4-fluoropiperidine orexin receptor antagonists

1. A compound of the formula I:

wherein:

A is selected from the group consisting of phenyl, napthyl and heteroaryl;

B is selected from the group consisting of phenyl, napthyl and heteroaryl;

X is —NR 4 —, —O— or —CH 2 —,

wherein R 4 is selected from the group consisting of:

(1) hydrogen,

(2) C 1-6 alkyl,

(3) —C 3-6 cycloalkyl, and

(4) —CF 3 ;

R 1a , R 1b and R 1c may be absent if the valency of A does not permit such substitution and are independently selected from the group consisting of:

(1) hydrogen,

(2) halogen,

(3) hydroxyl,

(4) —(C═O) m —O n —C 1-6 alkyl, where m is 0 or 1, n is 0 or 1 (wherein if m is 0 or n is 0, a bond is present) and where the alkyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(5) —(C═O) m —O n —C 3-6 cycloalkyl, where the cycloalkyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(6) —(C═O) m —C 2-4 alkenyl, where the alkenyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(7) —(C═O) m —C 2-4 alkynyl, where the alkynyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(8) —(C═O) m —O n -phenyl or —(C═O) m —O n -napthyl, where the phenyl or napthyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(9) —(C═O) m —O n -heterocycle, where the heterocycle is unsubstituted or substituted with one or more substituents selected from R 13 ,

(10) —(C═O) m —NR 10 R 11 , wherein R 10 and R 11 are independently selected from the group consisting of:

(a) hydrogen,

(b) C 1-6 alkyl, which is unsubstituted or substituted with R 14 ,

(c) C 3-6 alkenyl, which is unsubstituted or substituted with R 14 ,

(d) C 3-6 alkynyl, which is unsubstituted or substituted with R 14 ,

(e) C 3-6 cycloalkyl which is unsubstituted or substituted with R 14 ,

(f) phenyl, which is unsubstituted or substituted with R 14 , and

(g) heterocycle, which is unsubstituted or substituted with R 14 ,

(11) —S(O) 2 —NR 10 R 11 ,

(12) —S(O) q —R 12 , where q is 0, 1 or 2 and where R 12 is selected from the definitions of R 10 and R 11 ,

(13) —CO 2 H,

(14) —CN, and

(15) —NO 2 ;

R 2a , R 2b and R 2c may be absent if the valency of B does not permit such substitution and are independently selected from the group consisting of:

(1) hydrogen,

(2) halogen,

(3) hydroxyl,

(4) —(C═O) m —O n —C 1-6 alkyl, where the alkyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(5) —(C═O) m —O n —C 3-6 cycloalkyl, where the cycloalkyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(6) —(C═O) m —C 2-4 alkenyl, where the alkenyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(7) —(C═O) m —C 2-4 alkynyl, where the alkynyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(8) —(C═O) m —O n -phenyl or —(C═O) m —O n -napthyl, where the phenyl or napthyl is unsubstituted or substituted with one or more substituents selected from R 13 ,

(9) —(C═O) m —O n -heterocycle, where the heterocycle is unsubstituted or substituted with one or more substituents selected from R 13 ,

(10) 4C═O) m —NR 10 R 11 ,

(11) —S(O) 2 —NR 10 R 11 ,

(12) —S(O) q —R 12 ,

(13) —CO 2 H,

(14) —CN, and

(15) —NO 2 ;

R 3 is selected from the group consisting of:

(1) hydrogen,

(2) halogen, and

(3) C 1-6 alkyl, where the alkyl is unsubstituted or substituted with one or more substituents selected from R 14 ,

R 13 is selected from the group consisting of:

(1) halogen,

(2) hydroxyl,

(3) —(C═O) m —O n —C 1-6 alkyl, where the alkyl is unsubstituted or substituted with one or more substituents selected from R 14 ,

(4) —O n —(C 1-3 )perfluoroalkyl,

(5) —(C═O) m —O n —C 3-6 cycloalkyl, where the cycloalkyl is unsubstituted or substituted with one or more substituents selected from R 14 ,

