KOAc Figure XIII 4 7 c Also i so la ted as a resu l t of the freeze drying process was a quantity of potassium acetate. This material could only resu l t by the hydrolys is of the opened polyketide chain, reducing i t to i t s parent acetate u n i t s . It was not determined whether any s imi lar hydrolys is occurred i n the cases where methanolic and lO^/o aqueous methanolic media were used, since freeze drying of the aqueous so lut ion was not used i n the i s o l a t i o n of the products from these react ions . The hydrolys is of bispyrone ( 4 9 ) , i t can be seen, y i e l d s a polyketide chain which can undergo a ldo l condensation to y i e l d several o r s e l l i n i c ac id der ivat ives . By using a react ion medium which i s e s sent ia l ly one hundred percent methoxide i n methanol, i t i s possible for the mid-chain carboxyl group to be retained i n the f i n a l phenol. Methyl esters and methyl ethers are produced i n a hydrolys is medium r i c h i n methoxide. In methoxide-free hydro lys i s , only o r s e l l i n i c acid i s produced and w i l l decarboxylate to some extent to y i e l d orc ino l ( 3 l ) . We have thus performed a series of reactions i n v i t r o 0 c lose ly re lated to those postulated by the acetate theory and have established a new biogenetic type synthesis for o r s e l l i n i c acid and re lated compounds. The next fused pyrone compound to be hydrolyzed was a c e t y l -bispyrone ( 5 5 ) . Reaction of acetylbispyrone with N methanolic potassium hydroxide y ie lded only one product, (mp. 1 5 7 . 5 - 1 5 8 ° ) which gave a pos i t ive f e r r i c chloride tes t , but a negative sodium hydroxide test . This new compound c l e a r l y contained no free acid group, but contained an enolized 6 -d icarbony l system. The u l t r a -v i o l e t spectra were v i r t u a l l y i d e n t i c a l with those of orcaceto-48 \\ phenone , i . e . ^ m a x (ethanol) 315 sh, 283, 233 sh mu.; X (base) 335, 262 mu; X (acid.) 315 sh, 284, 234 sh mu; max ~ ma.v ' • ' ~ 7 max A (n-hexane) 324, 276 mu. The NMR spectrum showed a r ing methyl at 7 .48T , an acetyl methyl at 7 „ 4 0 T , and two aromatic protons at 3.73T. Mixed melting point and mixed TLC with authentic material confirmed tha t ih i s compound was orcacetophenone (63). Since acetylbispyrone contains a potent ia l polyketide chain with no terminal carboxyl group, condensation can resu l t i n only one product (see Figure XIV). o o (55) KOH/MeOH -CO, (a) or (b) (63) Figure XIV 49, Bispyrone (49), on hydrolys is and subsequent a ldol conden-sat ion, cyc l i zed i n a spec i f i c way; that i s , the compounds were o r s e l l i n i c acid der ivat ives . Trispyrone (56), on the other hand, contains a polyketide chain which i s one malonate uni t longer than the chain i n bispyrone. Hydrolysis and subsequent intramolecular condensation may y i e l d , therefore, three compounds or der ivat ives thereof (Figure XV\"); that i s , C-acetyl o r s e l l i n i c acid (64), curvu l in i c acid (65), or 2-malonylorcinol (66) or re lated compounds. Under suitable condit ions, these three compounds could each become b i c y c l i c structures by enol-lactone formation involv ing the side chains on the orc ino l r i n g . Thus, C-acetyl o r s e l l i n i c acid would form 3-methyl-6,8-dihydroxyisocoumarin (67), curvul in ic acid would form the compound (68), and 2-malonylorcinol could form 4,7-3 6 dihydroxy-5-methyl-coumarin (69). Of these six compounds,(64) , ( 6 5 ) 3 7 , ( 6 7 ) 3 6 , and (69)2* , are known compounds and were avai lable for comparison purposes. Since o r s e l l i n i c acids had been i so la ted from bispyrone hydro lys i s , i t was reasonable to expect a s imi lar type of condensation to occur with tr i spyrone. Trispyrone (56) was hydrolyzed i n N methanolic potassium hydroxide, and y ie lded a number of compounds as evidenced by pre l im-inary examination by TLC. A major component appeared at Rf 0.5, and was conveniently separated from the other react ion products by preparative TLC. This compound (mp. 2 5 0 - 2 5 3 ° ) gave a negative sodium bicarbonate test , and a pos i t ive f e r r i c chloride test; the compound contained no free carboxyl groups, but was phenolic i n nature. The u l t r a v i o l e t spectrum revealed a chromophoric system (327, 288, 277, 257, 244, 237 mu) very s imi lar to that cf 3-methyl-50, Figure XV 5 1 c 6 , 8 - d i h y d r o x y i s o c o u m a r i n ( 6 9 ) ( 3 1 7 , 2 7 6 , 2 6 0 , 2 4 4 , 2 3 7 mu) i s o l a t e d 3 6 b y H a s s a l l a n d c o w o r k e r s . The NMR s p e c t r u m r e v e a l e d a r i n g m e t h y l a t 7 . 7 7 8 T , a n d t h r e e a r o m a t i c p r o t o n s a t 3 C 6 2 T . E x a m i n a t i o n b y m a s s s p e c t r o m e t r y , s h o w e d t h a t t h e new c o m p o u n d h a d m o l e c u l a r w e i g h t 1 9 2 . P y r o l y s i s o f a s m a l l s a m p l e o f a u t h e n t i c C - a c e t y l o r s e l l i n i c 3 8 a c i d y i e l d e d a c o m p o u n d w i t h a n u l t r a v i o l e t s p e c t r u m a l m o s t i d e n t i c a l t o t h a t o f t h e new c o m p o u n d a b o v e . T h i s new c o m p o u n d i s t h e r e f o r e 3 - m e t h y l - 6 , 8 - d i h y d r o x y i s o c o u m a r i n ( 6 9 ) . F r e e z e d r y i n g o f t h e a q u e o u s s o l u t i o n y i e l d e d , as a m a j o r p r o d u c t , a c e t y l b i s p y r o n e ( 5 5 ) w h i c h was c h a r a c t e r i z e d b y m i x e d T L C . O O H o o ( 5 6 ) ( 5 5 ) A s e c o n d m e t h a n o l i c p o t a s s i u m h y d r o x i d e h y d r o l y s i s o f t r i s -p y r o n e ( 5 6 ) y i e l d e d a s t h e m a j o r p r o d u c t a c o m p o u n d d i s t i n c t f r o m t h e i s o c o u m a r i n ( 6 9 ) . I t was i s o l a t e d b y p r e p a r a t i v e T L C ( m p . 1 5 0 -1 5 2 ° ) a n d h a d a n u l t r a v i o l e t s p e c t r u m ( 3 1 6 , 2 4 8 , 2 3 1 mu) s i m i l a r t o t h a t o f t h e d i e s t e r ( 6 0 ) . The NMR i n d i c a t e d two m e t h o x y l g r o u p s a t 6 o 0 6 T a n d 6.02T,, M a s s s p e c t r o m e t r y s h o w e d t h e m o l e c u l a r w e i g h t t o be 220. I n s p i t e o f t h i s i n f o r m a t i o n , t h e s t r u c t u r e o f t h i s c o m p o u n d i s n o t k n o w n . V o r k i s c o n t i n u i n g i n o u r l a b o r a t o r i e s t o s o l v e t h i s s t r u c t u r e . 