| The synthesis of L-glucose from D-glucose was achieved. D-Glucose was converted to 1,2:5,6-di-O-isopropylidene-(alpha)-D-glucofuranose which in turn was oxidized to give 1,2:5,6-di-O-isopropylidene-(alpha)-D-ribo-hexofuranos-3-ulose. This compound was converted to 3-O-acetyl-1,2:5,6-di-O-isopropyl-idene-(alpha)-D-erythro-hex-3-enofuranose, which was reduced and deacetylated to give 1,2:5,6-di-O-isopropylidene-(alpha)-D-gulofuranose. This compound was converted into methyl 2,3-O-isopropylidene-(beta)-D-gulofuranoside, and selectively oxidized to the carboxylate at the primary carbon. The carboxylic acid was converted to calcium D-guluronate from which L-glucose was obtained by selective reduction.; The sucrase-isomaltase complex of the hamster intestinal brush border membrane (BBM) is known to catalyze the hydrolysis of D-sucrose. However the spectrum of activity of the enzyme complex was not fully known towards other disaccharides. To determine if the BBM of hamster contained an enzyme capable of catalyzing the hydrolysis of L-sucrose, the membrane was incubated separately with D- and L-sucrose and the reaction mixtures were analyzed by g.l.c. It was found that D-sucrose was hydrolyzed to its monomers but L-sucrose remained unhydrolyzed.; The synthesis of (alpha)-L-glucopyranosyl (alpha), (beta)-D-fructofuranosides was achieved by the coupling 2,3,4,6-tetra-O-benzyl-(alpha)-L-glucopyranosyl chloride with 1,3,4,6-tetra-O-benzyl-D-fructofuranose utilizing an improved procedure employing trifluoromethanesulfonic acid, molecular sieves and 2,4,6-trimethylpyridine.; A new nucleoside, 7-(2,3,6-trideoxy-(beta)-D-glycero-hex-2-enopyranos-4-ulosyl)theophylline, was synthesized. Methyl 3,6-dideoxy-(beta)-D-ribo-hexopyranoside was converted to 1,2,4-tri-O-acetyl-3,6-dideoxy-D-ribo-hexopyranose which was coupled to theophylline. After deacetylation, the sugar moiety was selectively benzoylated at C-2 and the product was oxidized at C-4 with subsequent elimination of benzoic acid to give the desired nucleoside.; A method for the extension of the carbon chain of alkyl compounds was applied to carbohydrate derivatives. The method involved the formation of an epoxysulfone from the reaction of an (alpha)-chlorosulfonyl derivative of a carbohydrate with an aldehyde or ketone. |
