Quinolone carboxylic acid derivatives

#The present invention relates to quinolonecarboxylic acid derivatives having more excellent and broad antibacterial activities than the existing quinolone-series antibiotics. More specifically, it pertains to novel quinolonecarboxylic acid derivatives represented by following formula 1, which have a derivative of 7-[8-(alkoxyimino)-2,6-diazaspiro[3.4]oct-6-yl] as a substituent, and pharmaceutically acceptable salts and isomers thereof:

#Wherein, A is C—H, C—F, C—Cl, C—O—CH13 or N; Y is H or amino; R1 is cyclopropyl or 2,4-difluorophenyl; R2 is C1-4 alkyl; and R3 is H or C1-4 alkyl.

#Quinolonecarboxylic acid derivatives are synthetic antibiotics which are well known to be useful for the treatment of infective diseases in human and animals due to their potent and broad antibacterial activities. Quinolone-series antibiotics such as norfloxacin, ofloxacin and ciprofloxacin are currently used very usefully for the treatment of human diseases and their efficacies are acknowledged. However, these medicines have a problem that: even though they show excellent antibacterial activities against gram-negative bacteria, they still show ordinary or relatively low antibacterial activities against gram-positive bacteria. Accordingly, there have been various studies for solving such problems of existing quinolone-series antibiotics and, finally, sparfloxacin having improved antibacterial activities against gram-positive bacteria has been developed.

#The present invention is characterized by quinolonecarboxylic acid derivatives represented by following formula 1, and pharmaceutically acceptable salts and isomers thereof:

#Wherein, A is C—H, C—F, C—Cl, C—O—CH3 or N; Y is H or amino; R1 is cyclopropyl or 2,4-difluorophenyl; R2 is C1-4 alkyl; and R3 is H or C1-4 alkyl.

#The present invention is described in more detail as follows.