Synthesis, Characterization and Biological Evaluation of Novel 3-Methyl-5-pyrazolone Derivatives

Recently, infectious diseases have increased enormously, causing a major threat to public health despite the marvelous progress in the medicinal chemistry. Fused pyrazole derivatives are having a wide range of pharmacological activities, playing a vital role as potential therapeutic agents in various pathological conditions. In the present study, novel fused pyrazoles derivatives were synthesized and evaluated for protein kinase inhibition, antioxidant, and antimicrobial activities. 3-Methyl-5-pyrazolone was first prepared by treating ethyl acetoacetate with hydrazine hydrate in absolute ethanol. Then it was treated with different aromatic aldehydes (benzaldehyde, salicylaldehyde, vanillin, 4-diamethylaminobanzaldehyde, and cinnamaldehyde) to form benzylidene derivatives of pyrazoles. These substituted pyrazoles were then treated with hydrazine and phenylhydrazine to produce fused pyrazole ring systems. The synthesized compounds were purified by recrystallization, and then characterized using the spectroscopic techniques. All the compounds exhibited moderate antibacterial activity. Antioxidant potential was determined by three methods and most of the compounds exhibited good antioxidant potential. Two compounds including, 5a and 5e demonstrated protein kinase inhibitory activity. The results indicated that, the fused pyrazoles ring systems possess prominent biological properties.