A compound of formula I where: R 1 is hydrogen, cyano, halo, alkyl, haloalkyl, alkoxy, or haloalkoxy; R 2 is hydrogen, cyano, halo, alkyl, cyanoalkyl, haloalkyl, cycloalkyl, cyanocycloalkyl, (alkoxycarbonyl)alkenyl, alkoxy, haloalkoxy, alkylthio, halaalkylthio, cycloalkylthio, alkylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylsulfinyl, cyclaalkylsulfinyl, phenylsulfinyl, alkylsulfonyl, haloalkylsulfonyl, cycloalkylsulfonyl, alkylcarbonylamino, morpholinyl, SO 2 N(R 4)(R 5); R 3 is hydrogen, cyano, halo, alkyl, haloalkyl, alkoxy, or haloalkoxy; or R 2 and R 3 taken together is -CH=CH-CH=CH-; R 4 is hydrogen or alkyl; R 5 is hydrogen or alkyl; or N(R 4)(R 5) taken together is azetidinyl, pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, and is substituted with 0-4 halo or alkyl substituents; Ar 1 is 3-pyridinyl, 2-pyrazinyl, 4-pyridazinyl, 4-pyrimidinyl, 4-pyrazolyl, 4-isothiazolyl, or 3-imidazo[1,2-b]pyridazinyl, and is substituted with 1 substituent selected from hydrogen, cyano, halo, alkyl, haloalkyl, hydroxyalkyl, (cycloalkyl)hydroxyalkyl, (dicycloalkyl)hydroxyalkyl, (hydroxy)haloalkyl, alkoxyalkyl, (N(R 4)(R 5))alkyl, cycloalkyl, hydroxycycloalkyl, cycloalkenyl, alkoxy, haloalkoxy, (cycloalkyl)alkoxy, ((alkyl)cycloalkyl)alkoxy, alkylcarbonyl, cycloalkylcarbonyl, tetrahydrofuranyl, (alkyl)tetrahydrofuranyl, dioxolanyl, (alkyl)dioxolanyl, (cycloalkyl)dioxolanyl, (phenyl)dioxolanyl, (dialkyl)dioxolanyl, (haloalkyl)(alkyl)dioxolanyl, (trialkyl)dioxolanyl, dihydrpyranyl, tetrahydropyranyl, hydroxytetrahydrapyranyl, N(R 4)(R 5), and Ar 2; and is also substituted with 0-1 substituent selected from hydrogen, cyano, halo, alkyl, haloalkyl, alkoxy, and haloalkoxy; Ar 2 is phenyl, pyridinyl, or pyrazolyl, and is substituted with 0-3 substituents selected from the group consisting of cyano, halo, alkyl, haloalkyl, alkoxy, and haloalkoxy; or a pharmaceutically acceptable salt thereof. R 1 is hydrogen, cyano, halo, alkyl, haloalkyl, alkoxy, or haloalkoxy; R 2 is hydrogen, cyano, halo, alkyl, cyanoalkyl, haloalkyl, cycloalkyl, cyanocycloalkyl, (alkoxycarbonyl)alkenyl, alkoxy, haloalkoxy, alkylthio, halaalkylthio, cycloalkylthio, alkylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylsulfinyl, cyclaalkylsulfinyl, phenylsulfinyl, alkylsulfonyl, haloalkylsulfonyl, cycloalkylsulfonyl, alkylcarbonylamino, morpholinyl, SO 2 N(R 4)(R 5); R 3 is hydrogen, cyano, halo, alkyl, haloalkyl, alkoxy, or haloalkoxy; or R 2 and R 3 taken together is -CH=CH-CH=CH-; R 4 is hydrogen or alkyl; R 5 is hydrogen or alkyl; or N(R 4)(R 5) taken together is azetidinyl, pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, and is substituted with 0-4 halo or alkyl substituents; Ar 1 is 3-pyridinyl, 2-pyrazinyl, 4-pyridazinyl, 4-pyrimidinyl, 4-pyrazolyl, 4-isothiazolyl, or 3-imidazo[1,2-b]pyridazinyl, and is substituted with 1 substituent selected from hydrogen, cyano, halo, alkyl, haloalkyl, hydroxyalkyl, (cycloalkyl)hydroxyalkyl, (dicycloalkyl)hydroxyalkyl, (hydroxy)haloalkyl, alkoxyalkyl, (N(R 4)(R 5))alkyl, cycloalkyl, hydroxycycloalkyl, cycloalkenyl, alkoxy, haloalkoxy, (cycloalkyl)alkoxy, ((alkyl)cycloalkyl)alkoxy, alkylcarbonyl, cycloalkylcarbonyl, tetrahydrofuranyl, (alkyl)tetrahydrofuranyl, dioxolanyl, (alkyl)dioxolanyl, (cycloalkyl)dioxolanyl, (phenyl)dioxolanyl, (dialkyl)dioxolanyl, (haloalkyl)(alkyl)dioxolanyl, (trialkyl)dioxolanyl, dihydrpyranyl, tetrahydropyranyl, hydroxytetrahydrapyranyl, N(R 4)(R 5), and Ar 2; and is also substituted with 0-1 substituent selected from hydrogen, cyano, halo, alkyl, haloalkyl, alkoxy, and haloalkoxy; Ar 2 is phenyl, pyridinyl, or pyrazolyl, and is substituted with 0-3 substituents selected from the group consisting of cyano, halo, alkyl, haloalkyl, alkoxy, and haloalkoxy; or a pharmaceutically acceptable salt thereof.