52. A q u e o u s p o t a s s i u m h y d r o x i d e h y d r o l y s i s o f t r i s p y r o n e y i e l d e d a c o m p l e x m i x t u r e a s s h o w n b y T L C . H o w e y e r , .a, m a j o r . ' c o m p o n e n t ; a p p e a r e d . E x a m i n a t i o n o f i t s u l t r a v i o l e t , i n f r a r e d , a n d NMR s p e c t r a c o u p l e d w i t h m i x e d TLC s h o w e d t h i s c o m p o u n d t o b e o r c a c e t o p h e n o n e ( 6 3 ) . O u r w o r k h a s d e m o n s t r a t e d t h a t p o l y p y r o n e s a n d a c e t y l p o l y -p y r o n e s p r o v i d e a n e l e g a n t v e h i c l e f o r t h e b i o g e n e t i c t y p e s y n t h e s i s 39 o f p h e n o l s . I t w o u l d s e e m u n l i k e l y t h a t l o n g c h a i n p o l y - P - k e t o a c i d s w i l l e v e r b e r e a d i l y a c c e s s i b l e a s s u c h , b u t o u r a p p r o a c h h a s e n a b l e d u s t o s y n t h e s i z e t h e s e c o m p o u n d s d i s g u i s e d a s \" p o l y p y r o n e s . I n t h i s w a y , t h e mode o f c y c l i z a t i o n o f p o l y - ( 3 - k e t o a c i d s c a n b e s t u d i e d . P r e s u m a b l y i n N a t u r e , t h e p o l y - p - k e t o a c i d c h a i n i s 4 0 s t a b i l i z e d b y t h e e n z y m e s u r f a c e s o t h a t , i n e f f e c t , we h a v e u t i l i z e d a s i m i l a r i d e a t o h a n d l e t h e s e i n t e r m e d i a t e s i n o u r s t u d y o f b i o g e n e t i c - t y p e s y n t h e s i s . V o r k i s c o n t i n u i n g i n o u r l a b o r a t o r i e s i n o r d e r t o e x t e n d o u r k n o w l e d g e o f t h e a p p l i c a t i o n o f t h e s e f u s e d p y r o n e s t r u c t u r e s i n b i o g e n e t i c s t u d i e s . 53. EXPERIMENTAL A l l melting points were determined using a Reicaert hot stage melting point apparatus, and are uncorrected. The microanalyses were performed by Dr. A l f red Berhnardt and his associates, Mikroanalytisches Laboratorium im Max- Planck-I n s t i t u t fur Kohlenforschung, 433 Mulheim (Ruhr), Vest Germany, and by Mrs. C. Jenkins, Chemistry Department, Univers i ty of B r i t i s h Columbia. The u l t r a v i o l e t spectra were recorded on a Unicam SP 800 recording spectrophotometer during the early part of the invest -i ga t ion , and on a Cary 11 or Cary 14 recording spectrophotometer during the l a t t e r port ion of the work. Infra-red spectra were recorded on a Perkin Elmer 137 spectrophotometer and on a Perkin Elmer 21 spectrophotometer. In describing the v , s = sharp, m = medium, b = broad, sh = shoulder. The muclear magnetic resonance spectra were measured at 60 megacycles on a Varian A60 instrument. Tetramethyl s i lane was used as the in terna l standard i n a l l cases. The mass spectrometric analyses were performed by Mr. Prank Bloss using an MS9 and an At las high reso lut ion mass spectometer. A l l pH measurements were made with universal indicator paper. 54. Dehydroacetic acid (30): Dehydroacetic acid from two sources was used. (a) I n i t i a l l y , (30) was synthesized from ethylacetoacetate by the 24 established method of Horning as., given i n ^Organic ' Syntheses\": Freshly d i s t i l l e d ethyl acetoacetate ( lOOg. , 0.77 moles) and sodium bicarbonate (0.05g, catalyst) were combined and heated c a r e f u l l y u n t i l the react ion mixture had reached 2 0 0 - 2 1 0 ° (5.25 hours) . During the react ion , approximately 43 ml. of d i s t i l l a t e , p r i n c i p a l l y ethanol, was co l lec ted and the react ion mixture became dark brown. D i s t i l l a t i o n i n vacuo of the react ion mixture y ie lded dehydroacetic acid at 1 4 0 ° (18mm.) after a forerun of ethylaceto-acetate. Y i e l d 14g., 2 2 ° / o ; mp. 1 0 9 ° . Spectral Propert ies : X (ethanol) 309 mix ( € = 11,200), 224 mu. (€ = 9770). v (chloroform) 1745, 1735, 1650, 1620, 1560 cm\" 1 . NMR ( t r i f l u o r o a c e t i c aci d) 7.60T(3H), 7 .16T(3H), 3 .70 T (1H) . Reaction with f e r r i c chloride i n ethanol y ie lded an orange complex. (b) Dehydroacetic ac id supplied by Eastman Organic Chemicals, mp. 108\"- 110u ', was equivalent i n every way to the product (30) above. A l l further work used dehydroacetic acid from th i s source. T r i a c e t i c lactone (48): Dehydroacetic ac id (30) ( lOOg. , 0.59 moles) was dissolved i n 90 per cent s u l f u r i c ac id (165 m l . ) . S l ight warming on the steam bath y ie lded a yellow so lut ion . The solut ion was heated i n an o i l bath ( 1 5 0 ° ) and s t i r r e d under nitrogen u n t i l the temperature of the 55. so lut ion had reached 1 3 0 ° . The temperature was maintained at 130 -1 3 6 ° for f ive minutes at which point the solut ion was deep red. The so lut ion was removed from the bath, cooled rap id ly by swir l ing i n an ice bath, and poured into ice-water (700 ml.) Within f ive minuted, c r y s t a l l i z a t i o n was essent ia l ly complete. The white s o l i d was co l lec ted i n a Buchner funnel, washed with cold water (500 m l . ) , and allowed to stand overnight. The moist prec ip i ta t e was dissolved i n ethyl acetate (500ml.) by vigorous b o i l i n g for ten minutes. After cooling i n an ice bath for two hours, the white c r y s t a l l i n e product was co l l ec ted . Y i e l d : 48 .6g. , 6 5 ° / o ; mp. 1 8 9 ° . Spectral Propert ies : X (ethanol) 283 mu. (€ = 6750). m£tx V (Nujol) 1700, 1645, 1575 cm\" 1 . NMR ( t r i f l u o r o a c e t i c acid) 7 .53T (3H ) , 3 .79T(1H), 3 .48 T (1H ) . Reported v a l u e s 4 1 : X (ethanol) 284 mu. ('€ = 7800). v 1719, 1661, 1620, 1594 cm\" 1 . NMR (deutero-chloroform + minimum of methanol) 7.76, 4.61, 4.10T. No react ion occurred with f e r r i c chloride i n ethanol. R e c r y s t a l l i z a t i o n of t r i a c e t i c lactone from ethylacetate removes unreacted dehydroacetic ac id because of i t s greater s o l u b i l i t y i n ethyl acetate. Bispyrone (49): Three