Probes for imaging huntingtin protein
Provided are imaging agents comprising a compound of Formula I, or a pharmaceutically acceptable salt thereof, and methods of their use.
1. A compound of Formula (I), or a pharmaceutically acceptable salt thereof,
wherein
X is O or S;
Y is CR 4 or N;
Z 1 , Z 2 , Z 3 , and Z 4 are independently chosen from CH and N, provided that at least two of Z 1 , Z 2 , Z 3 , and Z 4 are CH;
R 1 is chosen from heteroaryl, heterocycloalkenyl, and heterocycloalkyl, each of which is optionally substituted with one or two groups independently chosen from cyano, halo, lower alkyl optionally substituted with amino, alkylamino, or di(alkyl)amino, lower alkoxy optionally substituted with lower alkoxy, amino, alkylamino, di(alkyl)amino, haloalkyl, di(alkyl)aminocarbonyl, alkylaminocarbonyl, and aminocarbonyl,
L 1 is —O— and L 2 is —(CR 7 R 8 ) m —;
L 3 is absent;
R 2 is phenyl, pyridin-2-yl, pyridin-3-yl, pyrazin-2-yl, pyrimidin-5-yl, 1H-imidazol-4-yl, 1H-imidazol-2-yl, or 1H-pyrazol-4-yl, each of which is optionally substituted with one or two groups independently chosen from halo; haloalkyl; hydroxyl; lower alkoxy; lower alkoxy substituted with lower alkoxy, amino, (alkyl)amino, (dialkyl)amino, heterocycloalkyl, heteroaryl, or halo; lower alkyl; and lower alkyl substituted with hydroxyl, lower alkoxy, amino, (alkyl)amino, or (dialkyl)amino;
R 4 is chosen from hydrogen, halo, cyano, and lower alkyl;
R 5 is chosen from lower alkyl, lower alkoxy, and halo;
R 7 is chosen from hydrogen, hydroxyl, trifluoromethyl, and lower alkyl;
R 8 is chosen from hydrogen and lower alkyl;
n is 0 or 1; and
m is 0, 1, or 2.
2. The compound of claim 1 , wherein R 1 is chosen from pyridin-2-yl, pyridin-3-yl, pyridin-3-yl-1-oxide, pyridin-4-yl, 1H-pyrazol-4-yl, pyrazin-2-yl, pyridazin-3-yl, pyridazin-4-yl, pyrimidin-4-yl, pyrimidin-5-yl, 2,3-dihydropyridazin-3-one-6-yl, 1,2-dihydropyridin-2-one-5-yl, 1,2-dihydropyrazin-2-one-5-yl, 1,3-thiazol-5-yl, 5,6,7,8-tetrahydro-1,7-naphthyridine-7-yl, 1H-imidazol-1-yl, 1-benzofuran-2-yl, 1-benzofuran-5-yl, 2,3-dihydro-1-benzofuran-2-yl, quinolone-2-yl, and 5H,6H,7H,8H-imidazo[1,2-a]pyrazin-7-yl, each of which is optionally substituted with one or two groups independently chosen from halo, lower alkyl, lower alkoxy, alkylamino, di(alkyl)amino, and amino.
3. The compound of claim 1 , wherein R 1 is
wherein
W is chosen from N and N(O);
p is chosen from 0, 1, and 2;
for each occurrence, R 9 is independently chosen from cyano, halo, lower alkyl, lower haloalkyl, lower alkyl substituted with —NR 10 R 11 , lower alkoxy, —C(O)NR 10 R 11 , and —NR 10 R 11 ;
R 10 is chosen from hydrogen and lower alkyl; and
R 11 is chosen from hydrogen and lower alkyl.
4. The compound of claim 1 , wherein R 1 is
wherein
W 1 and W 2 are chosen from CH and N, provided that at least one of W 1 and W 2 is CH;
p is chosen from 0, 1, and 2; and
for each occurrence, R 9 is independently chosen from lower alkyl.
5. The compound of claim 1 , wherein R 2 is pyridin-2-yl, pyridin-3-yl, pyrazin-2-yl, pyrimidin-5-yl, 1H-imidazol-4-yl, 1H-imidazol-2-yl, or 1H-pyrazol-4-yl, each of which is optionally substituted with one or two groups independently chosen from lower alkyl, hydroxyl, lower alkoxy, lower alkoxy substituted with amino, (alkyl)amino, (dialkyl)amino, or lower alkoxy, lower alkyl, and lower alkyl substituted with hydroxyl, lower alkoxy, amino, (alkyl)amino, or (dialkyl)amino.
6. The compound of claim 1 , wherein X is O.
7. The compound of claim 1 , wherein X is S.
8. The compound of claim 1 , wherein Y is CR 4 .
9. The compound of claim 1 , wherein Y is N.
10. The compound of claim 1 , wherein the compound is labeled with one or more positron-emitting radionuclides selected from: 11 C, 13 N, 15 O, and 18 F.
11. A compound of Formula (I), or a pharmaceutically acceptable salt thereof,
wherein
X is NR 4 , O, or S;
Y is CR 4 or N;
Z 1 , Z 2 , Z 3 , and Z 4 are independently chosen from CH and N, provided that at least two of Z 1 , Z 2 , Z 3 , and Z 4 are CH;
R 1 is heterocycloalkenyl or heterocycloalkyl, each of which is optionally substituted with one or two groups independently chosen from cyano, halo, lower alkyl optionally substituted with amino, alkylamino, or di(alkyl)amino, lower alkoxy optionally substituted with lower alkoxy, optionally substituted amino, haloalkyl, di(alkyl)aminocarbonyl, alkylaminocarbonyl, and aminocarbonyl, or
R 1 is phenyl optionally substituted with one or two groups independently chosen from cyano, heteroaryl, halo, phenoxy, benzyloxy, lower alkyl optionally substituted with amino, (alkyl)amino, or di(alkyl)amino, lower alkoxy, optionally substituted amino, di(alkyl)aminocarbonyl, alkylaminocarbonyl, and aminocarbonyl;
L 1 is —NR 3 — and L 2 is —C(O)—, C—(R 7 R 8 ) m —, or —C(O)(R 7 R 8 ) m —;
L 3 is —CH═CH— or L 3 is absent;
R 2 is chosen from heterocycloalkyl, aryl and heteroaryl, each of which is optionally substituted with one or two groups chosen from
—OC(O)—R 6 ,
—C(O)O—R 6 ,
amino,
halo,
haloalkyl,
phenyl,
heteroaryl,
cyano,
(lower alkyl)thio,
phenoxy,
phenoxymethyl,
heteroaryloxy,
heteroaryloxy substituted with lower alkyl,
hydroxyl,
lower alkenyloxy,
lower alkoxy,
lower alkoxy substituted with lower alkoxy, amino, (alkyl)amino, (dialkyl)amino, heterocycloalkyl, heteroaryl, or halo,
lower alkyl, and
lower alkyl substituted with amino, (alkyl)amino, (dialkyl)amino, hydroxyl or lower alkoxy;
R 3 is chosen from hydrogen and lower alkyl;
R 4 is chosen from hydrogen, halo, cyano, and lower alkyl;
R 5 is chosen from lower alkyl, lower alkoxy, and halo;
R 6 is lower alkyl;
R 7 is chosen from hydrogen, hydroxyl, trifluoromethyl, and lower alkyl;
R 8 is chosen from hydrogen and lower alkyl;
n is 0 or 1; and
m is 0, 1, or 2.
12. The compound of claim 1 , wherein R 1 is heterocycloalkenyl.
13. The compound of claim 1 , wherein R 1 is 2,3-dihydropyridazin-3-one-6-yl optionally substituted with one or two groups independently chosen from halo, lower alkyl, lower alkoxy, alkylamino, di(alkyl)amino, and amino.
14. The compound of claim 1 , wherein R 1 is 2,3-dihydropyridazin-3-one-6-yl substituted with one or two lower alkyl groups.
15. The compound of claim 1 , wherein R 2 is pyridin-2-yl optionally substituted with one or two groups independently chosen from halo; haloalkyl; hydroxyl; lower alkoxy; lower alkoxy substituted with lower alkoxy, amino, (alkyl)amino, (dialkyl)amino, heterocycloalkyl, heteroaryl, or halo; lower alkyl; and lower alkyl substituted with hydroxyl, lower alkoxy, amino, (alkyl)amino, or (dialkyl)amino.
16. The compound of claim 1 , wherein R 2 is pyridin-2-yl substituted with lower alkoxy.
17. The compound of claim 1 , wherein Z 1 , Z 2 , Z 3 , and Z 4 are independently CH.
18. The compound of claim 11 , wherein R 1 is heterocycloalkenyl.
19. The compound of claim 11 , wherein R 1 is 2,3-dihydropyridazin-3-one-6-yl optionally substituted with one or two groups independently chosen from halo, lower alkyl, lower alkoxy, alkylamino, di(alkyl)amino, and amino.
20. The compound of claim 11 , wherein R 1 is 2,3-dihydropyridazin-3-one-6-yl substituted with one or two lower alkyl groups.
21. The compound of claim 11 , wherein R 2 is pyridin-2-yl optionally substituted with one or two groups independently chosen from halo; haloalkyl; hydroxyl; lower alkoxy; lower alkoxy substituted with lower alkoxy, amino, (alkyl)amino, (dialkyl)amino, heterocycloalkyl, heteroaryl, or halo; lower alkyl; and lower alkyl substituted with hydroxyl, lower alkoxy, amino, (alkyl)amino, or (dialkyl)amino.
22. The compound of claim 11 , wherein R 2 is pyridin-2-yl substituted with lower alkoxy.
23. The compound of claim 11 , wherein the compound is labeled with one or more positron-emitting radionuclides selected from: 11 C, 13 N, 15 O, and 18 F.