Imidazo[1,2-A]pyrimidines as orexin receptor antagonists

1. A compound of formula (I)

where Ar is selected from the group consisting of formula:

R 1 is (C 1-4 )alkyl, halo, halo(C 1-4 )alkyl, (C 1-4 )alkoxy, halo(C 1-4 )alkoxy, (C 1-4 )alkyl-O—(C 1-4 )alkyl, CN, NR 5 R 6 wherein R 5 is H or (C 1-4 )alkyl and R 6 is H or (C 1-4 )alkyl;

R 2 is (C 1-4 )alkyl, halo, halo(C 1-4 )alkyl, (C 1-4 alkoxy, halo(C 1-4 )alkoxy, (C 1-4 )alkyl-O—(C 1-4 )alkyl, CN, NR 7 R 8 wherein R 7 is H or (C 1-4 )-alkyl and R 8 is H or (C 1-4 )-alkyl;

R 3 is (C 1-4 )alkyl, halo, halo(C 1-4 )alkyl, (C 1-4 )alkoxy, halo(C 1-4 )alkoxy, (C 1-4 )alkyl-O—(C 1-4 )alkyl, CN, NR 9 R 10 wherein R 9 is H or (C 1-4 )-alkyl and R 10 is H or (C 1-4 )-alkyl;

n is 0 or 1;

p is 0 or 1; and

q is 0 or 1;

with the proviso that p and q are not both 0;

or a pharmaceutically acceptable salt thereof.

2. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (II), n is 1 and R 1 is halogen.

3. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (II), n is 1 and R 1 is chlorine.

4. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (II), n is 1, p is 1, q is 0, R 1 is chlorine and R 2 is methyl.

5. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (II), n is 0, p is 1, q is 0 and R 2 is methyl.

6. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (II), n is 0, p is 1, q is 1 and one of R 2 and R 3 is halo and the other is (C 1-4 -alkyl.

7. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (II), n is 0, p is 1, q is 1, R 2 is halo and R 3 is (C 1-4 )-alkyl.

8. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (II), n is 0, p is 1, q is 1, R 2 is chloro and R 3 is methyl.

9. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (III), n is 1 and R 1 is halogen.

10. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (III), n is 1 and R 1 is chlorine.

11. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (III), n is 1, p is 1, q is 0, R 1 is chlorine and R 2 is methyl.

12. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (III), n is 0, p is 1, q is 0 and R 2 is methyl.

13. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (III), n is 0, p is 1, q is 1 and one of R 2 and R 3 is halo and the other is (C 1-4 -alkyl.

14. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 wherein Ar is a group of formula (III), n is 0, p is 1, q is 1, R 2 is halo and R 3 is (C 1-4 )-alkyl.

15. The compound, or pharmaceutically acceptable salt thereof, according to claim 1 , wherein Ar is a group of formula (III), n is 0, p is 1, q is 1, R 2 is chloro and R 3 is methyl.

16. A compound which is:

7-methyl-2-({(2S)-1-[(2-methyl-5-phenyl-1,3-thiazol-4-yl)carbonyl]-2-piperidinyl}methyl)imidazo[1,2-a]pyrimidine;

3-chloro-7-methyl-2-({(2S)-1-[(2-methyl-5-phenyl-1,3-thiazol-4-yl)carbonyl]-2-piperidinyl}methyl)imidazo[1,2-a]pyrimidine;

7-chloro-6-methyl-2-({(2S)-1-[(2-methyl-5-phenyl-1,3-thiazol-4-yl)carbonyl]-2-piperidinyl}methyl)imidazo[1,2-a]pyrimidine;

or a pharmaceutically acceptable salt thereof.

17. A pharmaceutical composition comprising a) the compound, or pharmaceutically acceptable salt thereof, as defined in claim 1 , and b) a pharmaceutically acceptable carrier.