Heterocyclic amide derivatives as P2X7 receptor antagonists

1. A compound of the formula (I),

wherein

n represents 1 or 2;

one of X and Y represents —N— or —N(O)— and the other one represents —N— or —C(R 6 )—;

R 1 represents hydrogen or methyl and R 2 represents hydrogen, (C 1 -C 2 )alkyl, (C 1 -C 2 )deuteroalkyl, hydroxy-methyl or heterocyclyl-methyl; or

R 1 and R 2 form, together with the carbon atom to which they are attached, a saturated carbocyclic ring of 3 to 6 members; and

R 3 represents an aryl, an aryloxy, an aryl-(C 1 -C 2 )alkyl, a heteroaryl or a heteroaryloxy group wherein the aromatic moiety of the groups is independently mono-, di-, tri- or tetra-substituted, wherein the substituents are independently selected from the group consisting of (C 1 -C 3 )alkyl, (C 3 -C 6 )cycloalkyl, (C 1 -C 3 )alkoxy, hydroxy-(C 1 -C 2 )alkyl, (C 1 -C 3 )fluoroalkyl, (C 1 -C 3 )fluoroalkoxy, (C 1 -C 2 )alkylcarbonyl, cyano, —CONH 2 , halogen and phenoxy;

or

R 1 represents hydrogen and R 2 and R 3 form, together with the carbon atom to which they are attached, an indanyl or a tetrahydronaphthyl group wherein the aromatic moiety of the groups is independently mono-, di- or tri-substituted, wherein the substituents are independently selected from the group consisting of (C 1 -C 3 )alkyl, (C 1 -C 3 )fluoroalkyl and halogen; and

R 4 , R 5 and R 6 represent independently from each other hydrogen, (C 1 -C 3 )alkyl, (C 3 -C 6 )cycloalkyl, (C 1 -C 3 )alkoxy, (C 1 -C 3 )fluoroalkyl or halogen;

or a salt of such a compound.

2. A compound of formula (I) according to claim 1 , wherein

n represents 1 or 2;

one of X and Y represents —N— or —N(O)— and the other one represents —N— or —C(R 6 )—;

R 1 represents hydrogen and R 2 represents hydrogen, (C 1 -C 2 )alkyl, (C 1 -C 2 )deuteroalkyl or hydroxy-methyl; or

R 1 and R 2 form, together with the carbon atom to which they are attached, a saturated carbocyclic ring of 3 to 6 members; and

R 3 represents an aryl group which is di- or tri-substituted, wherein the substituents are independently selected from the group consisting of (C 1 -C 3 )alkyl, (C 3 -C 6 )cycloalkyl, hydroxy-(C 1 -C 2 )alkyl, (C 1 -C 3 )fluoroalkyl, (C 1 -C 3 )fluoroalkoxy, (C 1 -C 2 )alkylcarbonyl, cyano, —CONH 2 and halogen; or an aryl-(C 1 -C 2 )alkyl group wherein the aromatic moiety of the groups is mono- or di-substituted with halogen;

or

R 1 represents hydrogen and R 2 and R 3 form, together with the carbon atom to which they are attached, an indanyl group which is in the aromatic moiety mono- or di-substituted with halogen; and

R 4 , R 5 and R 6 represent independently from each other hydrogen, (C 1 -C 3 )alkyl, (C 3 -C 6 )cycloalkyl, methoxy, trifluoromethyl or halogen;

or a salt of such a compound.

3. A compound of formula (I) according to claim 1 , wherein

n represents 1;

or a salt of such a compound.

4. A compound of formula (I) according to claim 1 , wherein

n represents 2;

or a salt of such a compound.

5. A compound of formula (I) according to claim 1 , wherein

X represents —N— and Y represents —C(R 6 )— or —N—;

or a salt of such a compound.

