CONJUGATED AZOALKENES .9. NEW 1-AMINO-4-TRIPHENYLPHOSPHORANYLIDENE-5-OXO-2-PYRROLINES OR ALPHA,BETA-UNSATURATED HYDRAZONES BY REACTION OF AZOALKENES WITH CARBOALKOXYMETHYLENE TRIPHENYLPHOSPHORANE

New 1-amino-4-triphenylphosphoranylidene-5-oxo-2-pyrrolines or α,β-unsaturated hydrazones have been obtained in good yield under different reaction conditions by Wittig-type reaction of some conjugated azoalkenes with carboalkoxymethylene triphenylphosphorane. The isolation and characterization of 1,4-adduct intermediate showed that the reaction mechanism implicates only 1,6-zwitterionic intermediate without cycloadduct production, as usually suggested for the Wittig reaction. The crystal structure of one of 1-amino-4-tripheny1phosphorany1ide-ne-5-oxo-pyrrolines obtained has been elucidated by X-ray diffraction study, showing the resonance between the neutral and 1,4-dipolar form. © 1990.