QUINOLINECARBOXYLIC ACID DERIVATIVE AND SALT THEREOF

PURPOSE:To provide a new compound having broad antibacterial spectrum, useful for curing infectious diseases due to gram-positive bacteria, drug-resistant bacteria, methicillin-resistant staphylococcus etc. CONSTITUTION:The objective compound of formula I [R1 is (substituted) 1-6C alkyl, 2-6C alkenyl, aryl, etc.; R2 is H, halogen, (protected) hydroxyl group, etc.; R3-R5 are each H or 1-6C alkyl; A is N or of formula II (A' is H, halogen, 1-6C alkyl, etc.); D is N or O; E is single bond or of formula III (E' is H or amino); n is 1 or 2], e.g. 1-cyclopropyl-6-fluoro-1,4-dihydro-7-(4,5,6,7-tetrahydro-1H- pyrazolo [4,3-C]pyridine-5-yl)-8-methoxy-4-oxoquinoline-3-carboxylic acid. The compound of the formula I can be obtained by condensation between a compound of formula IV (HX is e.g. mineral acid capable of forming a salt with basic nitrogen) and a compound of formula V (Y is halogen, etc.).