Pyrazole, triazole and tetrazole orexin receptor antagonists

1. A compound of the formula I:

wherein:

X is N or C(R 7 );

Y is N or C(R 6 ), wherein when Y is N then X is also N;

A is selected from the group consisting of phenyl, pyridyl, thienyl, pyrazinyl, and pyrazolo[1,5-a]pyridinyl;

R 1a , R 1b and R 1c are independently selected from the group consisting of:

(1) hydrogen,

(2) halogen,

(3) hydroxyl,

(4) C 1-6 alkyl, which is unsubstituted or substituted with halogen, hydroxyl or phenyl,

(5) —O—C 1-6 alkyl, which is unsubstituted or substituted with halogen, hydroxyl or phenyl,

(6) —CN, and

(7) heteroaryl, wherein heteroaryl is selected from triazolyl, tetrazolyl, oxazolyl, pyrrolyl, imidazolyl, indolyl, pyridyl, and pyrimidinyl, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl or —NO 2 ;

R 3 is selected from C 1-6 alkyl and C 3-6 cycloalkyl, which is unsubstituted or substituted with one or more substituents selected from R 4 ;

R 4 is selected from the group consisting of:

(1) hydroxyl,

(2) halogen,

(3) C 1-6 alkyl,

(4) —C 3-6 cycloalkyl,

(5) —O—C 1-6 alkyl,

(6) —O(C═O)—C 1-6 alkyl,

(7) —NH 2 ,

(7) —NH—C 1-6 alkyl,

(8) —NO 2 ,

(9) phenyl,

(10) —CO 2 H, and

(11) —CN;

R 5 is selected from the group consisting of:

(1) hydrogen,

(2) halogen,

(3) C 1-6 alkyl, which is unsubstituted or substituted with halogen, hydroxyl, —O—C 1-6 alkyl, —NH 2 , —NH—C 1-6 alkyl, or —(C═O)O—C 1-6 alkyl,

(4) C 3-6 cycloalkyl, which is unsubstituted or substituted with C 1-6 alkyl, halogen, hydroxyl, —O—C 1-6 alkyl, —NH 2 , —NH—C 1-6 alkyl, or —(C═O)O—C 1-6 alkyl,

(5) —O—C 1-6 alkyl, which is unsubstituted or substituted with halogen, or hydroxyl,

(6) —(C═O)O—C 1-6 alkyl,

(7) —CN,

(8) —(C═O)NH 2 ,

(9) —(C═O)NH—C 1-6 alkyl, and

(10) —(C═O)NH—O—C 1-6 alkyl;

R 6 is selected from the group consisting of:

(1) hydrogen,

(2) halogen,

(3) C 1-6 alkyl, which is unsubstituted or substituted with halogen, hydroxyl, —O—C 1-6 alkyl, —NH 2 , —NH—C 1-6 alkyl, —(C═O)O—C 1-6 alkyl, or phenyl, wherein the phenyl is unsubstituted or substituted with C 1-6 alkyl, halogen, or C 1-6 alkyl-OH,

(4) C 3-6 cycloalkyl, which is unsubstituted or substituted with C 1-6 alkyl, halogen, hydroxyl, —O—C 1-6 alkyl, —NH 2 , —NH—C 1-6 alkyl, —(C═O)O—C 1-6 alkyl, or phenyl, wherein the phenyl is unsubstituted or substituted with C 1-6 alkyl, halogen, or C 1-6 alkyl-OH,

(5) —O—C 1-6 alkyl, which is unsubstituted or substituted with halogen, hydroxyl or phenyl, and

(6) —(C═O)O—C 1-6 alkyl,

(7) —CN,

(8) —(C═O)NH 2 ,

(9) —(C═O)NH—C 1-6 alkyl, and

(10) —(C═O)NH—O—C 1-6 alkyl;

R 7 is selected from the group consisting of:

(1) hydrogen and

(2) C 1-6 alkyl, or

a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 of the formula

or a pharmaceutically acceptable salt thereof.