experimental pathways to bispyrone from t r i a c e t i c lactone proved workable. (a) T r i a c e t i c lactone (48) ( l0 .06g . , 8.0 mmoles) and cyanoacetic 21 ac id ( l2 .11g . , 14.0 mmoles) were dissolved i n t r i f l u o r o a c e t i c acid 56., (30 ml.) and refluxed under nitrogen for s ix hours. Water (10 ml.) was added and the orange react ion so lut ion heated to ref lux for f ive minutes, and allowed to cool . No crysta l s were evident, but treatment with ethylacetate (40 ml.) and subsequent cooling at 0 ° for two hours y ie lded a quantity of c r y s t a l l i n e mater ia l . Y i e l d of red-orange powder: 2.81g. , l 8 ° / o ; mp. 200 - 2 2 0 ° , E e c r y s t a l l i z a t i o n from chloroform y ie lded a reddish material (mp. 227 - 2 3 1 ° ) . A l t e r n a t i v e l y , sublimation i n vacuo at 150° and o i l pump vacuum y ie lded a s o l i d which on c r y s t a l l i z a t i o n - ^ rom chloroform y ie lded white crys ta l s (mp. 225 - 2 3 2 ° ) . 2 5 (b) Ethylchloroformylacetate (prepared from d ie thy l malonate by 42 43 p a r t i a l hydrolys is , and subsequent reaction with oxaly l ch lor ide , 44 \\ / \\ or , a l t e r n a t i v e l y , with phosphorus pentachloride ) (1.02g. , 6.7 mmoles) was added over a 30 minute period to a so lut ion of t r i a c e t i c lactone (48) (646 mg., 5.12 mmoles) i n t r i f l u o r o a c e t i c ac id ( l ml.) held at 1 1 2 ° i n an o i l bath for three hours. Hydrogen chloride was evolved. The react ion mixture was heated to ref lux to destroy excess acid ch lor ide , and allowed to cool to room temperature. C r y s t a l l i z a t i o n occurred y i e l d i n g , after drying i n vacuo, 206 mg., 2 1 ° / o; mp. 228 - 2 3 0 ° . Comparison by TLC with the product from the react ion i n (a) with cyanoacetic ac id , showed the product from the two sources to be i d e n t i c a l . (c) T r i a c e t i c lactone (48) ( l „ 3 8 g . , 11.0 mmoles) and malonyl chloride^\"*\" (Aldr ich Chemical Company; also, from malonic ac id by react ion with th ionyl chlor ide ) were combined with t r i f l u o r o a c e t i c ac id (4 ml.) and s t i r r e d at room temperature for ten minutes, then placed in an o i l bath ( 8 0 ° ) . Hydrogen chloride was evolved. After 90 minutes, a p r e c i p i t a t e formed. After 4.5 hours, the temperature was raisad 5t. to 1 3 0 ° over f ive minutes, and, when hydrogen chloride evolution had ceased, the react ion mixture was cooled to room temperature, the product separated by f i l t r a t i o n , and dried i n vacuo. Y i e l d : 1 . 2 7 g « , 6 0 ° / o ; mp. 223 - 2 3 2 ° . Further p u r i f i c a t i o n of bispyrone was accomplished by 1.) r e c r y s t a l l i z a t i o n , sublimation, and recrys -t a l l i z a t i o n ; or 2.) chromatography ( s i l i c a gel/chloroform) and r e c r y s t a l l i z a t i o n . The second method proved to be the most convenient on a preparative scale, and was espec ia l ly e f f i c i e n t i n the removal of dark colored polymeric impur i t i e s . An a n a l y t i c a l sample was prepared by sublimation ( 1 4 0 ° , o i l pump vacuum), followed by three r e c r y s t a l l i z a t i o n s , from chloroform-ethyl acetate. Ana lys i s : Found: C, 55.90; H , 3.19; 0, 41.28. C g H ^ requires C, 55.68; H , 3.12; 0, 41.21. Spectral Propert ies : A (ethanol) 328 mu (€ = 6800), 269 mu (€ = 10,400). No sh i f t was observed on addit ion of d i lu te sodium hydroxide; however, the in tens i ty of the peak at 328 mu was decreased and of that at 269 mu enhanced. v (chloroform) rn&x 1770 sh, 1747 s, 1705 vs, 1645 m, 1640 sh, 1570 s cm\" 1 . NMR ( t r i f l u o r o a c e t i c aci d) 7 .44T (3H) , 4 .02T (1H ) , 3 .30T (1H) . Mass spectrometric analysis showed the parent peak at 194 mass units (cf . 194.15 for C 9 H 6 0 5 ) . Reaction with f e r r i c chloride i n ethanol y ie lded a red complex. For preparation purposes, the fol lowing react ion sequence was used: T r i a c e t i c lactone (20.Og., O.I5( moles) was dissolved i n t r i f l u o r o a c e t i c acie (70 ml.) and malonyl chloride (45g., 0.32 moles) 58. was added. The react ion solut ion was refluxed on the steam bath for three hours with a drying tube i n place. The dark solut ion was removed from the bath, and, after the addit ion of ethylacetate (30 m l . ) , c r y s t a l l i z a t i o n commenced and was completed by cooling under the cold tap. The crude product was f i l t e r e d off and A v a s h e d with a small addi t ional volume of ethyl acetate. ( Y i e l d : 20g. , 6 5 ° / o . ) This material was dissolved i n chloroform and f i l t e r e d through a column of s i l i c a gel (75g.) y i e l d i n g the white c r y s t a l l i n e product, mp. 228 - 2 3 1 ° . Acetyl Bispyrone (55): Acetylbispyrone was the p r i n c i p a l product i n at l east two attempts to synthesize trispyrone (56). On a preparative scale , however, the fol lowing react ion was used: Bispyrone ( l . 9 g . , 0.01 moles) was dissolved i n t r i f l u o r o -acet ic ac id (4.0 m l . ) , acety lchlor ide (2.2 m l . , 0.03 moles) added, and the mixture heated on a steam bath. Hydrogen chloride was evolved and after two hours, the react ion mixture was poured into ice-water (20 m l . ) . The prec ip i ta ted s o l i d was f i l t e r e d off and washed with water. Y i e l d : \"2.8g.; mp. 245 - 2 5 2 ° . R e c r y s t a l l i z a t i o n from chloroform y ie lded l i g h t brown crys ta l s ( l . 2 g . , 5 2 ° / o ) , , mp. 245 - 252 . TLC showed no s tar t ing mater ia l . The product was dissolved i n chloroform and f i l t e r e d through a column of s i l i c a gel (60g.) . E l u t i o n with chloroform (2 1.) and concentration of the co lor less eluate gave co lor less needles (675 m g „ ) , mp. 245 - 2 4 7 ° . 59. Analys i s : Found: C, 55.76; H, 3.50; 0, 40.74. C 1 : L H 8 0 6 requires C, 55.95; H, 3.41; 0, 40.64. Spectral Propert ies : X (ethanol) 3.47 mu (€ = 14,300), 261 mu (€ - 6,400), 225 mu (€ = 12,800). v m Q Y (Naijol) 1765 sh, 1730 s, 1650 m, 1550 s cm\" 1 . v (KBr) 1765 m, 1730 s, 1638 s, 1550 b cm\" 1 . . NMR ( t r i f l u o r o a c e t i c ac id ) : 7,48T(3H), 7 . 