Novel 4-bromo-2-(3-methyl-1-(substituted-phenylsulfonyl)-4,5-dihydro-1- H-pyrazol-5-yl)phenol Derivatives: Synthesis and Antibacterial Activity

A series of novel 4-bromo-2-(3-methyl-1-(substituted-phenylsulfonyl)-4,5-dihydro-1H-pyrazol-5-yl) phenol derivatives were synthesized and characterized by NMR, ESI-MS. Compound 3c was determined by X-ray. Biological activity tests results show that compound 3h displayed activity with MIC of 0.39, 0.78, 1.562 μg/mL against B. subtilis ATCC 6633, S. aureus ATCC 6538, P. fluorescens ATCC 13525 and could strongly inhibit S. aureus DNA gyrase and B. subtilis DNA gyrase with IC50s of 0.25 and 0.18 μg/mL respectively.