Heteroaryl pyrrolidine and piperidine orexin receptor agonists

1. A compound of the formula I:

wherein:

n is 1 or 2;

A is a furanyl, imidazolyl, isoquinolinyl, isothiazolyl, isoxazolyl, oxadiazolyl, phenyl, pyrazinyl, pyrazolyl, pyridinyl, pyrimidinyl, pyrrolopyridinyl, furopyridinyl, isoxazolopyridinyl, tetrazolyl, 1,3,4-thiadiazol, thiazolyl, thiophenyl or triazolyl ring, 1,2,4-thiadiazol-5-yl, or an N-oxide thereof;

Y is N or CH;

R 1a , R 1b and R 1c as present are independently selected from:

(1) hydrogen,

(2) halogen,

(3) hydroxyl,

(4) C 1-6 alkyl, which is unsubstituted or substituted with substituents selected from: hydroxy, fluoro and phenyl,

(5) —O—C 1-6 alkyl, which is unsubstituted or substituted with substituents selected from: fluoro and phenyl,

(6) C 3-6 cycloalkyl,

(7) C 2-6 alkynyl,

(8) —NH 2 ,

(9) —NH(C 1-6 alkyl),

(10) —N(C 1-6 alkyl) 2 ,

(11) —(CO)—O—C 1-6 alkyl,

(12) keto,

(13) -phenyl,

(14) -pyridyl, and

(15) —CN;

R 2 is selected from:

(1) hydrogen,

(2) —C 1-6 alkyl, where the alkyl is unsubstituted or substituted with one to six substituents independently selected from R 4 ,

(3) —C 3-6 cycloalkyl, where the cycloalkyl is unsubstituted or substituted with one to six substituents independently selected from R 4 ,

(4) -phenyl, where the phenyl is unsubstituted or substituted with one to three substituents independently selected from R 4 , and

(5) -heteroaryl, where the heteroaryl is selected from: pyridyl, pyrimidinyl, and pyrazinyl, and the heteroaryl is unsubstituted or substituted with one to three substituents independently selected from R 4 :

R 2a and R 2b are independently selected from:

(1) hydrogen,

(2) hydroxyl,

(3) halogen, and

(4) —C 1-6 alkyl, where the alkyl is unsubstituted or substituted with one to six substituents independently selected from halogen;

R 3 is selected from:

(1) —C 1-6 alkyl, where the alkyl is unsubstituted or substituted with one to six substituents independently selected from R 4 ,

(2) —C 3-6 cycloalkyl, where the cycloalkyl is unsubstituted or substituted with one to six substituents independently selected from R 4 ,

(3) -phenyl, where the phenyl is unsubstituted or substituted with one to three substituents independently selected from R 4 ,

(4) —NR 10 R 11 , wherein R 10 and R 11 are independently selected from:

(a) hydrogen, and

(b) C 1-6 alkyl, which is unsubstituted or substituted with one to six R 4 ;

R 4 is selected from:

(1) hydroxyl,

(2) halogen,

(3) C 1-6 alkyl, which is unsubstituted or substituted with one to six fluoro,

(4) —C 3-6 cycloalkyl,

(5) —O—C 1-6 alkyl,

(6) —O(C═O)—C 1-6 alkyl,

(7) —NH 2 ,

(8) —NH—C 1-6 alkyl,

(9) —NO 2 ,

(10) phenyl,

(11) —CO 2 H, and

(12) —CN;

R 5 and R 6 are independently selected from:

(1) hydrogen,

(2) C 1-6 alkyl, where the alkyl is unsubstituted or substituted with one to six substituents independently selected from R 4 , and

(3) —C 3-6 cycloalkyl, where the cycloalkyl is unsubstituted or substituted with one to six substituents independently selected from R 4 ,

or R 5 and R 6 are joined together with the carbon atoms to which they are attached to form a —C 3-6 cycloalkyl ring, where the cycloalkyl is unsubstituted or substituted with one to six substituents independently selected from R 4 ;

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein A is a furan-2-yl, imidazol-2-yl, imidazol-5-yl, isoquinolin-4-yl, isothiazol-5-yl, isoxazol-3-yl, 1,3,4-oxadiazol-2-yl, phenyl, pyrazin-2-yl, pyrazol-4-yl, pyridin-2-yl, pyridin-3-yl, pyridin-4-yl, pyridin-5-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrimidin-5-yl, pyrrolo[3,2-b]pyridin-6-yl, tetrazol-5-yl, 1,3,4-thiadiazol-2-yl, 1,2,4-thiadiazol-5-yl, thiazol-2-yl, thiazol-4-yl, thiazol-5-yl, thiophen-3-yl, 1,2,4-triazol-3-yl, 1,2,3-triazol-4-yl, or 1,2,4-triazol-5-yl ring.

3. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein Y is CH.

4. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 1a , R 1b and R 1c are independently selected from:

(1) hydrogen,

(2) fluoro,

(3) hydroxyl,

(4) —CH 3 ,

(5) —CHF 2 ,

(6) —CF 3 ,

(7) —CH 2 OH,

(8) —CH 2 CH 3 ,

(9) —CH(CH 3 )OH

(10) —OCH 3 ,

(11) —OCHF 2 ,

(12) —OCH 2 CH 2 F,

(13) —N(CH 3 ) 2 ,

(14) cyclopropyl, and

(15) phenyl.

5. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 2a is hydrogen and R 2b is hydrogen, and R 2 is selected from:

(1) hydrogen,

(2) CH(CH 3 ) 2

(3) —CF 3 ,

(4) —CH 2 CHF 2 ,

(5) —CH 2 CF 3 , and

(6) phenyl, which is unsubstituted or substituted with —CF 3 or —CH 2 CF 3 .

6. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 3 is selected from:

(1) methyl,

(2) —CF 3 ,

(3) —CH 2 F,

(4) ethyl,

(5) cyclopropyl,

(6) —CH(CH 3 ) 2 ,

(7) —NH(CH 3 ),

(8) —N(CH 3 ) 2 , and

(9) -phenyl.

7. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 5 is hydrogen or methyl and R 6 is hydrogen.

8. A compound which is selected from:

N-((CIS)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(5-phenylpyridin-3-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(1-methyl-1H-pyrazol-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(4-(trifluoromethyl)phenyl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(isoquinolin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(1-methyl-1H-1,2,4-triazol-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(4-methoxyphenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(1H-pyrrolo[3,2-b]pyridin-6-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(1-methyl-1H-1,2,3-triazol-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(2-methylthiazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)-methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(5-methyl-1,3,4-thiadiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(4-methyl-2-phenylthiazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-1-(4-(5-methyl-1,3,4-oxadiazol-2-yl)phenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)-methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(2-(pyridin-4-yl)thiazol-4-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-1H-1,2,4-triazol-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-1H-1,2,4-triazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(pyridin-2-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(isoxazol-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(isothiazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(thiophen-3-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(pyridin-3-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-(difluoromethyl)-4-fluorophenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-(difluoromethyl)-2-fluorophenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-(difluoromethyl)-6-oxo-1,6-dihydropyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-(difluoromethyl)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)-methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-cyanopyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(thiazol-5-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(thiazol-2-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-1H-imidazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1,5-dimethyl-1H-imidazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1,5-dimethyl-1H-pyrazol-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-1H-tetrazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1,2-dimethyl-1H-imidazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(1,2,4-thiadiazol-5-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(6-(trifluoromethyl)pyridin-3-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-(difluoromethoxy)pyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-(2-fluoroethoxy)phenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-methyl-1,3,4-oxadiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(pyrimidin-2-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-cyanofuran-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-1H-pyrazol-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(2-(trifluoromethyl)pyrimidin-5-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(pyrimidin-5-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-(hydroxymethyl)pyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-(2-hydroxypropan-2-yl)pyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)-methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-(hydroxymethyl)-5-methylpyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)-methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(6-(trifluoromethyl)pyrimidin-4-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-hydroxypyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-methylpyrimidin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-(hydroxymethyl)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(5-(trifluoromethyl)pyridin-3-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-methoxypyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-(difluoromethoxy)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-methoxypyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5,6-dimethoxypyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-methoxy-5-methylpyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-(hydroxymethyl)pyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(pyridin-4-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-(difluoromethoxy)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-methoxypyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-methylpyrimidin-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-(2-hydroxypropan-2-yl)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)-methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-methylpyrazin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3,5-difluoropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-methoxypyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-methylpyrazin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-cyclopropylpyrazin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-methylpyrimidin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-cyclopropylthiazol-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(3-(trifluoromethyl)pyridin-4-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-(hydroxymethyl)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-methoxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-(dimethylamino)pyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(1H-pyrazol-4-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((CIS)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(5-phenylpyridin-3-yl)piperidin-3-yl)methanesulfonamide;

N-((CIS)-1-(5-methyl-1,3,4-thiadiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)piperidin-3-yl)methanesulfonamide;

