Substituted piperidines thiazolyl acetamides as glycosidase inhibitors and uses thereof

1. A compound of formula I:

or a pharmaceutically acceptable salt thereof,

wherein:

R 1 is benzodioxolyl, dihydrobenzodioxinyl, oxoisoindolinyl, pyrazolyl, phenyl, pyridyl, pyrimidinyl or indolyl, wherein the benzodioxolyl, dihydrobenzodioxinyl, oxoisoindolinyl, pyrazolyl, phenyl, pyridyl, pyrimidinyl or indolyl is optionally substituted with one or more substituents selected from the group consisting of R 1a , R 1b and R 1c ;

R 2 is hydrogen or methyl;

R 3 is hydrogen or methyl;

R 4 is hydrogen or methyl; and

R 1a , R 1b and R 1c are independently halogen, C 1-6 alkyl, —OH, —O—C 1-6 alkyl, —O—C 3-6 alkenyl, —NO 2 , —NH 2 , —NH(C 1-6 alkyl), —N(C 1-6 alkyl) 2 , —C(═O)NH 2 , —C(═O)NH(C 1-6 alkyl), —C(═O)N(C 1-6 alkyl) 2 , —C(═O)—C 1-6 alkyl, —C(═O)O—C 1-6 alkyl, —OC(═O)O—C 1-6 alkyl, —S(═O) 2 NH 2 , S(═O) 2 N(C 1-6 alkyl) 2 , or phenyl, wherein the C 1-6 alkyl is optionally substituted with one or more substituents selected from the group consisting of —F, —OH, —OCH 3 , —O(CH 2 ) 2 OCH 3 , —C(═O)—C 1-6 alkyl, —NH 2 , —NH(C 1-6 alkyl), —N(C 1-6 alkyl) 2 and —NHC(═O)(C 1-6 alkyl), and further wherein the —O—C 1-6 alkyl is optionally substituted with one or more substituents selected from the group consisting of —F, —OH, —OCH 3 , —C(═O)—C 1-6 alkyl, —NH 2 , —NH(C 1-6 alkyl), —N(C 1-6 alkyl) 2 , and —NHC(═O)(C 1-6 alkyl).

2. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 1 is phenyl or pyridyl, each of which is optionally substituted with one or more substituents selected from the group consisting of R 1a , R 1b and R 1c .

3. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein:

R 1 is phenyl or pyridyl, each of which is optionally substituted with one or more substituents selected from the group consisting of R 1a and R 1b ; and

R 1a and R 1b are independently F, C 1-3 alkyl, -OH, or -O-C 1-3 alkyl, wherein the C 1-3 alkyl is optionally substituted with one or more substituents selected from the group consisting of F, -OH, and -OCH 3 , and further wherein the -O-C 1-3 alkyl is optionally substituted with one or more substituents selected from the group consisting of F, -OH, and -OCH 3 .

4. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein:

R 1 is phenyl or pyridyl, each of which is optionally substituted with one or more substituents selected from the group consisting of R 1a , R 1b and R 1c ; and

R 1a , R 1b and R 1c are independently halogen, C 1-6 alkyl, -OH, or -O-C 1-6 alkyl, wherein the C 1-6 alkyl is optionally substituted with one or more substituents selected from the group consisting of F, -OH, and -OCH 3 , and further wherein the -O-C 1-6 alkyl is optionally substituted with one or more substituents selected from the group consisting of F, -OH, and -OCH 3 .

5. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein:

R 1 is phenyl or pyridyl, each of which is optionally substituted with one or more substituents selected from the group consisting of R 1a , R 1b and R 1c ; and

R 1a , R 1b and R 1c are independently F, C 1-3 alkyl, -OH, or -O-C 1-3 alkyl, wherein the C 1-3 alkyl is optionally substituted with one or more substituents selected from the group consisting of F, -OH, and -OCH 3 , and further wherein the -O-C 1-3 alkyl is optionally substituted with one or more substituents selected from the group consisting of F, -OH, and -OCH 3 .