(6) —(C═O) m —C 2-4 alkenyl, where the alkenyl is unsubstituted or substituted with one or more substituents selected from R 14 ,

(7) —(C═O) m —C 2-4 alkynyl, where the alkynyl is unsubstituted or substituted with one or more substituents selected from R 14 ,

(8) —(C═O) m —O n -phenyl or —(C═O) m —O n -napthyl, where the phenyl or napthyl is unsubstituted or substituted with one or more substituents selected from R 14 ,

(9) —(C═O) m —O n -heterocycle, where the heterocycle is unsubstituted or substituted with one or more substituents selected from R 14 ,

(10) —(C═O) m —NR 10 R 11 ,

(11) —S(O) 2 —NR 10 R 11 ,

(12) —S(O) q —R 12 ,

(13) —CO 2 H,

(14) —CN, and

(15) oxo;

R 14 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—C 1-6 alkyl,

(8) phenyl,

(9) heterocycle,

(10) —CO 2 H, and

(11) —CN;

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 of the formula Ia:

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 of the formula Ib′:

or a pharmaceutically acceptable salt thereof.

5. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein A is selected from the group consisting of: phenyl, pyridyl, pyrimidinyl, pyrazinyl, pyrazolyl, thiazolyl, isothiazolyl, thiophneyl, benzimidazolyl, azabenzimidazolyl, benzimidazolonyl, indazolyl, dihydroindazolonyl, azaindazolyl, indolyl, indolonyl, dihydroisoindolonyl, azaindolyl, benzofuranyl, dihyrobenzofuranyl, benzoxazolyl, benzoxazolonyl, benzisoxazolyl, benzothiazolyl, benzoisothiazolyl, benzotriazolyl, imidazopyridinyl, tetrahydroimidazopyridinyl, imidazopyrazinyl, imidazopyridazinyl, imidazothiazolyl, pyrazolopyridinyl, pyrazolopyrimidinyl, pyrrolopyrimidinyl, pyrrolopyrazinyl, triazolopyridinyl, triazolopyrimidinyl, and tetrazolopyridinyl.

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

(1) phenyl,

(2) quinoline,

(3) isoquinoline,

(4) benzoxazole,

(5) thienopyridine,

(6) pyridine,

(7) quinazoline,

(8) pyrimidine,

(9) benzothiazole, and

(10) quinoxaline.

7. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein 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 or napthyl,

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

(6) heteroaryl, wherein heteroaryl is selected from triazolyl, oxazolyl, imidazolyl, pyrazolyl, thiazolyl, oxadiazolyl, tetrazolyl, imidazolidinonyl, oxazolidinonyl, pyrrolidinonyl, pyridyl, and pyrimidinyl, which is unsubstituted or substituted with halogen, hydroxyl or C 1-6 alkyl,

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

(8) C 3-6 cycloalkyl, which is unsubstituted or substituted with halogen, hydroxyl or phenyl, and

(9) —CN.

8. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 2a , R 2b and R 2c 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, and

(6) —CN.

9. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein R 3 is fluoro.

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

(3 S)-(4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl)(2,6-difluoro-3-methoxyphenyl)methanone;

(S)-(3-(1H-1,2,3-triazol-1-yl)phenyl)(3-(benzo[d]thiazol-2-yloxy)-4,4-difluoropiperidin-1-yl)methanone;

2-[(4,4-difluoro-1-{[5-methyl-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(3 S)-(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-({4,4-difluoro-1-[(5-fluoro-2-pyrimidin-2-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(4-fluoro-2-pyrimidin-2-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-[(4,4-difluoro-1-{[2-(3-methyl-1,2,4-oxadiazol-5-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(1-{[5-bromo-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-4,4-difluoropiperidin-3-yl)oxy]quinoline;

