Pyrazole and imidazole derivatives useful as orexin antagonists

1. A compound of formula (I)

wherein

R 1 represents aryl or 5- to 10-membered heteroaryl, wherein the aryl or 5- to 10-membered heteroaryl independently is unsubstituted, or mono-, di-, or tri-substituted; wherein the substituents are independently selected from the group consisting of:

(C 1-4 )alkyl, (C 1-4 )alkoxy, halogen, cyano, (C 1-3 )fluoroalkyl, (C 1-3 )fluoroalkoxy; and

—NR 4 R 5 , wherein R 4 and R 5 are independently hydrogen or (C 1-4 )alkyl; or R 4 and R 5 together with the nitrogen atom to which they are attached to form a saturated 5- to 7-membered ring optionally containing an oxygen atom; and

phenyl or 5- or 6-membered heteroaryl, wherein the phenyl or 5- or 6-membered heteroaryl independently is unsubstituted, or mono-, or di-substituted; wherein the substituents are independently selected from the group consisting of (C 1-4 )alkyl, (C 1-4 )alkoxy, halogen, cyano, (C 1-3 )fluoroalkyl, (C 1-3 )fluoroalkoxy;

wherein at maximum one substituent selected from —NR 4 R 5 and phenyl or 5- or 6-membered heteroaryl is present;

U represents CH, and V represents N; or U represents N and V represents CH;

(R 2 ) n represents one or two optional substituents, wherein each R 2 independently is (C 1-3 )alkyl; and

Y represents O or S; and

ring A represents aryl or 5- to 10-membered heteroaryl, wherein said aryl or 5- to 10-membered heteroaryl independently is optionally substituted with (R 3 ) m ; wherein

(R 3 ) m represents one, two or three optional substituents, wherein each R 3 independently is selected from the group consisting of:

(C 1-4 )alkyl, (C 1-4 )alkoxy, halogen, cyano, (C 1-3 )fluoroalkyl, (C 1-3 )fluoroalkoxy; and

phenyl or 5- or 6-membered heteroaryl, wherein the phenyl or 5- or 6-membered heteroaryl independently is unsubstituted, or mono-, or di-substituted; wherein the substituents are independently selected from the group consisting of (C 1-4 )alkyl, (C 1-4 )alkoxy, halogen, cyano, (C 1-3 )fluoroalkyl, (C 1-3 )fluoroalkoxy;

wherein at maximum one phenyl or 5- or 6-membered heteroaryl substituent is present;

or (R 3 ) m represents two substituents which form a non-aromatic 5- or 6-membered ring fused to ring A, wherein said 5- or 6-membered ring optionally contains one or two oxygen atoms;

L represents a group —(CH 2 ) m —, wherein m represents the integer 2 or 3; wherein said group L is optionally substituted with R 6 ; wherein R 6 , if present, represents (C 1-3 )alkyl; and

X represents a direct bond, O, S or NR 7 ;

wherein, in case X represents NR 7 ,

R 7 represents hydrogen or (C 1-3 )alkyl; or, additionally,

R 7 and R 6 may form a 5- to 7-membered saturated ring including the nitrogen to which R 7 is attached to; or

R 7 together with one of the substituents R 3 may form a non-aromatic 5- to 7-membered ring including the nitrogen to which R 7 is attached to, which ring is fused to ring A; wherein R 6 is absent; and the remaining of said substituents R 3 , if present, independently are selected from the group consisting of (C 1-4 )alkyl, (C 1-4 )alkoxy, halogen, cyano, (C 1-3 )fluoroalkyl, and (C 1-3 )fluoroalkoxy;

or a salt thereof.

2. A compound according to claim 1 ; wherein R 1 represents phenyl which is unsubstituted, or mono-, or di-substituted; wherein the substituents are independently selected from the group consisting of (C 1-4 )alkyl, (C 1-4 )alkoxy, halogen, cyano, (C 1-3 )fluoroalkyl, (C 1-3 )fluoroalkoxy;

or a salt thereof.

3. A compound according to claim 1 ; wherein U represents CH, and V represents N;

or a salt thereof.

4. A compound according to claim 1 ; wherein Y represents O;

or a salt thereof.

5. A compound according to claim 1 ; wherein L represents a group —(CH 2 ) m —, wherein m represents the integer 2 or 3; wherein, in case m represents the integer 2, said group L is optionally substituted at the carbon atom which is adjacent to X with R 6 ; wherein R 6 , if present, represents methyl; or, in case X represents NR 7 , R 7 and R 6 additionally may form a piperidine or a pyrrolidine ring including the nitrogen to which R 7 is attached to;

or a salt thereof.

