Factor XI activation inhibitors

1. A compound of the formula:

wherein

R 1 is phenyl or heteroaryl, which may be monocyclic or bicyclic, wherein said phenyl and heteroaryl groups are optionally substituted with one to three substituents independently selected from the group consisting of halo, oxo, cyano, R 4 , OR 4 , R 6 and NO 2 ;

R 2 is piperidinyl, NR 4 R 5 or NR 4 R 6 , wherein said piperidinyl group is optionally substituted with one to three halo;

R 3 is heterocyclyl, which may be monocyclic or bicyclic, or NHC(CH 3 ) 2 R 6 , wherein said heterocyclyl is optionally substituted with one to three substituents independently selected from the group consisting of halo, cyano, R 4 , OR 4 , R 6 , CONR 4 R 5 , NR 4 COR 5 , (C 1-3 alkyl) R 6 and SO 2 R 4 ,

R 4 is hydrogen or C 1-6 alkyl, which is optionally substituted with one to three halo;

R 5 is hydrogen or C 1-6 alkyl, which is optionally substituted with one to three halo;

R 6 is phenyl, C 3-6 cycloalkyl, heterocyclyl or heteroaryl, wherein said heteroaryl is optionally substituted with one to three substituents independently selected from the group consisting of C 1-6 alkyl and halo;

R x is hydrogen, halo or C 1-6 alkyl;

n is an integer from one to three;

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 wherein R 1 is selected from benzoimidazolyl, benzoisoxazolyl, benzooxadiazolyl, benzooxazolyl, benzothiadiazolyl, benzothiazolyl, benzotriazolyl, dihydroindazolyl, dihydroisobenzofuranyl, imidazopyridinyl, phenyl, pyrazolopyridinyl, pyridinyl or pyrrolyl wherein said groups are optionally substituted with one or two substituents independently selected from the group consisting of methyl, chloro, fluoro, oxo, cyano, NO 2 , CF 3 , OCHF 2 , OCF 3 and OCH 3 ; or a pharmaceutically acceptable salt thereof.

3. The compound of claim 1 wherein R 2 is piperidinyl, or a pharmaceutically acceptable salt thereof.

4. The compound of claim 1 wherein R 3 is piperidinyl, piperazinyl, azaspiroocatnyl or pyrrolidinyl, wherein said groups are optionally substituted with one or two substituents independently selected from the group consisting of methyl, fluoro, hydroxyl, cyano, pyrazolyl, phenyl, triazolyl, piperidinyl, CONH 2 , NHCOCH 3 , CH 2 CF 3 , CH(CH 3 )CF 3 , CH 2 CHF 2 , and SO 2 CH 3 ; or a pharmaceutically acceptable salt thereof.

5. The compound of claim 1 wherein R 3 is piperidinyl, which is optionally substituted with one or two substituents independently selected from the group consisting of methyl, fluoro, hydroxyl, cyano, pyrazolyl, phenyl, triazolyl, piperidinyl, CONH 2 , NHCOCH 3 , CH 2 CF 3 , CH(CH 3 )CF 3 , CH 2 CHF 2 , and SO 2 CH 3 ; or a pharmaceutically acceptable salt thereof.

6. The compound of claim 1 wherein R 1 is heteroaryl, which is bicyclic, and is optionally substituted with one to three substituents independently selected from the group consisting of halo, oxo, cyano and R 4 ; or a pharmaceutically acceptable salt thereof.

7. A compound selected from

or a pharmaceutically acceptable salt thereof.

8. A pharmaceutical composition comprising a compound of claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.

9. A method for inhibiting thrombus formation in blood or treating thrombus formation in blood comprising administering a pharmaceutical composition of claim 8 to a mammal in need of thereof.

10. A method for preventing thrombus formation in blood comprising administering a pharmaceutical composition of claim 8 to a mammal in need thereof.

11. A method of treating venous thromboembolism or pulmonary embolism in a mammal comprising administering a pharmaceutical composition of claim 8 to a mammal in need thereof.

12. A method of treating deep vein thrombosis in a mammal comprising administering a pharmaceutical composition of claim 8 to a mammal in need thereof.

13. A method of treating thromboembolic stroke in a mammal comprising administering a pharmaceutical composition of claim 8 to a mammal in need thereof.