Synthesis, structure and antibacterial activity of novel 1-(5-substituted-3-substituted-4,5-dihydropyrazol-1-yl)ethanone oxime ester derivatives

A series of novel 1-(5-substituted-3-substituted-4,5-dihydropyrazol-1-yl)ethanone oxime ester derivatives are synthesized. The results show that compounds 14 and 26c can strongly inhibit Staphylococcus aureus DNA gyrase and Escherichia coli DNA gyrase (with IC50 of 0.25 and 0.125 μg/mL against S. aureus DNA gyrase, 0.125 and 0.25 μg/mL against E. coli DNA gyrase). On the basis of the biological results, structure–activity relationships are also discussed.

A series of novel 1-(5-substituted-3-substituted-4,5-dihydropyrazol-1-yl)ethanone oxime ester derivatives and the unusual heterocyclic compound 2,5,5-trimethyl-1,5,6,10b-tetrahydropyrazolo[5,1-a]isoquinoline are synthesized. The title compounds 14 and 26c showed potent antibacterial activities against Staphylococcus aureus and Escherichia coli which was superior to the positive control penicillin.Figure optionsDownload as PowerPoint slide