A compound of Formula I: wherein: R 1 is pyridyl, pyrimidinyl, or pyrazinyl, attached through a carbon atom of the heteroaryl ring, optionally substituted with 1, 2, or 3 R 5, or wherein R 1 is thiophenyl, quinolinyl, isoquinolinyl, benzofuranyl, benzothiophenyl, or pyrazolyl each optionally substituted with 1, 2, or 3 R 5; A and D are CH, and B is CR 2; each R 2 is independently C 1-10 alkyl, C 1-10 haloalkyl, halo, cyano, or -SO 2 C 1-6 alkyl; R 3 and R 3a are independently hydrogen, or C 1-10 alkyl; R 4 and R 4a independently are hydrogen, C 1-10 alkyl, C 1-10 haloalkyl, C 3-10 cycloalkyl, C 1-10 alkC 3-10 cycloalkyl, or C 1-10 alkNR 7 R 7a, wherein R 7 and R 7a are independently H or C 1-10 alkyl, or R 4 and R 4a together with the nitrogen through which they are attached, form a piperdinyl, piperazinyl, pyrrolidinyl, or morpholinyl ring, wherein the nitrogen atom of the piperazinyl ring is optionally substituted with R 6; each R 5 is independently halo, cyano, hydroxy, C 1-10 alkyl, C 1-10 haloalkyl, C 1-10 alkoxy, C 1-10 haloalkoxy, C 3-10 cycloalky, C 3-10 cycloalkoxy, amino, C 1-10 alkylamino, C 1-10 dialkylamino, C 3-10 cycloalkyamino, pyrrolidinyl, C 1-10 alkylsulfonyl, sulfamoyl, C 1-10 alkylsulfamoyl or C 1-10 dialkylsulfamoyl; and R 6 is C 1-10 alkyl, or acetyl; or a pharmaceutically acceptable salt, enantiomer, or diastereoisomer thereof; wherein the term "heteroaryl" refers to a mono-, di-, tri-, or other multicyclic aromatic ring system which has 3 to 50 carbon atoms and that includes at least one heteroatom ring members, each heteroatom ring member independently being sulfur, oxygen, or nitrogen and which is attached to the rest of the molecule through a carbon atom. R 1 is pyridyl, pyrimidinyl, or pyrazinyl, attached through a carbon atom of the heteroaryl ring, optionally substituted with 1, 2, or 3 R 5, or wherein R 1 is thiophenyl, quinolinyl, isoquinolinyl, benzofuranyl, benzothiophenyl, or pyrazolyl each optionally substituted with 1, 2, or 3 R 5; A and D are CH, and B is CR 2; each R 2 is independently C 1-10 alkyl, C 1-10 haloalkyl, halo, cyano, or -SO 2 C 1-6 alkyl; R 3 and R 3a are independently hydrogen, or C 1-10 alkyl; R 4 and R 4a independently are hydrogen, C 1-10 alkyl, C 1-10 haloalkyl, C 3-10 cycloalkyl, C 1-10 alkC 3-10 cycloalkyl, or C 1-10 alkNR 7 R 7a, wherein R 7 and R 7a are independently H or C 1-10 alkyl, or R 4 and R 4a together with the nitrogen through which they are attached, form a piperdinyl, piperazinyl, pyrrolidinyl, or morpholinyl ring, wherein the nitrogen atom of the piperazinyl ring is optionally substituted with R 6; each R 5 is independently halo, cyano, hydroxy, C 1-10 alkyl, C 1-10 haloalkyl, C 1-10 alkoxy, C 1-10 haloalkoxy, C 3-10 cycloalky, C 3-10 cycloalkoxy, amino, C 1-10 alkylamino, C 1-10 dialkylamino, C 3-10 cycloalkyamino, pyrrolidinyl, C 1-10 alkylsulfonyl, sulfamoyl, C 1-10 alkylsulfamoyl or C 1-10 dialkylsulfamoyl; and R 6 is C 1-10 alkyl, or acetyl; or a pharmaceutically acceptable salt, enantiomer, or diastereoisomer thereof; wherein the term "heteroaryl" refers to a mono-, di-, tri-, or other multicyclic aromatic ring system which has 3 to 50 carbon atoms and that includes at least one heteroatom ring members, each heteroatom ring member independently being sulfur, oxygen, or nitrogen and which is attached to the rest of the molecule through a carbon atom.