A compound of formula wherein R is H or selected from the group consisting of (C 1 -C 4)alkyl, (C 1 -C 4)haloalkyl and 5-6 membered heteroaryl, wherein each of said heteroaryl may be optionally substituted by one or more group selected from (C 1 -C 4)alkyl, halo, (C 1 -C 4)haloalkyl; 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, halo, (C 1 -C 4)haloalkyl and (C 3 -C 8)cycloalkyl; R 3 is H or (C 1 -C 4)alkyl; A is selected from the group consisting of 5-6 membered heteroaryl wherein each of said heteroaryl 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, heteroaryl optionally substituted by one or more (C 1 -C 4)alkyl and (C 1 -C 4)haloalkyl, R C is selected from the group consisting of 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. R is H or selected from the group consisting of (C 1 -C 4)alkyl, (C 1 -C 4)haloalkyl and 5-6 membered heteroaryl, wherein each of said heteroaryl may be optionally substituted by one or more group selected from (C 1 -C 4)alkyl, halo, (C 1 -C 4)haloalkyl; 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, halo, (C 1 -C 4)haloalkyl and (C 3 -C 8)cycloalkyl; R 3 is H or (C 1 -C 4)alkyl; A is selected from the group consisting of 5-6 membered heteroaryl wherein each of said heteroaryl 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, heteroaryl optionally substituted by one or more (C 1 -C 4)alkyl and (C 1 -C 4)haloalkyl, R C is selected from the group consisting of 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.