Abstract: Compounds of formula (I) and pharmaceutically acceptable salts and in-vivo hydrolysable esters thereof: ##STR1## wherein X is hydrogen or a group NHR.sup.1, wherein R.sup.1 is hydrogen or an amino protecting group, and R is an optionally substituted 5-membered or 6-membered saturated heterocyclic group containing 1 or 2 heteroatoms selected from oxygen, sulphur or nitrogen, are useful in the treatment of bacterial infections in humans and animals.

Abstract: Compounds of formula (I) and their salts and esters: ##STR1## wherein X is hydrogen or a group NHR.sup.1, wherein R.sup.1 is hydrogen or an amino protecting group, and R is optionally substituted C.sub.5-8 cycloalkyl or cycloalkenyl, are useful in the treatment of bacterial infections.

Abstract: A monocyclic .beta.-lactam antibiotic having a formamido substituent at the 3S-position, including compounds of the formula (I): ##STR1## and salts thereof wherein R is --SO.sub.3 H; --PO(OH)Y wherein Y is C.sub.1-6 alkoxy, hydroxy, aryloxy, C.sub.1-6 alkyl or aryl; ##STR2## wherein Z represents C.sub.1-6 alkyl or aryl; ##STR3## wherein Z.sup.1 and Z.sup.2 may be the same or different and each represents hydrogen, C.sub.1-6 alkyl, aryl, amino or C.sub.1-6 alkoxy, or Z.sup.1 and Z.sup.2 together form the residue of a heterocyclic ring; --OSO.sub.3 H; or ##STR4## where X is hydrogen or hydroxy; R.sup.1 is an amino, protected amino or carboxylic acylamino group, and R.sup.2 and R.sup.3 are independently selected from hydrogen or a hydrocarbon group of 1 to 18 carbon atoms.

Abstract: A monocyclic .beta.-lactam antibiotic having a formamido substitutent at the 3S-position, including compounds of the formula (I): ##STR1## and salts thereof wherein R is --SO.sub.3 H; --PO(OH)Y wherein Y is C.sub.1-6 alkoxy, hydroxy, aryloxy, C.sub.1-6 alkyl or aryl; ##STR2## wherein Z represents C.sub.1-6 alkyl or aryl; ##STR3## wherein Z.sup.1 and Z.sup.2 may be the same or different and each represents hydrogen, C.sub.1-6 alkyl, aryl, amino or C.sub.1-6 alkoxy, or Z.sup.1 and Z.sup.2 together form the residue of a heterocyclic ring; --OSO.sub.3 H; or ##STR4## where X is hydrogen or hydroxy; R.sup.1 is an amino, protected amino or carboxylic acylamino group, and R.sup.2 and R.sup.3 are independently selected from hydrogen or a hydrocarbon group of 1 to 18 carbon atoms.

Abstract: A monocyclic .beta.-lactam antibiotic having a formamido substituent at the 3S-position, including compounds of the formula (I): ##STR1## and salts thereof wherein R is --SO.sub.3 H; --PO(OH)Y wherein Y is C.sub.1-6 alkoxy, hydroxy, aryloxy, C.sub.1-6 alkyl or aryl; ##STR2## wherein Z represents C.sub.1-6 alkyl or aryl; ##STR3## wherein Z.sup.1 and Z.sup.2 may be the same or different and each represents hydrogen, C.sub.1-6 alkyl, aryl, amino or C.sub.1-6 alkoxy, or Z.sup.1 and Z.sup.2 together form the residue of a heterocyclic ring; --OSO.sub.3 H; or ##STR4## where X is hydrogen or hydroxy; R.sup.1 is an amino, protected amino or carboxylic acylamino group, and R.sup.2 and R.sup.3 are independently selected from hydrogen or a hydrocarbon group of 1 to 18 carbon atoms.

Abstract: The compounds of the formula (II): ##STR1## and salts and esters thereof wherein R is an inert organic group of up to 18 carbon atoms and are able to inhibit the action of various bacterial .beta.-lactamases. Thus when a compound of the formula (II) or its salt or ester is used together with a penicillin or cephalosporin, the effectiveness of that penicillin or cephalosporin can be considerably enhanced. These novel synergysts can be prepared by etherification of an ester of clavulanic acid followed if desired by deesterification. The novel synergysts also possess antibacterial activity.

