Synthesis of a spacer-containing disaccharide fragment of Bordetella pertussis lipopolysaccharide

The disaccharide 2-(p-aminophenyl)ethyl. 4-0-(2-acetamido-2-deoxy-alpha-D-g lucopyranosyl)-2,3-diacetamido-2,3- dideoxy-alpha-D-mannopyranoside uronate , which is assumed to be a partial structure of the Bordetella pertussis po lysaccharide, was synthesized starting from D-glucose and D-glucosamine, re spectively. The major synthetic transformations were conversion of D-glucos amine into the donor ethyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-1-thio-beta-D -glucopyranoside and conversion of glucose, by a sequence involving 2,3-epo xide formation/opening, nucleophilic triflate displacement in the 3-positio n, and necessary protecting group manipulations, into the acceptor 2-(p-tri fluoroacetamidophenyl)ethyl 6-O-benzyl-2,3-diazido-2,3-dideoxy-alpha-D-mann opyranoside. Coupling of the donor and acceptor units promoted by dimethyl( methylthio)sulfonium triflate followed by selective oxidation of the 6'-pos ition and deprotection gave the target disaccharide. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.