ANTIBACTERIAL AGENTS

Compounds of formula (I) have antibacterial activity; wherein Q represents a radical of formula -N(OH)CH(-O) or formula -C(-O)NH(OH); Y represents -C(-O)-, -C(-S)-, -S(-O)-, or -SO2-; R1 represents hydrogen, C1-C6 alkyl or C1-C6 alkyl substituted by one or more halogen atoms, or, except when Q is a radical of formula -N(OH)CH(-O), a hydroxy, C1-C6 alkoxy, C1-C6 alkenyloxy, halogen, amino, C1-C6 alkylamino, or di-(C1-C6 alkyl)amino group; R2 represents a substituted or unsubstituted C1-C6 alkyl, C1-C3 alkyl-O-C1-C3 alkyl, C1-C3 alkyl-S-C1-C3 alkyl, cycloalkyl(C1-C3 alkyl)-, aryl(C1-C3alkyl)-, heterocyclyl(C1-C3 alkyl)-, or R1R2N-C1-C3 alkyl group wherein R1 represents hydrogen or C1-C3 alkyl and R2 represents C1-C3 alkyl, or R1R2N-represents a cyclic amino group; R3 and R4 taken together with the nitrogen atoms to which they are respectively attached form a saturated heterocyclic ring of from 4 to 7 ring atoms, which may be fused to a second carbocyclic or heterocyclic ring, either of which rings may optionally be substituted; and A represents a primary, secondary or tertiary amino group or a group -R5, -OR5, wherein R5 is a substituted or unsubstituted C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, cycloalkyl, aryl, heterocyclyl, C1-C3 alkyl-O-C1-C3alkyl, C1-C3 alkyl-S-C1-C3 alkyl, cycloalkyl(C1-C3 alkyl)-, heterocyclic(C1-C3 alkyl, aryl(C1-C3 alkyl)-or R1R2N-C1-C3 alkyl group wherein R1 represents hydrogen or C1-C3 alkyl and R2 represents C1-C3 alkyl, or R1R2N-represents a cyclic amino group.