Amino-acids and peptides. Part XXVIII. Determination of racemization in peptide synthesis by nuclear magnetic resonance spectroscopy

Abstract

Diastereoisomeric aromatic alanyl peptides possess different n.m.r. spectra owing to a diamagnetic shielding phenomenon. Observation of the shifted methyl resonance is an excellent procedure for the study of racemization in peptide synthesis. Eight alanyl dipeptides are available as models for the evaluation and testing of any N-acyl protecting group or coupling agent. The method is general, convenient, rapid, and sensitive.