Amino Group Blocking. Improved Method for N-Phthaloylation Using N-(Ethoxycarbonyl)phthalimide

N-Phthaloylation, as a means of protecting primary amino groups, especially in the synthesis of peptides, has been known for some time.1 That N-phthaloylamines generally are easily crystallized, and that the phthaloyl group can readily be removed by hydrazinolysis or phenylhydrazinolysis have been recognized advantages in using this approach for the protection of amino groups during syntheses.1,2,3 The reaction of phthalic anhydride