6. A compound of formula (I) according to claim 1 , wherein

R 1 represents hydrogen or methyl and R 2 represents hydrogen, (C 1 -C 2 )alkyl, (C 1 -C 2 )deuteroalkyl, hydroxy-methyl or heterocyclyl-methyl; or

R 1 and R 2 form, together with the carbon atom to which they are attached, a saturated carbocyclic ring of 3 to 5 members; and

R 3 represents an aryl, an aryl-(C 1 -C 2 )alkyl, a heteroaryl or a heteroaryloxy group wherein the aromatic moiety of the groups is independently di-, tri- or tetra-substituted, wherein the substituents are independently selected from the group consisting of (C 1 -C 3 )alkyl, (C 3 -C 6 )cycloalkyl, (C 1 -C 3 )alkoxy, hydroxy-(C 1 -C 2 )alkyl, (C 1 -C 3 )fluoroalkyl, (C 1 -C 3 )fluoro-alkoxy, (C 1 -C 2 )alkylcarbonyl, cyano, —CONH 2 and halogen;

or a salt of such a compound.

7. A compound of formula (I) according to claim 1 , wherein

R 1 represents hydrogen and R 2 and R 3 form, together with the carbon atom to which they are attached, an indanyl or a tetrahydronaphthyl group wherein the aromatic moiety of the groups is independently mono-, di- or tri-substituted, wherein the substituents are independently selected from the group consisting of (C 1 -C 3 )alkyl, (C 1 -C 3 )fluoroalkyl and halogen;

or a salt of such a compound.

8. A compound of formula (I) according to claim 1 , wherein

R 1 and R 2 represent hydrogen;

or a salt of such a compound.

9. A compound of formula (I) according to claim 1 , wherein

R 1 and R 2 form, together with the carbon atom to which they are attached, a saturated carbocyclic ring of 3 to 5 members;

or a salt of such a compound.

10. A compound of formula (I) according to claim 1 , wherein

R 3 represents a phenyl group which is di-, tri- or tetra-substituted, wherein the substituents are independently selected from the group consisting of (C 1 -C 3 )alkyl, (C 3 -C 6 )cycloalkyl, (C 1 -C 3 )alkoxy, hydroxy-(C 1 -C 2 )alkyl, (C 1 -C 3 )fluoroalkyl, (C 1 -C 3 )fluoroalkoxy, (C 1 -C 2 )alkylcarbonyl, cyano, —CONH 2 and halogen; a phenyl-methyl or phenyl-ethyl group wherein the aromatic moiety of the groups is independently mono- or di-substituted with halogen; a heteroaryl group which is mono- or di-substituted, wherein the substituents are independently selected from the group consisting of (C 1 -C 3 )alkyl and halogen; or a heteroaryloxy group which is mono- or di-substituted with (C 1 -C 3 )alkyl;

or a salt of such a compound.

11. A compound of formula (I) according to claim 1 , selected from the group consisting of:

2-(2,4-Dichloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-4-fluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N—(S)-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N—(R)-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N—(S)-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N—(R)-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2-Cyano-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-o-tolyl-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(2-methoxy-phenyl)-acetamide;

2-(4-Cyano-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-p-tolyl-acetamide;

2-(4-Chloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(4-trifluoromethyl-phenyl)-acetamide;

2-(2,4-Difluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(4-fluoro-2-trifluoromethyl-phenyl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(2,4-dimethoxy-phenyl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(2-fluoro-4-methoxy-phenyl)-acetamide;

2-(3,4-Dichloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(2,4,6-trifluoro-phenyl)-acetamide;

2-(4-Chloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

1-(2,4-Dichloro-phenyl)-cyclopropanecarboxylic acid (2,3-dihydro-furo[2,3-b]pyridin-3-yl)-amide;

1-(2-Chloro-4-fluoro-phenyl)-cyclopentanecarboxylic acid (2,3-dihydro-furo[2,3-b]pyridin-3-yl)-amide;

2-(4-Chloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-isobutyramide;

