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I. Reactions of omega-linked disaccharides. II. Synthesis of the 2,4-di-O-methyl

University of British Columbia

I. Reactions of ∝-Linked Disaccharides Through reaction of specifically substituted maltoses, ∝-glucosidic disaccharide derivatives have been prepared. Catalytic oxidation of benzyl β-maltoside yielded maltobiouronic acid. Tritylation of 1,6-anhydro-β-maltose made possible the preparation of the 6'-0-tosyl ester. Replacement of the tosylate with azide ion followed by reduction and hydrolysis yielded a small amount of 6'-amino-6' deoxy-maltose. Replacement of the tosylate with thiolacetate allowed the preparation of 6'-deoxy-6’-mercapto-maltose. Iodide replacement of the sulphonyl ester followed by reduction gave the 6’-deoxy-1, 6-anhydro derivative which was converted to 6’-deoxy-maltose by acetolysis and deacetylation. A route for the preparation of 4-0-(∝-D-glucopy-ranosyluronic acid)-D-xylose by selective decarboxylation of maltosyldiuronic acid was attempted and found unfeasible. Attempts to prepare 6-substituted maltoses by reaction of benzyl 4',6'-0-benzylidene-β-maltoside with various reagents were unsuccessful. II. Synthesis of the 2,4-Di-0-methyl Tetroses The four isomeric 2,4-di-0-methyl tetroses were prepared by periodate oxidation of known methylated sugars. 2,4-Di-0-methyl-D-and L-erythroses were prepared from 4,6-di-0-methyl-D-glucose and 3,5-di-0-methyl-L-arabinose respectively. 2,4-Di-0-methyl-D-and L-threoses were prepared from 3,5-di-0-methyl-D-xylose and 1,4,6-tri-0-methyl-L-sorbose. The tetroses were characterized as their crystalline 2,4-dinitrophenylhydrazones. The Rf and RG values of the free sugars were recorded in a variety of solvents including a silica gel thin-layer chromatography system.

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2011-11-09

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http://hdl.handle.net/2429/38896

Chemistry

University of British Columbia

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