Abstract: A pyridonecarboxylic acid derivative or a salt thereof is represented by Formula (1), where R1 is hydrogen, a halogen atom, a lower alkyl group, or an amino group; R2 is —NH—R6, where R6 is hydrogen, a lower alkyl group, an amino lower alkyl group, or the like; —O—R7, where R7 is hydrogen, a lower alkyl group, or the like; —(CH2)m—R8, where R8 is an amino group or the like, m is 1, 2, 3 or 4; or a cyclic amino group of Formula (2), where Y represents NH or C—R9aR9b, where R9a and R9b are each independently hydrogen, a lower alkyl group, an amino group, a lower alkyl amino group, or the like; n and p are 1 or 2; R3 is hydrogen, a halogen atom, a lower alkyl group, or the like; R4 is hydrogen or a carboxyl group-protecting group; and R5 is hydrogen or a hydroxyl group-protecting group.

Abstract: A pyridonecarboxylic acid derivative or a salt thereof is represented by Formula (1), where R1 is hydrogen, a halogen atom, a lower alkyl group, or an amino group; R2 is —NH—R6, where R6 is hydrogen, a lower alkyl group, an amino lower alkyl group, or the like; —O—R7, where R7 is hydrogen, a lower alkyl group, or the like; —(CH2)m—R8, where R8 is an amino group or the like, m is 1, 2, 3 or 4; or a cyclic amino group of Formula (2), where Y represents NH or C—R9aR9b, where R9a and R9b are each independently hydrogen, a lower alkyl group, an amino group, a lower alkyl amino group, or the like; n and p are 1 or 2; R3 is hydrogen, a halogen atom, a lower alkyl group, or the like; R4 is hydrogen or a carboxyl group-protecting group; and R5 is hydrogen or a hydroxyl group-protecting group.

Abstract: The present invention provides an agent which exhibits excellent antibacterial activity, low toxicity, improved bioavailability, and low binding rate to serum proteins. The present invention is directed to a pyridonecarboxylic acid derivative represented by formula (1): or a salt thereof, wherein R1 represents a methyl group, a fluorine atom, or a chlorine atom; R2 represents a hydrogen atom or a lower alkyl group; R3 represents an isopropyl group or a tert-butyl group; R4 represents a methyl group or a halogen atom; and R5 represents a fluorine atom or a chlorine atom. The present invention is also directed to an antibacterial agent and a medicament containing the derivative or the salt thereof as an active ingredient.

Abstract: The present invention provides an agent which exhibits excellent antibacterial activity, low toxicity, improved bioavailability, and low binding rate to serum proteins. The present invention is directed to a pyridonecarboxylic acid derivative represented by formula (1): or a salt thereof, wherein R1 represents a methyl group, a fluorine atom, or a chlorine atom; R2 represents a hydrogen atom or a lower alkyl group; R3 represents an isopropyl group or a tert-butyl group; R4 represents a methyl group or a halogen atom; and R5 represents a fluorine atom or a chlorine atom. The present invention is also directed to an antibacterial agent and a medicament containing the derivative or the salt thereof as an active ingredient.

Abstract: This invention relates to 1-(6-amino-3,5-difluoropyridin-2-yl)-8-bromo-7-(3-ethylaminoazetidin-1-yl)-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid or a salt thereof, and also to a medicine containing the same. This compound has characteristic features that, when administered orally, it has extremely high blood half-life and bioavailability while retaining properties that it has extremely high antimicrobial effects and has low toxicity. It can be used widely as preventives, therapeutics and the like for various infectious diseases of human and animals.

Abstract: The present invention relates a 1-(6-amino-3,5-difluoropyridin-2-yl)-6-fluoro-7-(3-hydroxyazetidin-1-yl)-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid or salt thereof; and drugs containing the same as the active ingredient. Since this compound or salt thereof is highly stable to light while sustaining the excellent properties inherent to quinolone antibacterial agents, an antibacterial agent comprising, as an active ingredient, the invention compound or salt thereof can be stored over a long period of time without suffering from any decrease in the drug effect and can therefore be supplied as stable preparations such as injections, eye drops and surgical medicines.

