Synthesis of N-(4-arylmethylene-Δ2-oxazolin-5-ylidene)ammonium salts and their conversion into 5-imino-Δ2-oxazolines and 1,3-diazafulvenes

Abstract

Treatment of seven secondary or tertiary amides of α-benzamidocinnamic acids with acetic anhydride–perchloric acid gave N-(4-arylmethylene-2-phenyl-Δ²-oxazolin-5-ylidene)ammonium perchlorates. The N-monosubstituted iminium salts were deprotonated to yield the corresponding 4-arylmethylene-5-imino-Δ²-oxazolines; successive treatment of two NN-disubstituted iminium perchlorates with ammonia and sodium hydroxide produced novel 1,3-diazafulvenes (4-arylmethylene-5-dimethylamino-2-phenyl-4H-imidazoles).