The formation of the condensation products obtained when pyruvic acid and aromatic amines are allowed to react, can be explained by condensation of one mole of the imine of pyruvic acid with one mole of the enamine isomer, either through the C atom or through the N atom, followed by elimination and lactonization to give a γ-lactone carboxylate or an azlactone carboxylate, which on decarboxylation give an iminobutanolide or an azlactone ...
