A synthesis of 4-acetamido-4-deoxy- L-xylopyranose

Abstract

Acetonation of 2-deoxy-2-(2,4-dinitroanilino)- D-glucitol ( 1) gave the 3,4:5,6-diisopropylidene acetal ( 2), which was converted by mild, acid hydrolysis into the 3,4-monoisopropylidene acetal ( 3). Periodate oxidation of 3, followed by mild hydrolysis of the oxidation product ( 4) gave 4-deoxy-4-(2,4-dinitroanilino)- L-xylopyranose ( 5), which underwent condensation with acetone to give the 1,2- O-isopropylidene derivative ( 6). Removal of the N-substituent from 6 gave 4-amino-4-deoxy-1,2- O-isopropylidene-α- L-xylopyranose ( 7), which was acetylated to give 4-acetamido-3- O-acetyl-4-deoxy-1,2- O-isopropylidene-α- L-xylopyranose ( 8). O-Deacetylation of 8, followed by mild hydrolysis of the product ( 9), gave 4-acetamido-4-deoxy- L-xylose ( 10); substance 10 was also prepared from 7 in one step. In aqueous solution, the acetamido sugar ( 10) underwent equilibration to give a mixture of the α- L and β- L pyranose anomers in 2:3 ratio. Structural assignments were supported by n.m.r. and other physical data.