Collect. Czech. Chem. Commun. 1989, 54, 706-712

Studies in Vilsmeier-Haack reaction: Reaction of 3-methyl-1-phenyl-4-arylidene-5-pyrazolone

Ibrahim M. A. Awad and Khairy M. Hassan

Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt


The 3-methyl group in Ia, b has been found to undergo diformylation by Vilsmeier reagent to give the aminoacrolein derivatives (IIa, b). Treatment of IIa, b with different reagents affords the related 1-phenyl-4-arylidene-5-pyrazolone derivatives with different heterocyclic systems in the 3-position. The Vilsmeier reaction on pyrazolopyrazole (XIII) have been utilized to prove chemically that new heterocyclic systems are formed only at the 3-position and no addition on the carbon-carbon double bond in the conjugated system O=C-C=C-(B) takes place.