Compounds of formula (IA) or (IB) have antibacterial activity : wherein W is =C(H)- or =N- R3 is a radical of formula -(Alk1)m-(Z1)p-(Alk2)n-Q wherein m, p and n are independently 0 or 1, provided that at least one of m, p and n is 1, Z1 is -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, -N(CH2CH3)-, -C(-O)-, -0-(C=O)-, -C(=O)-O-, or an optionally substituted divalent monocyclic carbocyclic or heterocyclic radical having 3 to 6 ring atoms or an optionally substituted divalent bicyclic carbocyclic or heterocyclic radical having 5 to 10 ring atoms AIk1 and AIk2 are optionally substituted C1-C6 alkylene, C2-C6 alkenylene, or C2-C6 alkynylene radicals, which may optionally terminate with or be interrupted by -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, Or -N(CH2CH3)- and Q is hydrogen, halogen, nitrile, or hydroxyl, or an optionally substituted monocyclic carbocyclic or heterocyclic radical having 3 to 6 ring atoms or an optionally substituted bicyclic carbocyclic or heterocyclic radical having 5 to 10 ring atoms R4 and R5 are optional substituents and R2, R6 and R7 are independently hydrogen or a radical of formula -(Alk3)x- (Z2)y-(Alk4)z-H wherein x, y and z are independently 0 or 1, Z2 is -O-, -S-, -S(O)-, -S(O2)-, - NH-, -N(CH3)-, -N(CH2CH3)-, -C(-O)-, -0-(C=O)- or -C(=O)-O- AIk3 and AIk4 are optionally substituted C1-C3 alkylene, C2-C3 alkenylene, or C2-C3 alkynylene radicals, which may optionally terminate with or be interrupted by -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, or - N(CH2CH3)-.Linvention porte sur des composés représentés par la formule (IA) ou (IB) qui ont une activité antibactérienne : dans laquelle W représente =C(H)- ou =N- R3 représente un radical de formule -(Alk1)m-(Z1)p-(Alk2)n-Q dans laquelle m, p et n représentent indépendamment 0 ou 1, à la condition quau moins lun parmi m, p et n représente 1, que Z1 représente -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, -N(CH2CH3)-, -C(-O)-, -O-(C=O)-, -C(=O)-O- ou un radical carbocyclique ou hétérocyclique monoc
