Abstract: This invention relates to heterocyclic compounds which are inhibitors of the enzyme aromatase, to processes for their preparation, to pharmaceutical compositions containing them and to their use in medicine.Particular compounds of the invention are compounds of formula (I) ##STR1## wherein R.sup.1 represents a cyano or nitro group; R.sup.2 represents hydrogen or one or more halogen atoms;R.sup.3 represents a C.sub.1-6 alkyl group and R.sup.4 represents hydrogen or aC.sub.1-6 alkyl group or R.sup.3 and R.sup.4 together represent a C.sub.3-6 cycloalkyl group; andR.sup.5 represents hydrogen or one or more halogen atoms or C.sub.1-6 alkoxy groups and pharmaceutically acceptable salts and solvates thereof.

Abstract: There are described new compounds of formula (1) ##STR1## wherein R.sup.1 represents an acyl group;X.sup.1 represents phenylalanine or p-methoxyphenylalanine bonded N-terminally to R.sup.1 and C-terminally to X.sup.2 ;X.sup.2 represents histidine or N-methylhistidine bonded N-terminally to X.sup.1 and C-terminally to the group --NH--;R.sup.2 represents a C.sub.4-6 cycloalkyl group;R.sup.3 represents a group CHR.sup.6 R.sup.7 (where R.sup.6 is a hydrogen atom or a hydroxyl group and R.sup.7 is a pyridinyl ring);X.sup.3 represents a C.sub.2-6 alkylene chain optionally substituted by one or more C.sub.1-4 alkyl groups;R.sup.4, and R.sup.5, which may be the same or different, each independently represent a hydrogen atom or a C.sub.1-4 alkyl group, or NR.sup.4 R.sup.5 may form a 5- or 6- membered polymethylenimine ring;and salts and solvates thereof.The new compounds have been found to exhibit activity as renin inhibitors, combining good duration of action with significant oral potency.

Abstract: Compounds of the general formula (I) ##STR1## (R is H, alkyl, alkenyl, alkynyl, cycloalkyl, aralkyl or CHO, R.sup.1 and R.sup.2 are independently halogen, alkyl, alkoxy, hydroxyl, cyano, nitro or --NR.sup.3 R.sup.4 where R.sup.3 and R.sup.4 are independently H or alkyl and R.sup.2 may be H) and their salts have selective .alpha..sub.2 -adrenoreceptor antagonist action.The compounds may be prepared by amination of compounds of the general formula (II) ##STR2## (where R.sup.1 and R.sup.2 are as defined above and X is a leaving group.

Abstract: Compounds of the general formula (I) ##STR1## (wherein R is H, alkyl, alkenyl, alkynyl, cycloalkyl, aralkyl or CHO; and R.sup.1 and R.sup.2 each represents H, fluorine or chlorine);and their salts have selective .alpha..sub.2 -adrenoreceptor antagonist action.The compounds may be prepared by amination of compounds of the general formula (II): ##STR2## (wherein X is a leaving group).

Abstract: 2-Vinylclavem compounds are disclosed which have been found of value in the synthesis of thio-derivatives of clavulanic acid which possess antibiotic and .beta.-lactamase inhibitory activity. Methods for preparing the vinylclavem compounds are disclosed and processes for preparing the thio-derivatives are given.

Abstract: Novel halogen derivatives of clavulanic acid are described which are of value in the preparation of a range of clavulins which either inhibit .beta.-lactamases or show activity against strains of both gram-positive and gram-negative bacteria. Processes for preparing the halogen derivatives are described and methods for converting them into the active clavulins are given.

Abstract: .beta.-Lactam compounds of the formula (I) ##STR1## (wherein R represents an esterified carboxyl group, --NR.sup.1 R.sup.2 R.sup.3 represents the residue of a nitrogen base, and R.sup.4 represents a hydrogen atom, a hydroxyl group or acylated or etherified hydroxyl group or the residue of a sulphur nucleophile) are disclosed, together with processes for their preparation. The compounds are valuable intermediates for the preparation or purification of further .beta.-lactam compounds having .beta.-lactamase inhibitory activity.