Abstract: There is provided a process for the preparation of a compound according to Formula (II): which includes the step of cyclizing a compound of Formula (III): wherein R1, R2, R3, R4, X and m have meanings which are given in the description.

Abstract: There is provided a process for the preparation of a compound according to Formula (II): which includes the step of cyclising a compound of Formula (III): wherein R1, R2, R3, R4, X and m have meanings which are given in the description.

Abstract: There is provided a process for the preparation of a compound according to Formula (II): 1

Abstract: Compounds of formula (I) or salts thereof: ##STR1## wherein R.sup.1 is hydrogen, methoxy or formamido; R.sup.2 is an acyl group; CO.sub.2 R.sup.3 is a carboxy group or a carboxylate anion, or R.sup.3 is a carboxy protecting group, pharmaceutically acceptable salt-forming group or in vivo hydrolysable ester group; R.sup.4 represents hydrogen or up to four substituents; X is O, S, SO or SO.sub.2 ; Y is O, S, SO or SO.sub.2 ; n is 0 or 1; and m is 1 or 2. The compounds have antibacterial activity. Methods of synthesis of, and pharmaceutical formulations containing, compounds (I) are also described.

Abstract: A method of treatment of bacterial infections in humans or animals which comprises administering, in combination with a .beta.-lactam antibiotic, a therapeutically effective amount of an amino acid derivative of Formula (I) or a pharmaceutically acceptable salt, solvate or in vivo hydrolysable ester thereof, ##STR1## wherein: R is hydrogen, a salt forming cation or an in vivo hydrolysable ester-forming group; R.sub.1 is hydrogen, (C.sub.1-6)alkyl optionally substituted by up to three halogen atoms or by a mercapto, (C.sub.1-6)alkoxy, hydroxy, amino, nitro, carboxy, (C.sub.1-6)alkylcarbonyloxy, (C.sub.1-6)alkoxycarbonyl, formyl or (C.sub.1-6)alkylcarbonyl group, (C.sub.3-7)cycloalkyl, (C.sub.3-7)cycloalkyl(C.sub.2-6)alkyl, (C.sub.2-6)alkenyl, (C.sub.2-6)alkynyl, aryl, aryl(C.sub.1-6)alkyl, heterocyclyl or heterocyclyl(C.sub.1-6)alkyl; R.sub.2 is hydrogen, (C.sub.1-6)alkyl or aryl(C.sub.1-6)alkyl; R.sub.3 is hydrogen, (C.sub.1-6)alkyl optionally substituted by up to three halogen atoms, (C.sub.

Abstract: Compounds of formula (I) or salts thereof: ##STR1## wherein R.sup.1 is hydrogen, methoxy or formamido; R.sup.2 is an acyl group; CO.sub.2 R.sup.3 is a carboxy group or a carboxylate anion, or R.sup.3 is a carboxy protecting group, pharmaceutically acceptable salt-forming group or in vivo hydrolysable ester group; R.sup.4 represents hydrogen or up to four substituents; X is O, S, SO or SO.sub.2 ; Y is O, S, SO or SO.sub.2 ; n is 0 or 1; and m is 1 or 2. The compounds have antibacterial activity. Methods of synthesis of, and pharmaceutical formulations containing, compounds (I) are also described.