A compound of the formula (I'): or a pharmaceutically acceptable salt thereof, wherein: R 1 is C 1-7 alkyl; for each occurrence, R 2 is independently C 1-7 alkyl, NO 2, CN, halo, C 3-7 cycloalkyl, hydroxy, C 1-7 alkoxy, halo-C 1-7 alkyl, NR b R c, C 6-10 aryl, heteroaryl or heterocyclyl; wherein R b and R c for each occurrence, are independently H or C 1-7 alkyl; R 3 is A 2 -R 4; R 4 is C 6-10 aryl or a heteroaryl, which can be monocyclic or bicyclic and which can be optionally substituted with one or more substituents independently selected from hydroxy, hydroxy-C 1-7 alkyl, NR b R c, nitro, C 1-7 alkoxy, halo, C 1-7 alkyl, halo-C 1-7 alkyl, C 2-7 alkenyl, C 6-10 aryl, heteroaryl, -C C 1-7 alkyl, -NHS 2- C 1-7 alkyl, -SO 2 C 1-7 alkyl and benzyl; R 5 is H, halo, hydroxy, C 1-7 alkoxy, C 1-7 alkyl or halo-C 1-7 akyl; and X is OH, -O-C 1-7 alkyl, -NR b R c, -NHS 2 -C 1-7 alkyl, -NHS 2 -benzyl or -O-C 6-10 aryl; wherein alkyl is optionally substituted with one or more substituents independently selected from the group consisting of aryl, heteroaryl, heterocyclyl, -C NH 2, -C NH- C 1-6 alkyl, and-C N(C 1-6 alkyl) 2; A 2 is a bond or a linear or branched C 1-7 alkylene which is optionally substituted with one or more substituents independently selected from the group consisting of halo, C 1-7 alkoxy, hydroxy, O-Acetate and C 3-7 cycloalkyl; and n is 0, 1, 2, 3, 4 or 5; wherein each heteroaryl is a monocyclic or bicyclic aromatic ring comprising 5-10 ring atoms selected from carbon atoms and 1 to 5 heteroatoms, and each heterocyclyl is a monocyclic saturated or partially saturated but non-aromatic moiety comprising 4-7 ring atoms selected from carbon atoms and 1-5 heteroatoms, wherein each heteroatom of a heteroaryl or a heterocyclyl is independently selected from O, N and S. R 1 is C 1-7 alkyl; for each occurrence, R 2 is independently C 1-7 alkyl, NO 2, CN, halo, C 3-7 cycloalkyl, hydroxy, C 1-7 alkoxy, halo-C 1-7 alkyl, NR b R c, C 6-10 aryl, heteroaryl or heterocyclyl; wherein R b and R c for each occurrence, are independently H or C 1-7 alkyl; R 3 is A 2 -R 4; R 4 is C 6-10 aryl or a heteroaryl, which can be monocyclic or bicyclic and which can be optionally substituted with one or more substituents independently selected from hydroxy, hydroxy-C 1-7 alkyl, NR b R c, nitro, C 1-7 alkoxy, halo, C 1-7 alkyl, halo-C 1-7 alkyl, C 2-7 alkenyl, C 6-10 aryl, heteroaryl, -C C 1-7 alkyl, -NHS 2- C 1-7 alkyl, -SO 2 C 1-7 alkyl and benzyl; R 5 is H, halo, hydroxy, C 1-7 alkoxy, C 1-7 alkyl or halo-C 1-7 akyl; and X is OH, -O-C 1-7 alkyl, -NR b R c, -NHS 2 -C 1-7 alkyl, -NHS 2 -benzyl or -O-C 6-10 aryl; wherein alkyl is optionally substituted with one or more substituents independently selected from the group consisting of aryl, heteroaryl, heterocyclyl, -C NH 2, -C NH- C 1-6 alkyl, and-C N(C 1-6 alkyl) 2; A 2 is a bond or a linear or branched C 1-7 alkylene which is optionally substituted with one or more substituents independently selected from the group consisting of halo, C 1-7 alkoxy, hydroxy, O-Acetate and C 3-7 cycloalkyl; and n is 0, 1, 2, 3, 4 or 5; wherein each heteroaryl is a monocyclic or bicyclic aromatic ring comprising 5-10 ring atoms selected from carbon atoms and 1 to 5 heteroatoms, and each heterocyclyl is a monocyclic saturated or partially saturated but non-aromatic moiety comprising 4-7 ring atoms selected from carbon atoms and 1-5 heteroatoms, wherein each heteroatom of a heteroaryl or a heterocyclyl is independently selected from O, N and S. wherein each heteroaryl is a monocyclic or bicyclic aromatic ring comprising 5-10 ring atoms selected from carbon atoms and 1 to 5 heteroatoms, and each heterocyclyl is a monocyclic saturated or partially saturated but non-aromatic moiety comprising 4-7 ring atoms selected from carbon atoms and 1-5 heteroatoms, wherein each heteroatom of a heteroaryl or a heterocyclyl is independently selected from O, N and S.