3. The compound of claim 1 of the formula Ib:

or a pharmaceutically acceptable salt thereof.

4. The compound of claim 1 , wherein Y is C(R 6 ).

5. The compound of claim 1 , wherein X is N and Y is C(R 6 ).

6. The compound of claim 1 , wherein X is C(R 7 ) and Y is C(R 6 ).

7. The compound of claim 1 , wherein X is N and Y is N.

8. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 3 is methyl or ethyl.

9. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 5 is selected from the group consisting of:

(1) —C(CH 3 ) 2 OH,

(2) —CH(OH)CF 3 ,

(2) —CH(OH)CH 3 ,

(2) —C(OH)(CF 3 )CH 3 ,

(3) —C(═O)OCH 3 , and

(4) bromo.

10. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 6 is hydrogen or methyl.

11. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 7 is hydrogen or methyl.

12. A compound which is selected from the group consisting of:

1-(2-((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidine-1-carbonyl) phenyl)cyclopropanecarbonitrile;

[1,1′-biphenyl]-2-yl((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-propylpyridin-3-yl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-propylphenyl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-isopropylphenyl)methanone;

(2-cyclopropylphenyl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

(2-(difluoromethoxy)pyridin-3-yl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

methyl 3-((2R,5R)-5-(4-(2-hy-droxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidine-1-carbonyl)picolinate;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-(2,2,2-trifluoroethyl)phenyl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-(4-methyl-1H-pyrazol-1-yl)pyridin-3-yl)methanone;

2-{2-[(3R,6R)-6-methyl-1-({2-[(trifluoromethyl)sulfanyl]phenyl}carbonyl)piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

(2-ethoxyphenyl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperi-din-1-yl)methanone;

(2-(2,2-difluoroethoxy)pyridin-3-yl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-(2,2,2-trifluoroethoxy)pyridin-3-yl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-isopro-poxypyridin-3-yl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-(2,2,2-trifluoroethoxy)phenyl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-isopropoxyphenyl)methanone;

(2-(2,2-difluoroethoxy)phenyl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)(2-(trifluoromethoxy)phenyl)methanone;

methyl 2-((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidine-1-carbonyl)benzoate;

(2-(difluoromethoxy)phenyl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

2-{2-[(3R,6R)-1-({2-[(1S)-2,2-difluorocyclopropyl]phenyl}carbonyl)-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-({2-[(1R)-2,2-difluorocyclopropyl]phenyl}carbonyl)-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

methyl 2-((3R,6R)-1-(2-(2H-1,2,3-triazol-2-yl)benzoyl)-6-methylpiperidin-3-yl)-2H-1,2,3-triazole-4-carboxylate;

(2-(2H-1,2,3-triazol-2-yl)phenyl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

(2-(2H-1,2,3-triazol-2-yl)phenyl) ((2R,5R)-2-methyl-5-(4-((S)-2,2,2-trifluoro-1-hydroxyethyl)-2H-1,2,3-triazol-2-yl)piperidin-1-yl)methanone;

(2-(2H-1,2,3-triazol-2-yl)phenyl)((2R,5R)-2-methyl-5-(4-((R)-2,2,2-trifluoro-1-hydroxyethyl)-2H-1,2,3-triazol-2-yl)piperidin-1-yl)methanone;

(2-(2H-1,2,3-triazol-2-yl)phenyl)((2R,5R)-2-methyl-5-(4-phenyl-2H-1,2,3-triazol-2-yl)piperidin-1-yl)methanone;

(2-(2H-1,2,3-triazol-2-yl)phenyl)((2R,5R)-5-(4-bromo-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

(5-fluoro-2-(5-methyl-1,2,4-oxadiazol-3-yl)phenyl)((2R,5R)-5-(4-(2-hydroxypropan-2-yl)-2H-1,2,3-triazol-2-yl)-2-methylpiperidin-1-yl)methanone;