3-(2,4-Dichloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N—(S)-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N—(R)-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N—(S)-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N—(R)-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-6-ethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(4-Chloro-2-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(4-phenoxy-phenyl)-acetamide;

2-(2,4-Dichloro-6-cyano-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-4-fluoro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-6-cyclopropyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(4-Chloro-2-fluoro-3-methyl-6-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-5-fluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-6-fluoro-3-methyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(5-Chloro-2-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(4-Cyano-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

N-(3,4-Dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-2-(4-trifluoromethyl-phenyl)-acetamide;

N-(3,4-Dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-2-(3-trifluoromethyl-phenyl)-acetamide;

N-(3,4-Dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-2-(4-phenoxy-phenyl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2-Chloro-6-fluoro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Difluoro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

N-(3,4-Dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-2-(4-fluoro-2-trifluoromethyl-phenyl)-acetamide;

2-(4-Chloro-2-trifluoromethyl-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,3-Dichloro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(3,4-Dichloro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-6-trifluoromethyl-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,4-Dichloro-5-fluoro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

1-(2,4-Dichloro-phenyl)-cyclopropanecarboxylic acid (3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-amide;

1-(2-Chloro-4-fluoro-phenyl)-cyclopentanecarboxylic acid (3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-amide;

2-(2-Chloro-pyridin-3-yl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

N-(3,4-Dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-2-(2,6-dimethyl-pyridin-3-yloxy)-acetamide;

N-(3,4-Dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-2-(3-methyl-isoxazol-5-yl)-acetamide;

N-(3,4-Dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-2-(5-methyl-pyrazol-1-yl)-acetamide;

2-(4-Chloro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-propionamide;

3-(2,4-Dichloro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-propionamide;

2-(2,3-Dichloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,3-Dichloro-6-fluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(2-fluoro-6-trifluoromethyl-phenyl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(3-fluoro-4-trifluoromethoxy-phenyl)-acetamide;

2-(2,4-Dichloro-6-fluoro-phenyl)-N-(3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)-acetamide;

2-(2,3-Dichloro-6-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,6-Dichloro-3-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N—(S)-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N—(R)-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide; and

2-(2-Chloro-3-cyano-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

or a salt of such a compound.

12. A compound of formula (I) according to claim 1 , selected from the group consisting of:

2-(2,4-Dichloro-6-fluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(3,6-Dichloro-2-fluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3,6-difluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N-2,3-dihydro-furo[2,3-b]pyridin-3-yl-3-hydroxy-propionamide;

2-Chloro-3-[(2,3-dihydro-furo[2,3-b]pyridin-3-ylcarbamoyl)-methyl]-benzamide;

2-(2,4-Dichloro-phenyl)-N-2,3-dihydro-furo[2,3-b]pyridin-3-yl-3-pyrrolidin-1-yl-propionamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-4-(4-fluoro-phenyl)-butyramide;

2-(2,4-Dichloro-phenyl)-N-(2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N-2,3-dihydro-furo[2,3-b]pyridin-3-yl-butyramide;

2-(2,4-Dichloro-phenyl)-N-2,3-dihydro-furo[2,3-b]pyridin-3-yl-propionamide;

2-(2,4-Dichloro-phenyl)-2-trideuteromethyl-N-2,3-dihydro-furo[2,3-b]pyridin-3-yl-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2-Chloro-4-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(2-fluoro-3-trifluoromethyl-phenyl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-2,3-dihydro-furo[2,3-b]pyridin-3-yl-propionamide;

(S)-2-(2,4-Dichloro-phenyl)-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

(S)-2-(2,4-Dichloro-phenyl)-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

(R)-2-(2,4-Dichloro-phenyl)-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

(R)-2-(2,4-Dichloro-phenyl)-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

2-(2-Chloro-4-cyano-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(3-Chloro-2-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-cyano-phenyl)-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-cyano-phenyl)-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-phenyl)-N-(7-methyl-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N—((R)-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N—((S)-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-hydroxymethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(7-Cyclopropyl-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-2-(2,4-dichloro-phenyl)-acetamide;