6. The compound of claim 1 , wherein the compound is of formula Ia:

or a pharmaceutically acceptable salt thereof.

7. A pharmaceutical composition comprising an inert carrier and a compound of claim 1 , or a pharmaceutically acceptable salt thereof.

8. A method for inhibiting O-linked N-acetylglucosaminidase activity in a human patient, comprising administering to a human patient in need thereof a therapeutically effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof.

9. The method of claim 8 , wherein the human patient has a disease or disorder selected from the group consisting of consisting of Alzheimer's disease, Huntington's disease, Parkinson's disease, amyotrophic lateral sclerosis, progressive supranuclear palsy, glaucoma, schizophrenia, mild cognitive impairment, neuropathy, and cancer.

10. The method of claim 9 , wherein the human patient has been diagnosed with a need for treatment of the disease or disorder prior to administering the compound of claim 9 , or a pharmaceutically acceptable salt thereof.

11. A compound selected from the group consisting of:

N-(5-((4-(3,4-dimethoxybenzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-((6-fluoropyridin-3-yl)methylene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-((6-hydroxypyridin-3-yl)methylene)piperidin-1-yl)methyl)thiazol-2-ypacetamide;

N-[5-({4-[(4-hydroxyphenyl)methylidene]-piperidin-1-yl)methyl)-1,3-thiazol-2-yl]acetamide;

4-((142-acetamidothiazol-5-yl)methyl)piperidin-4-ylidene)methyl)phenyltert-butyl carbonate;

N-[5-({4-[(6-aminopyridin-3-yl)methylidene]piperidin-1-yl(methyl)-1,3-thiazol-2-yl]acetamide;

N-(5-((4-(3-(hydroxymethyl)-benzylidene)piperidin-1-yl)methypthiazol-2-y)pacetamide;

N-(5-((4-((1H-pyrazol-4-yl)methylene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

4-((1-((2-acetamidothiazol-5-yl)methyl)-piperidin-4-ylidene)methyl)benzamide;

2-(3-((142-acetamidothiazol-5-yl)methyl)-piperidin-4-ylidene)methyl)phenyl)-acetamide;

N-(5-((4-(4-(trifluoromethoxy)benzylidene)-piperidin-1-yl)methypthiazol-2-y)pacetamide;

N-(5-((4-(4-ethylbenzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-(4-methylb enzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-(4-ethoxybenzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-(pyrimidin-5-ylmethylene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-[5-({4-[(2,3-dimethoxyphenyl)methylidene]piperidin-1-yl}methyl)-1,3-thiazol-2-yl]acetamide;

N-(5-((4-(4-(N,N-dimethyl sulfamoyl)benzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-{[4-(1H-indo1-5-ylmethylidene)piperidin-1-yl]methyl}-1,3-thiazol-2-ypacetamide;

N-(5-{[441,3-benzodioxo1-5-ylmethylidene)piperidin-1-yl]methyl}-1,3-thiazol-2-ypacetamide;

N-(5-{[4-(2,3-dihydro-1,4-benzodioxin-6-ylmethylidene)piperidin-1-yl]methyl}-1,3-thiazol-2-yl)acetamide;

N-(5-((4-((1-oxoisoindolin-5-yl)methylene)piperidin-1-yl)methypthiazol-2-ypacetamide;

N- [5-({4-[(4-hydroxy-3-methoxyphenyl)methylidene]piperidin-1-yl }methyl)-1,3-thiazol -2-yl]acetamide;

N45-({4-[(3-hydroxy-4-methoxyphenyl)methylidene]piperidin-1-yl}methyl)-1,3-thiazol-2-yl]acetamide;

methyl4-((1-((2-acetamidothiazol-5-yl)methyl)piperidin-4-ylidene)methyl)benzoate;

N-{5-[(4-{[4-(hydroxymethyl)phenyl]-methylidene}piperidin-1-yl)methyl]-1,3-thiazol-2-yl}acetamide;