2-{2-[(3R,6R)-1-{[3-fluoro-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[3-(2H-1,2,3-triazol-2-yl)thiophen-2-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)thiophen-3-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[2-(2H-tetrazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[5-fluoro-2-(3-methyl-1,2,4-oxadiazol-5-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[2-(3-methyl-1,2,4-oxadiazol-5-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[3-fluoro-2-(5-methyl-1,2,4-oxadiazol-3-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[5-fluoro-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[4-fluoro-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[4-fluoro-2-(5-methyl-1,2,4-oxadiazol-3-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[4-fluoro-2-(3-methyl-1,2,4-oxadiazol-5-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-(2-{(3R,6R)-6-methyl-1-[(3-pyridin-2-ylpyrazin-2-yl)carbonyl]piperidin-3-yl}-2H-1,2,3-triazol-4-yl)propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[3-(1H-pyrazol-1-yl)pyrazin-2-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[2-(2-methoxyethyl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[6-methoxy-2-(2H-1,2,3-triazol-2-yl)pyridin-3-yl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[3-methyl-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[2-(5-methyl-1,2,4-oxadiazol-3-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[3-fluoro-2-(3-methyl-1,2,4-oxadiazol-5-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-(2-{(3R,6R)-6-methyl-1-[(2-pyrrolidin-1-ylphenyl)carbonyl]piperidin-3-yl}-2H-1,2,3-triazol-4-yl)propan-2-ol;

2-(2-{(3R,6R)-6-methyl-1-[(3-phenoxyphenyl)carbonyl]piperidin-3-yl}-2H-1,2,3-triazol-4-yl)propan-2-ol;

2-{2-[(3R,6R)-1-{[2-methoxy-6-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[5-methyl-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[2-methyl-6-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[4-methoxy-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[6-methyl-2-(2H-1,2,3-triazol-2-yl)pyridin-3-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[2-(methoxymethyl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-Methyl-1-(pyrazolo[1,5-a]pyridin-7-ylcarbonyl)piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-Methyl-1-{[3-(2H-1,2,3-triazol-2-yl)pyridin-2-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-6-Methyl-1-{[2-(2H-1,2,3-triazol-2-yl)pyridin-3-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-(2-{(3R,6R)-1-[(2-cyclopropylpyridin-3-yl)carbonyl]-6-methylpiperidin-3-yl}-2H-1,2,3-triazol-4-yl)propan-2-ol;

1-{2-[(3R,6R)-1-{[2-(2,2-difluoroethoxy)pyridin-3-yl]carbonyl}-6-methylpiperidin-3-yl]-2H-1,2,3-triazol-4-yl}ethanol;

2-{5-methyl-2-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{5-methyl-2-[(3R,6R)-6-methyl-1-{[2-(1-methylethoxy)pyridin-3-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[2-(2,2-difluoroethoxy)pyridin-3-yl]carbonyl}-6-methylpiperidin-3-yl]-5-methyl-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-(2-{(3R,6R)-1-[(2-ethoxypyridin-3-yl)carbonyl]-6-methylpiperidin-3-yl}-5-methyl-2H-1,2,3-triazol-4-yl)propan-2-ol;

2-{2-[(3R,6R)-1-{[2-(difluoromethoxy)phenyl]carbonyl}-6-methylpiperidin-3-yl]-5-methyl-2H-1,2,3-triazol-4-yl}propan-2-ol

2-{5-methyl-2-[(3R,6R)-6-methyl-1-{[2-(trifluoromethoxy)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{5-methyl-2-[(3R,6R)-6-methyl-1-{[2-(2,2,2-trifluoroethoxy)pyridin-3-yl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-(2-{(3R,6R)-1-[(2-ethoxyphenyl)carbonyl]-6-methylpiperidin-3-yl}-5-methyl-2H-1,2,3-triazol-4-yl)propan-2-ol;

2-(2-{(3R,6R)-1-[(2-cyclopropylphenyl)carbonyl]-6-methylpiperidin-3-yl}-5-methyl-2H-1,2,3-triazol-4-yl)propan-2-ol;