2-(2,4-Dichloro-phenyl)-N-(7-methoxy-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

N-(7-Chloro-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-2-(2,4-dichloro-phenyl)-acetamide;

2-(2-Chloro-3-cyano-4-fluoro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethoxy-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(5,6-dihydro-furo[2,3-c]pyridazin-5-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(5,6-dihydro-furo[2,3-c]pyridazin-5-yl)-acetamide;

2-(3-Acetyl-2-chloro-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-3-cyano-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(3-Cyano-2-trifluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-difluoromethyl-phenyl)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(5-Chloro-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-2-(2-chloro-3-trifluoromethyl-phenyl)-acetamide;

N-(5-Chloro-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-2-(2,4-dichloro-phenyl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(5-methyl-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

(S)-2-(2-Chloro-3-trifluoromethyl-phenyl)-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

(S)-2-(2-Chloro-3-trifluoromethyl-phenyl)-2-trideuteromethyl-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

(S)-2-(2-Chloro-3-trifluoromethyl-phenyl)-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

(S)-2-(2-Chloro-3-trifluoromethyl-phenyl)-2-trideuteromethyl-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

(R)-2-(2-Chloro-3-trifluoromethyl-phenyl)-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

(R)-2-(2-Chloro-3-trifluoromethyl-phenyl)-2-trideuteromethyl-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

(R)-2-(2-Chloro-3-trifluoromethyl-phenyl)-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-propionamide;

(R)-2-(2-Chloro-3-trifluoromethyl-phenyl)-2-trideuteromethyl-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-2-trideuteromethyl-N—((R)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-2-trideuteromethyl-N—((S)-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(4-methyl-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(7-oxy-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

5,7-dichloro-N-(2,3-dihydrofuro[2,3-b]pyridin-3-yl)-2,3-dihydro-1H-indene-1-carboxamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(4-methyl-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(4-cyclopropyl-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(6-methyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(6-methyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(4-methoxy-6-methyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(4-ethoxy-6-methyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(4-methyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(4-methyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(4-methoxy-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(2,4-Dichloro-phenoxy)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

2-(3,4-Dichloro-phenoxy)-N-(2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

N-(2,3-Dihydro-furo[2,3-b]pyridin-3-yl)-2-(2,4-dimethyl-phenoxy)-acetamide;

N-(6-Chloro-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-2-(2-chloro-3-trifluoromethyl-phenyl)-acetamide;

N-(6-Chloro-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-2-(2,4-dichloro-6-methyl-phenyl)-acetamide;

5-chloro-N-(2,3-dihydrofuro[2,3-b]pyridin-3-yl)-2,3-dihydro-1H-indene-1-carboxamide;

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(6-oxy-2,3-dihydro-furo[2,3-c]pyridin-3-yl)-acetamide;

5-chloro-N—((R)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)-2,3-dihydro-1H-indene-2-carboxamide;

5-chloro-N—((S)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)-2,3-dihydro-1H-indene-2-carboxamide;

2-(2,4-Dichloro-6-methyl-phenyl)-N-(4-trifluoromethyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide; and

2-(2-Chloro-3-trifluoromethyl-phenyl)-N-(4-trifluoromethyl-2,3-dihydro-furo[2,3-b]pyridin-3-yl)-acetamide;

or a salt of such a compound.

13. A pharmaceutical composition containing, as active principle, a compound of formula (I) according to claim 1 , or a pharmaceutically acceptable salt thereof, and at least one therapeutically inert excipient.

14. The method for treatment of a disease, which is associated with the activation of the P2X 7 comprising the administration of an effective amount of a compound of formula (I) according to claim 1 , wherein the disease is selected from the group consisting of: pain; rheumatoid arthritis, osteoarthritis, irritable bowel disease, and chronic obstructive pulmonary disease (COPD).