A compound of formula: and pharmaceutically acceptable salts thereof, wherein R 1 represents -NR 2 R 3, or a nitrogen containing C 5-10 heterocyclyl; wherein said heterocyclyl is optionally substituted with one or more of R a; R 2 and R 3 independently represent (a) hydroxy, (b) -O-C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of R a; (c) -C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of R a; (d) -hydrogen; R a represents: (a) halogen, (b) hydroxy, (c) -O-C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of halo; (d) -C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of halo; (e) cyano, (f) -NR A R B, wherein R A and R B are selected from the group consisting of (i) hydrogen, (ii) -C 1-6 alkyl, or R A and R B are linked together with the nitrogen to which they are both attached to form a 2-6 membered carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur, and the carbocyclic is optionally substituted with one or more C 1-6 alkyl, (g) -C(=O)-R C, -S n -R C; C 5-10 heterocyclyl, or C 6-10 aryl, said heterocyclyl and aryl optionally substituted with 1 to 3 groups of R C; and wherein R C is selected from the group consisting of (i) hydrogen, (ii) -C 1-6 alkyl, (iii) -O-C 1-6 alkyl, (iv) CF 3, (v) halogen, (vi) cyano, n is 0, 1 or 2. R 1 represents -NR 2 R 3, or a nitrogen containing C 5-10 heterocyclyl; wherein said heterocyclyl is optionally substituted with one or more of R a; R 2 and R 3 independently represent (a) hydroxy, (b) -O-C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of R a; (c) -C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of R a; (d) -hydrogen; (a) hydroxy, (b) -O-C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of R a; (c) -C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of R a; (d) -hydrogen; R a represents: (a) halogen, (b) hydroxy, (c) -O-C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of halo; (d) -C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of halo; (e) cyano, (f) -NR A R B, wherein R A and R B are selected from the group consisting of (i) hydrogen, (ii) -C 1-6 alkyl, or R A and R B are linked together with the nitrogen to which they are both attached to form a 2-6 membered carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur, and the carbocyclic is optionally substituted with one or more C 1-6 alkyl, (g) -C(=O)-R C, -S n -R C; C 5-10 heterocyclyl, or C 6-10 aryl, said heterocyclyl and aryl optionally substituted with 1 to 3 groups of R C; and wherein R C is selected from the group consisting of (i) hydrogen, (ii) -C 1-6 alkyl, (iii) -O-C 1-6 alkyl, (iv) CF 3, (v) halogen, (vi) cyano, (a) halogen, (b) hydroxy, (c) -O-C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of halo; (d) -C 1-6 alkyl, said alkyl optionally substituted with 1 to 3 groups of halo; (e) cyano, (f) -NR A R B, wherein R A and R B are selected from the group consisting of (i) hydrogen, (ii) -C 1-6 alkyl, or R A and R B are linked together with the nitrogen to which they are both attached to form a 2-6 membered carbocyclic ring, wherein one or two of the ring carbon atoms is replaced by a nitrogen, oxygen or sulfur, and the carbocyclic is optionally substituted with one or more C 1-6 alkyl, (i) hydrogen, (ii) -C 1-6 alkyl, (g) -C(=O)-R C, -S n -R C; C 5-10 heterocyclyl, or C 6-10 aryl, said heterocyclyl and aryl optionally substituted with 1 to 3 groups of R C; and wherein R C is selected from the group consisting of (i) hydrogen, (ii) -C 1-6 alkyl, (iii) -O-C 1-6 alkyl, (iv) CF 3, (v) halogen, (vi) cyano, (i) hydrogen, (ii) -C 1-6 alkyl, (iii) -O-C 1-6 alkyl, (iv) CF 3, (v) halogen, (vi) cyano, n is 0, 1 or 2.