Synthesis of trisaccharides containing 3-deoxy-d-manno-2-octulosonic acid residues related to the KDO-region of enterobacterial lipopolysaccharides

Abstract

Glycosylation of methyl (allyl 7,8-O-carbonyl-3-deoxy-α-d-manno-2-octulopyranosid)onate with an α-(2→4) linked per-O-acetylated KDO-disaccharide bromide derivative under Helferich conditions afforded a 2:1 mixture of the α- and β-linked trisaccharide derivatives in 50% yield. Removal of the protecting groups gave sodium O-[sodium (3-deoxy-α-d-manno-2-octulopyranosyl)onate]-(2→4)-O-[sodium (3-deoxy-α- and -β-d-manno-2-octulopyranosyl)onate]-(2→4)-sodium (allyl 3-deoxy-α-d-manno-2-octulopyranosid)onate. Radical copolymerization of the allyl glycosides afforded artificial antigens, suitable for defining antibody specificities directed against the KDO-region of enterobacterial lipopolysaccharides. © 1989.