Solid‐Phase Synthesis of Sialyl Tn Antigen

Abstract

Solid‐phase synthesis of sialyl Tn [α‐Neu5Ac‐(2→6)‐α‐GalNAc‐(1→O)‐Ser] antigen with Kenner's acylsulfonamide linker is described. The acylsulfonamide bond was found to be stable under glycosylation reactions using dimethyl(methylthio)sulfonium triflate (DMTST) as a promoter and basic conditions used for the removal of protecting groups. The solid‐phase reaction was monitored by the inverse gated decoupling 13C NMR technique, which enabled quantitative analysis of the reaction progress. At the end of the synthesis, the sulfamyl group of the linker was activated by treatment with (trimethylsilyl)diazomethane to provide a N‐methyl‐N‐acylsulfonamide. The acyl group was displaced with hydroxide to give the corresponding precursors of sialyl Tn antigen and its anomeric isomers, which were deprotected to afford the target molecules.