A new class of fluoroquinolones: benzenesulfonamidefluoroquinolones (BSFQs), antibacterial activity and SAR studies

N-Sulfanilylnorfloxacin was chosen as lead compound to develop a new series of benzenesulfonamidefluoroquinolones (BSFQs). Eight new compounds with di fferent p-substituents on the phenyl group were prepared and their in vitro antibacterial activities were evaluated. The presence of the benzenesulfon ylamido groups (BS) bound to the piperazinyl ring shifted the activity of c lassic antimicrobial fluoroquinolones from being more active against Gram n egative to Gram positive strains. Analogs with p-NHCH3, p-H or p-NO2 were m ore active than norfloxacin. QSAR studies through Hansch analysis showed a linear correlation of the activity with electronic distribution (empirical descriptors) along with Sterimol parameters. Small electron-donor groups wi th hydrophilic properties increase the in vitro activity against Gram posit ive bacteria. (C) Elsevier, Paris.