N-((CIS)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(1,2,4-thiadiazol-5-yl)piperidin-3-yl)methanesulfonamide;

N-((2R,3S,5R)-5-methyl-1-(1-methyl-1H-tetrazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)-methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-methylpyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-methylpyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-methylthiazol-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-methylthiazol-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S,5S)-1-(5-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)-5-(methoxymethyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoro-1-methyl-4-oxo-1,4-dihydropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-4-oxo-1,4-dihydropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-fluoro-1-methyl-4-oxo-1,4-dihydropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-(2,2-difluoroethyl)-5-fluoro-4-oxo-1,4-dihydropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(isoxazolo[5,4-b]pyridin-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(furo[3,2-b]pyridin-6-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(furo[2,3-b]pyridin-5-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N′-((2R,3S,5S)-1-(5-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)-5-(methoxymethyl)pyrrolidin-3-yl)-N,N-dimethyl-sulfamide;

N′-((2R,3S,5R)-1-(5-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)-5-methylpyrrolidin-3-yl)-N,N-dimethyl-sulfamide;

N′-((2R,3S,5R)-1-(5-chloro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)-5-methylpyrrolidin-3-yl)-N,N-dimethyl-sulfamide;

N-((2R,3S)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-chloro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-chloro-3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3,5-difluoro-4-methoxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3,5-difluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-(hydroxymethyl)thiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

methyl 2-((2R,3S)-3-(methylsulfonamido)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-1-yl)thiazole-4-carboxylate;

methyl 2-((2R,3S)-3-(methylsulfonamido)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-1-yl)thiazole-5-carboxylate;

N-((2R,3S)-1-(4-hydroxy-5-methylthiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-bromo-5-methylthiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-hydroxythiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-bromothiazol-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-methylthiazol-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(thiazol-4-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-2-oxo-1,2-dihydropyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-6-oxo-1,6-dihydropyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-chloro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-chloro-3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoro-4-methoxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-6-oxo-1,6-dihydropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(1-methyl-2-oxo-1,2-dihydropyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-hydroxy-5-methoxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-chloro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-(difluoromethyl)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-hydroxypyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-(benzyloxy)pyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-(difluoromethyl)pyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-methylpyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(3-(trifluoromethyl)pyridin-2-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(3-(trifluoromethoxy)pyridin-2-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-methoxy-4-methylpyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-fluoro-2-hydroxypyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(5-(trifluoromethyl)pyridin-2-yl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-cyanopyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-cyanopyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

3-((2R,3S)-3-(methylsulfonamido)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-1-yl)pyridine 1-oxide;

N-((2R,3S)-1-(3-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-cyanopyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-cyanopyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-cyanopyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-(difluoromethoxy)-5-fluoropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-methoxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4,6-bis(difluoromethyl)pyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-(difluoromethyl)pyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(4-methylpyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-cyanopyridin-3-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-methoxyphenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-cyanophenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-oxo-1,6-dihydropyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-hydroxypyrazin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-hydroxypyrimidin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(6-methoxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(5-fluoro-2-hydroxypyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(2-oxo-1,2-dihydropyridin-4-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-hydroxyphenyl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N′-((2R,3S,5R)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)-5-methylpyrrolidin-3-yl)-N,N-dimethyl-sulfamide;

N′-((2R,3S,5R)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)-1-(4-hydroxypyridin-2-yl)-5-methylpyrrolidin-3-yl)-N,N-dimethyl-sulfamide;

N-((2R,3S)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)piperidin-3-yl)methanesulfonamide;

N-(2-((((CIS)-4-phenylcyclohexyl)oxy)methyl)-1-(pyridin-3-yl)piperidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-(((4-(2-(trifluoromethyl)phenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(2,3,6-trifluorophenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3-fluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-isopropylcyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide;

N-((2R,3S)-1-(3,5-difluoro-4-hydroxypyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)pyrrolidin-3-yl)methanesulfonamide; and

N-((2R,3S,5R)-1-(3-fluoro-4-oxo-1,4-dihydropyridin-2-yl)-2-((((CIS)-4-(3-fluorophenyl)cyclohexyl)oxy)methyl)-5-methylpyrrolidin-3-yl)methanesulfonamide;

or a pharmaceutically acceptable salt thereof.

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

10. A method for treating narcolepsy in a mammalian subject which comprises administering to the mammalian subject an effective amount of the compound of claim 1 or a pharmaceutically acceptable salt thereof.

11. A method for treating hypersomnia in a mammalian subject which comprises administering to the mammalian subject an effective amount of the compound of claim 1 or a pharmaceutically acceptable salt thereof.