A compound of formula wherein R is H or selected from the group consisting of (C 1 -C 4)alkyl, halo, (C 1 -C 4)haloalkyl, -NO 2, -C OR 1, -OR 1, -O(C 1 -C 4)haloalkyl, -NR A R B, -OC NR A R B, -C Rc, -C NR A R B, and -(C 1 -C 4)alkylene-NR A R B; R 1 is H or (C 1 -C 4)alkyl; R 2 is H or selected from the group consisting of (C 1 -C 4)alkyl, (C 1 -C 4)haloalkyl, -(C 1 -C 4)alkylene-OR 1 and (C 3 -C 8)cycloalkyl; R 3 is H or selected form the group consisting of (C 1 -C 4)alkyl; A is selected from the group consisting of 5-6 membered heteroaryl and aryl wherein each of said heteroaryl and aryl may be optionally substituted by one or more group selected from (C 1 -C 4)alkyl, -C R 1, -C OR 1, -C R 1, (C 1 -C 4)haloalkyl, halo, -NR A C R 1, -NR A C OR 1, -NR A C -(C 1 -C 4)alkylene-OR 1, -NR A C R C, -NR A C NR A R B, -N(C 1 -C 4)alkylene-NR A R B, aryl and heteroaryl optionally substituted by one or more (C 1 -C 4)alkyl and (C 1 -C 4)haloalkyl, or when A is aryl it may be fused to a second saturated or unsaturated ring optionally containing one or more heteroatoms selected from N, O and S to form a bicyclic ring system optionally substituted by one or more group selected from -C R 1, (C 1 -C 4)alkyl and oxo; R C is selected from the group consisting of from heteroaryl, aryl, (C 3 -C 8) cycloalkyl and (C 4 -C 8) heterocycloalkyl wherein said heteroaryl, aryl, heterocycloalkyl and cycloalkyl may be optionally substituted by one or more (C 1 -C 4)alkyl and -C OR 1; R A and R B are at each occurrence independently H or selected from the group consisting of (C 1 -C 4)alkyl, (C 3 -C 8)cycloalkyl, (C 1 -C 6)haloalkyl and halo, or R A and R B may form together with the nitrogen atom to which they are attached a 4-6 membered saturated heterocyclic ring system optionally containing a further heteroatom selected from N, S and O, said heterocyclic ring system may be optionally substituted by one or more groups selected from (C 1 -C 4)alkyl, (C 1 -C 4) haloalkyl and halo, with the proviso that when R 2 is H, R is not H. R is H or selected from the group consisting of (C 1 -C 4)alkyl, halo, (C 1 -C 4)haloalkyl, -NO 2, -C OR 1, -OR 1, -O(C 1 -C 4)haloalkyl, -NR A R B, -OC NR A R B, -C Rc, -C NR A R B, and -(C 1 -C 4)alkylene-NR A R B; R 1 is H or (C 1 -C 4)alkyl; R 2 is H or selected from the group consisting of (C 1 -C 4)alkyl, (C 1 -C 4)haloalkyl, -(C 1 -C 4)alkylene-OR 1 and (C 3 -C 8)cycloalkyl; R 3 is H or selected form the group consisting of (C 1 -C 4)alkyl; A is selected from the group consisting of 5-6 membered heteroaryl and aryl wherein each of said heteroaryl and aryl may be optionally substituted by one or more group selected from (C 1 -C 4)alkyl, -C R 1, -C OR 1, -C R 1, (C 1 -C 4)haloalkyl, halo, -NR A C R 1, -NR A C OR 1, -NR A C -(C 1 -C 4)alkylene-OR 1, -NR A C R C, -NR A C NR A R B, -N(C 1 -C 4)alkylene-NR A R B, aryl and heteroaryl optionally substituted by one or more (C 1 -C 4)alkyl and (C 1 -C 4)haloalkyl, or when A is aryl it may be fused to a second saturated or unsaturated ring optionally containing one or more heteroatoms selected from N, O and S to form a bicyclic ring system optionally substituted by one or more group selected from -C R 1, (C 1 -C 4)alkyl and oxo; R C is selected from the group consisting of from heteroaryl, aryl, (C 3 -C 8) cycloalkyl and (C 4 -C 8) heterocycloalkyl wherein said heteroaryl, aryl, heterocycloalkyl and cycloalkyl may be optionally substituted by one or more (C 1 -C 4)alkyl and -C OR 1; R A and R B are at each occurrence independently H or selected from the group consisting of (C 1 -C 4)alkyl, (C 3 -C 8)cycloalkyl, (C 1 -C 6)haloalkyl and halo, or R A and R B may form together with the nitrogen atom to which they are attached a 4-6 membered saturated heterocyclic ring system optionally containing a further heteroatom selected from N, S and O, said heterocyclic ring system may be optionally substituted by one or more groups selected from (C 1 -C 4)alkyl, (C 1 -C 4) haloalkyl and halo, with the proviso that when R 2 is H, R is not H.