Compounds of formula (I) have antibacterial activity wherein R represents hydrogen or 1, 2 or 3 optional substituents W is =C(R1)- or =N- R1 is hydrogen or an optional substituent and R2 is hydrogen, methyl, or fluorine or R1 and R2 taken together are -CH2-, -CH2CH2-, -O-, or, in either orientation, -O- CH2- Or -OCH2CH2- R3 is a radical of formula -(Alk<1>)m-(Z)p-(Alk<2>)n-Q wherein m, p and n are independently 0 or 1, provided that at least one of m, p and n is 1, Z is -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, -N(CH2CH3)-, -C(=O)-, -O-(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 heterocyclic radical having 5 to 10 ring atoms Alk<1> and Alk<2> are optionally substituted C1C6 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 heterocyclic radical having 5 to 10 ring atoms.
