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(O)CH=CH 2 , and -(CH 2 )NHC(O)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(O)CH=CH 2 , and -(CH 2 )NHC(O)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 . <EOS>