Heterocyclic derivatives

1. A heterocyclic derivative of formula I

wherein

R 1 is H, C 1-8 alkyl, C 2-8 alkenyl, C 2-8 alkynyl, C 3-8 cycloalkyl, C 3-8 cycloalkylC 1-2 alkyl, Z—C 1-2 alkyl or a 4-8 membered heterocyclyl comprising one or more heteroatomic moiety independently selected from O, S, SO and SO 2 , wherein Z is a 5-6 membered heteroaryl comprising one or more heteroatom independently selected from O, N, and S, said C 1-8 alkyl, C 3-8 cycloalkyl, C 3-8 cycloalkylC 1-2 alkyl, 5-6 membered heteroaryl and 4-8 membered heterocyclyl being optionally substituted with one or more substituent independently selected from halogen, hydroxyl, C 1-6 alkoxyl, CONR 3 R 4 , SO 2 NR 5 R 6 and CO 2 C 1-6 alkyl;

R 2 is H, C 1-8 alkyl, C 3-8 cycloalkyl or C 3-8 cycloalkylC 1-2 alkyl, said C 1-8 alkyl, C 3-8 cycloalkyl and C 3-8 cycloalkylC 1-2 alkyl being optionally substituted with one or more substituent independently selected from halogen, hydroxyl and methoxy or

R 2 is C 6-10 aryl optionally substituted with one or more substituent independently selected from halogen, hydroxy, cyano, C 1-8 alkyl, C 3-8 cycloalkyl, C 1-6 alkyloxy and C 3-6 cycloalkyloxy, said C 1-8 alkyl, C 3-8 cycloalkyl, C 1-6 alkyloxy and C 3-6 cycloalkyloxy being optionally substituted with one or more halogens or

R 2 is a 5-10 membered heteroaryl ring system comprising a heteroatom selected from N, O and S and optionally substituted with methyl, C 1-6 alkyloxy, halogen or cyano;

R 3 and R 4 are independently H or C 1-6 alkyl or R 3 and R 4 together with the N to which they are bonded form a 4-7 membered heterocyclic ring optionally comprising a further heteroatomic moiety selected from 0, S, SO and SO 2 , said C 1-6 alkyl and 4-7 membered heterocyclic ring being optionally substituted with one or more halogens;

R 5 and R 6 are independently H or C 1-6 alkyl or R 5 and R 6 together with the N to which they are bonded form a 4-7 membered heterocyclic ring optionally comprising a further heteroatomic moiety selected from 0, S, SO and SO 2 , said C 1-6 alkyl and 4-7 membered heterocyclic ring being optionally substituted with one or more halogens;

X 1 is CO;

X 2 is N;

is a moiety selected from:

R 7 is (Y) m R 8 , wherein

Y is O, NR 9 or CR 10 R 11 ,

m is 0 or 1, and

R 8 is a moiety selected from the group consisting of:

wherein a, b and c are independently 1 or 2;

wherein d, e and f are independently 1 or 2;

wherein g, h and i are independently 1 or 2;

wherein j, and k are independently 1 or 2;

wherein l, and o are independently 1 or 2; and

wherein w, x, y and z are independently 1 or 2;

R 9 is H or C 1-6 alkyl;

R 10 and R 11 are independently H or C 1-6 alkyl;

R 12 and R 13 are independently H, C 1-6 alkyl or oxo;

R 14 is a further optional substituent selected from methyl, halogen and cyano;

n is 0 or 1, and

p is 0 or 1,

with the proviso that when R 7 is 1,4-diazabicyclo[3.2.2]non-4-yl or octahydropyrrolo[1,2-a]pyrazin-2-yl, one or both of R 3 and R 4 cannot be H,

or a pharmaceutically acceptable salt thereof.

2. The heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 1 is H, methyl, ethyl, propyl or isopropyl, optionally substituted with hydroxyl or methoxyl.

3. The heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 1 is H or methyl.

4. The heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 2 is H, methyl, ethyl, isopropyl, t-butyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

5. The heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 2 is phenyl optionally substituted with one or two substituents selected from chloro, fluoro, methyl, methoxyl and cyano.

6. The heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 2 is pyridyl, thiazolyl or furanyl optionally substituted with methyl or halogen.

7. The heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 7 is selected from the group consisting of:

8. The heterocyclic derivative according to claim 7 or a pharmaceutically acceptable salt thereof, wherein a is 2, b is 2 and c is 1.

9. The heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 7 is

10. A heterocyclic derivative selected from the group consisting of:

or a pharmaceutically acceptable salt thereof.

11. A pharmaceutical composition comprising a heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof in admixture with one or more pharmaceutically acceptable excipients.

12. A method for treating schizophrenia in a patient in need thereof, the method comprising administering to the patient a therapeutically effective amount of a heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof.

13. A method for treating Alzheimer's Disease in a patient in need thereof, the method comprising administering to the patient a therapeutically effective amount of a heterocyclic derivative according to claim 1 or a pharmaceutically acceptable salt thereof.

14. A pharmaceutical composition comprising a heterocyclic derivative according to claim 10 or a pharmaceutically acceptable salt thereof in admixture with one or more pharmaceutically acceptable excipients.

15. A method for treating schizophrenia in a patient in need thereof, the method comprising administering to the patient a therapeutically effective amount of a heterocyclic derivative according to claim 10 or a pharmaceutically acceptable salt thereof.

16. A method for treating Alzheimer's Disease in a patient in need thereof, the method comprising administering to the patient a therapeutically effective amount of a heterocyclic derivative according to claim 10 or a pharmaceutically acceptable salt thereof.