2-pyridyl substituted imidazoles as ALK5 and/or ALK4 inhibitors

A compound of formula (I):

• wherein R1 is naphthyl, anthracenyl, or phenyl optionally substituted with substituents selected from halo, OH, —O—C1-6alkyl, —S—C1-6alkyl, C1-6alkyl, C1-6haloalkyl, —O— (CH2)n-Ph, —S— (CH2)n-Ph, cyano, phenyl, and CO2R, wherein R is H or C1-6alkyl, and n is 0, 1, 2, or 3;
• or R1 is phenyl or pyridyl fused with an aromatic or non-aromatic cyclic ring of 5-7 members wherein said cyclic ring optionally contains up to three heteroatoms, independently selected from N, O and S, and the fused phenyl or pyridyl may be further optionally substituted by halo, OH, —O—C1-6alkyl, —S—C1-6alkyl, C1-6alkyl, C1-6haloalkyl, cyano, phenyl or ═O;
• R2 is H, OH, —O—C1-6alkyl, —S—C1-6alkyl, C1-6alkyl, phenyl, C1-6haloalkyl, NH2, NH(CH2)n-Ph, NH—C1-6alkyl, halo, CN, NO2, CONHR or SO2NHR, wherein R is H or C1-6alkyl, and n is 0, 1, 2, or 3;
• R3 is or R3 is a heteroaromatic cyclic ring optionally substituted
• with substituents selected from halo, OH, —O—C1-6alkyl, —S—C1-6alkyl, C1-6alkyl, C1-6haloalkyl, amino, C1-6alkylamino, di(C1-6alkyl)amino, —O— (CH2)n-Ph, —S— (CH2)n-Ph, cyano, phenyl, and CO2R, wherein R is H or C1-6alkyl, and n is 0, 1, 2, or 3;
• or R3 is phenyl fused with an aromatic or non-aromatic cyclic ring of 5-7 members wherein said cyclic ring optionally contains up to three heteroatoms, independently selected from N, O and S, and the fused phenyl may be further optionally substituted by halo, OH, —O—C1-6alkyl, —S—C1-6alkyl, C1-6alkyl, C1-6haloalkyl, cyano, or phenyl;
• R4 is halo, C1-6haloalkyl, or —SO2C1-6alkyl;
• R5 and R6 are independently H, halo, C1-6alkyl, C3-7cycloalkyl, —(CH2)p—NO2, —(CH2)p—NR7R8, —(CH2)p—CHO, —(CH2)p—CONHOH, —(CH2)p—CN, —(CH2)p—CO2H, (CH2)p—CO2R7, —CH2)p—CONR7R8, —(CH2)p—C(═NR7)NR7R8, —(CH2)p-tetrazole, —(CH2)p—COR7, —(CH2)q—(OR9)2, —(CH2)p—OR7, —(CH2)p—CH═CH—CN, —(CH2)p—CH═CH—CO2H, —(CH2)p—CH═CH—CO2R7, —(CH2)p—CH═CH—CONR7R8, —(CH2)p—NHCOR7, —(CH2)p—NHCO2R7, —(CH2)p—CONHSO2R7, —(CH2)p—NHSO2R7 or —(CH2)p—CH═CH-tetrazole;
• R7 and R8 are independently H, phenyl or C1-6alkyl wherein phenyl or C1-6alkyl is optionally substituted by —(CH2)q—CONHOH, —(CH2)q—CN, —CH2)q—CO2R10, —(CH2)q—CONR11R12, —(CH2)q-tetrazole, —(CH2)r—OR10, —(CH2)r—R13, —(CH2)r—NR11R12;
• or R7 and R8 are taken together to form a non-aromatic cyclic ring of 3-6 members wherein said cyclic ring optionally contains up to three heteroatoms, independently selected from N, O and S;
• R9 is H or C1-6alkyl;
• R10, R11 and R12 are independently H or C1-6alkyl;
• R13 is H or a 3-7 membered heterocyclic ring optionally substituted at one, two or three positions by halo, OH, —O—C1-6alkyl, —S—C1-6alkyl, C1-6alkyl, C1-6haloalkyl, amino, C1-6alkylamino, di(C1-6alkyl)amino, cyano, oxo, carboxy or nitro;
• p is 0, 1, 2, 3, or 4;
• q is 1, 2, 3, or 4;
• r is 2, 3, or 4;
• X is C1-10alkylene, C2-10alkenylene or C2-10alkynylene;
• one of A1 and A2 is N and the other is NR14;
• and
• R14 is H, OH, C1-6alkyl, or C3-7cycloalkyl;
• or a pharmaceutically acceptable salt thereof.