P-Methoxybenzyl esters of amino acids-their preparation and use in peptide synthesis

Abstract

Various N-protected amino acids have been alkylated with p- methoxybenzyl chloride to give the corresponding esters. These were then converted into amino acid p-methoxybenzyl esters by selective acidolysis of the N-o-nitrophenylsulphenyl and N-trityl derivatives, or in poor yield by hydrazinolysis of the N-phthaloyl derivative. S- Benzylcysteine p-methoxybenzyl ester is obtained without racemiza- tion. These esters have been applied to the syntheses of several dipeptides, the ester group being cleaved by cold trifluoroacetic acid.