A compound of formula: a tautomer thereof, or a pharmaceutically acceptable salt of said compound or tautomer, wherein: X is selected from O, N(R h), and C(R i)(R j); R a is selected from hydrogen, fluoro, C 1 -C 3 alkyl, and C 1 -C 3 alkoxy; R b, R c, R d, and R e, are each independently selected from hydrogen and C 1 -C 3 alkyl; R f and R g are each independently selected from hydrogen, fluoro, cyano, C 1 -C 3 alkyl, and C 1 -C 3 alkoxy; when X is O or N(R h), neither of R a, R f or R g, is fluoro or C 1 -C 3 alkoxy; R h is selected from hydrogen, C 1 -C 3 alkyl, C R', S 2 R', and phenyl; R' is C 1 -C 3 alkyl; R i and R j are each independently selected from hydrogen, fluoro, cyano, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, and phenyl; R 1 is selected from hydrogen and C 1 -C 3 alkyl; R 2 is selected from a 5 to 10 membered, monocyclic or bicyclic, optionally substituted heteroaryl or aryl ring, and a 3 to 10 membered, monocyclic or bicyclic, substituted heterocyclyl or cycloalkyl ring; or R 1 and R 2 together form a 5 to 10 membered, monocyclic or bicyclic, optionally substituted heteroaryl ring, or a 4 to 10 membered, monocyclic or bicyclic, substituted heterocyclyl ring; wherein R 2, or the ring formed by R 1 together with R 2, when substituted, is substituted with one to four -Q 1 (R 3) n, which may be the same or different, wherein: n is 0 or 1; when n is 0, Q 1 represents Q 1a; when n is 1, Q 1 represents Q 1b; wherein Q 1a is selected from halo, cyano, C 1 -C 6 alkyl and C 1 -C 6 alkoxy; Q 1b is a covalent bond; R 3 is a 3 to 10 membered monocyclic or bicyclic heterocyclyl, heteroaryl, cycloalkyl or aryl ring; wherein R 3 is optionally substituted with one to four substituents independently selected from halo, cyano, oxo, nitro, hydroxyl, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, -Q 2a -R 11, and Q 2a -CONR 8 R 9; wherein said alkyl and alkoxy groups are optionally substituted by one or more halo; wherein Q 2a represents a covalent bond, C 1 -C 6 alkylene or C 2 -C 6 alkenylene; R 8 and R 9 are each independently selected from hydrogen and C 1 -C 6 alkyl; R 11 is a 3 to 10 membered heterocyclyl, heteroaryl, aryl or cycloalkyl; and wherein each heteroaryl or heterocyclyl ring comprises one to three heteroatoms independently selected from nitrogen, oxygen and sulfur. X is selected from O, N(R h), and C(R i)(R j); R a is selected from hydrogen, fluoro, C 1 -C 3 alkyl, and C 1 -C 3 alkoxy; R b, R c, R d, and R e, are each independently selected from hydrogen and C 1 -C 3 alkyl; R f and R g are each independently selected from hydrogen, fluoro, cyano, C 1 -C 3 alkyl, and C 1 -C 3 alkoxy; when X is O or N(R h), neither of R a, R f or R g, is fluoro or C 1 -C 3 alkoxy; R h is selected from hydrogen, C 1 -C 3 alkyl, C R', S 2 R', and phenyl; R' is C 1 -C 3 alkyl; R i and R j are each independently selected from hydrogen, fluoro, cyano, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, and phenyl; R 1 is selected from hydrogen and C 1 -C 3 alkyl; R 2 is selected from a 5 to 10 membered, monocyclic or bicyclic, optionally substituted heteroaryl or aryl ring, and a 3 to 10 membered, monocyclic or bicyclic, substituted heterocyclyl or cycloalkyl ring; or R 1 and R 2 together form a 5 to 10 membered, monocyclic or bicyclic, optionally substituted heteroaryl ring, or a 4 to 10 membered, monocyclic or bicyclic, substituted heterocyclyl ring; wherein R 2, or the ring formed by R 1 together with R 2, when substituted, is substituted with one to four -Q 1 (R 3) n, which may be the same or different, wherein: n is 0 or 1; when n is 0, Q 1 represents Q 1a; when n is 1, Q 1 represents Q 1b; wherein Q 1a is selected from halo, cyano, C 1 -C 6 alkyl and C 1 -C 6 alkoxy; Q 1b is a covalent bond; R 3 is a 3 to 10 membered monocyclic or bicyclic heterocyclyl, heteroaryl, cycloalkyl or aryl ring; wherein R 3 is optionally substituted with one to four substituents independently selected from halo, cyano, oxo, nitro, hydroxyl, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, -Q 2a -R 11, and Q 2a -CONR 8 R 9; wherein said alkyl and alkoxy groups are optionally substituted by one or more halo; wherein Q 2a represents a covalent bond, C 1 -C 6 alkylene or C 2 -C 6 alkenylene; R 8 and R 9 are each independently selected from hydrogen and C 1 -C 6 alkyl; R 11 is a 3 to 10 membered heterocyclyl, heteroaryl, aryl or cycloalkyl; and wherein each heteroaryl or heterocyclyl ring comprises one to three heteroatoms independently selected from nitrogen, oxygen and sulfur. n is 0 or 1; when n is 0, Q 1 represents Q 1a; when n is 1, Q 1 represents Q 1b; wherein Q 1a is selected from halo, cyano, C 1 -C 6 alkyl and C 1 -C 6 alkoxy; Q 1b is a covalent bond; R 3 is a 3 to 10 membered monocyclic or bicyclic heterocyclyl, heteroaryl, cycloalkyl or aryl ring; wherein R 3 is optionally substituted with one to four substituents independently selected from halo, cyano, oxo, nitro, hydroxyl, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, -Q 2a -R 11, and Q 2a -CONR 8 R 9; wherein said alkyl and alkoxy groups are optionally substituted by one or more halo; wherein Q 2a represents a covalent bond, C 1 -C 6 alkylene or C 2 -C 6 alkenylene; R 8 and R 9 are each independently selected from hydrogen and C 1 -C 6 alkyl; R 11 is a 3 to 10 membered heterocyclyl, heteroaryl, aryl or cycloalkyl; and wherein each heteroaryl or heterocyclyl ring comprises one to three heteroatoms independently selected from nitrogen, oxygen and sulfur.