Bicyclic piperazines as metabotropic glutatmate receptor antagonists

1 . A compound of formula I:

wherein

Ar 1 is an optionally-substituted aryl or heteroaryl group, wherein the substituents are selected from the group consisting of F, Cl, Br, I, OH, nitro, Cl 1-6 -alkyl, Cl 1-6 -alkylhalo, OCl 1-6 -alkyl, OC 1-6 -alkylhalo, C 2-6 -alkenyl, C 2-6 -alkynyl, CN, CO 2 R 2 , SR 2 , S(O)R 2 , SO 2 R 2 , aryl, heteroaryl, cycloalkyl and heterocycloalkyl, wherein any cyclic group may be further substituted with at least one substituent selected from the group consisting of F, Cl, Br, I, OH, nitro, C 1-6 -alkyl, C 1-6 -alkylhalo, OC 1-6 -alkyl, OC 1-6 -alkylhalo, C 2-6 -alkenyl, C 2-6 -alkynyl, CN, CO 2 R 2 , SR 2 , S(O)R 2 and SO 2 R 2 ;

A is selected from the group consisting of Ar 1 , CO 2 R 2 , CONR 2 R 3 , S(O)R 2 and SO 2 R 2 ;

R 1 , in each instance, is independently selected from the group consisting of F, Cl, Br, I, OH, CN, nitro, C 1-6 -alkyl, OC 1-6 -alkyl, C 1-6 -alkylhalo, OC 1-6 -alkylhalo, (CO)R 2 , O(CO)R 2 , O(CO)OR 2 , CO 2 R 2 , —CONR 2 R 3 , Cl 1-6 -alkyleneOR 2 , OC 2-6 -alkyleneOR C 1-6 -alkylenecyano;

R 2 and R 3 are independently selected from the group consisting of H, C 1-6 -alkyl, C 1-6 -alklhalo, C 2-6 -alkenyl, C 2-6 alkynyl and cycloalkyl;

Hy is a 5-membered heterocyclic ring containing two, three or four heteroatoms independently selected from the group consisting of N, O and S, wherein the ring is optionally substituted with one or more substituents selected from the group consisting of F, Cl, Br, I, OH, nitro, C 1-6 -alkyl, C 1-6 -alkylhalo, OC 1-6 -alkyl, OC 1-6 -alkylhalo, CN, CO 2 R 2 , NR 2 R 3 , SR 2 , S(O)R 2 and SO 2 R 2 ;

m is an integer selected from the group consisting of 0, 1, 2, 3 and 4; and

n is an integer selected from the group consisting of 1, 2 and 3;

or a pharmaceutically acceptable salt, hydrate, solvate, isoform, tautomer, optical isomer, or combination thereof.

2 . A compound according to claim 1 wherein Ar 1 is an optionally-substituted phenyl group.

3 . A compound according to claim 2 wherein A is selected from the group consisting of an optionally-substituted pyridyl group and an optionally-substituted pyrazinyl group.

4 . A compound according to claim 3 wherein A is selected from the group consisting of an optionally-substituted 2-pyridyl group and an optionally-substituted 2-pyrazinyl group.

5 . A compound according to claim 4 wherein Hy is selected from the group consisting of oxazole, isoxazole, 1,2,4-oxadiazole and 1,2,3-triazole

6 . A compound selected from the group consisting of:

(±)-2-[(6R,8aS)-6-[1-(3-fluorophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,8aS)-6-[1-(3-fluorophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-2-[(6R,8aS)-6-[ 1- (3 -chlorophenyl)-1H-1, 2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,8aS)-6-[1-(3-chlorophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-2-[(6R,8aS)-6-[1-(3-bromophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,8aS)-6-[1-(3-bromophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-2-[(6R,8aS)-6-[1-(3-cyanophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,8aS)-6-[1-(3-cyanophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[2-(3-chlorophenyl)-2H-tetrazol-5-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-2-[(6R,8aS)-6-[2-(3-chlorophenyl)-2H-tetrazol-5-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,8aS)-6-[2-(3-methylphenyl)-2H-tetrazol-5-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-2-[(6R,8aS)-6-[2-(3-methylphenyl)-2H-tetrazol-5-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,8aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-6-[(6R,8aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-2-[(6R,8aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,8aS)-6-{5-[3-(trifluoromethyl)phenyl]isoxazol-3-yl}hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[5-(3-methylphenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-(5-pyridin-3-ylisoxazol-3-yl)hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[5-(3-methoxyphenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[5-(2-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[5-(6-methylpyridin-2-yl)isoxazol-3-yl]hexahydropyrrolo[1,2α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[5-(5-fluoropyridin-2-yl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-Ethyl (6R,8aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazine-2(1H)-carboxylate,

(±)-3-[(6R,8aS)-6-[3-(3-chlorophenyl)isoxazol-5-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-6-[(6R,9aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile,

