Polypeptides. Part XIII. The use of β-methylthioethyl esters for the protection of carboxyl groups in peptide synthesis

Abstract

The methiodides and sulphones derived from the β-methylthioethyl esters of amino-acids and peptides are split to the parent carboxylic acids under extremely mild alkaline conditions. Methods for the preparation of β-methylthioethyl esters of amino-acids are described and their use in peptide synthesis is explored. The β-methylthioethyl ester group is advocated as a useful new carboxyl protecting group in such syntheses.