C6H4CO2NH

Phthalimide Phthal"i*mide, n. [Phthalic + imide.] (Chem.) An imido derivative of phthalic acid, obtained as a white crystalline substance, {C6H4.(CO)2NH}, which has itself (like succinimide) acid properties, and forms a series of salts. Cf. {Imido acid}, under {Imido}. [1913 Webster]