(±)-6-[(6R,9aS)-6-[5-(3-cyanophenyl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile,

(±)-2-[(6R,9aS)-6-[3-(3-chlorophenyl)isoxazol-5-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]nicotinonitrile,

(±)-2-[(6R,9aS)-6-[3-(3-cyanophenyl)isoxazol-5-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]nicotinonitrile,

(±)-2-[(6R,8aS)-6-[1-(3-chlorophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrol[1,2-a]pyrazin-2(1H)-yl]-5-fluoronicotinonitrile,

(±)-6-[(6R,9aS)-6-[5-(3-cyanophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-a]pyrazin-2-yl]-5-fluoronicotinonitrile,

(±)-2-[(6R,9aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-6-[(6R,9aS)-6-[5-(3-cyanophenyl)-1,2,3-triazol-4-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile,

(±)-6-[(6R,9aS)-6-[5-(3-chloro-phenyl)-1,2,3-triazol-4-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile,

(±)-6-[(6R,9aS)-6-[5-(3-cyanophenyl)-1,2,3-triazol-4-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-6-[(6R,9aS)-6-[5-(3-chloro-phenyl)-1,2,3-triazol-4-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2(1H)-yl]nicotinonitrile,

(±)-3-[(6R,9aS)-6-[5-(3-cyanophenyl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,9aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile,

(±)-2-[(6R,9aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]nicotinonitrile,

(±)-2-[(6R,9aS)-6-[5-(6-methylpyrid-2-yl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]nicotinonitrile,

(±)-6-[(6R,9aS)-6-[5-(pyrid-2-yl)isoxazol-3-yl]octahydro-2H-pyrido[1,2-a]pyrazin-2-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[1-(3-methylphenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-(1-pyridin-4-yl-1H-1,2,3-triazol-4-yl)hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[1-(3-trifluoromethylphenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

(±)-3-[(6R,8aS)-6-[1-(2-methylpyridin-4-yl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[5-(3-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[5-(3-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-a]pyrazin -2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[1-(3-chlorophenyl)-1H-i ,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[1-(3-chlorophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-{5-[3-(trifluoromethyl)phenyl]isoxazol-3-yl}hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-{5-[3-(trifluoromethyl)phenyl]isoxazol-3-yl}hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[5-(3-methylphenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S, 8aR)-6-[5-(3-methylphenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-(5-pyridin-3-ylisoxazol-3-yl)hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-(5-pyridin-3-ylisoxazol-3-yl)hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[5-(3-methoxyphenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[5-(3-methoxyphenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile, 3-[(6R,8aS)-6-[5-(2-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[5-(2-chlorophenyl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[5-(6-methylpyridin-2-yl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[5-(6-methylpyridin-2-yl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[5-(5-fluoropyridin-2-yl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[5-(5-fluoropyridin-2-yl)isoxazol-3-yl]hexahydropyrrolo[1,2-α]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[2-(3-methylphenyl)-2H-tetrazol-5-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[2-(3-methylphenyl)-2H-tetrazol-5-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[1-(3-methylphenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[1-(3-methylphenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-(1-pyridin-4-yl-1H-1,2,3-triazol-4-yl)hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-(1-pyridin-4-yl-1H-1,2,3-triazol-4-yl)hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[1-(3-trifluoromethylphenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[1-(3-trifluoromethylphenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[1-(3-cyanophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6S,8aR)-6-[1-(3-cyanophenyl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile,

3-[(6R,8aS)-6-[1-(2-methylpyridin-4-yl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile and

3-[(6S,8aR)-6-[1-(2-methylpyridin-4-yl)-1H-1,2,3-triazol-4-yl]hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]pyrazine-2-carbonitrile.

7 . A pharmaceutical composition comprising as active ingredient a therapeutically effective amount of the compound according to claim 1 , in association with one or more pharmaceutically acceptable diluents, excipients and/or inert carriers.

8 . The pharmaceutical composition according to claim 7 , for use in the treatment of mGluR 5 mediated disorders.

9 . The compound according to claim 1 for use in therapy.

10 . The compound according to claim 1 for use in treatment of mGluR5-mediated disorders.

11 . Use of the compound according to claim 1 , in the manufacture of a medicament for the treatment of mGluR5-mediated disorders.

12 . A method of treatment of mGluR5-mediated disorders, comprising administering to a mammal a therapeutically effective amount of the compound according to claim 1 .

13 . The method according to claim 12 , wherein the mammal is a human.

14 . The method according to claim 12 , wherein the disorders are neurological disorders.

15 . The method according to claim 12 , wherein the disorders are psychiatric disorders.

16 . The method according to claim 12 , wherein the disorders are chronic and acute pain disorders.

17 . The method according to claim 12 , wherein the disorders are gastrointestinal disorders.

18 . A method for inhibiting activation of mGluR5 receptors, comprising treating a cell containing said receptor with an effective amount of the compound according to claim 1.