6. A compound according to claim 1 ; wherein ring A represents aryl or 5- to 10-membered heteroaryl, wherein said aryl or 5- to 10-membered heteroaryl independently is optionally substituted with (R 3 ) m ; wherein

(R 3 ) m represents one, two or three optional substituents, wherein each R 3 independently is selected from the group consisting of:

(C 1-4 )alkyl, (C 1-4 )alkoxy, halogen, cyano, (C 1-3 )fluoroalkyl, and (C 1-3 )fluoroalkoxy; and phenyl

wherein at maximum one phenyl substituent is present;

or (R 3 ) m represents two substituents which form a fragment —O—(CH 2 ) q —O—, wherein q represents the integer 1 or 2;

or, in case X represents NR 7 , (R 3 ) m additionally may represent one substituent, wherein R 7 together with said substituent R 3 forms a non-aromatic 5- to 7-membered ring including the nitrogen to which R 7 is attached to, which ring is fused to ring A;

or a salt thereof.

7. A compound according to claim 1 ; wherein X represents a direct bond, O or NR 7 ;

or a salt thereof.

8. A compound according to claim 1 ; wherein, in case X represents NR 7 ,

R 7 represents hydrogen or (C 1-3 )alkyl; or, additionally,

R 7 and R 6 may form a piperidine or a pyrrolidine ring including the nitrogen to which R 7 is attached to; or

X being NR 7 together with (R 3 ) m and ring A represents 2,3-dihydro-indol-1-yl;

or a salt thereof.

9. A compound according to claim 1 ; wherein

L represents a group —(CH 2 ) m —, wherein m represents the integer 2 or 3;

X represents a direct bond; and

ring A represents a group selected from the group consisting of pyrrol-1-yl, imidazol-1-yl, pyrazol-1-yl, triazol-1-yl, indol-1-yl, isoindol-2-yl, indazol-1-yl, benzimidazol-1-yl, benzotriazol-1-yl, 1H-pyrrolo[3,2-b]pyridin-1-yl, 1H-pyrrolo[2,3-b]pyridin-1-yl, 1H-pyrrolo[3,2-c]pyridin-1-yl, 1H-pyrrolo[2,3-c]pyridin-1-yl, 7H-pyrrolo[2,3-d]pyrimidin-7-yl, 5H-pyrrolo[3,2-d]pyrimidin-5-yl, 4H-furo[3,2-b]pyrrol-4-yl, 7H-purin-7-yl, and 9H-purin-9-yl; wherein each of said groups independently is optionally substituted with (R 3 ) m ; wherein (R 3 ) m represents one, or two optional substituents, wherein each R 3 independently is selected from the group consisting of (C 1-4 )alkyl, (C 1-4 )alkoxy, and halogen; or

L represents a group —(CH 2 ) m —, wherein m represents the integer 2 or 3;

X represents a direct bond; and

ring A represents a group selected from the group consisting of pyrimidin-2-yl, indol-3-yl, and 1H-pyrrolo[3,2-b]pyridin-3-yl; wherein each of said groups independently is optionally substituted with (R 3 ) m ; wherein (R 3 ) m represents one, or two optional substituents, wherein each R 3 independently is selected from the group consisting of (C 1-4 )alkyl, (C 1-4 )alkoxy, and halogen; or

L represents a group —(CH 2 ) m —, wherein m represents the integer 2 or 3;

X represents a O or NR 7 ;

R 7 represents hydrogen or (C 1-3 )alkyl; and

ring A represents a group selected from the group consisting of oxazol-2-yl, thiazol-2-yl, imidazol-2-yl, pyrazol-3-yl, pyridin-2-yl, pyrimid-2-yl, pyrimid-4-yl, pyridazin-3-yl, pyrazin-2-yl, benzimidazol-2-yl, benzoxazol-2-yl, benzothiazol-2-yl, quinolin-2-yl, quinazolin-2-yl, and quinoxalin-2-yl; wherein each of said groups independently is optionally substituted with (R 3 ) m ; wherein (R 3 ) m represents one, or two optional substituents, wherein each R 3 independently is selected from the group consisting of (C 1-4 )alkyl, (C 1-4 )alkoxy, and halogen.

or a salt thereof.