1 T ( 3 H ) , 3.45f ( lH) . Mass spectrometric analysis showed the parent peak at 236 mass units (cf . 236.18 for C^HgOg). No react ion occurred with f e r r i c chloride i n ethanol. Trispyrone (56): Attempts were made to synthesize tr ispyrone from bispyrone (49) by condensation with malonyl chloride and ethylchloroformyl-acetate under a var ie ty of condit ions. The most successful method, the one used for preparative purposes, was carr ied out i n the fol lowing way: Bi spyrone (49) (5 .0g . , 0.02 moles) was dissolved i n t r i f l u o r o -acet ic acid (15 ml.) and malonyl chloride ( 2 9 . l g . , 0.206 moles) was added. The react ion solut ion was ref luxed on a steam bath for 1.5 hours with a drying tube i n place . Hydrogen chloride was evolved. After heating for 30 minutes, the so lut ion turneditor a dark brown tar which p a r t i a l l y s o l i d i f i e d on further re f lux ing . The mixture was allowed to coo l , and ether (30 ml.) was added, converting the t a r to a brown powder which was i so la ted by f i l t r a t i o n and washed with an addi t iona l volume of ether. Y i e l d : 13 . l g . (par t ly polymeric mater ia l ) . 6 0 . The s o l i d m a t e r i a l was e x t r a c t e d wi th hot e t h y l a c e t a t e (2 1.) and the s o l u t i o n thus ob ta ined was evaporated to d ryness . The r e s u l t i n g s o l i d was r e c r y s t a l l i z e d from acetone. Y i e l d : 3,2g, , 4 7 ° / o , Th i s crude m a t e r i a l was taken up i n hot e t h y l a c e t a t e , t r e a t e d w i th a c t i v a t e d c h a r c o a l , f i l t e r e d , and c r y s t a l l i z e d . Th i s p rocess was repea ted y i e l d i n g a y e l l o w powder. Y i e l d : l , 0 5 g , . 16°/o o v e r a l l } mp, 262 - 268°d, A n a l y s i s . Pound: C, 5495, 54,44; H, 2,59, 2,71; 0, 42,46. 42,85. c i 2 H 6 ° 7 r e < l u i r e s c » 54,9.7$. H, 2.31$ 0, 42,72, S p e c t r a l P r o p e r t i e s : >-mav ( e thano l ) 373 mu ( 6 a 10,100), 282 mu,(€ = 8,750), 255 mu. ( 6 = 6,700) sh, . v „. (Nujo l ) 1775 s, 1730 s, 1640 m, 1540 s c m \" 1 . v m n v (KBr) 1750 b, 1710 s, 1640 sh, ill A A 1622 m, 1565 sh, 1535 s c m \" 1 . NMR ( t r i f l u o r o a c e t i c a c i d ) : 7.42T (3H), 3 , 9 6T ( 1 H ) , 3 , 3 0T ( 1 H ) , Mass spec t romet r i c a n a l y s i s showed the pa rent peak a t 262 mass u n i t s ( c f , 262,17 f o r C]_2^6^7^* Reac t i on w i th f e r r i c c h l o r i d e i n e thano l gave an orange complex. Seve ra l o ther attempts were made to s yn thes i ze t r i s p y r o n e : (a) B i spyrone (49) (0 ,79g , , 4,07 mmoles) was d i s s o l v e d i n t r i f l u o r o -a c e t i c a c i d (1.5 ml. ) and malony l c h l o r i d e ( l . 2 3 g . , 8.73 mmoles) was added. The r e a c t i o n s o l u t i o n was r e f l u x e d on a steam bath wi th a d r y i n g tube i n p l a c e . Hydrogen c h l o r i d e was evo l ved , and, a f t e r four hour s , e t h y l a c e t a t e (6 ml . ) added to the dark red-brown s o l u t i o n . S o l i d p r e c i p i t a t e d from the s o l u t i o n on c o o l i n g . Y i e l d : 0 ,83g , , 8 6 ° / o , R e c r y s t a l l i z a t i o n from ch lo ro fo rm y i e l d e d a l i g h t red c r y s t a l l i n e powder, rap, 255 - 257, 61. Examination of the product by TLC showed no s tar t ing mater ia l , but showed that the product behaved d i f f e r e n t l y , both i n Rf value and i n fluorescence under u l t r a v i o l e t l i g h t , from the expected tr i spyrone , U .V. and NMR spectra showed the compound to be acety l bispyrone (55). TLC (10 per cent acetic ac id - chloroform/ s i l i c a gel) confirmed th i s conclusion. (b) Reaction (a) was repeated with bispyrone (49) ( l . 5 5 g . , 800 mmoles) and malonyl chloride (2.30g. , 16.30 mmoles) i n t r i f l u o r o a c e t i c acid (4 ml,'), The react ion was run at ref lux for 2 hours and the product which prec ip i ta ted without the addit ion of ethylacetate, was co l l e c t ed . Y i e l d : 1.68g., 8 9 ° / o , mp. 255 - 2 5 7 ° . A l l properties of th is product showed i t to be i d e n t i c a l with that from (a) and with acetyl bispyrone. (c) Bispyrone (49) (0,92g. , 4.84 mmoles) was dissolved i n t r i f l u o r o -acet ic acid (4ml.) and ethylchlorof ormyl acetate )5..16g., 31.2 mmoles) was added and s t i r r e d overnight i n an o i l bath at 60° with a drying tube i n p lace , then at room temperature for a further day. Hydrogen chloride was evolved. The react ion so lut ion , i n i t i a l l y a pale yel low, became dark orange. On cooling to room temperature, a white s o l i d prec ip i ta ted which proved to be p r i n c i p a l l y s tart ing mater ia l . (d) Reaction (c) was repeated with the modif ication that the react ion so lut ion was held at 120° for three hours, then allowed to stand overnight at room temperature. The s o l i d which prec ip i ta ted at room temperature was i so la ted by f i l t r a t i o n , mp. 2 2 7 - 2 3 1 ° , 2 4 5 ° . TLC examination of this product (10 per cent acetic acid-chloroform/ s i l i c a gel) revealed a ser ies of spots corresponding to bispyrone and acetylbispyrone. A very minor spot corresponding, to trispyrone was also present. : 62. (e) Bispyrone (49) ( l . O g . , 5.50 mmoles) was added to pyridine (15 m l . ) , i n which i t only p a r t i a l l y dissolved, g iv ing i n i t i a l l y a l i g h t green s lurry which subsequently became purple-grey after s t i r r i n g for three hours at room temperature. Ethyl chloroformyl acetate ( 4 g „ , 26.6 mmoles) was added, the react ion mixture cooled i n an ice-water bath for 15 minutes, then s t i r r e d at room temp-erature overnight. The react ion mixture was poured into ice-water (100 ml.) and adjusted to pH 2 with 6N hydrochloric ac id . This a c i d i f i e d so lut ion was extracted with ether (4 x 50 ml . ) . Evaporation of the ether i n vacuo y ie lded a red-orange powder which proved to be p r i n c i p a l l y bispyrone (UV, TLC, and f e r r i c chloride t e s t ) . (f) Bispyrone (49) (2 .1g . , 0.018 moles) was dissolved i n a hot mixture of dimethyl formamide (30 ml.) and pyridine (20 m l . ) . The so lut ion was kept i n an o