Preparation of ketimine derivatives of amino acids for peptide synthesis

Abstract

Condensates of some 2-hydroxyaryl ketones with protein amino acids have been prepared. The reaction has been shown to proceed without racemization and the derivatives have been isolated as free acids. Their unusual stability is ascribed to the presence of a strong intramolecular hydrogen bond. The N-arylmethylene function is cleaved under mild conditions of acid hydrolysis. Ketimines derived from D-phenylglycine decarboxylate at room temperature.