Nitrophthaloyl and aminophthaloyl derivatives of amino acids

A RECENT paper (3) described the preparation and some of the properties of the nitrophthaloyl and aminophthaloyl derivatives of glycine. This work has been extended to the preparation of the nitrophthaloyl and aminophthaloyl derivatives of a number of other amino acids. Although it gives excellent results with glycine, the use of nitrobenzene as a solvent for nitrophthaloylations was unsatisfactory with other amino acids. The phthaloylation method of Billman and Harting (2) gave satisfactory nitrophthaloylations in most cases. The nitrophthalic acids were as effective as their anhydrides in achieving nitrophthaloylation by this method. The aminophthaloyl derivatives were prepared by hydrogenation of the nitrophthaloyl derivatives.