Abstract Aroylhydrazines 2 reacted with 3-benzylidene-2, 4-pentanedione (1) to give 1-aroyl- 3, 5-dimethyl-1H-pyrazoles 5 and benzaldehyde aroylhydrazones 6. From the reaction of 3- methoxymethylene-2, 4-pentanedione (7) with aroylhydrazines 2 the unknown N-aroyl-4- acetyl-1H-pyrazoles 9 were exclusively isolated in good yields.