i l bath at 9 0 ° . A solut ion of e thy l -chlorof ormylacetate ( 4 „ 8 g . , 0.031 moles) i n dimethyl formamide (10ml.) was added dropwise to the s t i r r e d , hot react ion mixture. Nitrogen was passed through the apparatus and a drying tube was used. The react ion mixture was s t i r r e d at 9 0 ° for 2.5 hours, after which time the brown solut ion was poured into ice-water and a c i d i f i e d with concentrated hydrochloric ac id . Extract ion of the aqueous so lut ion with choroform and evaporation of the solvent y ie lded a small amount of a dimethylformamide solut ion from which crys ta l s separated. The crys ta l s were co l lec ted on a f i l t e r and washed with methanol. Examination of the product by TLC showed that i t was i d e n t i c a l to s tar t ing mater ia l . ' ' 63. Acety l tr i spyrone (57): Trispyrone (56) (517 mg. 2 mmoles was dissolved i n t r i f l u o r o -acet ic ac id (3 ml.) and acetyl chloride (1.9 m l . , 12 mmoles) was added. The mixture was heated on a steam bath for 24 hours. Hydrogen chloride was evolved. The react ion mixture was poured into ice-water (25 ml.) p r e c i p i t a t i n g a yellow s o l i d which was f i l t e r e d off and washed several times with cold water. The crude material was dissolved i n hot ethylacetate (600 m l . ) , treated with act ivated charcoal , and f i l t e r e d through a c e l i t e f i l t e r . The pale yellow f i l t r a t e was concentrated i n vacuo u n t i l c r y s t a l l i z a t i o n occurred at which point the s o l i d was f i l t e r e d off and washed twice with cold ethyl acetate. Y i e l d : 410 mg., 6 8 ° / o ; mp. 2 8 5 - 3 0 0 ° . Analys i s : Pound: G, 55.02; H, 2.50; 0, 42.48. C 1 4 H 8 C 8 requires C, 55.27; H, 2.65; 0, 42.08. Spectral Propert ies : X (ethanol) 430 mu (€ =2,000) shoulder, 390 mu (€ = 12,000) shoulder, 373 mu (€ = 16, 000), 269 mu (€ = 9000). v m (Nujol) 1750 b, 1640 s, 1600 s, 1540 b cm\" 1. NMR ( t r i f l u o r o a c e t i c acid) 7.45T (3H)', 7 . 1 8 T ( 3 H ) , 3 .40T (1H) C No react ion occurred with f e r r i c chloride i n ethanol. Acetyl trispyrone was also obtained when the molar ra t io of tr ispyrone to acetyl chloride was 1:1 and 1:2; however, some s tar t ing material remained i n each case, as was shown by TLC and UV (1:1, A (ethanol) 375,.278 mu; 1:2, X (ethanol) 377, 275 mu). Only a small amount of tr ispyrone remained when the 1:4 ra t io was used. 64, Acetyl tr ispyrone was the major product furing. i n i t i a l attempts to synthesize tetrapyrone (58), Tetrapyrone (58,) ' Two attempts were made to synthesize tetrapyrone from t r i spyrone: (a) Trispyrone (56) (0 ,7g , , 2,67 mmoles) was dissolved i n t r i f l u o r o -acet ic ac id (5 ml,)' and malonyl chloride (3 ,0g , , 21,3 mmoles) was added. The mixture was heated on the steam bath for three hours. Hydrogen chloride, was evolved. The s lurry was treated with ether and the re su l t ing s o l i d f i l t e r e d off and washed several times with ether. Y i e l d : 850 mg, , (part ly polymeric mater ia l ) . The product was dissolved i n hot ethyl acetate (500 ml.) and the brown solut ion treated with act ivated charcoal . After f i l t r a t i o n and concentration of the yellow f i l t r a t e u n t i l c r y s t a l -l i z a t i o n occurred the s o l i d was f i l t e r e d off and washed with ethyl acetate and ether. Y i e l d : 270mg., 3 . 3 3 ° / o , A l l properties indicated that th is product was i d e n t i c a l with acety l tr i spryone , (b) Trispyrone (56) (0 .4g . , 1,53 mmoles) was dissolved i n t r i f l u o r o -acet ic ac id (2 ml.) and malonyl chloride (3 .0g. , 21.3 mmoles) was added. The mixture was heated on the steam bath for 90 minutes y i e l d i n g a thick black tar . On treatment with e i ther , a brown so l id was obtained which was f i l t e r e d off and washed with ether. Y i e l d : l . O g , (part ly polymeric mater ia l ) . The s o l i d s o l i d was dissolved i n hot ethylacetate (300ml,) y i e l d i n g a dark brown solution which was treated with act ivated charcoal and f i l t e r e d through c e l i t e . The yellow f i l t r a t e was concentrated in vacuo u n t i l c r y s t a l l i z a t i o n commenced, and the s o l i d 65 . i s o l a t e d by f i l t r a t i o n . O n l y a few m i l l i g r a m s o f m a t e r i a l r e s u l t e d . TLC (50 p e r c e n t a c e t i c a c i d - c h l o r o f o r m / s i l i c a g e l ) r e v e a l e d a s p o t a t R f = 0,3 ( c f , a c e t y l t r i s p y r o n e , R f = 0 , 3 5 ) , G e n e r a t i o n o f P o l y a c e t a t e C h a i n s and S u b s e q u e n t A l d o l C o n d e n s a t i o n 1. O p e n i n g o f B i s p y r o n e ( 4 9 ) : ( a ) B i s p y r o n e ( 3 . 0 g . , 0.0155 m o l e s ) was a l m o s t c o m p l e t e l y d i s s o l v e d i n N m e t h a n o l i c p o t a s s i u m h y d r o x i d e (1200 m l . 1.20 m o l e s ) and 2 ? s t i r r e d a t room t e m p e r a t u r e u n d e r n i t r o g e n f o r 35 h o u r s A t t h i s t i m e , a s m a l l amount o f s o l i d r e m a i n e d i n t h e b o t t o m o f t h e r e a c t i o n f l a s k . The r e a c t i o n s o l u t i o n i n i t i a l l y was y e l l o w , b u t became o r a n g e , and f i n a l l y brown a f t e r 35 h o u r s . The r e a c t i o n m i x t u r e was r e d u c e d i n v o l u m e t o 250 m l . i n v a c u o , w a t e r and i c e a dded ( t o 500 m l . ) , and t h e pH a d j u s t e d c a r e f u l l y t o 6 ( i n d i c a t o r p a p e r ) a t 0° ( i c e - w a t e r b a t h w i t h 6N h y d r o c h l o r i c a c i d . A q u a n t i t y o f f e a t h e r y w h i t e c r y s t a l s p r e c i p i t a t e d w h i c h were f i l t e r e d f r e e . Y i e l d 200 mg., 5.4°/o. R e c r y s t a l l i z a t i o n f r o m a c e t o n e - p e t r o l e u m e t h e r y e i l d e d w h i t e n e e d l e s , mp. 112-113°. T h i s compound was shown t o be d i m e t h y l - 2 , 4 - o r c i n o l d i c a r b o x y l a t e (compound A) (60)„ A n a l y s i s : F o u n d : C, 55.27; H, 5.24; 0, 39.49. Ci2°ll°6 r e q u i r e s C, 55.00; H, 5.05; 0, 39.95. S p e c t r a l P r o p e r t i e s : ^ m a x ( e t h a n o l ) 315 mu (€ = 5 5 8 0 ) , 260 mu (€ = 12,400) s h o u l d e r , 247 mu (€ = 5 5 8 0 ) , 232 mu (€. = 3 3 , 3 0 0 ) ; X ( b a s e ) 289 mu, V ( N u j o l ) 1650 b, 1620 s, 1570 s cm\" 1. NMR ( t r i f l u o r o a c e t i c a c i d ) : 7 . 