Abstract: The compounds of the formula (II): ##STR1## and salts and esters thereof wherein R is an inert ogranic group of up to 18 carbon atoms and are able to inhibit the action of various bacterial .beta.-lactamases. Thus when a compound of the formula (II) or its salt or ester is used together with a penicillin or cephalosporin, the effectiveness of that penicillin or cephalosporin can be considerably enhanced. These novel synergysts can be prepared by etherification of an ester of clavulanic acid followed if desired by deesterification. The novel synergysts also possess antibacterial activity.

Abstract: Compounds of the formula ##STR1## wherein X is S, SO or SO.sub.2 and R is an inert hydrocarbon of up to 20 carbon atoms which will not lead to rapid degradation of the above compound unsubstituted or substituted and A is a group such and CO.sub.2 A represents a carboxylic acid group or a salt or ester thereof, are useful for their antibacterial activity and for their .beta.-lactamase inhibitory activity.

Abstract: A process for the preparation of an antibacterially active compound of the formula (I): ##STR1## and salts and esters thereof wherein R.sup.1 and R.sup.2 independently are hydrogen or an organic group, and R.sup.3 is an organic group bonded via a carbon atom to the sulphur atom, which comprises reacting a compound of the formula (II): ##STR2## wherein R.sup.4 is an organic group different to R.sup.3 and R.sup.a is hydrogen or a carboxy-blocking group, with a thiol R.sup.3 SH or reactive derivative thereof. In addition certain compounds within the formula (II) are novel and useful antibacterial agents in their own right.

Abstract: The compounds of the formula (II): ##STR1## wherein R.sub.1 is a group such that CO.sub.2 R.sub.1 is a carboxylic acid group or a salt or ester thereof; R.sub.2 is a group of the sub-formula (a) or (b):--CR.sub.4 .dbd.C(R.sub.5) NH.CO.sub.n R.sub.6 (a)--CR.sub.7 .dbd.C(R.sub.8)R.sub.9 (b)wherein R.sub.4 is a hydrogen atom or a lower alkyl group; R.sub.5 is a hydrogen atom or a lower alkyl group; R.sub.6 is a lower alkyl, phenyl, fluorophenyl, chlorophenyl, bromophenyl or benzyl group; and n is 1 or 2; R.sub.7 is a hydrogen or a lower alkyl group; R.sub.8 is a hydrogen atom or a lower alkyl group; R.sub.9 is a hydrogen atom or a lower alkyl or phenyl group; R.sub.3 is a group of the sub-formula (c):CR.sub.10 R.sub.11 R.sub.12 (c)wherein R.sub.10 is a hydrogen atom or a hydroxyl or O.CO.R.sub.13 or O.CO.OR.sub.13 group where R.sub.13 is a lower alkyl, phenyl, benzyl, fluorobenzyl, chlorobenzyl, bromobenzyl, lower alkoxybenzyl or nitrobenzyl group; R.sub.11 is a hydrogen atom or a lower alkyl group; R.sub.

Abstract: The compounds of the formula (II): ##STR1## and salts and esters thereof wherein R.sub.1 is an inert organic group of up to 14 carbon atoms and R.sub.2 is an inert organic group of up to 16 carbon atoms, the group NR.sub.1 R.sub.2 containing up to 22 carbon atoms, are antibacterial agents able to enhance the effectiveness of penicillins and cephalosporins against certain .beta.-lactamase producing bacteria.

Abstract: Compounds of the formula ##STR1## wherein X is S, SO or SO.sub.2 and R is an organic group of up to 20 carbon atoms and A is a group such that CO.sub.2 A represents a carboxylic acid group or a salt or ester thereof, are useful for their antibacterial activity and for their .beta.-lactamase inhibitory activity.

Abstract: The present invention provides a compound of formula (I): ##STR1## wherein R.sup.1 is a group such that COOR.sup.1 is a carboxyic acid group or a salt or ester thereof;R.sup.3 is hydrogen or an organic radical;n is zero or 1;R.sup.4 and R.sup.5 are independently hydrogen or C.sub.1 -C.sub.3 alkyl;X is C.sub.1 -C.sub.6 alkylene optionally substituted by hydroxy or a carboxylic acid group or a salt or ester thereof;Y is an amino, or substituted amino, wherein the substituent is carboxylic acyl, C.sub.1 -C.sub.6 alkyl or a group .dbd.C(R.sup.14)NR.sup.15 R.sup.16 wherein R.sup.15 and or C.sub.1 -C.sub.6 alkyl and R.sup.14 is hydrogen or C.sub.1 -C.sub.6 alkyl, or a group --NR.sup.A R.sup.B wherein R.sup.A and R.sup.B are independently hydrogen or C.sub.1 -C.sub.6 alkyl.

