Abstract: Novel 4-oxoquinoline-3-carboxylic acid compounds of the formula: ##STR1## wherein R.sup.3 is C.sub.1 -C.sub.6 alkyl and R.sup.F is C.sub.1 -C.sub.6 alkyl, and a pharmaceutically acceptable salts thereof, said compounds having excellent antimicrobial activity and hence being useful as an antimicrobial agent, and a pharmaceutical composition containing said compound as an active ingredient.

Abstract: Novel 4-oxoquinoline-3-carboxylic acid compounds of the formula: ##STR1## wherein R.sup.2 is 1-pyrrolidinyl which may have 1 to 2 substituents selected from the group consisting of (i) C.sub.1 -C.sub.6 alkyl, (ii) amino-(C.sub.1 -C.sub.6)alkyl, said amino being optionally substituted by 1 or 2 substituents selected from C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkanoyl, and C.sub.1 -C.sub.6 alkoxycarbonyl, (iii) amino which may be substituted by 1 or 2 substituents selected from C.sub.1 -C.sub.6 alkyl, phenyl(C.sub.1 -C.sub.6)alkyl, C.sub.1 -C.sub.6 alkoxycarbonyl, and C.sub.1 -C.sub.6 alkanoyl, and (iv) 2-oxo-1,3-dioxolenemethylamino which is substituted by C.sub.1 -C.sub.6 alkyl; or 1-piperidinyl which may have 1 to 3 substituents selected from oxo, hydroxy, halogen and C.sub.1 -C.sub.6 alkyl, and R.sup.3 is C.sub.1 -C.sub.

Abstract: Novel 1-thienyl-4-oxoquinoline-3-carboxylic acid compounds of the formula ##STR1## wherein R.sup.1 is an amino (lower) alkyl, R.sup.2 is thienyl, and X is a halogen atom, and a pharmaceutically acceptable salt thereof, said compounds having excellent antimicrobial activity and hence being useful as an antimicrobial agent, and a pharmaceutical composition comprising as an active ingredient said 1-thienyl-4-oxoquinoline-3-carboxylic acid compounds or a pharmaceutically acceptable salt thereof in admixture with a pharmaceutically acceptable diluent or carrier.

Abstract: Novel 1-substituted phenyl-4-oxoquinoline-3-carboxylic acid compounds of the formula: ##STR1## wherein R.sup.1 is hydrogen atom or an alkyl having 1 to 2 carbon atoms, R.sup.2 is hydrogen atom or fluorine atom, and R.sup.3 is hydroxy, fluorine atom or an alkanoyloxy having 1 to 6 carbon atoms, and a pharmaceutically acceptable salt thereof, said compounds having excellent antimicrobial activity and hence being useful as an antimicrobial agent, and a pharmaceutical composition comprising as an active ingredient said 1-substituted phenyl-4-oxoquinoline-3-carboxylic acid compounds or a pharmaceutically acceptable salt thereof in admixture with a pharmaceutically acceptable diluent or carrier.

Abstract: Novel 1-substituted phenyl-4-oxoquinoline-3-carboxylic acid compounds of the formula: ##STR1## wherein R is hydrogen atom or fluorine atom, R.degree. is hydroxy, fluorine atom or an alkanoyloxy having 1 to 6 carbon atoms, and X.sup.1 is hydrogen atom or fluorine atom, and a pharmaceutically acceptable salt thereof, said compounds having excellent antimicrobial activity and hence being useful as an antimicrobial agent, and a pharmaceutical composition comprising as an active ingredient said 1-substituted phenyl-4-oxoquinoline-3-carboxylic acid compounds or a pharmaceutically acceptable salt thereof in admixture with a pharmaceutically acceptable diluent or carrier.

Abstract: Benzo-heterocyclic compounds of the formula: ##STR1## wherein R.sup.1 is a lower alkyl group; R.sup.2 is a halogen atom or a group of the formula ##STR2## (wherein R.sup.4 and R.sup.5 combine together with the nitrogen atom to which they bind to form a 5- or 6-membered saturated heterocyclic group which may optionally contain an oxygen atom or nitrogen atom within the ring as an additional hetero atom and may also optionally have a substituent selected from a lower alkyl or hydroxy group on the hetero ring); R.sup.3 is an amino or nitro group; X is a halogen atom; and n is an integer of 1 or 2, and a salt thereof, which have excellent antimicrobial activities and are useful as an antimicrobial agent, or as an intermediate for the preparation of an active compound.