A synthesis of 3-acetamido-3-deoxy-D-glycero-D-gulo-heptose and 3-acetamido-3-deoxy-D-glycero-D-ido-heptose from 2-acetamido-2-deoxy-D-glucose

Abstract

The reluctance of 2-acetamido-2-deoxy-D-glucose to undergo base catalyzed addition with nitromethane was overcome by using the acetamidoglycose in the form of a substituted acyclic aldehydo derivative. 2-Acetamido-2-deoxy-D-glucose diethyl dithioacetal was isopropylidenated to yield 2-acetamido-2-deoxy-3,4:5,6-di-O-isopropylidene-D-glucose diethyl dithioacetal which on demercaptalation afforded 2-acetamido-2-deoxy-3,4:5,6-di-O-isopropylidene-aldehydo-D-glucose. The aldehydo derivative readily underwent base catalyzed addition of nitromethane to give the expected epimers 3-acetamido 1,3-dideoxy-4,5:6,7-di O-isopropylidene-1-nitro-D-glycero-D-gulo-heptitol and 3-acetamido-1,3-dideoxy-4,5:6,7-di-O-isopropylidene-1-nitro-D-glycero-D-ido-heptitol which, after deisopropylidenation by mild acid treatment, were converted under modified Nef reaction conditions to give 3-acetamido-3-deoxy-D-glycero-D-gulo-heptose and 3-acetamido-3-deoxy-D-glycero-D-ido-heptose, respectively.