Synthesis and structure-activity relationship of 1-aryl-6,8-difluoroquinolone antibacterial agents

A series of new arylfluoroquinolones has been prepared. These derivatives are characterized by having fluorine atoms at the 6- and 8-positions, substituted amino groups at the 7-position, and substituted phenyl groups at the 1-position. The in vitro antibacterial potency is greatest when the 1-substituent is 2,4-difluorophenyl and the 7-substituent is a 3-amino-1-pyrrolidinyl group. 1-(4-Fluorophenyl)-6,8-difluoro-7-piperazin-1-yl-1,4-dihydro-4-oxo quinoline-3- carboxylic acid (22) was found to possess excellent in vitro potency and in vivo efficacy.