New Azoolefines and their Acidic cleavage to Aryldiimines
3‐Amino‐1‐aryl‐3′,3′‐dimethyl‐pyrazolin‐4‐spiro‐2′‐oxiran‐5‐ones (3a–c) undergo ring opening with methoxide forming methyl 3‐amino‐3‐arylazo‐propenoates (5a–c). 5a–c are cleaved under acidic conditions. The main products of the cleavage of 5c with methanolic hydrochloric acid are nitrogen, 2, 4, 6‐trichloro‐benzen (6), 2, 4, 6‐trichloro‐aniline (9) and 2, 4, 6‐trichlorophenylhydrazine (10). Intermediates of the cleavage of 5 are aryldiimines trapped with benzaldehyde as the corresponding benzhydrazides (12a, b).