Inhibitors of histone deacetylase-3 useful for the treatment of cancer, inflammation, neurodegeneration diseases and diabetes

1. A compound of the formula:

wherein

is a five-membered heteroaryl ring which is optionally substituted with halo, cyano or C 1-3 alkyl;

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 , R 6 , OR 4 , NHR 4 , NR 4 R 5 , NO 2 and SR 4 ;

R 1 is naphthalenyl or quinolinyl wherein said naphthalenyl and quinolinyl groups are optionally substituted with one to two groups independently selected from the group consisting of halo, oxo, cyano, R 4 and OR 4 ;

R 2 is selected from the group consisting of NH(C═O)R 6 , NH(C═O)CH(CH 3 )R 6 and NH(C═O)R 4 ;

R 3 is hydrogen or C 1-6 alkyl;

or R 2 and R 3 can be taken together with the atoms to which they are attached to form a 5-membered heterocyclyl group which is optionally substituted with oxo;

each R 4 is independently hydrogen or C 1-6 alkyl, which is optionally substituted with one to three groups independently selected from the group consisting of halo, cyano and OR 5 ;

each R 5 is independently hydrogen or C 1-6 alkyl;

R 6 is

(a) heterocyclyl, which may be monocyclic or bicyclic,

(b) C 3-6 cycloalkyl,

(c) phenyl, or

(d) heteroaryl, which may be monocyclic or bicyclic,

wherein said heterocyclyl, cycloalkyl, phenyl and heteroaryl groups are optionally substituted with one to two groups independently selected from the group consisting of oxo, R 4 and OR 4 ;

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 wherein

is imidazolyl, or a pharmaceutically acceptable salt thereof.

3. The compound of claim 1 wherein

is selected from phenyl, pyridinyl, pyrazolyl, pyrazolopyrimidinyl, oxadiazolyl, thiadiazolyl, isothiazolyl, or dihydroindenyl, wherein said groups are optionally substituted with one to three substituents independently selected from the group consisting of halo, oxo, cyano, R 4 , R 6 , OR 4 , NHR 4 , NR 4 R 5 , NO 2 and SR 4 ; or a pharmaceutically acceptable salt thereof.

4. The compound of claim 1 wherein R 1 is naphthalenyl or quinolinyl wherein said quinolinyl group is optionally substituted with OR 4 ; or a pharmaceutically acceptable salt thereof.

5. The compound of claim 1 wherein R 2 is NH(C═O)R 6 or NH(C═O)C(CH 3 )R 6 , and R 6 is selected from the group consisting of azetidinyl, piperidinyl, pyrazolyl, tetrahydropyranyl and thiazolyl; or a pharmaceutically acceptable salt thereof.

6. The compound of claim 1 wherein R 2 is NH(C═O)thiazolyl, or a pharmaceutically acceptable salt thereof.

7. A compound selected from

or a pharmaceutically acceptable salt thereof.

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

9. A method for the inhibition of HDAC in a subject in need thereof which comprises administering to the subject an effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof.

10. A method for the treatment of infection by HIV or for the treatment, prophylaxis, or delay in the onset or progression of AIDS in a subject in need thereof, which comprises administering to the subject an effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof.

11. A compound of claim 1 , or a pharmaceutically acceptable salt thereof, for use in the preparation of a medicament for the inhibition of HDAC, for the treatment or prophylaxis of infection by HIV, or for the treatment, prophylaxis, or delay in the onset or progression of AIDS in a subject in need thereof.

12. The pharmaceutical composition of claim 8 , further comprising one or more additional therapeutic agents selected from raltegravir, lamivudine, abacavir, ritonavir, darunavir, atazanavir, emtricitabine, tenofovir, rilpivirine, doravirine, EFdA and lopinavir.

13. The method of claim 10 , further comprising administering to the subject one or more additional therapeutic agents selected from raltegravir, lamivudine, abacavir, ritonavir, darunavir, atazanavir, emtricitabine, tenofovir, rilpivirine, doravirine, EFdA and lopinavir, wherein the amounts administered of the compound of claim 1 and the one or more additional therapeutic agents, are together effective to treat infection by HIV or to treat, prevent or delay the onset or progression of AIDS.