2-[(1-{[5-chloro-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-4,4-difluoropiperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[3-methyl-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[3-(1,3-thiazol-4-yl)pyridin-2-yl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1,3-thiazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1,3-thiazol-5-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1,3-oxazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(5-methyl-1,2,4-oxadiazol-3-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1-methyl-1H-pyrazol-4-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-{[4,4-difluoro-1-(quinolin-6-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}phenol;

2-({4,4-difluoro-1-[(2-fluorophenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(2-methylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-[(4,4-difluoro-1-{[2-(trifluoromethyl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-({4,4-difluoro-1-[(3-methoxyphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({1-[(2-ethoxyphenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(3-methylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}benzonitrile

2-({1-[(3-cyclopropylphenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-[(4,4-difluoro-1-{[2-(methyl sulfanyl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1H-imidazol-1-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1H-1,2,4-triazol-5-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1H-imidazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(1H-pyrazol-4-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-({4,4-difluoro-1-[(2-methoxyphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-[(4,4-difluoro-1-{[2-(1H-1,2,4-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-(methyl sulfanyl)-1H-benzimidazol-7-yl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-{[4,4-difluoro-1-(1H-indazol-7-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({4,4-difluoro-1-[(2-pyrazin-2-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(3-methyl-1H-indol-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-[(4,4-difluoro-1-1 [2-methyl-6-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl-piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-fluoro-6-(1,3-thiazol-4-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[5-fluoro-2-(1,3-thiazol-4-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-{[4,4-difluoro-1-(imidazo[1,2-a]pyrazin-5-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[4,4-difluoro-1-([1,2,4]triazolo[1, 5-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

3-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-2-fluorophenol;

2-[(4,4-difluoro-1-1 [4-(2H-1,2,3-triazol-2-yl)pyridin-3-yl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[2-fluoro-6-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-piperidin-3-yl)oxy]quinoline;

[3-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-(2H-1,2,3-triazol-2-yl)phenyl]methanol;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)thiophen-3-yl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[3-(2H-1,2,3-triazol-2-yl)thiophen-2-yl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[ 2 -(4-methyl-1H-pyrazol-1-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-{[4,4-difluoro-1-(tetrazolo[1, 5-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({4,4-difluoro-1-[(4-pyrrolidin-1-ylpyridin-2-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-(1H-pyrazol-1-yl)phenol;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-(1H-imidazol-4-yl)phenol;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-(1,3-thiazol-4-yl)phenol;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-(1H-pyrazol-3-yl)phenol;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-(1,3-oxazol-4-yl)phenol;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-(1,3-oxazol-2-yl)phenol;

2-[(1-{[2-chloro-5-(1H-pyrazol-1-yl)phenyl]carbonyl}-4,4-difluoropiperidin-3-yl)oxy]quinoline;

2-({4,4-difluoro-1-[(5-furan-2-yl-1-methyl-1H-pyrazol-3-yl)carbonyl]piperidin-3-yl}oxy)quinoline; 2-[(4,4-difluoro-1-1 [3-(1,3-oxazol-5-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-({1-[(2,6-dimethoxyphenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-({1-[(5-chloro-2-methylphenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-({1-[(2, 5-difluorophenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(2-fluoro-6-methoxyphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[1-(2,3-dihydro-1-benzofuran-7-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-({4,4-difluoro-1-[(2-fluoro-3-methoxyphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({1-[(2,3-difluorophenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(2-methoxy-5-methylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-[(4,4-difluoro-1-{[3-(1H-imidazol-1-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-({4,4-difluoro-1-[(3-furan-2-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(3-methoxy-5-methylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({4,4-difluoro-1-[(2-methyl-1-benzofuran-7-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[4,4-difluoro-1-(1H-imidazo[4,5-c]pyridin-7-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(pyrazolo[1, 5-a]pyridin-7-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(2-fluoro-5-methoxyphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[4,4-difluoro-1-(imidazo[2,1-b][1,3]thiazol-6-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(2-methyl-2H-indazol-3-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-1-(1,2-benzisoxazol-3-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(2-phenylpyridin-3-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({(3S)-4,4-difluoro-1-[(4-phenylpyridin-3-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-(pyrazolo[1, 5-a]pyrimidin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(pyrazolo[1, 5-a]pyridin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[2,3-b]pyridin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[3,2-b]pyridin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-indol-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-indazol-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(1-methyl-1H-indazol-3-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,5-a]pyridin-1-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,5-a]pyridin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(5H-pyrrolo[2,3-b]pyrazin-7-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

