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: Carbapenem compounds of formula I and their pharmaceutically acceptable salts and esters are provided: ##STR1## wherein R, R.sup.1, R.sup.2, R.sup.3, p, q and r are as defined herein, which are useful as antibacterial agents.

Abstract: A compound of the formula: ##STR1## wherein R is a hydrogen atom or a methyl group, R.sup.1 is a hydrogen atom or a negative charge, each of R.sup.2 and R.sup.3 which may be the same or different, is a hydrogen atom, a lower alkyl group, a hydroxy lower alkyl group, a formimidoyl group, an acetoimidoyl group, --COOR.sup.4, --CON(R.sup.5)R.sup.6, --N(R.sup.5)R.sup.6, --CH.sub.2 COOR.sup.4, --CH.sub.2 N(R.sup.5)R.sup.6 or --CH.sub.2 CON(R.sup.5)R.sup.6 (wherein R.sup.4 is a hydrogen atom or a lower alkyl group, 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.6 form together with the adjacent nitrogen atom a heterocyclic group selected from the group consisting of an aziridinyl group, an azetidinyl group, a pyrrolidinyl group and a piperidyl group), A is .dbd.NR.sup.7, .dbd.N.sup.+ (R.sup.7)R.sup.8, wherein each of R.sup.7 and R.sup.

Abstract: A compound of the formula: ##STR1## wherein R is a hydrogen atom or a methyl group, R.sup.1 is a hydrogen atom or a negative charge, R.sup.2 is a lower alkyl group, a lower alkyl group substituted with a hydroxyl group or --COOR.sup.3 (wherein R.sup.3 is a hydrogen atom or a lower alkyl group), A is .dbd.NH, .dbd.NR.sup.4 or .dbd.N(R.sup.4)R.sup.5 (wherein each of R.sup.4 and R.sup.5 which may be the same or different, is a lower alkyl group or a lower alkyl group substituted with a hydroxyl group), p is an integer of from 0 to 3, and each of q and r which may be the same or different, is an integer of from 0 to 5, provided that q and r are not simultaneously 0 and q +r.ltoreq.6; or a pharmaceutically acceptable salt or ester thereof.

Abstract: A cephalosporin derivative having the formula: ##STR1## wherein R.sup.1 is a substituted amino group, X is an alkylene group, R.sup.2 is an aryl or heterocyclic group which may be substituted and R.sup.3 is a hydrogen atom, a negative charge or a residue of an ester which can form a pharmaceutically acceptable ester hydrolyzable in a living body; or a pharmaceutically acceptable salt thereof.

Abstract: A process for producing a compound of the formula: ##STR1## wherein R.sup.1 is a hydrogen atom, a lower alkyl group or an aralkyl group, and R.sup.2 is a hydrogen atom or a hydroxyl-protecting group, or a salt thereof, which comprises removing from a compound of the formula: ##STR2## wherein R.sup.3 is a hydrogen atom or a hydroxyl-protecting group, R.sup.4 and R.sup.5 which may be the same or different are N-protecting groups selected from the group consisting of lower alkyl groups and aralkyl groups, and X.sup..crclbar. is an anion, the N-protecting group(s), if necessary, together with the hydroxyl-protecting group.

Abstract: A cephalosporin derivative having the formula: ##STR1## wherein R.sup.1 is a substituted amino group, X is an alkylene group, R.sup.2 is an aryl or heterocyclic group which may be substituted and R.sup.3 is a hydrogen atom, a negative charge or a residue of an ester which can form a pharmaceutically acceptable ester hydrolyzable in a living body; or a pharmaceutically acceptable salt thereof.