Novel pyridonecarboxylic acid derivatives or their salts and antibacterial agent comprising the same as the active ingredient

摘要

Pyridine carboxylic acid derivs. of formula (I) and their salts are new: R1 = H or carboxy protecting gp; R2 = OH, lower alkoxy or opt. substd. amino; R3 = H or halo; R4 = H or halo; R5 = halo or opt. substd. cyclic amino; R6 = H, halo, NO2 or opt. protected amino; X, Y, Z = N, CH or CR7; R7 = lower alkyl, halo or CN; provided that /- 1 of X-Z = N; W = N or CR8; R8 = H, halo or lower alkyl.