Synthesis of Sialic Acid Pseudopolysaccharides by Coupling of Spacer-Connected Neu5Ac With Activated Polymer

A new approach to the synthesis of polyvalent sialosides (pseudopolysaccharides) of Neu5Ac is described. Two monovalent sialosides, namely 4-acetamido- and 4-glycylamidobenzyl α-glycosides of Neu5Ac (and their β-anomers) have been synthesized. The latter, each having a free amino group, have been coupled with poly(4-nitrophenylacrylate) followed by treatment with sodium hydroxide or ethanolamine to give water soluble polyvalent sialosides differing in the nature of polymeric backbone. The coupling proceeded quantitatively providing polymers with a desired number of spacer-connected Neu5Ac residues attached. The polymers are shown to have considerable activity as inhibitors of influenza virus adhesion.