4-Methoxy-2,3,6-trimethylbenzenesulphonyl (Mtr):a new amino protecting group in peptide synthesis

Abstract

The 4-methoxy-2,3,6-trimethylbenzenesulphonyl (Mtr) group used to protect the ε-amino function of lysine can be readily removed with 0.15–0.3 M methanesulphonic acid in trifluoroacetic acid–thioanisole (9:1) but is completely resistant to hydrogenolysis or treatment with neat trifluoroacetic acid hydrogen chloride, and thus can be used in the solution synthesis of methionine-containing peptides, such as mastoparan X and chicken gastrin releasing peptide (c-GRP).