AbstractThe peptidylanthranilic acid ester is stable during the reactions leading to the elongation of peptides. However, when the ester is hydrolyzed, the amide bond of peptidylanthranilic acid is catalytically hydrolyzed at pH 7, owing to the effect of the free carboxyl group of the anthranilic residue, into peptide and anthranilic acid. In this reaction, no decomposition or significant racemization of peptide was observed, and the protected peptide was easily obtained. Only in the case of glycylanthraniloyl derivatives did the rearrangement into peptide and anthranilic acid occur in aqueous solution.