Abstract: Compounds of formula (I) are antibacterials: wherein: R1 represents hydrogen, or C1-C6 alkyl or C1-C6 alkyl substituted by one or more halogen atoms; R2 represents a group R10—(X)n-(ALK)m- wherein R10 represents hydrogen, or a C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, cycloalkyl, aryl, or heterocyclyl group, any of which may be unsubstituted or substituted by (C1-C6)alkyl, (C1-C6)alkoxy, hydroxy, mercapto, (C1-C6)alkylthio, amino, halo (including fluoro, chloro, bromo and iodo), trifluoromethyl, cyano, nitro, —COOH, —CONH2, —COORA, —NHCORA, —CONHRA, —NHRA, —NRARB, or —CONRARB wherein RA and RB are independently a (C1-C6)alkyl group, and ALK represents a straight or branched divalent C1-C6 alkylene, C2-C6 alkenylene, or C2-C6 alkynylene radical, and may be interrupted by one or more non-adjacent —NH—, —O— or —S— linkages, X represents —NH—, —O— or —S—, and m and n are independently 0 or 1; and A represents a group as defined in the specification.

Abstract: Compounds of formula (II) are antibacterial agents wherein Q represents a radical of the formula: —N(OH)CH(?O) or the formula: —C(?O)NH(OH); 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 the formula: —N(OH)CH(?O), a hydroxy, C1-C6 alkoxy, C1-C6 alkenyloxy, amino, C1-C6 alkylamino, or di-( C1-C6 alkyl)amino group; R2 represents a substituted or unsubstituted C1-C6 alkyl, cycloalkyl(C1-C6 alkyl)- or aryl(C1-C6 alkyl)-group; and A represents a group of formula (IIA), or (IIB) wherein R4 represents the side chain of a natural or non-natural alpha amino acid, and R5 and R6 when taken together with the nitrogen atom to which they are attached form a saturated heterocyclic first ring of 5 to 7 atoms as specified in the description.

Abstract: Compounds of formula (I) are antibacterials: wherein: R1 represents hydrogen, or C1-C6 alkyl or C1-C6 alkyl substituted by one or more halogen atoms; R2 represents a group R10—(X)n-(ALK)m- wherein R10 represents hydrogen, or a C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, cycloalkyl, aryl, or heterocyclyl group, any of which may be unsubstituted or substituted by (C1-C6)alkyl, (C1-C6)alkoxy, hydroxy, mercapto, (C1-C6)alkylthio, amino, halo (including fluoro, chloro, bromo and iodo), trifluoromethyl, cyano, nitro, —COOH, —CONH2, —COORA, —NHCORA, —CONHRA, —NHRA, —NRARB, or —CONRARB wherein RA and RB are independently a (C1-C6)alkyl group, and ALK represents a straight or branched divalent C1-C6 alkylene, C2-C6 alkenylene, or C2-C6 alkynylene radical, and may be interrupted by one or more non-adjacent —NH—, —O— or —S— linkages, X represents —NH—, —O— or —S—, and m and n are independently 0 or 1; and A represents a group as defined in the specification.