Efficient Microwave-Assisted Tandem <i>N-</i> to <i>S</i>-Acyl Transfer and Thioester Exchange for the Preparation of a Glycosylated Peptide Thioester

Abstract

A peptide carrying a mercaptomethylated proline derivative at the C-terminus was prepared by solid-phase peptide synthesis (SPPS) and converted to the thioester of 3-mercaptopropionic acid (MPA) by aqueous MPA under microwave irradiation conditions. This post-SPPS thioesterification reaction was successfully applied to the synthesis of a glycopeptide thioester composed of 25 amino acid (AA) residues, which was then used for the preparation of a 61-AA glycopeptide by the thioester condensation method.