SYNTHESIS OF A TETRASACCHARIDE DONOR CORRESPONDING TO THE O-SPECIFIC POLYSACCHARIDE OF SHIGELLA-DYSENTERIAE TYPE-1

nzoyl-3-O-chloroacetyl-alpha-L-rhamnopyranosyl)-(1 --> -(3,4,6-tri-O-b enzoyl-alpha-D-galactopyranosyl)-(1 --> 4,6-di-O-acetyl-2-deoxy-alpha- D-glucopyranosyl)-(1 --> 3)-2,4-di-O-benzoyl-alpha-L-rhamnopyranosyl t richloroacetimidate (1) was synthesized in a stepwise manner, using th e following monosaccharide units: 2-(trimethylsilyl)ethyl 2,4-di-O-ben zoyl-alpha-L-rhamnopyranoside, ene-3-O-chloroacetyl-2-deoxy-beta-D-glu copyranosyl chloride, methyl (4-methoxybenzyl)-1-thio-beta-D-galactopy ranoside, and O-benzoyl-3-O-chloroacetyl-alpha-L-rhamnopyranosyl chlor ide. Compound 1 corresponds to a complete tetrasaccharide repeating un it of the O-specific polysaccharide of the lipopolysaccharide of Shige lla dysenteriae type 1.