Quinolone Antibacterial Agents. Synthesis and Structure-Activity Relationships of 8-Substituted Quinoline-3-carboxylic Acids and 1,8-Naphthyridine-3-carboxylic Acids

Article abstract of DOI:10.1021/jm00400a016

A series of 7,8-disubstituted 1-cyclopropyl-6-fluoroquinoline-3-carboxylic acids, 7-substituted 1-cyclopropyl-6-fluoro-1,8-naphthyridine-3-carboxylic acids, and 10-substituted 9-fluoropyridobenzoxazine-6-carboxylic acids has been prepared and evaluated for antibacterial activity.The side chains examined at the 7-position (benzoxazine 10-position) included piperazinyl (g), 3-aminopyrrolidinyl (a), 3-(aminomethyl)pyrrolidinyl (b), and alkylated 3-(aminomethyl)pyrrolidinyl (c-f).Variations ta C-8 of the quinolone ring system included hydrogen, nitro, amino, fluorine and chlorine.The relative enhancement of in vitro activities by the side chains on the 8-hydrogen quinolone and 1,8-naphthyridine against Gram-negative organisms was a > b > g > c-f.The activity imparted to the substituted quinolone nucleus by the 8-substituent was in the order F > Cl > naphthyridine > H > benzoxazine > NH2 > NO2.These trends were retained in vivo.