A simple preparation of phthaloyl amino acids via a mild phthaloylation

Phthaloyl amino acids can be synthesized from N-carboethoxy phthalimide and amino acid salts under very mild conditions in water. The preparation of 11 of these phthaloyl derivatives is described, some of which are new. Up to the present the method has only failed with tryptophane. Retention of the optical configuration during the reaction is shown.