Abstract: Compounds of formula (I) and (IA) have antibacterial or antiprotozoal activity: formula (1) formula (2) wherein: Z represents a radical of formula N(OH)CH(?O) or of formula C(?O)NH(OH); R1 represents hydrogen, methyl or trifluoromethyl, or, except when Z is a radical of formula N(OH)CH(?O), a hydroxy or amino group; R2 represents a radical of formula R10—(X)n-(ALK)m- wherein R10 represents hydrogen, or an optionally substituted c1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, cycloalkyl, aryl, or heterocyclyl group, 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; R3 represents hydrogen, C1-C6alkyl, or benzyl; and R4 is as defined in the specification.

Abstract: Compounds of formula (I) are antibacterial agents: wherein: Z is —N(OH)CH(?O) or —C(?O)NH(OH); R1 represents hydrogen, methyl or trifluoromethyl or, except when Z is a radical of formula —N(OH)CH(?O), a hydroxy, halo or amino group; R2, R3 and R4 independently represents hydrogen or a group R10—(D)n—(ALK)m— wherein R10, D, n, m and ALK are as defined in the claims; or R3 and R4 taken together with the nitrogen atom to which they are attached form an optionally substituted monocyclic heterocyclic ring containing from 5 to 7 ring atoms, one of which is the nitrogen atom to which R4 and R5 are attached and the remaining ring atoms being selected from compatible combinations of carbon, oxygen, sulfur and nitrogen

Abstract: Compounds of formula (II) have antibacterial activity: wherein Q represents a radical of formula —N(OH)CH(?0) or formula —C(?O)NH(OH); R1 represents hydrogen, methyl or trifluoromethyl, or, except when Z is a radical of formula —N(OH)CH(?0), a hydroxy, halo or amino group; R2 represents a group R10-(V)n-(ALK)m- wherein R10 represents hydrogen, or an optionally substituted C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, cycloalkyl, aryl, or heterocyclyl group, 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, V represents —NH—, —O— or —S—, m and n are independently 0 or 1; R3 represents the side chain of a natural or non-natural alpha amino acid; R4 represents hydrogen or C1-C3 alkyl; Y represents N or CH; ring A is optionally substituted on one or more ring carbon atoms by C1-C3 alkyl, C1-C3 alkoxy, or halo; and R5 represents a group (IIA): wherein m is 0 or 1; Alk1 represents a

Abstract: Compounds of formula (I) are antibacterial agents: wherein: Z is —N(OH)CH(?O) or —C(?O)NH(OH); R1 represents hydrogen, methyl or trifluoromethyl or, except when Z is a radical of formula —N(OH)CH(?O), a hydroxy, halo or amino group; R2, R3 and R4 independently represents hydrogen or a group R10-(D)n-(ALK)m- wherein R10, D, n, m and ALK are as defined in the claims; or R3 and R4 taken together with the nitrogen atom to which they are attached form an optionally substituted monocyclic heterocyclic ring containing from 5 to 7 ring atoms, one of which is the nitrogen atom to which R4 and R5 are attached and the remaining ring atoms being selected from compatible combinations of carbon, oxygen, sulfur and nitrogen.

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) and (IA) have antibacterial or antiprotozoal activity: formula (1) formula (2) wherein: Z represents a radical of formula N(OH)CH(═O) or of formula C(═O)NH(OH); R1 represents hydrogen, methyl or trifluoromethyl, or, except when Z is a radical of formula N(OH)CH(═O), a hydroxy or amino group; R2 represents a radical of formula R10—(X)n-(ALK)m— wherein R10 represents hydrogen, or an optionally substituted c1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, cycloalkyl, aryl, or heterocyclyl group, 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; R3 represents hydrogen, C1-C6alkyl, or benzyl; and R4 is as defined in the specification.