A compound having formula I: or a pharmaceutically acceptable salt, hydrate, or solvate thereof, wherein: the moiety is U is a single bond; V is selected from C and N, provided that when V is N, one of R 2a, R 2b, or R 2c is absent; X is selected from hydrogen, deuterium, methyl, CF 3, and halogen; taken together two of R 2a, R 2b, and R 2c form a C 3 -C 8 cycloalkyl ring, C 4 -C 8 cycloalkenyl ring, or 3 to 8 membered, saturated or partially unsaturated, heterocyclic ring, and the remaining R 2a, R 2b, or R 2c is absent or selected from hydrogen, halogen, OH, NH 2, and C 1 -C 8 alkyl, further wherein said cycloalkyl ring, cycloalkenyl ring, and heterocyclic ring are unsubstituted or substituted with one or more R x; each R x is independently selected from (CH 2) z NH 2, (CH 2) z NHR 3, (CH 2) z NR 3 R 3, OR 3, OCF 3, OCH 2 F, OCHF 2, (CH 2) z -aromatic ring, (CH 2) z -heterocyclic ring, hydroxyl, halogen, C 1 -C 8 alkyl, (C 1 -C 8 alkyl)CF 3, (C 1 -C 8 alkyl)OH, C R 3, (CH 2) z C NH 2, (CH 2) z C NHR 3, (CH 2),C NR 3 R 3, (CH 2) z NHC R 4, and (CH 2) z NR 4 C R 4; or taken together two R x attached to the same carbon atom of a cycloalkyl ring, cycloalkenyl ring or heterocyclic ring form =O; or taken together two R x form a C 3 -C 8 cycloalkyl ring, C 4 -C 8 cycloalkenyl ring, or 3 to 8 membered, saturated or partially unsaturated, heterocyclic ring, further wherein said cycloalkyl ring, cycloalkenyl ring, and heterocyclic ring are unsubstituted or substituted with one or more R z; or taken together two R x form an aromatic ring or heteroaromatic ring, further wherein said aromatic ring and heteroaromatic ring are unsubstituted or substituted with one or more R z; each R z is independently selected from halogen, C 1 -C 4 alkyl, OH, OR 3, CF 3, OCF 3, OCH 2 F, OCHF 2, NH 2, NHR 3, NR 3 R 3, and C CH 3; R 3 is selected from C 1 -C 8 alkyl and O(C 1 -C 8 alkyl); R 4 is selected from C 1 -C 8 alkyl and CF 3; R 5 is hydrogen; t is 0; and z is selected from 0, 1, 2, and 3; with the proviso that the compound is not of any of the formulae: U is a single bond; V is selected from C and N, provided that when V is N, one of R 2a, R 2b, or R 2c is absent; X is selected from hydrogen, deuterium, methyl, CF 3, and halogen; taken together two of R 2a, R 2b, and R 2c form a C 3 -C 8 cycloalkyl ring, C 4 -C 8 cycloalkenyl ring, or 3 to 8 membered, saturated or partially unsaturated, heterocyclic ring, and the remaining R 2a, R 2b, or R 2c is absent or selected from hydrogen, halogen, OH, NH 2, and C 1 -C 8 alkyl, further wherein said cycloalkyl ring, cycloalkenyl ring, and heterocyclic ring are unsubstituted or substituted with one or more R x; each R x is independently selected from (CH 2) z NH 2, (CH 2) z NHR 3, (CH 2) z NR 3 R 3, OR 3, OCF 3, OCH 2 F, OCHF 2, (CH 2) z -aromatic ring, (CH 2) z -heterocyclic ring, hydroxyl, halogen, C 1 -C 8 alkyl, (C 1 -C 8 alkyl)CF 3, (C 1 -C 8 alkyl)OH, C R 3, (CH 2) z C NH 2, (CH 2) z C NHR 3, (CH 2),C NR 3 R 3, (CH 2) z NHC R 4, and (CH 2) z NR 4 C R 4; or taken together two R x attached to the same carbon atom of a cycloalkyl ring, cycloalkenyl ring or heterocyclic ring form =O; or taken together two R x form a C 3 -C 8 cycloalkyl ring, C 4 -C 8 cycloalkenyl ring, or 3 to 8 membered, saturated or partially unsaturated, heterocyclic ring, further wherein said cycloalkyl ring, cycloalkenyl ring, and heterocyclic ring are unsubstituted or substituted with one or more R z; or taken together two R x form an aromatic ring or heteroaromatic ring, further wherein said aromatic ring and heteroaromatic ring are unsubstituted or substituted with one or more R z; each R z is independently selected from halogen, C 1 -C 4 alkyl, OH, OR 3, CF 3, OCF 3, OCH 2 F, OCHF 2, NH 2, NHR 3, NR 3 R 3, and C CH 3; R 3 is selected from C 1 -C 8 alkyl and O(C 1 -C 8 alkyl); R 4 is selected from C 1 -C 8 alkyl and CF 3; R 5 is hydrogen; t is 0; and z is selected from 0, 1, 2, and 3; with the proviso that the compound is not of any of the formulae: