Antagonists of the muscarinic acetylcholine receptor M

1. A compound of formula (Ia):

or a pharmaceutically acceptable salt thereof, wherein:

Q is NR a or O;

m is 0, 1, or 2;

R 1 is a 5- or 6-membered heteroaryl having 1, 2, or 3 heteroatoms independently selected from the group consisting of N, O, and S, wherein the heteroaryl is unsubstituted or substituted with 1, 2, or 3 substituents independently selected from the group consisting of halo, C 1 -C 4 alkyl, and C 1 -C 4 haloalkyl;

R 3 is hydrogen and or C 1 -C 4 alkyl;

R 4 is (CR g R h ) p —Y′ or C 4 -C 6 alkyl;

Y′ is C 3 C 10 cycloalkyl, C 3 -C 8 cycloalkenyl, aryl 5- or 6-membered heteroaryl having 1, 2, or 3 heteroatoms independently selected from the group consisting of N, O, and S, or a 5-, 6-, or 7-membered heterocycle having 1, 2, or 3 heteroatoms independently selected from the group consisting of N, O, and S, wherein Y′ is unsubstituted or substituted with one or two substituents independently selected from the group consisting of halo and C 1 -C 4 alkyl;

R a is hydrogen or C 1 -C 4 alkyl;

R g is hydrogen;

R h is hydrogen; and

p is 0, 1, 2, or 3.

2. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein

Q is NR a ; and

R a is hydrogen.

3. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein

Q is O.

4. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein

R 3 is hydrogen.

5. The compound of claim 1 , wherein the compound is selected from:

2-(3,3-dimethylbutyl)-N-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-amine;

2-(1-adamantylmethyl)-N-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-amine;

2-(5-bicyclo[2.2.1]hept-2-enylmethyl)-N-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-amine;

4-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]oxy-2-[(3-methyl-2-pyridyl)methyl]-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrole;

2-(3,3-dimethylbutyl)-4-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]oxy-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrole;

2-(1-adamantylmethyl)-4-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]oxy-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrole;

2-(5-bicyclo[2.2.1]hept-2-enylmethyl)-4-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]oxy-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrole;

2-benzyl-4-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]oxy-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrole;

4-[6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-yl]oxy-2-(2-phenylethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrole;

N-[2-[2-(3,3-dimethylbutyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[2-[2-(tetrahydropyran-3-ylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[2-[2-(tetrahydropyran-4-ylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]pyridazin-3-amine;

N-[2-[2-(5-bicyclo[2.2.1]hept-2-enylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[2-[2-[(3-methyl-2-pyridyl)methyl]-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]pyridazin-3-amine;

N-[2-(2-benzyl-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl)ethyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[2-[2-(2-phenylethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[2-[2-(3-phenylpropyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]pyridazin-3-amine;

N-[2-[2-(1-adamantylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]ethyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine;

N-[[2-(3,3-dimethylbutyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]methyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine;

N-[[2-(1-adamantylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]methyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine;

N-[[2-(5-bicyclo[2.2.1]hept-2-enylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]methyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[[2-[(3-methyl-2-pyridyl)methyl]-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]methyl]pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[[2-(2-phenylethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]methyl]pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[[2-(tetrahydropyran-3-ylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]methyl]pyridazin-3-amine;

6-(2,4-dimethylpyrazol-3-yl)-N-[[2-(tetrahydropyran-4-ylmethyl)-3,3a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl]methyl]pyridazin-3-amine; and

N-[(2-benzyl-3,3 a,4,5,6,6a-hexahydro-1H-cyclopenta[c]pyrrol-4-yl)methyl]-6-(2,4-dimethylpyrazol-3-yl)pyridazin-3-amine,

or a pharmaceutically acceptable salt thereof.

6. A pharmaceutical composition comprising the compound of claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

7. A method for antagonizing mAChR M 4 in a subject, comprising a step of administering to a subject in need thereof a therapeutically effective amount of the compound of claim 1 , or a pharmaceutically acceptable salt thereof.

8. The method of claim 7 , wherein the subject has a neurodegenerative disorder, a movement disorder, or a brain disorder.

9. The method of claim 8 , wherein the subject has a movement disorder.

10. The method of claim 7 , wherein the subject has a disorder selected from the group consisting of Parkinson's disease, drug-induced Parkinsonism, dystonia, Tourette's syndrome, dyskinesias, schizophrenia, cognitive deficits associated with schizophrenia, excessive daytime sleepiness, attention deficit hyperactivity disorder (ADHD), Huntington's disease, chorea, cerebral palsy, and progressive supranuclear palsy.

11. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 1 is a 5-membered heteroaryl having 1, 2, or 3 heteroatoms independently selected from the group consisting of N, O, and S, wherein the heteroaryl is unsubstituted or substituted with 1, 2, or 3 substituents independently selected from the group consisting of halo, C 1 -C 4 alkyl, and C 1 -C 4 haloalkyl.

12. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 1 is pyrazolyl substituted with two C 1 -C 4 alkyl.

13. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 1 is 2,4-dimethylpyrazol-3-yl.

14. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 4 is C 4 -C 6 alkyl.

15. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 4 is (CR g R h ) p —Y′.

16. The compound of claim 15 , or a pharmaceutically acceptable salt thereof, wherein Y′ is cyclohexyl, cycloheptyl, adamantyl, bicyclo[2.2.1]heptenyl, tetrahydropyranyl, oxabicyclo[2.2.1]heptanyl, phenyl, or pyridyl, wherein the phenyl and pyridyl are unsubstituted or substituted with 1 or 2 substituents independently selected from the group consisting of halo and C 1 -C 4 alkyl.

17. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein m is 0.

18. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein m is 1.

19. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein m is 2.