N-(5-((4-(4-(fluoromethyl)benzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-(4-(2-fluoroethyl)-benzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-(4-(2-fluoroethyl)benzylidene)-piperidin-1-yl)methyl)thiazol-2-yl)-N-methylacetamide;

4-[(1-{[2-(acetylamino)-1,3-thiazol-5-yl]methyl}piperidin-4-ylidene)methyl]benzoic acid;

4-[(1-{[2-(acetylamino)-1,3-thiazol -5-yl]methyl}piperidin-4-ylidene)methyl]-N-methylbenzamide;

4-((1-((2-acetamidothiazol-5-yl)methyl)piperidin-4-ylidene)methyl)-N,N-dimethylbenzamide;

N-[5 -({4-[(4-fluorophenyl)methylidene]piperidin-1-yl }methyl)-1,3-thiazol-2-yl]acetamide;

N-(5-{[4-(phenyl-methylidene)piperidin-1-yl]methyl}-1,3-thiazol -2-yl)acetamide;

(S,Z)-N-(5-((4-benzylidene-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(R,Z)-N-(5-((4-benzylidene-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(R,E)-N-(5-((4-benzylidene-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(S,E)-N-(5-((4-benzylidene-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(S,Z)-N-(5-((4-(4-methoxybenzylidene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(R,E)-N-(5-((4-(4-methoxybenzylidene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(R,Z)-N-(5-((4-(4-methoxybenzylidene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(S,E)-N-(5-((4-(4-methoxybenzylidene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-{5-[(4-{[4-(2-fluoroethoxy)phenyl]methylidene}piperidin-1-yl)methyl]-1,3-thiazol-2-yl }acetamide;

N-(5-((4-(3-methoxybenzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-(3-hydroxybenzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-{5-[(4-{[4-(prop-2-en-1-yloxy)phenyl]methylidene}piperidin-1-yl)methyl]-1,3-thiazol -2-yl}acetamide;

N-[5-({4-[(4-methoxyphenyl)methylidene]piperidin-l-yl }methyl)-1,3-thiazol-2-yl]acetamide;

N-(5-((4-(2-methoxybenzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-([1, 1’-biphenyl]-4-ylmethylene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-((6-nitropyridin-3-yl)methylene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

N-(5-((4-(4-(2-hydroxyethyl)benzylidene)piperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(R,Z)-N-(5-((4-((6-fluoropyridin-3-yl)methylene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(S,Z)-N-(5-((4-((6-fluoropyridin-3-yl)methylene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

(R,E)-N-(5-((4-((6-fluoropyridin-3-yl)methylene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide; and

(S,E)-N-(5-((4-((6-fluoropyridin-3-yl)methylene)-2-methylpiperidin-1-yl)methyl)thiazol-2-yl)acetamide;

or a pharmaceutically acceptable salt thereof.

12. A compound which is:

or a pharmaceutically acceptable salt thereof.

13. A compound which is:

or a pharmaceutically acceptable salt thereof.

14. A compound which is:

or a pharmaceutically acceptable salt thereof.

15. A compound which is:

or a pharmaceutically acceptable salt thereof.

16. A compound which is:

or a pharmaceutically acceptable salt thereof.

17. A pharmaceutical composition comprising an inert carrier and a compound of claim 11 , or a pharmaceutically acceptable salt thereof.

18. A pharmaceutical composition comprising an inert carrier and a compound of claim 12 , or a pharmaceutically acceptable salt thereof.

19. A pharmaceutical composition comprising an inert carrier and a compound of claim 13 , or a pharmaceutically acceptable salt thereof.

20. A pharmaceutical composition comprising an inert carrier and a compound of claim 14 , or a pharmaceutically acceptable salt thereof.

21. A pharmaceutical composition comprising an inert carrier and a compound of claim 15 , or a pharmaceutically acceptable salt thereof.