5 3 T ( 3 H ) , 5 . 9 1 T ( 3 H ) , 5 , 8 5 T ( 3 H ) , 3 . 4 8 T ( 1 H ) . Mass s p e c t r o m e t r i c a n a l y s i s showed t h e p a r e n t peak a t 240 mass u n i t s , ( c f . 240. 21 f o r C, oH,,0..) LZ 11 D 6.6. Reaction with f e r r i c chloride i n ethanol y ie lded a dark red complex. No react ion with sodium bicarbonate was observed. The mother l iquors from compound A were extracted with chloroform (900 m l . ) . The very pale yellow solut ion was evaporated to dryness i n vacuo y i e l d i n g a c r y s t a l l i n e s o l i d . Washing with a l i t t l e benzene removed the yellow o i l y contamination leaving a white c r y s t a l l i n e s o l i d , compound B. Y i e l d : 0 .5g . , 1 8 ° / o ; mpt, 1 0 0 - 1 2 8 ° . R e c r y s t a l l i z a t i o n from benzene y ie lded white prisms mp. 138 - 140 . Sublimati on under high vacuum yie lded white prisms, mp. 138-139. 5 ° . This compound was shown to be methyl o r s e l l i n a t e (6 l ) . Spectral Propert ies : X (ethanol) 301 mu, (€ = 9,600), 265 mu (€ = 25,600); X (base) 305 mu (€ = 12,700), 240 mu m six (€ = 8050). v (KBr) 1645 b, 1617 s, 1585 s cm\" 1 . NMR (deutero-max acetone): 7 .54 T (3H ) , 6 .11T (3H) , 3 .73T (2H ) , 1 .03T(1H) , - 1 . 5 8 T ( 1H). Mass spectrometric analysis showed the parent peak at 182 (cf . 182. for C 9 H 1 0 0 4 ) . Reaction with f e r r i c chloride i n ethanol y ie lded a brown-green complex. No react ion with sodium bicarbonate was observed. TLC (50 per cent acetic a c i d - c h l o r o f o r m / s i l i c a gel) showed compound B to be i d e n t i c a l with authentic methyl o r s e l l i n a t e . A l l other propert ies agreed with th i s conclusion. This aqueous layer from the chloroform extract ion y i e l d i n g compound B was care fu l ly taken to pH 2 with d i lu te hydrochloric acid and the red solut ion extracted with chloroform (900 m l . ) . The deep yellow so lut ion was taken to dryness i n vacuo y i e l d i n g a 67, yellow t inted crude c r y s t a l l i n e s o l i d . Washing with benzene and r e c r y s t a l l i z a t i o n from benzene y ie lded a pale yellow t inted s o l i d , compound C, mp. 1 4 0 - 1 6 3 ° with effervescence, R e c r y s t a l l i z a t i o n from benzene y ie lded crysta l s melting at 1 5 7 - 1 6 7 ° with effervescence, TLC showed th i s to be one compound. Sublimation at high vacuum y ie lded white prisms, mp, 166° needles form; 1 9 0 - 1 9 0 . 5 ° melting with effervescence. This compound was shown to be the para-methyl ether of o r s e l -l i n i c ac id , p-0-methyl o r s e l l i n i c ac id (62). Spectral Propert ies : X (ethanol) 302 mu (€ = 2,620), max 260 mu (€ = 7,410); X f f l a x (base) 300 mp, (€ = 7,170) shoulder, 270 mu. (€ = 8,650) shoulder, 249 mu (€ = 11,820). v (KB ) 1640 b, nicix 1L 1585 m cm\" 1 . NMR (deuteroacetone) 7.43T (3H), 6.16x (3H), 3.64T (2H). Mass spectrometric analysis showed the parent peak at 182 mass units (cf . 182.17 for C 9 H 1 0 0 4 ) . Reaction with f e r r i c chloride i n ethanol y ie lded a brown-green complex. Reaction with sodium bicarbonate produced effervescence. TLC dist inguished (62) from authentic methyl o r s e l l i n a t e , 34 / \\ authentic o r s e l l i n i c acid , and (60). (b) Bispyrone (49) ( l . 4 7 g . , 0.00758 moles) was dissolved i n N 10 per cent aqueous methanolic potassium hydroxide (150 m l . , 0,150 moles) and s t i r r e d at room temperature under nitrogen for two days. The react ion so lut ion , colored as i n the 100 per cent methanolic case, was concentrated to 40 ml. i n vacuo. Ice and water 68. •were added to bring the volume to 100 ml. and the pH was carefully adjusted at 0° to 2 with 6N hydrochloric acid. At pH 3, the solution became turbid and at pH 2 a quantity of s o l i d precipitated. Y i e l d : 65 mg, 4.7°/o; mpt. 150-167° with effervescence. Recrystal-l i z a t i o n from acetone-petroleum ether yielded white crystals mpt. 152-160° with effervescence. This compound was shown to be i d e n t i c a l i n every way with compound B (62) from the previous : reaction. The mother liquors from the above s o l i d were extracted with chloroform (200 ml.) and the solution taken to dryness i_n vacuo. A quantity of c r y s t a l l i n e material remained which, on washing with a l i t t l e chloroform, yielded white crystals, mp. 100-135°. R e c r y s t a l l i z a t i o n from chloroform-benzene yielded white prisms. Y i e l d : 251 mg,,.18,2°/o; mp. 110-135°. Sublimation under high vacuum yielded white prisms, mp. 126-135°. This compound was shown to be i d e n t i c a l i n every way with authentic methyl o r s e l l i n a t e ( 6 l ) . Mixed melting point and mixed TLC confirmed this conclusion. (c) Bispyrone (49) (2.2g., 0.011 moles) was dissolved i n N aqueous potassium hydroxide (150 ml., 0.150 moles) and s t i r r e d at room temperature under nitrogen for 70 minutes. The reaction solution was adjusted to pH 2 at 0° with concentrated hydrochloric acid. The usual chloroform extraction yielded only 53 mg. of mat-e r i a l , and was shown by TLC (50 per, cent acetic acid-chloroform/ . s i l i c a gel) to contain a mixture of compounds. Consequently, i t was decided to reduce the aqueous solution to dryness by freeze drying. A quantity of yellow s o l i d remained and was extracted with hot acetone (150 ml,). The white s o l i d residue, separated by f i l t r a t i o n , on examination proved to be potassium acetate. 