Abstract: A pyridonecarboxylic acid derivative represented by the following general formula (1): ##STR1## [wherein R.sup.1 represents hydrogen atom or a carboxyl protective group; R.sup.2 represents hydroxyl group, a lower alkoxy group, or a substituted or unsubstituted amino group; R.sup.3 represents hydrogen atom or a halogen atom; R.sup.4 represents hydrogen atom or a halogen atom; R.sup.5 represents a halogen atom or an optionally substituted saturated cyclic amino group; R.sup.6 represents hydrogen atom, a halogen atom, nitro group, or an optionally protected amino group; X, Y and Z may be the same or different and respectively represent nitrogen atom, --CH.dbd. or --CR.sup.7 .dbd. (wherein R.sup.7 represents a lower alkyl group, a halogen atom, or cyano group) (with the proviso that at least one of X, Y and Z represent the nitrogen atom), and W represents nitrogen atom or --CR.sup.8 .dbd. (wherein R.sup.

Abstract: The invention relates to pyridonecarboxylic acid derivatives represented by the general formula (1): ##STR1## wherein R.sup.1 is --OH, a carboxy-protecting group or (alkyl)amino group, R.sup.2 is H, or --NO.sub.2, (protected) amino, (protected) hydroxyl, lower alkyl or lower alkoxyl group, R.sup.3 is a halogen atom, H, or --NO.sub.2, lower alkyl, lower alkoxyl or amino group, R.sup.4 is an azido, (substituted) hydrazino, (substituted) amino, lower alkoxyl or hydroxyl group, R.sup.5, R.sup.6 and R.sup.7 are independently H, --NO.sub.2, halogen atom or lower alkyl group, R.sup.8 is a --NO.sub.2, (substituted) amino, --OH or lower alkoxyl group, A is N or C--R.sup.12, in which R.sup.12 is H, halogen atom, or (substituted) lower alkyl, lower alkenyl, lower alkynyl, lower alkoxyl, lower alkylthio or nitro group, and B is N or C--R.sup.13, in which R.sup.13 is H or halogen atom, or salts thereof, and medicine comprising such a compound as an active ingredient.

Abstract: A pyridonecarboxylic acid derivative represented by the following general formula (1): ##STR1## [wherein R.sup.1 represents hydrogen atom or a carboxyl protective group; R.sup.2 represents hydroxyl group, a lower alkoxy group, or a substituted or unsubstituted amino group; R.sup.3 represents hydrogen atom or a halogen atom; R.sup.4 represents hydrogen atom or a halogen atom; R.sup.5 represents a halogen atom or an optionally substituted saturated cyclic amino group; R.sup.6 represents hydrogen atom, a halogen atom, nitro group, or an optionally protected amino group; X, Y and Z may be the same or different and respectively represent nitrogen atom, --CH.dbd. or --CR.sup.7 .dbd. (wherein R.sup.7 represents a lower alkyl group, a halogen atom, or cyano group) (with the proviso that at least one of X, Y and Z represent the nitrogen atom), and W represents nitrogen atom or --CR.sup.8 .dbd. (wherein R.sup.

Abstract: A pyridonecarboxylic acid derivative represented by the following general formula (1): ##STR1## [wherein R.sup.1 represents hydrogen atom or a carboxyl protective group; R.sup.2 represents hydroxyl group, a lower alkoxy group, or a substituted or unsubstituted amino group; R.sup.3 represents hydrogen atom or a halogen atom; R.sup.4 represents hydrogen atom or a halogen atom; R.sup.5 represents a halogen atom or an optionally substituted saturated cyclic amino group; R.sup.6 represents hydrogen atom, a halogen atom, nitro group, or an optionally protected amino group; X, Y and Z may be the same or different and respectively represent nitrogen atom, --CH.dbd. or --CR.sup.7 .dbd. (wherein R.sup.7 represents a lower alkyl group, a halogen atom, or cyano group) (with the proviso that at least one of X, Y and Z represent the nitrogen atom), and W represents nitrogen atom or --CR.sup.8 .dbd. (wherein R.sup.

Abstract: The invention provides a pyridonecarboxylic acid derivative of the following general formula (1): ##STR1## wherein R.sup.1 is a hydrogen atom or carboxy protecting group, R.sup.2 is a nitro or substituted or unsubstituted amino group, R.sup.3 is a halogen atom, each of R.sup.4 and R.sup.5, which may be the same or different, is a hydrogen atom, halogen atom, lower alkyl group or lower alkoxy group, A is a nitrogen atom or --CX.dbd. wherein X is a hydrogen atom, halogen atom, lower alkyl group or lower alkoxy group, and Z is a halogen atom or a saturated cyclic amino group which may have a substituent, or a salt thereof and an antibacterial agent comprising the same.

