Pyridonecarboxylic acid derivatives or their salts, and antibacterial agents containing the same as their effective components

摘要

A pyridonecarboxylic acid derivative represented by the following general formula (1): [wherein R1 represents hydrogen atom or a carboxyl protective group; R2 represents hydroxyl group, a lower alkoxy group, or a substituted or unsubstituted amino group; R3 represents hydrogen atom or a halogen atom; R4 represents hydrogen atom or a halogen atom; R5 represents a halogen atom or an optionally substituted saturated cyclic amino group; R6 represents hydrogen atom, a halogen atom, nitro group, or an optionally protected amino group; X, Y and Z may be the same or different and respectively represent nitrogen atom, -CH= or -CR7= (wherein R7 represents a lower alkyl group, a halogen atom, or cyano group) (with the proviso that at least one of X, Y and Z represent the nitrogen atom), and W represents nitrogen atom or -CR8= (wherein R8 represents hydrogen atom, a halogen atom, or a lower alkyl group)] or its salt, as well as an antibacterial agent containing such compound are provided.