69. F u r t h e r c o n c e n t r a t i o n o f t h e a c e t o n e s o l u t i o n p r e c i p i t a t e d t h e r e m a i n d e r o f t h e p o t a s s i u m a c e t a t e , w h i l e t h e m o t h e r l i q u o r on e v a p o r a t i o n y i e l d e d a r e d gum. T r e a t m e n t o f t h e gum w i t h a c e t o n e and w a t e r y i e l d e d a mass o f c r y s t a l s . Y i e l d : 123 mg., 6°/o; mp. 174-177° w i t h e f f e r v e s c e n c e and d e c o m p o s i t i o n . R e c r y s t a l l i z a t i o n f r o m w a t e r - a c e t o n e y i e l d e d n e e d l e s m e l t i n g a t 180—188 w i t h e f f e r v e s c e n c e and d e c o m p o s i t i o n . T h i s compound was shown t o be o r s e l l i n i c a c i d (27)„ S p e c t r a l P r o p e r t i e s : A ( e t h a n o l ) 300 mu, (€ = 2 7 4 0 ) , 260 mu (€ = 7 2 9 0 ) ; A (b a s e ) 298 mu (€ = 4 4 2 0 ) , 274 mu (€ = 6 0 6 0 ) . v ( K B r ) 1643 b. NMR ( d e u t e r o a c e t o n e ) 7 . 4 7 T ( 3 H ) , 3 . 7 3 T ( 2 H ) . R e a c t i o n w i t h f e r r i c c h l o r i d e i n e t h a n o l y i e l d e d a b r o w n -g r e e n c o m p l e x . R e a c t i o n w i t h s o d i u m b i c a r b o n a t e p r o c e e d w i t h e f f e r v e s c e n c e . E x a m i n a t i o n by TLC and m i x e d m e l t i n g p o i n t showed t h e compound t o be i d e n t i c a l w i t h a u t h e n t i c o r s e l l i n i c a c i d ( p r e -p a r e d f r o m d i c a r b c m e t h o x y o r s e l l i n i c a c i d b y t h e method o f H o e s c h ) . 2. O p e n i n g o f A c e t y l b i s p y r o n e ( 5 5 ) : A c e t y l b i s p y r o n e ( l . 4 2 g . , 0.006 m o l e s ) was d i s s o l v e d i n N m e t h a n o l i c p o t a s s i u m h y d r o x i d e (300 m l . , 0.30 m o l e s ) , and s t i r r e d a t room t e m p e r a t u r e u n d e r n i t r o g e n f o r two d a y s . The r e a c t i o n s o l -u t i o n was c l e a r o r a n g e and became l i g h t brown a t t h e end o f t h e r e a c t i o n . The s o l u t i o n was c o n c e n t r a t e d i n v a c u o w i t h h e a t i n g ( i n i t i a l l y a t 60° and f i n a l l y on a steam b a t h ) and t h e pH o f t h e m i x t u r e r e v e r s e d w i t h c o n c e n t r a t e d h y d r o c h l o r i c a c i d , d u r i n g w h i c h , e f f e r v e s c e n c e o c c u r r e d . The pH was a d j u s t e d t o 7 w i t h 6N s o d i u m h y d r o x i d e , and t h e r e a c t i o n m i x t u r e e x t r a c t e d w i t h c h l o r o f o r m 7 0 . ( 1 5 0 m l . ) . T h i s s o l u t i o n w a s e v a p o r a t e d t o d r y n e s s i n v a c u o a n d c r y s t a l s f o r m e d f r o m t h e o i l y r e s i d u e . W a s h i n g w i t h a l i t t l e c h l o r o f o r m a n d r e c r y s t a l l i z a t i o n f r o m c h l o r o f o r m y i e l d e d w h i t e n e e d l e s . Y i e l d : 65 m g . , 5 . 4 ° / o : m p . 1 5 2 - 1 5 3 ° . F u r t h e r r e c r y s -t a l l i z a t i o n f r o m c h l o r o f o r m y i e l d e d w h i t e n e e d l e s , mp . 1 5 7 . 5 - 1 5 8 ° . 4 7 4 8 T h i s c o m p o u n d w a s s h o w n t o b e o r c a c e t o p h e n o n e ( 6 3 ) . ' S p e c t r a l P r o p e r t i e s : A. ( e t h a n o l ) 3 1 5 mu ( € = 3 4 4 0 ) m E L X s h o u l d e r , 2 8 3 mu ( € = 7 5 6 0 ) , 2 3 3 mu ( € = 5 9 6 0 ) s h o u l d e r ; X ( b a s e ) 3 3 5 mu ( € = 6 0 2 0 ) , 2 6 2 mu ( € = 2 0 , 1 0 0 ) ; X ( a c i d ) 3 1 5 mu m a x ( € = 3 4 4 0 ) s h o u l d e r , 2 8 4 mu ( € = 7 5 6 0 ) , 2 3 4 mu ( € = 5 9 6 0 ) s h o u l d e r ; X ( n - h e x a n e ) 3 2 4 mu ( € = 8 8 9 ) , 2 7 6 mu ( € = 3 2 6 ) . v ( K B r ) 1 6 1 0 b , 1 5 6 5 b c m \" 1 . NMR ( d e u t e r o a c e t o n e ) 7 . 48T ( 3 H ) , 7.40T ( 3 H ) , . 3.73T ( 2 H ) , -0.13T ( I H ) , -3.99T ( l H ) . 35 R e p o r t e d v a l u e s : • X ( e t h a n o l ) 2 8 3 mu (.6 = 1 0 , 0 0 0 ) ; X ( b a s e ) 3 3 0 mu ( € = 1 1 , 7 0 0 ) ; X _ ( a c i d ) 2 8 3 ( € • = 1 0 , 0 0 0 ) ; X ( n - h e x a n e ) 3 2 1 ( € = 4 1 7 0 ) , 2 7 5 mu (6 = 1 0 , 2 0 0 ) . XX cLX R e a c t i o n w i t h f e r r i c c h l o r i d e y i e l d e d a d a r k r e d c o m p l e x . T L C , m i x e d m e l t i n g p o i n t , a n d t h e s p e c t r a l d a t a s h o w e d t h i s c o m p o u n d t o . 47 b e i d e n t i c a l w i t h a u t h e n t i c o r c a c e t o p h e n o n e ( 6 3 ) . 3 . O p e n i n g o f T r i s p y r o n e ( 5 6 ) : S e v e r a l s e t s o f r e a c t i o n c o n d i t i o n s w e r e e x a m i n e d i n t h e a t t e m p t t o o p e n t r i s p y r o n e a n d o b t a i n a w o r k a b l e p r o d u c t . T h e m e t h o d w h i c h g a v e t h e b e s t r e s u l t s i s o u t l i n e d b e l o w . 71. Trispyrone (56) ( l . 0 9 g . , 0,0042 moles) was dissolved i n N methanolic potassium hydroxide (1000 m l . , 1.00 mole) and s t i r r e d at room temperature under nitrogen for 2 days. The so lut ion , which was i n i t i a l l y a b r i l l i a n t green, quickly darkened and became orange, then pale yellow, a period of an hour. The so lut ion was concentrated i n vacuo leaving a l i g h t brown syrup. Ice and water were added and the solut ion adjusted to pH 2 with concentrated hydrochloric ac id ( f i n a l volume 800 m l . ) . This aqueous solut ion was extracted with chloroform (450 ml.) and the chloroform evaporated to dryness i n vacuo y i e l d i n g a yellow residue. Y i e l d : 291 mg. The to ta l residue was separated on a preparative thin layer plate (8 X 20 i n , ) ( s i l i c a gel with organic phosphor; 10 per cent acid - chloroform). The plate was divided into seven main bands which were scraped off and eluted. The central f rac t ion (Rf = 4.5-6.0) y ie lded 34.7 mg. of c r y s t a l l i n e mater ia l . Further separation of th is f rac t ion on a preparative th in layer plate ( 2 X 8 i n . ) y ie lded one major and two minor f r a c t i o n s . The major f r a c t i o n y ie lded a compound which was p u r i f i e d by r e c r y s t a l l i z a t i o n from water-acetone y i e l d i n g needles. Y i e l d : 17 mg., 2 . 3 ° / o ; mp. 2 4 7 - 2 5 1 . 5 ° . After drying in vacuo, the melting point was ra i sed to 2 5 0 - 2 5 3 ° with sublimation. This compound was shown to be 3-methyl-6,9-dihydroxyisocoumarin (67). Spectral Propert ies . A (ethanol) 237 mu (€ = 4,900), in ctx 288 mu ( 6 = 4000), 277 mu (€ = 5640), 257 mu ( 6 = 9000), 244 mu (€ = 39,000), 237 mu (€ = 34,000); X (base) 345 mu (€ = 11,500) shoulder, 332 mu (€ = 14,300) shoulder, 307 mu (€ = 19,900), 26o mu (6 = 27,200) shoulder, 254 mu (€ = 43,700), 243 mu (6 = 41,600). 72. v (KBr) 1685 b, 1627 s cm\" 1 . NMR (deuteroacetone): 7.78T (3H). 