Hydrogenation of alkyl 2-oximino-α-D-arabino-hexopyranosides

Abstract

Hydrogenation of alkyl 2 -oximino -[alpha] -D-arabino -hexopyranosides in the presence of Pd on charcoal and HC1 gave mixtures of the alkyl 2-amino-2-deoxy-of-D-hexopyranoside hydrochlorides with the gluco and manno configurations in about 90% yields. The fraction of gluco compound varied substantially with the nature of the alkyl group; viz., methyl, 71%; ethyl or n-propyl, 62%; isopropyl, 80%. More of the manno compound is formed, viz., isopropyl, 50%, when the 3,4,6-triacetate of the oximinoglycoside is hydrogenated. Hydrogenation of methyl 6-0-(2-oximino-a-D-arabino-hexopyranosyl)-[beta]-D-gluco-pyranoside gave an about equimolar mixture of the 2 configurations.