10. A compound according to claim 1 selected from the group consisting of:

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-methoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-methoxy-benzoimidazol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-methoxy-pyrrolo[2,3-b]pyridin-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Dimethylamino-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-yloxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-yloxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-Phenyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-yloxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid [1-(2-benzoimidazol-1-yl-ethyl)-1H-pyrazol-4-yl]-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Fluoro-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-yloxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(2,4-dimethoxy-pyrrolo[2,3-d]pyrimidin-7-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrrolo[2,3-b]pyridin-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-fluoro-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-imidazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4-methoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-pyrrolo[2,3-c]pyridin-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-methoxy-pyrrolo[3,2-c]pyridin-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5,6-dichloro-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(2-methyl-benzoimidazol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-chloro-pyrrolo[2,3-b]pyridin-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(benzooxazol-2-ylsulfanyl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid [1-(2-indol-1-yl-ethyl)-1H-pyrazol-4-yl]-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[3-(4,6-dimethoxy-pyrimidin-2-ylamino)-propyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-thiazole-4-carboxylic acid {1-[2-(quinoxalin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(quinazolin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid [1-(2-pyrrolo[2,3-b]pyridin-1-yl-ethyl)-1H-pyrazol-4-yl]-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(7-fluoro-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Morpholin-4-yl-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-methyl-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(quinazolin-2-yloxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(benzooxazol-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-thiazole-4-carboxylic acid {1-[2-(benzooxazol-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethyl-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(quinoxalin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(quinazolin-2-ylamino)-ethyl]-1H-imidazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(7-methyl-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(3-methoxy-phenyl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(benzo[1,3]dioxol-5-yloxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-fluoro-pyridin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethyl-pyridin-2-yloxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-methoxy-purin-7-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-chloro-benzooxazol-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(3-methoxy-phenoxy)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4-methoxy-pyrrolo[2,3-b]pyridin-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-Phenyl-oxazole-4-carboxylic acid {1-[2-(2-methyl-benzoimidazol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(4-Trifluoromethyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-chloro-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[3-(2,3-dihydro-indol-1-yl)-propyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-3,5-dimethyl-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid [1-(3-indol-1-yl-propyl)-1H-pyrazol-4-yl]-amide;

5-(2-Fluoro-phenyl)-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4-fluoro-pyridin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(2,3-dihydro-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[(R)-2-(4,6-dimethoxy-pyrimidin-2-ylamino)-propyl]-1H-pyrazol-4-yl}-amide;

5-(3-Cyano-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-Phenyl-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

rac-5-m-Tolyl-oxazole-4-carboxylic acid {1-[1-(4,6-dimethoxy-pyrimidin-2-yl)-pyrrolidin-2-ylmethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid [1-(2-pyrrolo[3,2-b]pyridin-1-yl-ethyl)-1H-pyrazol-4-yl]-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[(S)-2-(4,6-dimethoxy-pyrimidin-2-ylamino)-propyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(1-methyl-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4-methoxy-pyridin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3,4-Dimethyl-phenyl)-thiazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[3-(6-methoxy-2,3-dihydro-indol-1-yl)-propyl]-1H-pyrazol-4-yl}-amide;

5-(6-Methoxy-pyridin-3-yl)-thiazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(6-methoxy-pyrrolo[3,2-c]pyridin-1-yl)-ethyl]-3,5-dimethyl-1H-pyrazol-4-yl}-amide;

5-(3-Methoxy-4-methyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(4-Methoxy-phenyl)-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Pyrrolidin-1-yl-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid [1-(2-indol-1-yl-ethyl)-3,5-dimethyl-1H-pyrazol-4-yl]-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-5-methyl-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Fluoro-phenyl)-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Methoxy-4-methyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-Phenyl-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(4-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Methoxy-4-methyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(4-Methoxy-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-fluoro-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[3-(4-ethoxy-6-methoxy-pyrimidin-2-yl)-propyl]-1H-pyrazol-4-yl}-amide;

5-Biphenyl-3-yl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-Phenyl-thiazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-benzoimidazol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-Isoxazol-3-yl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3,4-Dimethyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3,4-Dimethyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[3-(6-methoxy-indol-1-yl)-propyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[3-(4-methoxy-pyrimidin-2-ylamino)-propyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-chloro-6-methoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(4-Methoxy-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-thiazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(2,6-dimethoxy-pyrimidin-4-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[3-(4,6-dimethoxy-pyrimidin-2-yl)-propyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-imidazol-4-yl}-amide;

5-(3-Fluoro-phenyl)-oxazole-4-carboxylic acid {1-[2-(4,6-dimethoxy-pyrimidin-2-ylamino)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3,4-Dimethyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(5,6-dimethoxy-indol-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1-methyl-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Chloro-phenyl)-thiazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Methyl-isoxazol-5-yl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Trifluoromethyl-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-m-Tolyl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-pyrrolo[3,2-b]pyridin-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Trifluoromethoxy-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(2-Fluoro-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Fluoro-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

5-(3-Chloro-phenyl)-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide; and

5-Phenyl-oxazole-4-carboxylic acid {1-[2-(5-methoxy-1H-indol-3-yl)-ethyl]-1H-pyrazol-4-yl}-amide;

or a salt thereof.

11. A pharmaceutical composition comprising, as active principle, one or more compounds according to claim 1 , or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable carrier.

12. A method for the or treatment of an insomnia, post-traumatic stress disorder (PTSD), or cognitive dysfunction in learning and/or memory, comprising administering to a patient in need thereof an effective amount of a compound according to claim 1 , in free form or a pharmaceutically acceptable salt thereof.