2-{5-methyl-2-[(3R,6R)-6-methyl-1-{[2-(1H-pyrazol-1-yl)phenyl]carbonyl}piperidin-3-yl]-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-{2-[(3R,6R)-1-{[4-fluoro-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-5-methyl-2H-1,2,3-triazol-4-yl}propan-2-ol;

2-(5-methyl-2-{(3R,6R)-6-methyl-1-[(2-phenylpyridin-3-yl)carbonyl]piperidin-3-yl}-2H-1,2,3-triazol-4-yl)propan-2-ol;

2-{2-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-2H-tetrazol-5-yl}propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-(1-{(3R,6R)-6-methyl-1-[(2-propylphenyl)carbonyl]piperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-(1-{(3R,6R)-1-[(2-ethoxyphenyl)carbonyl]-6-methylpiperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-(1-{(3R,6R)-1-[(2-cyclopropylphenyl)carbonyl]-6-methylpiperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-{1-[(3R,6R)-1-{[2-(2,2-difluoroethoxy)phenyl]carbonyl}-6-methylpiperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(2,2,2-trifluoroethoxy)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(1-methylethoxy)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(1-methylethyl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(trifluoromethoxy)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-1-{[2-(difluoromethoxy)phenyl]carbonyl}-6-methylpiperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-1-({2-[(1S)-2,2-difluorocyclopropyl]phenyl}carbonyl)-6-methylpiperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-1-({2-[(1R)-2,2-difluorocyclopropyl]phenyl}carbonyl)-6-methylpiperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-(1-{(3R,6R)-1-[(2-cyclobutylphenyl)carbonyl]-6-methylpiperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-({2-[(trifluoromethyl)sulfanyl]phenyl}carbonyl)piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-(1-{(3R,6R)-1-[(2-ethoxypyridin-3-yl)carbonyl]-6-methylpiperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(1H-pyrazol-1-yl)pyridin-3-yl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-1-{[4-fluoro-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-(1-{(3R,6R)-6-methyl-1-[(2-phenylpyridin-3-yl)carbonyl]piperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(1H-pyrazol-1-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(2,2,2-trifluoroethoxy)pyridin-3-yl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[3-(1H-pyrazol-1-yl)pyrazin-2-yl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-(1-{(3R,6R)-1-[(2-cyclopropyl-6-methoxypyridin-3-yl)carbonyl]-6-methylpiperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[2-(1-methylethoxy)pyridin-3-yl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-1-{[2-(2,2-difluoroethoxy)pyridin-3-yl]carbonyl}-6-methylpiperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{1-[(3R,6R)-1-{[2-(2,2-difluoroethyl)phenyl]carbonyl}-6-methylpiperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-(1-{(3R,6R)-1-[(2-cyclobutyl-6-methoxypyridin-3-yl)carbonyl]-6-methylpiperidin-3-yl}-1H-pyrazol-4-yl)propan-2-ol;

2-{1-[(3R,6R)-6-methyl-1-{[3-(2H-1,2,3-triazol-2-yl)pyrazin-2-yl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

(1R)-2,2,2-trifluoro-1-{1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}ethanol;

(1S)-2,2,2-trifluoro-1-{1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}ethanol;

1,1,1-trifluoro-2-{1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

(2R)-1,1,1-trifluoro-2-{1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

(2S)-1,1,1-trifluoro-2-{1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

2-{3-methyl-1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol; and

2-{5-methyl-1-[(3R,6R)-6-methyl-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]-1H-pyrazol-4-yl}propan-2-ol;

or a pharmaceutically acceptable salt thereof.

13. A pharmaceutical composition which comprises an inert carrier and a compound of claim 1 or a pharmaceutically acceptable salt thereof.

14. A method for treating insomnia in a mammalian patient in need thereof which comprises administering to the patient a therapeutically effective amount of the compound of claim 1 or a pharmaceutically acceptable salt thereof.