Synthesis of new pyrazolones and fused pyrazole derivatives as antimicrobial agents

SOME new pyrazolone and fused pyrazole derivatives start ⋯⋯from enaminone-type precursor. This approach constitutes a novel and advantageous alternative for the synthesis of the target heterocycles. Thus, the reaction of pyrazolone 1 and DMFDMA afforded 4-(dimeth-ylamino) methylidenepyrazol-3-one (2). Enaminone 2 was utilized as a key intermediate for the synthesis of new pyrazolones 8,9, 12, and 14, fused pyrazolones 4-7, and 10 and the spiro adducts 15a, b. The antimicrobial activity of some of the newly synthesized adducts were evaluated against six strains of Gram positive, Gram negative and fungi in comparison with Ampicillin and Nystatine.