Synthesis of nitrogenous sugars.

Abstract

The nitromethane cyclization of L'-methoxy diglycolic aldehyde was shown to furnish methyl 3-nitro-3-deoxy-alpha-L-arabino-pyranoside and methyl 3-nitro-3-deoxy-beta-D-arabinopyranoside as coproducts of the previously obtained beta-D-ribo isomer. The enantiometric dialdehyde, D'-methoxy-diglycolic aldehyde, afforded the corresponding alpha-D- and beta-L- arabino derivatives in addition to the main beta-L- ribo isomer. Catalytic hydrogenation of the four new nitroglycosides gave the corresponding aminoglycoside hydrochlorides. Acid hydrolysis of methyl 3-amino-3-deoxy-beta-D-arabinopyranoside hydrochloride and methyl 3-amino-3-deoxy-alpha-L-arabinopyranoside hydrochloride yielded the known 3-amino-3-deoxy-L-arabinose hydrochloride, respectively, as mutarotating beta-forms. The spontaneous epimerization, in aqueous solution, of aci -nitropentoside sodium salts was investigated and shown to lead to equilibria in which the erythro configuration predominates. The results of this first part of the thesis have been published.* The nitromethane cyclization was extended to a disaccharidic dialdehyde leading to an aci-nitro condensation product (yield 58%). Deionization and catalytic hydrogenation of the aci-nitro salt mixture afforded a crystalline alpha-D-glucopyranosyl 4-amino-4-deoxy-beta-D-heptulo-pyranoside hydrochloride that was subsequently converted to its crystalline N-acetate. The configuration of the nitrogenous heptulose moiety of the above disaccharides was partially elucidated by degradative studies, in the course of which a number of new nitrogenous heptulose derivatives was obtained. *H.H. Baer and A. Ahammad, Can. J. Chem., 41, 2931 (1963).