A compound having the formula I: or a pharmaceutically acceptable salt thereof, wherein: D 1 is C 3-8 cycloalkyl, optionally substituted with from 1 to 4 substituents independently selected from the group consisting of: C 1-8 alkyl, amino, hydroxy, C 1-8 alkylcarbonyl, aminocarbonyl, C 1-8 alkoxycarbonylamino, arylC 1-8 alkoxycarbonylamino, phenyl and heterocyclylC 1-8 alkylene; R 1 is selected from the group consisting of H, C 1-8 alkyl, amino, aminocarbonyl, hydroxyl, C 1-8 alkoxy, C 1-8 haloalkyl, C 2-8 alkenyl, C 2-8 alkynyl, oxo, cyano, C 1-8 alkoxycarbonyl, C 3-8 cycloalkyl, aryl and heterocyclyl; and each heterocyclyl is optionally substituted with from 1 to 4 substituents selected from the group consisting of: C 1-8 alkyl, halo, oxo, amino, C 1-8 alkoxy, C 1-8 alkylcarbonyl, arylC 1-8 alkoxycarbonyl, aminocarbonyl, arylC 1-8 alkylenecarbonyl and C 1-8 alkylsulfonyl; Y 1 is selected from the group consisting of (a) aryl; optionally substituted with from 1 to 3 substituents, R 4a, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxyC 1-8 alkyl, aminocarbonyl-, hydroxyl, oxo, halogen, hydroxy, C 1-8 alkoxy and C 1-8 alkylsulfonyl; (b) heteroaryl, optionally substituted with from 1 to 3 substituents, R 4a, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxyC 1-8 alkyl, aminocarbonyl-, hydroxyl, oxo, halogen, hydroxy, C 1-8 alkoxy and C 1-8 alkylsulfonyl; R 2 is a heterocyclyl or heteroaryl substituted with at least one group, R 3, selected from the group consisting of aminoC 1-8 alkyl-, C 1-8 alkoxyC 1-8 alkyl-, oxo-, C 1-8 alkylcarbonyl, C 3-8 cycloalkylcarbonyl, heterocyclylcarbonyl, C 1-8 alkylcarbonylamino, C 3-8 cycloalkylcarbonylamino, heterocyclylcarbonylamino, C 1-8 alkylsulfonyl, C 3-8 cycloalkylsulfonyl and heterocyclylsulfonyl; and wherein R 2 is further optionally substituted with from 1 to 2 substituents, R 4c, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxy, halo, aminocarbonyl, oxo, hydroxyl, aminoC 1-8 alkylene, C 1-8 alkoxyC 1-8 alkylene, C 1-8 alkylcarbonyl, C 3-8 cycloalkylcarbonyl, heterocyclylcarbonyl, C 1-8 alkylcarbonylamino, C 3-8 cycloalkylcarbonylamino, heterocyclylcarbonylamino, C 1-8 alkylsulfonyl, C 3-8 cycloalkylsulfonyl, heterocyclylsulfonyl, C 3-8 cycloalkyl, C 1-8 alkylcycloalkylene, heteroaryl; where cycloalkyl refers to a mono-or polycyclic hydrocarbon alkyl, alkenyl or alkynyl group which may form a bridged ring or a spiro ring, and which may have one or more double or triple bond(s). D 1 is C 3-8 cycloalkyl, optionally substituted with from 1 to 4 substituents independently selected from the group consisting of: C 1-8 alkyl, amino, hydroxy, C 1-8 alkylcarbonyl, aminocarbonyl, C 1-8 alkoxycarbonylamino, arylC 1-8 alkoxycarbonylamino, phenyl and heterocyclylC 1-8 alkylene; R 1 is selected from the group consisting of H, C 1-8 alkyl, amino, aminocarbonyl, hydroxyl, C 1-8 alkoxy, C 1-8 haloalkyl, C 2-8 alkenyl, C 2-8 alkynyl, oxo, cyano, C 1-8 alkoxycarbonyl, C 3-8 cycloalkyl, aryl and heterocyclyl; and each heterocyclyl is optionally substituted with from 1 to 4 substituents selected from the group consisting of: C 1-8 alkyl, halo, oxo, amino, C 1-8 alkoxy, C 1-8 alkylcarbonyl, arylC 1-8 alkoxycarbonyl, aminocarbonyl, arylC 1-8 alkylenecarbonyl and C 1-8 alkylsulfonyl; Y 1 is selected from the group consisting of (a) aryl; optionally substituted with from 1 to 3 substituents, R 4a, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxyC 1-8 alkyl, aminocarbonyl-, hydroxyl, oxo, halogen, hydroxy, C 1-8 alkoxy and C 1-8 alkylsulfonyl; (b) heteroaryl, optionally substituted with from 1 to 3 substituents, R 4a, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxyC 1-8 alkyl, aminocarbonyl-, hydroxyl, oxo, halogen, hydroxy, C 1-8 alkoxy and C 1-8 alkylsulfonyl; (a) aryl; optionally substituted with from 1 to 3 substituents, R 4a, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxyC 1-8 alkyl, aminocarbonyl-, hydroxyl, oxo, halogen, hydroxy, C 1-8 alkoxy and C 1-8 alkylsulfonyl; (b) heteroaryl, optionally substituted with from 1 to 3 substituents, R 4a, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxyC 1-8 alkyl, aminocarbonyl-, hydroxyl, oxo, halogen, hydroxy, C 1-8 alkoxy and C 1-8 alkylsulfonyl; R 2 is a heterocyclyl or heteroaryl substituted with at least one group, R 3, selected from the group consisting of aminoC 1-8 alkyl-, C 1-8 alkoxyC 1-8 alkyl-, oxo-, C 1-8 alkylcarbonyl, C 3-8 cycloalkylcarbonyl, heterocyclylcarbonyl, C 1-8 alkylcarbonylamino, C 3-8 cycloalkylcarbonylamino, heterocyclylcarbonylamino, C 1-8 alkylsulfonyl, C 3-8 cycloalkylsulfonyl and heterocyclylsulfonyl; and wherein R 2 is further optionally substituted with from 1 to 2 substituents, R 4c, independently selected from the group consisting of C 1-8 alkyl, C 1-8 alkoxy, halo, aminocarbonyl, oxo, hydroxyl, aminoC 1-8 alkylene, C 1-8 alkoxyC 1-8 alkylene, C 1-8 alkylcarbonyl, C 3-8 cycloalkylcarbonyl, heterocyclylcarbonyl, C 1-8 alkylcarbonylamino, C 3-8 cycloalkylcarbonylamino, heterocyclylcarbonylamino, C 1-8 alkylsulfonyl, C 3-8 cycloalkylsulfonyl, heterocyclylsulfonyl, C 3-8 cycloalkyl, C 1-8 alkylcycloalkylene, heteroaryl; where cycloalkyl refers to a mono-or polycyclic hydrocarbon alkyl, alkenyl or alkynyl group which may form a bridged ring or a spiro ring, and which may have one or more double or triple bond(s).