Abstract: A compound of formula (1) or a pharmaceutically acceptable salt or in vivo hydrolysable ester thereof: ##STR1## wherein R.sup.1 is phenyl, substituted phenyl 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;X represents; ##STR2## wherein R.sup.Y is methyl or acetyl; R.sup.2 and R.sup.3 may be the same or different and each is hydrogen, an aryl group, a heterocyclyl group or a C.sub.1-6 alkyl group optionally substituted by an aryl group or a heterocyclyl group; and R.sup.4 is hydrogen, a C.sub.1-6 alkylcarbonyl group, an aryl group, a heterocyclyl group, a C.sub.1-6 alkyl group optionally substituted by an aryl group or a heterocyclyl group;R.sup.5 represents, hydrogen, methoxy or --NHCHO; and Y is: ##STR3## wherein Y.sup.1 is oxygen, sulphur or --CH.sub.2 -- and Z represents hydrogen, halogen or an organic group such as C.sub.1-4 alkoxy, --CH.sub.2 Q or --CH.dbd.

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: This invention relates to a new class of penicillins (I) and their pharmaceutically acceptable salts and esters which are useful as antibiotics: ##STR1## wherein the stylized radical (hereafter referred to as R'): ##STR2## attached to the 6-amino nitrogen moiety of the penicillin (or ring analogue thereof) nucleus represents a mono- or polycyclic N-containing heterocyclic group;X is S, SO, CH.sub.2, or O; m is 0, 1 or 2;R is, inter alia, hydrogen, substituted and unsubstituted: alkyl, aryl, alkenyl, heterocyclylalkyl, heterocyclylalkenyl, aralkenyl, aralkyl, --NR.sub.2, COOR, CONR.sub.2, --OR, or CN;R.sup.2 is H, or lower alkoxyl.