抄録
Reaction of 2, 3, 4, 5-tetrafluoro-1-nitrobenzene [4] with N-(ethoxycarbonyl)piperazine in aqueous ethanol gave 4-(4-ethoxycarbonyl-1-piperazinyl)-2, 3, 5-trifluoro-1-nitrobenzene [5] in 89% yield, which could be quantitatively converted into its 2-cyclopropylamino derivative [6]. Malonate [7] prepared from [6] and diethyl ethoxymethylenemalonate in 73% yield, was cyclized in the reaction with acetic anhydride and conc. sulfuric acid, accompanying elimination of the nitro group, to give [8] in 41% yield. Saponification of [8] gave quinolonecarboxylic acid [3] which possesses potent antibacterial activity both in vivo and in vitro, in 92% yield.
