A compound of the formula: wherein: Ar/Het is a 5 membered heteroaryl selected from the group consisting of pyrazolyl, thiazolyl, oxazolyl, imidazolyl, isoxazolyl, 3,5-dimethylpyrazolyl and isothiazolyl; X is-Y-[C(R a) 2] a [C(R b) 2] b; wherein: Y is CR c =CR d; a is 1-3; b is 0-3; each occurrence of R a and R b is independently selected from H, F and C1-C6 alkyl: each of R c and R d is H; each of R4 and R5 is, independently, selected from H, C1-C6 alkyl and F; R1 is: (i) C6-C10 aryl, which is optionally substituted with from 1-3 R o; or (ii) monocyclic or bicyclic heteroaryl including from 5-10 ring atoms, which is optionally substituted with from 1-3 R o; wherein from 1-4 of the ring atoms is/are a heteroatom independently selected from O, N, N-H, N-R o, and S; or (iii) heterocyclyl including from 4-10 ring atoms, which is optionally substituted with from 1-3 R o; wherein from 1-4 of the ring atoms is/are a heteroatom independently selected from O, N, N-H, N-R o, and S; each occurrence of R o is independently selected from the group consisting of: • halogen; • C1-C6 alkyl; fluoro(C1-C6)alkyl; • hydroxyl; • hydroxy(C1-C4)alkyl; • C1-C6 alkoxy; fluoro(C1-C6)alkoxy; • (C1-C6 alkyl)C -; • (C1-C6 alkyl)NH-; (C1-C6 alkyl) 2 N-; • formyl; formyl(C1-C4) alkyl; cyano; cyano(C1-C4) alkyl; • SO 2 -(C1-C6)alkyl; SO-(C1-C6)alkyl; and • nitro; R2 is H; and R3 is H, F, or Cl; or a pharmaceutically acceptable salt thereof. Ar/Het is a 5 membered heteroaryl selected from the group consisting of pyrazolyl, thiazolyl, oxazolyl, imidazolyl, isoxazolyl, 3,5-dimethylpyrazolyl and isothiazolyl; X is-Y-[C(R a) 2] a [C(R b) 2] b; wherein: Y is CR c =CR d; a is 1-3; b is 0-3; each occurrence of R a and R b is independently selected from H, F and C1-C6 alkyl: each of R c and R d is H; Y is CR c =CR d; a is 1-3; b is 0-3; each occurrence of R a and R b is independently selected from H, F and C1-C6 alkyl: each of R c and R d is H; each of R4 and R5 is, independently, selected from H, C1-C6 alkyl and F; R1 is: (i) C6-C10 aryl, which is optionally substituted with from 1-3 R o; or (ii) monocyclic or bicyclic heteroaryl including from 5-10 ring atoms, which is optionally substituted with from 1-3 R o; wherein from 1-4 of the ring atoms is/are a heteroatom independently selected from O, N, N-H, N-R o, and S; or (iii) heterocyclyl including from 4-10 ring atoms, which is optionally substituted with from 1-3 R o; wherein from 1-4 of the ring atoms is/are a heteroatom independently selected from O, N, N-H, N-R o, and S; (i) C6-C10 aryl, which is optionally substituted with from 1-3 R o; or (ii) monocyclic or bicyclic heteroaryl including from 5-10 ring atoms, which is optionally substituted with from 1-3 R o; wherein from 1-4 of the ring atoms is/are a heteroatom independently selected from O, N, N-H, N-R o, and S; or (iii) heterocyclyl including from 4-10 ring atoms, which is optionally substituted with from 1-3 R o; wherein from 1-4 of the ring atoms is/are a heteroatom independently selected from O, N, N-H, N-R o, and S; each occurrence of R o is independently selected from the group consisting of: • halogen; • C1-C6 alkyl; fluoro(C1-C6)alkyl; • hydroxyl; • hydroxy(C1-C4)alkyl; • C1-C6 alkoxy; fluoro(C1-C6)alkoxy; • (C1-C6 alkyl)C -; • (C1-C6 alkyl)NH-; (C1-C6 alkyl) 2 N-; • formyl; formyl(C1-C4) alkyl; cyano; cyano(C1-C4) alkyl; • SO 2 -(C1-C6)alkyl; SO-(C1-C6)alkyl; and • nitro; • halogen; • C1-C6 alkyl; fluoro(C1-C6)alkyl; • hydroxyl; • hydroxy(C1-C4)alkyl; • C1-C6 alkoxy; fluoro(C1-C6)alkoxy; • (C1-C6 alkyl)C -; • (C1-C6 alkyl)NH-; (C1-C6 alkyl) 2 N-; • formyl; formyl(C1-C4) alkyl; cyano; cyano(C1-C4) alkyl; • SO 2 -(C1-C6)alkyl; SO-(C1-C6)alkyl; and • nitro; R2 is H; and R3 is H, F, or Cl;