Abstract: A compound of the formula: ##STR1## wherein R.sup.1 is a hydrogen atom or a methyl group, R.sup.2 is a hydrogen atom or a negative charge, R.sup.3 is a hydrogen atom, a halogen atom, a hydroxyl group, a lower alkoxy group, a lower alkanoyloxy group, an amino group, an N-lower alkylamino group, an N,N-di-lower alkylamino group, a lower alkanoylamino group, an aroylamino group, a (lower alkylsulfonyl)amino group, a sulfamoylamino group, a cyano group, a nitro group, a group of --COOR.sup.4 (wherein R.sup.4 is a hydrogen atom or a lower alkyl group) or a group of --CON(R.sup.5)R.sup.6 (wherein each of R.sup.5 and R.sup.6 which may be the same or different, is a hydrogen atom or a lower alkyl group, or R.sup.5 and R.sup.

Abstract: A compound of the formula: ##STR1## wherein R.sup.1 is a hydrogen atom or a methyl group, R.sup.2 is a hydrogen atom or a negative charge, X is a group of --N(R.sup.3)R.sup.4 (wherein R.sup.3 is a lower alkyl group, and R.sup.4 is a hydrogen atom or a lower alkyl group) or a group of --N.sup.+ (R.sup.5)(R.sup.6)R.sup.7 (wherein each of R.sup.5, R.sup.6 and R.sup.7 which may be the same or different, is a lower alkyl group), and n is an integer of from 2 to 4; or a pharmaceutically acceptable salt or ester thereof.

Abstract: The present invention relates to a compound represented by the structural formula I: ##STR1## its pharmaceutically acceptable salt or ester, or its crystalline, which is a novel optically active compound useful as a curing agent for bacterial infections, a process for production thereof and a use thereof.

Abstract: The present invention relates to a compound represented by the structural formula: ##STR1## or its pharmaceutically acceptable salt or ester, which is a novel optically active compound useful as a curing agent for bacterial infections, a process for production thereof and a use thereof.

Abstract: The present invention relates to a compound having the formula: ##STR1## wherein R is a hydrogen atom, a carboxyl-protecting group or a negative charge and Q is a hydrogen atom, a halogen atom, a hydroxyl group, an acetoxy group, a carbamoyloxy group, an azide group, a substituted or unsubstituted quarternary ammonio group or a substituted or unsubstituted heterocyclic thio group having at least one hetero atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom, or a non-toxic salt or physiologically hydrolyzable non-toxic ester thereof; a process for producing it; and an antibacterial agent comprising it as an active ingredient.Further, the present invention also relates to a compound having the formula: ##STR2## wherein R.sup.3 is a hydrogen atom or an amino-protecting group, and each of R.sup.4 and R.sup.5 which may be the same or different is a hydrogen atom or a carboxyl-protecting group, or a salt thereof; and a process for producing it.

Abstract: The present invention relates to a compound having the formula: ##STR1## wherein R is a hydrogen atom, a carboxyl-protecting group or a negative charge and Q is a hydrogen atom, a halogen atom, a hydroxyl group, an acetoxy group, a carbamoyl group, an azide group, a substituted or unsubstituted quarternary ammonio group or a substituted or unsubstituted heterocyclic thio group having at least one hetero atom selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom, or a non-toxic salt or physiologically hydrolyzable non-toxic ester thereof; a process for producing it; and an antibacterial agent comprising it as an active ingredient.Further, the present invention also relates to a compound having the formula: ##STR2## wherein R.sup.3 is a hydrogen atom or an amino-protecting group, and each of R.sup.4 and R.sup.5 which may be the same or different is a hydrogen atom or a carboxyl-protecting group, or a salt thereof; and a process for producing it.

Abstract: A compound having the formula: ##STR1## wherein R is a straight chain or branched chain lower alkyl, cyclic lower alkyl, lower alkenyl (except for 1-carboxy-1-vinyl), lower alkynyl, aralkyl, phenyl or 2-pyrrolidon-3-yl group which may be substituted, and Q is ##STR2## (wherein R.sup.1 is a hydrogen atom or an acetyl group, R.sup.2 is a hydrogen atom, a carboxyl group or a carboxymethyl group, Y is a sulfur atom or an oxygen atom, Z is a sulfur atom, an oxygen atom or an imino group which may be substituted by a lower alkyl group); or a pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

Abstract: A compound having the formula: ##STR1## wherein R is a vinyl, phenyl or aralkyl group which may be substituted; or a pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

Abstract: A compound having the formula: ##STR1## wherein R is a vinyl, phenyl or aralkyl group which may be substituted; or a pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.