3.62T.(3H), 0.47T (IH), -1.17T ( lH) . Mass spectrometric analysis, showed the parent peak at 192 mass units (cf . 192.2 for C^QHgO^). Reported values: A (ethanol) 317 mu, (€ = 6,300), 276 mu IBEX (€ = 29,500) 260 mu (30,900), 244 mu (€ = 56,200), 237 mu (€ = 44,600). Reaction with f e r r i c chloride i n ethanol gave a brown complex. Testing with sodium bicarbonate so lut ion gave no effervescence. Freeze drying of the aqueous layer from above y ie lded a yellow s o l i d which, on extract ion with hot chloroform y ie lded a small quantity of gum. Examination by TLC showed the major product to be acetyl bispyrone, a conclusion confirmed by i s o l a t i o n of the corresponding band from a preparative TLC plate (8 * 20 i n . ) and examination by UT, IR, NMR and mixed TLC. A repeat of the above react ion gave a d i f f erent major product although (67) was present as a minor product. This new product with Rf = 0.7, was not i d e n t i f i e d although i t was examined thoroughly; mp. 1 5 0 - 1 5 2 ° . Spectral Propert ies : ^ m a x (ethanol) 316, 265 sh, 248, 230 mu; A (base) 348, 272, 249 mu. V (KBr) 1712 m, 1670 s, 1650 sh, 1610 b, 1570 m.cnT 1 . NMR (deuterochloroforrn) : 7.28T, 6.11T, 5.97T, 3.64T probably 3:6:4:1 but not c l ear . Mass spectrometric analysis showed the parent peak at 220 mass un i t s . Reaction with f e r r i c chloride i n ethanol y ie lded a pink complex. A sodium bicarbonate test y ie lded inconclusive r e s u l t s . Reaction with 2 ,4-dini trophenyl hydrogen gave a yellow s o l i d . 73. Other attempts to open trispyrone met with varying degrees of success: (a) This method was i d e n t i c a l to the one above with the exception that separation of the products was attempted using a s i l i c a gel column (lOg.). Only very crude separation resulted and the frac-tions were combined for chromatrography on a preparative thin layer plate. (b) Trispyrone (56) (300 mg,, 1.15 mmoles) was dissolved i n N aqueous ethanolic potassium hydroxide (100 ml., 100 mmoles) and s t i r r e d at room temperature under nitrogen for 2 days. The solution went from green through orange to yellow as before. The solution was concentrated iri vacuo and adjusted to pH 7 with dilute hydrochloric acid and this solution was extracted with chloroform. The chloroform layer was extracted with sodium bicarbonate solution which was, i n turn, extracted with ether. TLC examination of this product showed a major spot corresponding to (67), but there was too l i t t l e material for further work. (c) A large scale reaction with trispyrone (56) (2.47g., 0.0094 moles) i n N ethanolic potassium hydroxide (1000 ml., 1.0 mole) f a i l e d to produce encouraging r e s u l t s . This was largely due to, the sparing s o l u b i l i t y of trispyrone i n this reaction medium. (d) Trispyrone (56) (l06mg., 0.405 mmoles) was dissolved i n N aqueous potassium hydroxide (60 ml., 60 mmoles) and allowed to stand under nitrogen at room temperature for 75 minutes. The solution was adjusted to pH 2 at 0° with concentrated hydrochloric acid, and extracted with chloroform (200 ml.). This solution was reduced to dryness i n vacuo. Examination of the residue by TLC showed that the major component of the reaction mixture was orcacetophenone (63). 74. Table III SPECTRAL TABLES Compound Dehydroacetic acid (30) Tria c e t i c lactone (48) Bispyrone (49) Acetylbispyrone (55) Trispyrone (56) UV mu. ., IR' m\" -1 NMH : T 309 (11,200) 1745 7.60 (3H) 224 (9,770) 1735 7.16 (3H) 1650 3.70 (IH) 1620 1560 283 (6,750) 1700 7.53 (3H) 1645 3.79 (IH) 1575 3.48 (IH) 328 (6,800) 1770 sh 7.44 (3H) 269 (10,400) 1745 s 4.02 (IH) 1705 vs 3.30 (IH) 1645 sh 1570 s 347 (14,300) 1765 m 261 (6,400) 1730 s 7.48 (3H) 225 (12,800) 1630 s 7.17 (3H) 1550 3.45 (IH) 373 (10,000) 1750 b 7.42 (3H) 282 (8,750) 1710 s 3.96 (IH) 205 (6,700) 1640 sh 3.30 (IH) C o m p o u n d U V mu I R m \" 1 NMR T 1 6 2 2 m 1 5 6 5 s h 1 5 3 5 s A c e t y l 4 3 0 ( 2 , 0 0 0 ) s h 1 7 5 0 b 7 . 4 5 (3H) t r i s p y r o n e ( 5 7 ) 3 9 0 ( 1 2 , 0 0 0 ) s h 1 6 4 0 s 7 . 1 8 ( 3 H ) 3 7 3 ( 1 6 , 0 0 0 ) 1 6 0 0 s 3 . 4 0 ( I H ) 2 6 9 ( 9 , 0 0 0 ) 1 5 4 0 b D i m e t h y l - 2 , 4 - 3 1 5 ( 5 , 5 8 0 ) 1 6 5 0 b 7 . 5 3 ( 3 H ) o r c i n o l d i c a r -b o x y l a t e ( 6 0 ) 2 6 0 ( 1 2 , 4 0 0 ) s h 1 6 2 0 s 5 . 9 1 ( 3 H ) 2 4 7 ( 1 6 , 2 0 0 ) s h . 1 5 7 0 s 5 . 8 5 ( 3 H ) 2 3 2 ( 3 3 , 3 0 0 ) 3 . 4 0 ( I H ) ( b a s e ) 2 8 9 M e t h y l o r s e l - 3 0 1 ( 9 , 6 0 0 ) 1 6 4 5 b 7 . 5 4 ( 3 H ) l i n a t e ( 6 l ) 2 6 5 ( 2 5 , 6 0 0 ) 1 6 1 7 s 6 . 1 1 (3H) ( b a s e ) 3 0 5 ( 1 2 , 7 0 0 ) 1 5 8 5 s 3 . 7 3 ( 2 H ) 2 4 0 ( 8 , 0 5 0 ) 1 . 0 3 ( I H ) - 1 . 5 8 ( I H ) O r s e l l i n i c a c i d 3 0 2 ( 2 , 6 2 0 ) 1 6 4 0 b 7 . 4 3 ( 3 H ) m e t h y l e t h e r ( 6 2 ) 2 6 0 ( 7 , 4 1 0 ) 1 6 2 0 b 6 . 1 6 ( 3 H ) ( b a s e ) 3 0 0 ( 7 , 1 7 0 ) s h 1 5 8 5 m 3 . 6 4 ( 2 H ) 2 7 0 ( 8 , 6 5 0 ) s h 2 4 9 ( 1 1 , 8 2 0 ) 76, O r s e l l i n i c acid (27) Orcaceto-phenone (63) Compound UV 300 (2,740 260 (7,290 (base)298 (4,420 274 (6,060 315 (3,440 283 (7,560 233 (5,960 (b ase )335 (6,020 262 (20,100 (acid)315 (3,440 284 (7,560 234 (5,960 (n-hexane)324 (889 276 (326 3~Methyl-6,8-dihydroxyiso-coumarin (67) 327 (4,900 288 (4,000 277 (5,640 257 (9,000 244 (39,000 237 (34,000 (base)345 (11,500 332 (14,300 307 (19,900 260 (27,200 254 (43,700 243 (41,600 sh sh sh sh sh sh sh IR 1643 b 1610 b 1565 b 1685 b 1627 s NMR 7.47 (3H) 3.73 (2H) 7.48 (3H) 7.40 (3H) 3.73 (2H) -0.12 (IH) -3.99 (IH) 7.78 (3H) 3.62 (3H) 0.47 (IH) -1.17 (IH) 77. 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"@en ; edm:hasType "Thesis/Dissertation"@en ; edm:isShownAt "10.14288/1.0062132"@en ; dcterms:language "eng"@en ; ns0:degreeDiscipline "Chemistry"@en ; edm:provider "Vancouver : University of British Columbia Library"@en ; dcterms:publisher "University of British Columbia"@en ; dcterms:rights "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en ; ns0:scholarLevel "Graduate"@en ; dcterms:title "An aspect of pyrone chemistry"@en ; dcterms:type "Text"@en ; ns0:identifierURI "http://hdl.handle.net/2429/37513"@en .