A compound having a structure represented by a formula: or a pharmaceutically acceptable salt thereof, wherein each of R 1a, R 1b, and R 1c is independently hydrogen, halogen, -SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, -N(CH 3) 2, -(CH 2)-phenyl, -(CH 2)-pyridinyl, -(CH 2)-pyrimidinyl, -O-phenyl, -O-pyridinyl, or -O-pyrimidinyl, provided that at least one of R 1a, R 1b, and R 1c is not hydrogen; or wherein R 1a and R 1b are optionally covalently bonded and, together with the intermediate atoms, comprise an optionally substituted 3- to 7-membered fused aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalklyl, or heterocycloalkenyl; and wherein R 1c is hydrogen, halogen, -OH, -SCF 3,-SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, or -N(CH 3) 2; R 3 is Ar 1 or -(C1 -C3 alkyl)-Ar 1; and wherein Ar 1 is phenyl independently substituted with 0, 1,2, or 3 groups selected from halogen, -SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, and -N(CH 3) 2, or is pyridinyl having a structure represented by a formula: wherein each of R 20a, R 20b, R 20c, and R 20d is independently selected from hydrogen, halogen, -SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, -N(CH 3) 2, -NHC CH=CH 2, and -(CH 2)NHC CH=CH 2, provided that at least one of R 20a, R 20b, R 20c, and R 20d is hydrogen, wherein when R 3 is Ar 1, R 2 is C3-C6 alkyl, —(C1-C3 alkyl)-cyclopropyl, -(C1-C3 alkyl)-cyclobutyl, -(C1-C3 alkyl)-cyclopentyl, -(C1-C3 alkyl)-cyclohexyl, and wherein when R 3 is -(C1 -C3 alkyl)-Ar 1, R 2 is C3-C6 alkyl, -(C1 -C6 alkl)-CF 3, -(C1-C6 alkyl)-C=CH, -(C1-C3 alkyl)-cyclopropyl, -(C1-C3 alkyl)-cyclobutyl, —(C1-C3 alkyl)-cyclopentyl, -(C1-C3 alkyl)-cyclohexyl, -(C1-C3 alkyl)-heteroaryl, or -SO 2 -(C1-C6 alkyl); and wherein R 2 is substituted with 0, 1, 2, or 3 groups independently selected from halogen, -OH, -SCF 3,-SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, and -N(CH 3) 2. each of R 1a, R 1b, and R 1c is independently hydrogen, halogen, -SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, -N(CH 3) 2, -(CH 2)-phenyl, -(CH 2)-pyridinyl, -(CH 2)-pyrimidinyl, -O-phenyl, -O-pyridinyl, or -O-pyrimidinyl, provided that at least one of R 1a, R 1b, and R 1c is not hydrogen; or wherein R 1a and R 1b are optionally covalently bonded and, together with the intermediate atoms, comprise an optionally substituted 3- to 7-membered fused aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalklyl, or heterocycloalkenyl; and wherein R 1c is hydrogen, halogen, -OH, -SCF 3,-SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, or -N(CH 3) 2; R 3 is Ar 1 or -(C1 -C3 alkyl)-Ar 1; and wherein Ar 1 is phenyl independently substituted with 0, 1,2, or 3 groups selected from halogen, -SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, and -N(CH 3) 2, or is pyridinyl having a structure represented by a formula: wherein each of R 20a, R 20b, R 20c, and R 20d is independently selected from hydrogen, halogen, -SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, -N(CH 3) 2, -NHC CH=CH 2, and -(CH 2)NHC CH=CH 2, provided that at least one of R 20a, R 20b, R 20c, and R 20d is hydrogen, wherein when R 3 is Ar 1, R 2 is C3-C6 alkyl, —(C1-C3 alkyl)-cyclopropyl, -(C1-C3 alkyl)-cyclobutyl, -(C1-C3 alkyl)-cyclopentyl, -(C1-C3 alkyl)-cyclohexyl, and wherein when R 3 is -(C1 -C3 alkyl)-Ar 1, R 2 is C3-C6 alkyl, -(C1 -C6 alkl)-CF 3, -(C1-C6 alkyl)-C=CH, -(C1-C3 alkyl)-cyclopropyl, -(C1-C3 alkyl)-cyclobutyl, —(C1-C3 alkyl)-cyclopentyl, -(C1-C3 alkyl)-cyclohexyl, -(C1-C3 alkyl)-heteroaryl, or -SO 2 -(C1-C6 alkyl); and wherein R 2 is substituted with 0, 1, 2, or 3 groups independently selected from halogen, -OH, -SCF 3,-SF 5, -NO 2, -CH 3, -CH 2 F, -CHF 2, -CF 3, -OCF 3, -NHCH 3, and -N(CH 3) 2.