Abstract: .beta.-Lactam antibiotics having an .alpha.-formamido substituent on the carbon atom adjacent to the carbonyl group of the .beta.-lactam ring and in particular bicyclic compounds having the partial structure: ##STR1## Intermediates and processes for the preparation of the compounds are further disclosed.

Abstract: A compound having the partial structure (A): ##STR1## wherein n is 1 or 2.

Abstract: A compound of formula (I) or a pharmaceutically acceptable salt or in vivo hydrolyzable ester thereof: ##STR1## R is phenyl, substituted phenyl, C.sub.3-6 cycloalkyl cyclohexenyl, cyclohexadienyl, or a 5- or 6-membered heterocyclic ring containing up to three hetero-atoms slected from oxygen, sulphur or nitrogen, optionally substituted with hydroxy, amino, halogen, substituted amino or C.sub.1-6 alkoxy; Q represents acetoxy, carbamoyloxy, heterocyclylthio group, or a nitrogen containing heterocyclic group bonded via nitrogen; R.sup.1 is hydrogen or a C.sub.1-6 alkyl group and R.sup.2 is an optionally substituted 5- or 6-membered heterocyclic group containing one or two heteroatoms; or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached form an optionally substituted five- or six-membered heterocyclic group containing one or two nitrogen heteroatoms; a process for the preparation of such compounds and pharmaceutical compositions comprising them.

Abstract: .beta.-Lactam antibiotics having an .alpha.-formamido substituent on the carbon atom adjacent to the carbonyl group of the .beta.-lactam ring and in particular bicyclic compounds having the partial structure: ##STR1## Intermediates and processes for the preparation of the compounds are further disclosed.

Abstract: A process for the preparation of a .beta.-lactam having the partial structure (I): ##STR1## wherein R.sub.1 is an acyl group, which process comprises treating an imine having the partial structure (II): ##STR2## with a nucleophilic derivative of formamide.

Abstract: .beta.-Lactam antibiotics having an .alpha.-formamido substituent on the carbon atom adjacent to the carbonyl group of the .beta.-lactam ring and in particular bicyclic compounds having the partial structure: ##STR1## Intermediates and processes for the preparation of the compounds are further disclosed.

Abstract: A compound of formula (I) or a pharmaceutically acceptable salt or in vivo hydrolysable ester thereof: ##STR1## wherein R is phenyl, 4-hydroxyphenyl, or a 5- or 6-membered heterocyclic ring containing up to three heteroatoms selected from oxygen, sulphur or nitrogen, optionally substituted with hydroxy, amino, halogen or C.sub.1-6 alkoxy;R.sup.1 represents hydrogen or C.sub.1-6 alkyl;R.sup.2 and R.sup.3 are the same or different and represent hydrogen, C.sub.1-6 alkyl, halogen, amino, hydroxy, or C.sub.1-6 alkoxy;X represents oxygen or sulphur; andA represents hydrogen, pyridyl, acetoxy, carbamoyloxy or a heterocyclicthio group;Their preparation and use is described.

Abstract: A compound of formula (I) or a pharmaceutically acceptable salt or in vivo hydrolyzable ester thereof: ##STR1## wherein R is phenyl 4-hydroxy phenyl, or a 5- 6- membered heterocyclic ring containing up to three heteroatoms selected from oxygen, sulphur or nitrogen, optionally substituted with hydroxy, amino, halogen or C.sub.1-6 alkoxy;R.sup.1 represents hydrogen or C.sub.1-6 alkyl;R.sup.2 and R.sup.3 are the same or different and represent hydrogen, C.sub.1-6 alkyl, halogen, amino, hydroxy, or C.sub.1-6 alkoxy.Their preparation and use is described.