Abstract: Antibacterial quinolone derivatives represented by the following formula [I] and salts thereof are disclosed. ##STR1## wherein R.sup.1 means a hydrogen atom or a carboxyl-protecting group;R.sup.2 denotes a hydrogen or halogen atom or a hydroxyl, lower alkoxyl, amino, aralkylamino, or mono- or di-(lower alkyl)amino group;A represents an oxygen or sulfur atom or N-R.sup.3 in which R.sup.3 is a hydrogen atom or an amino-protecting group;X is a hydrogen or halogen atom;Y means a nitrogen atom or C-R.sup.4 in which R.sup.4 is a hydrogen or halogen atom or a lower alkyl or lower alkoxyl group; andZ denotes a halogen atom or a substituted or unsubstituted heterocyclic group having at least one nitrogen atom as a hetero atom.

Abstract: A tricyclic compound represented by the general formula (1) and salts thereof are disclosed. ##STR1## A method for producing the tricyclic compound and salts thereof, and an antimicrobial agent containing the tricyclic compound and salts thereof as an active ingredient are also disclosed.

Abstract: A tricyclic compound represented by the general formula (1) and salts thereof. ##STR1## A method for producing the tricyclic compound and salts thereof, and an antimicrobial agent containing the tricyclic compound and salts thereof as an active ingredient are also disclosed.

Abstract: Antibacterial quinolone derivatives represented by the following formula [I] and salts thereof are disclosed. ##STR1## wherein R.sup.1 means a hydrogen atom or a carboxyl-protecting group; R.sup.2 denotes a hydrogen or halogen atom or a hydroxyl, lower alkoxyl, amino, aralkylamino, or mono- or di-(lower alkyl)amino group; A represents an oxygen or sulfur atom or N--R.sup.3 in which R.sup.3 is a hydrogen atom or an amino-protecting group; X is a hydrogen or halogen atom; Y means a nitrogen atom or C--R.sup.4 in which R.sup.4 is a hydrogen or halogen atom or a lower alkyl or lower alkoxyl group; and Z denotes a halogen atom or a substituted or unsubstituted heterocyclic group having at least one nitrogen atom as a hetero atom.

Abstract: Antibacterial quinolone derivatives represented by the following formula and salts thereof are disclosed. ##STR1## wherein R.sup.1 meawns a substituted or unsubstituted lower alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted lower alkenyl group or a substituted or unsubstituted phenyl group, R.sup.2 denotes a hydrogen atom or a carboxyl-protecting group, R.sup.3 represents a hydrogen or halogen atom or an amino, mono- or di-(lower alkyl)amino, hydroxyl or lower alkoxyl group, X is a hydrogen or halogen atom, Y means a nitrogen atom or a group C-R.sup.4 in which R.sup.4 is a hydrogen or halogen atom or a lower alkyl or lower alkoxyl group or is a group ##STR2## which forms a ring together with R.sup.1 (i.e., the asterisked carbon atoms are linked to the N(1) atom of the quinolone skeleton), and A denotes a specific N-containing group. Preparation processes of the quinolone derivatives and antibacterial agents containing the same are also disclosed.

Abstract: A method of deprotection which comprises reacting a compound having at least one of amino, hydroxyl, mercapto and carboxyl groups protected by a substituted or unsubstituted benzyloxycarbonyl group or by a substituted or unsubstituted benzyl group with zinc in a buffer, thereby splitting off the protective benzyloxycarbonyl or benzyl group.

Abstract: An azetidin-2-one derivative represented by the following formula (I) ##STR1## wherein R.sup.1 represents a hydrogen atom, a lower alkyl group, an aryl group, an aralkyl group, a lower alkoxy group, aralkoxy group, a lower alkylthio group, an aralkylthio group, or a substituted amino group, R.sup.2 represents a hydrogen atom, a lower alkyl group, an aryl group or an aralkyl group, and R.sup.3 represents a hydrogen atom or a group of the formula ##STR2## in which R.sup.4 represents a hydrogen atom or a protective group for the hydroxyl group; and a process for production thereof.