Abstract: A compound of formula I, having antibacterial activity and a pharmaceutical composition containing the compound of formula I: ##STR1## wherein Q represents a partial structure of formula II: ##STR2## wherein all substituents are defined in the specification.

Abstract: This invention provides novel pyridonecarboxylic acid derivatives having a quite high antimicrobial activity. The derivatives have the following formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 represent each a hydrogen or C.sub.1-C.sub.6 alkyl group; R.sup.4 represents an ethyl, 2-fluoroethyl, vinyl, isopropyl, isopropenyl or cyclopropyl group; and X represents CH, C--F, C--Cl or Ncharacterized in that R.sup.2 and R.sup.3 are not hydrogen at the same time.

Abstract: An optically active pyridobenzoxazine derivative represented by formula (I): ##STR1## wherein R.sup.1 and R.sup.2 wherein R.sup.1 and R.sup.2, which may be the same or different, each represent an alkyl group having from 1 to 6 carbon atoms, a halogenated alkyl group having from 1 to 6 carbon atoms, a hydroxyalkyl group having from 1 to 6 carbon atoms, or an alkoxymethyl group having from 2 to 7 carbon atoms; R.sup.3 represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an acyl group having from 2 to 7 carbon atoms, a halogen-substituted or unsubstituted alkyloxycarbonyl group having from 2 to 7 carbon atoms, a phenylmethyloxycarbonyl group, or a phenylmethyloxycarbonyl group whose phenyl moiety is substituted with a halogen atom, a nitro group, or a methoxy group; R.sup.4 represents a methyl or fluoromethyl group which is in a .beta.-configuration; R.sup.

Abstract: This invention provides novel pyridonecarboxylic acid derivatives having a quite high antimicrobial activity. The derivatives have the following formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 represent each a hydrogen or C.sub.1 -C.sub.6 alkyl group; R.sup.4 represents an ethyl, 2-fluoroethyl, vinyl, isopropyl, isopropenyl or cyclopropyl group; and X represents CH, C--F, C--Cl or N characterized in that R.sup.2 and R.sup.3 are not hydrogen at the same time.

Abstract: This invention provides novel pyridonecarboxylic acid derivatives having a quite high antimicrobial activity. The derivatives have the following formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 represent each a hydrogen or C.sub.1 -C.sub.6 alkyl group; R.sup.4 represents an ethyl, 2-fluoroethyl, vinyl, isopropyl, isopropenyl or cyclopropyl group; and X represents CH, C--F, C--Cl or N characterized in that R.sup.2 and R.sup.3 are not hydrogen at the same time.

Abstract: The present invention relates to spiro compounds of general formula I: ##STR1## wherein the substituents are herein below defined. The present invention relates to antibacterial spiro compounds which are of value as drugs for humans, veterinary drugs or drugs for use in fish culture or as preservatives, and to antibacterial compositions containing one or more of the same compounds as active ingredients.

Abstract: An optically action pyridobenzoxazine derivative, a process for preparing the same and a novel intermediate useful for preparing the optically active pyridobenzoxazine derivative are disclosed. The optically active pyridobenzoxazine derivative possesses increased antimicrobial activity and reduced toxicity. The intermediate is useful for preparing such optically active pyridobenzoxazine derivatives such as Ofloxacin and anolog compounds.

Abstract: This invention provides novel pyridonecarboxylic acid derivatives having a quite high antimicrobial activity. The derivatives have the following formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 represent each a hydrogen or C.sub.1 -C.sub.6 alkyl group; R.sup.4 represents an ethyl, 2-fluoroethyl, vinyl, isopropyl, isopropenyl or cyclopropyl group; and X represents CH, C-F, C-Cl or N wherein (i) one of R.sup.1, R.sup.2 and R.sup.3 represents a hydrogen or C.sub.1 -C.sub.6 alkyl group, and (ii) either R.sup.1 forms a methylene chain having 2 to 4 carbon atoms together with R.sup.2 or R.sup.3, or R.sup.2 and R.sup.3 form together an alkylene chain having 2 to 5 atoms and R.sup.4 represents an ethyl, 2-fluorethyl, vinyl, isopropyl, isopropenyl or cyclopropyl group and X represents CH, C-F, or C-Cl and salt thereof.

Abstract: An optically action pyridobenzoxazine derivative, a process for preparing the same and a novel intermediate useful for preparing the optically active pyridobenzoxazine derivative are disclosed. The optically active pyridobenzoxazine derivative possesses increased antimicrobial activity and reduced toxicity. The intermediate is useful for preparing such optically active pyridobenzoxazine derivatives such as Ofloxacin and anolog compounds.

Abstract: An optically action pyridobenzoxazine derivative, a process for preparing the same and a novel intermediate useful for preparing the optically active pyridobenzoxazine derivative are disclosed. The optically active pyridobenzoxazine derivative possesses increased antimicrobial activity and reduced toxicity. The intermediate is useful for preparing such optically active pyridobenzoxazine derivatives such as Ofloxacin and anolog compounds.

Abstract: An optically active 3,4-dihydrobenzoxazine derivative, a process for preparing the same and an intermediate of 2H-benzoxazine useful for synthesizing the above mentioned optically active 3,4-dihydrobenzoxazine are disclosed.

Abstract: Novel 4-oxoguinoline-3-carboxylic acid derivatives having the formula ##STR1## wherein X.sup.1 represents a halogen or hydrogen atom, X.sup.2 represents a halogen or hydrogen atom, X.sup.3 represents a halogen atom, and R.sup.1, R.sup.2 and R.sup.3 each represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and physiologically acceptable salts thereof, are disclosed. These compounds have excellent antibacterial activity against gram-positive and gram-negative bacteria and beneficial pharmacokinetic properties.