Racemization of N-Acylaspartic Acids

Abstract

AN exception to the general applicability of the method devised by du Vigneaud and Meyer¹ for the racemization of N-acyl-α-amino-acids has been discovered in the course of an attempt to racemize N-acetyl- and N-benzoyl-L-aspartic acids. The method of du Vigneaud and Meyer depends for its success upon the intermediate formation of a readily racemizable oxazolone when an aqueous solution of the sodium salt of such an acid is stirred with acetic anhydride. This treatment, which leads to the complete racemization of the N-acetyl derivatives of optically active methionine, cystine, arginine, tyrosine, phenylalanine, tryptophane and glutamic acid^1,2, achieves, however, only 13 per cent and 24 per cent racemization when applied to N-acetyl- and N-benzoyl-L-aspartic acids respectively.