Abstract: This invention relates to pyridonecarboxylic acid derivatives of the following general formula, esters thereof and salts thereof, as well as pharmaceutical preparations containing them. ##STR1## wherein: R is cycloalkyl which may be substituted by halogen, or the like;X is hydrogen, lower alkyl, amino or the like;Y is hydrogen or halogen;A is nitrogen or a group of the formula C--Z in which Z is lower alkoxy that may be substituted by halogen, or the like;R.sub.1 and R.sub.2 may be the same or different and are each hydrogen or the like;R.sub.3 is hydrogen or lower alkyl;R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8 and R.sub.9 may be the same or different and are each hydrogen, halogen or lower alkyl;m is 0 or 1; andn and p may be the same or different and are each 0 or 1.This invention also relates to bicyclic amine compounds useful as direct intermediates for the synthesis of the above-described pyridonecarboxylic acid derivatives.

Abstract: This invention relates to bicyclic amino group-substituted pyridonecarboxylic acid derivatives of the general formulaA--Priesters thereof and salts thereof, wherein: Pri is a pyridonecarboxylic acid residue, and A is a bicyclic amino group represented by the following formula and joined to the 7-position of the pyridonecarboxylic acid or a position equivalent to the 7-position thereof. ##STR1## wherein R.sub.1 and R.sub.2 may be the same or different and each represents a hydrogen atom, a lower alkyl group or an amino-protecting group; R.sub.3 and R.sub.4 may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, a hydroxyl group, an oxo group, a lower alkoxy group or a lower alkyl group; and n is an integer of 0 or 1.The above-described pyridonecarboxylic acid derivatives, esters thereof and salts thereof are useful as antibacterial agents.

Abstract: This invention relates to pyridone-carboxylic acid derivatives of the following formula or salts thereof: ##STR1## wherein R.sub.1 is a hydrogen atom, a halogen atom, etc.,R.sub.2 is a carboxyl group etc.,R.sub.3 is a hydrogen atom etc.,A is a nitrogen atom or CH,m is 1 or 2, andY is an eliminable group or a group having the following formula: ##STR2## wherein R.sub.4 is a hydrogen atom or a lower alkyl group,Z is a hydrogen atom, a lower alkyl group, etc.,R.sub.5 is a hydrogen atom, a lower alkyl group, etc.,n is 0 or 1, andp is 1, 2, 3 or 4and to processes for the preparation of these compounds, and further to anti-tumor agents which contain the above compounds as effective ingredients.

Abstract: The present invention relates to a 1,8-naphthyridine derivative of the formula ##STR1## wherein X is a fluorine or chlorine atom, and R is a hydrogen atom, or a methyl or ethyl group;and esters thereof and salts thereof are processes for preparation thereof. These compounds show excellent anti-bacterial activity and are useful antibacterial agents.