Abstract: Compounds of the general formula (II): ##STR1## in which N.sup.+ denotes an unsubstituted or substituted nitrogen-containing heterocyclyl ring bonded to the remainder of the molecule through a ring nitrogen atom and carrying a positive charge on said nitrogen atom;and the wavy line denotes either the E- or Z-isomeric position,are novel and are useful in the treatment of antibacterial infection in humans or animals.

Abstract: The compounds of the formula (II): ##STR1## or pharmaceutically acceptable salts or esters thereof wherein A is a hydrogen atom or an esterifying radical; X is an alkyl group of 1-12 carbon atoms optionally substituted by a hydroxy, amino, acylamino of C.sub.1-6 alkoxy group, which substituents are not on the carbon atom adjacent to the nitrogen atom; or a C.sub.5-7 cycloalkyl group; or a phenylalkyl group wherein the carbon atom content of the alkyl part is 1-6 and the phenyl part is optionally substituted with a fluorine, bromine, chlorine, C.sub.1-6 alkyl, or C.sub.1-6 alkoxy; with the proviso that when X represents an optionally substituted phenylalkyl group and A represents C.sub.1-3 alkyl, then the --CO.sub.2 A group is attached to the alkyl part of the phenylalkyl group; have been found to be .beta.-lactamase inhibitors and antibacterial agents. Their preparation and use is described.

Abstract: The compounds of the formula (II): ##STR1## or pharmaceutically acceptable salts or esters thereof wherein A is a hydrogen atom or an esterifying radical; X is an alkyl group of 1-12 carbon atoms optionally substituted by a hydroxy, amino, acylamino of C.sub.1-6 alkoxy group, which substituents are not on the carbon atom adjacent to the nitrogen atom; or a C.sub.5-7 cycloalkyl group; or a phenylalkyl group wherein the carbon atom content of the alkyl part is 1-6 and the phenyl part is optionally substituted with a fluorine, bromine, chlorine, C.sub.1-6 alkyl, or C.sub.1-6 alkoxy; with the proviso that when X represents an optionally substituted phenylalkyl group and A represents C.sub.1-3 alkyl, then the --CO.sub.2 A group is attached to the alkyl part of the phenylalkyl group; have been found to be .beta.-lactamase inhibitors and antibacterial agents. Their preparation and use is described.

Abstract: A compound of formula (I) or a pharmaceutically acceptable salt or in vivo hydrolysable ester thereof: ##STR1## wherein R represents an alkyl or aralkyl group, substituted on an alkyl carbon atom other than that adjacent to --NH-- group, with one or more functional groups selected from halogen, non-aromatic heterocyclyl linked through carbon, aromatic heterocyclyl, nitro, oxo, --OR.sup.1, SR.sup.1 --P(O)R.sup.2 R.sup.3, --NR.sup.4 R.sup.5, .dbd.NR.sup.6, or a sulphur linked organic radical, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are various organic radicals.Processes for the preparation of these compounds and pharmaceutical compositions containing them are also disclosed.

Abstract: The compounds of the formula (I): ##STR1## and esters thereof wherein R.sub.1 is a lower alkyl group or a phenyl group and R.sub.2 is a hydrogen atom or R.sub.2 together with R.sub.1 represents the residue of a fused benzene ring are .beta.-lactamase inhibitors and anti-bacterial agents. Their preparation and use is described.

Abstract: Secondary amines of clavulanic acid are useful as beta-lactamase inhibitors that enhance the effectiveness of penicillins or cephalosphorins and also have antibacterial properties in their own right.

Abstract: The compounds of the formula (II): ##STR1## pharmaceutically acceptable salts thereof, esters thereof and acid addition salts thereof wherein X is a C.sub.1-6 alkylene group, a C.sub.3-8 cycloalkylene group or a C.sub.3-8 cycloalkyl C.sub.1-4 alkylene group, have been found to be .beta.-lactamase inhibitors and antibacterial agents. Their preparation and use is described.

Abstract: The compounds of the formula (XVII) ##STR1## and their esters wherein R.sub.2 is a hydrogen, fluorine, chlorine or bromine atom or an alkyl group of 1-3 carbon atoms, an alkoxyl group of 1-3 carbon atoms, an acyloxyl group of 1-3 atoms, a hydroxyl group, an alkoxycarbonyl group containing 1-3 carbon atoms in the alkoxy part, or a group --N(R.sub.5)CO.R.sub.6, --N(R.sub.5)SO.sub.2 R.sub.6 or --CO-NR.sub.5 R.sub.6 where R.sub.5 is a hydrogen atom or an alkyl group of 1-3 carbon atoms or a phenyl or benzyl group and R.sub.6 is an alkyl group of 1-3 carbon atoms or a phenyl or benzyl group; R.sub.3 is a hydrogen, fluorine or chlorine atom or an alkyl group of 1-3 carbon atoms, an alkoxyl group of 1-3 carbon atoms; or an acyloxyl group of 1-3 carbon atoms R.sub.4 is a hydrogen fluorine or chlorine atom or an alkyl group of 1-3 atoms or an alkoxyl group of 1-3 carbon atoms; and X is a bond or alkylene group of 1-4 carbon atoms; have been found to be .beta.-lactamase inhibitors and antibacterial agents.

Abstract: The compounds of the formula (II): ##STR1## and pharmaceutically acceptable salts and esters thereof wherein X is a C.sub.1-6 alkylene group; m is 1, 2 or 3; n is 1, 2 or 3; A is oxygen, sulphur, --CH.sub.2 -- or --NR.sup.3 -- wherein R.sup.3 is hydrogen, C.sub.1-6 alkyl, phenyl or phenyl (C.sub.1-6)alkyl; R.sup.1 is hydrogen, oxo, C.sub.1-6 alkyl, C.sub.1-6 alkoxy, hydroxy or phenyl; and R.sup.2 is hydrogen, oxo, C.sub.1-6 alkyl or phenyl: with the proviso that if m and n are both 1 then A is --CH.sub.2 -- and R.sup.2 is not oxo: have been found to be .beta.-lactamase inhibitors and antibacterial agents. Their preparation and use are described.

Abstract: The compounds of the formula (I): ##STR1## and esters thereof wherein R.sub.1 is a lower alkyl group or a phenyl group and R.sub.2 is a hydrogen atom or R.sub.2 together with R.sub.1 represents the residue of a fused benzene ring are .beta.-lactamase inhibitors and anti-bacterial agents. Their preparation and use is described.