Abstract: The present invention provides a compound of the formula (I): ##STR1## or a pharmaceutically acceptable salt or in-vivo hydrolyzable ester thereof wherein R.sup.1 is a hydrogen atom, an .alpha.-sulphonato-oxyethyl group, an .alpha.-sulphonato-oxypropyl group or is a group CR.sup.3 R.sup.4 R.sup.5 wherein R.sup.3 is a hydrogen atom or a hydroxy group; R.sup.4 is a hydrogen atom or a C.sub.1-6 alkyl group; and R.sup.5 is a hydrogen atom or a C.sub.1-6 alkyl group, a benzyl group, a phenyl group or is joined to R.sup.4 to form together with the carbon atom to which they are joined a carbocyclic ring of 5 to 7 carbon atoms; R.sup.2 is a pyrimidinyl group substituted by one two or three groups selected from nitro, halo, amino or substituted amino, and in addition may be optionally substituted by one or two C.sub.1-6 alkyl groups as the degree of substitution permits; and x is zero or one.These compounds are antibacterial agents. Their preparation and use are described.

Abstract: The compounds of the formula (II): ##STR1## and salts and esters theereof wherein R.sub.1 is an inert organic group of up to 14 carbon atoms and R.sub.2 is an inert organic group of up to 16 carbon atoms, the group NR.sub.1 R.sub.2 containing up to 22 carbon atoms, are antibacterial agents able to enhance the effectiveness of penicillins and cephalosporins against certain .beta.-lactamase producing bacteria.

Abstract: The present invention relates to sodium, thallium, silver or lithium salts of the compoundHS--CH=CHNHC(O).sub.n R.sub.6wherein n is 1 or 2, R.sub.6 is alkyl, phenyl or substituted phenyl. The salts are useful as reagents for the preparation of sulfur containing Clavulanic acid derivatives.

Abstract: The present invention provides the antibacterial agents of the formula (II): ##STR1## wherein R.sub.1 is a group such that CO.sub.2 R.sub.1 is a carboxylic acid group or a salt thereof or is a group of the formula CO.sub.2 R.sub.1.sup.1 wherein R.sub.1.sup.1 is a group such that CO.sub.2 R.sub.1.sup.1 is an ester group, R.sub.2 is a hydrogen atom or a lower alkyl group; R.sub.3 is a hydrogen atom or a lower alkyl group; and R.sub.4 is a phenyl group or a phenyl group substituted by one or two groups selected from fluorine, chlorine, OR.sub.5, NH.CO.R.sub.5, NH.CO.sub.2 R.sub.5 or CO.sub.2 R.sub.5 where R.sub.5 is a lower alkyl or benzyl group.A process for their preparation and their use in pharmaceutical compositions is also described.

Abstract: The compounds of the formula (II): ##STR1## and salts and esters thereof wherein R.sub.1 is an inert organic group of up to 14 carbon atoms and R.sub.2 is an inert organic group of up to 16 carbon atoms, the group NR.sub.1 R.sub.2 containing up to 22 carbon atoms, are antibacterial agents able to enhance the effectiveness of penicillins and cephalosporins against certain .beta.-lactamase producing bacteria.

Abstract: The present invention provides the antibacterial agents of the formula (II): ##STR1## wherein R.sub.1 is a group such that CO.sub.2 R.sub.1 is a carboxylic acid group or a salt thereof or is a group of the formula CO.sub.2 R.sub.1.sup.1 wherein R.sub.1.sup.1 is a group such that CO.sub.2 R.sub.1.sup.1 is an ester group, R.sub.2 is a hydrogen atom or a lower alkyl group; R.sub.3 is a hydrogen atom or a lower alkyl group; and R.sub.4 is a NH. CO.sub.n R.sub.6 group where R.sub.6 is a lower alkyl group, a phenyl group or a phenyl group substituted by one or two halogen atoms, lower alkyl or lower alkoxyl groups; and n is 1 or 2.A process for their preparation and their use in pharmaceutical compositions is also described.

Abstract: Compounds of the formula (III): ##STR1## wherein R.sub.1 is alkyl of up to 3 carbon atoms and R.sub.2 is alkyl of up to 3 carbon atoms optionally joined to R.sub.1 so that R.sub.1 and R.sub.2 and the carbon atom to which they are attached form a spiro-cyclopentyl or spiro-cyclohexyl ring, and wherein the configuration about the .beta.-lactam ring is trans, are useful in the preparation of antibacterial .beta.-lactam compounds.A process for the preparation of the compounds of the formula (III), is also desired.