4-( 3 -{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}phenyl)-1,3-thiazol-2-amine;

2-{[(3 S)-4,4-difluoro-1-{[2-(1H-tetrazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[2-(2H-tetrazol-2-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[2-fluoro-5-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[2-fluoro-5-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}-piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-1-{[5-bromo-2-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[2-fluoro-5-(1H-pyrazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1,2,4-oxadiazol-3-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1,3-oxazol-2-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

(3 S)-(4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl)(imidazo[1,2-a]pyridin-8-yl)methanone;

2-({(3S)-1-[(2,6-difluoro-3-methoxyphenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-fluoro-5-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}-piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-fluoro-5-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}-piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-1-{[3-bromo-5-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[4-(1H-1,2,3-triazol-1-yl)pyridin-2-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[4-(2H-1,2,3-triazol-2-yl)pyridin-2-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3 S)-1-[(3-chloroimidazo[1,2-a]pyridin-8-yl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1,3-thiazol-2-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-pyrazol-3-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(2-methyl-1,3-thiazol-4-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[4-(1H-imidazol-1-yl)pyridin-2-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,4-triazol-5-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(2-pyridin-3-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-1-(1H-benzimidazol-4-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(1-methyl-1H-indazol-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

1-(3-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}phenyl)-imidazolidin-2-one;

2-{[(3 S)-4,4-difluoro-1-{[2-(1H-pyrazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(3-phenylpyridin-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-pyrazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-pyrazol-4-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3S)-1-[(2,5-dimethoxyphenyl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-imidazol-2-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(3-phenylpyridin-2-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-1-(1H-benzimidazol-5-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-indazol-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-fluoro-2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[2-(5-methyl-2H-tetrazol-2-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-1-{[2-chloro-5-(4H-1,2,4-triazol-4-yl)phenyl]carbonyl}-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-4-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-1-(1,3-benzoxazol-4-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(2-pyridin-2-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S,4 S)-4-fluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S,4 S)-4-fluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[6-(1H-pyrazol-1-yl)pyridin-2-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[4-(1H-pyrazol-1-yl)pyridin-2-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

1-(3-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-fluorophenyl)imidazolidin-2-one;

2-{[(3 S)-4,4-difluoro-1-{[2-(1H-1,2,3-triazol-5-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyrazin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-imidazo[4,5-c]pyridin-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(3-pyrimidin-2-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({(3 S)-4,4-difluoro-1-[(2-methyl-1H-benzimidazol-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({(3S)-4,4-difluoro-1-[(6-fluoro-1H-benzimidazol-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({(3S)-4,4-difluoro-1-[(2-pyridin-4-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}-6-fluoro-1,3-benzothiazole;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-6-fluoro-1,3-benzothiazole;

7-{[(3 S)-4,4-difluoro-3-{[5-(trifluoromethyl)pyridin-2-yl]oxy}piperidin-1-yl]carbonyl}pyrazolo[1,5-a]pyridine;

2-({(3S)-4,4-difluoro-1-[(6-fluoroimidazo[1,2-a]pyridin-8-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({(3S)-4,4-difluoro-1-[(2-pyrimidin-5-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-{[4-(1,3-oxazol-2-yl)pyridin-2-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

7-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-1,3-benzoxazol-2(3H)-one;

2-{[(3 S)-4,4-difluoro-1-{[2-(trifluoromethyl)-1H-benzimidazol-4-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3 S)-1-[(7-chloroimidazo[1,2-a]pyridin-8-yl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

3-(3-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}phenyl)-1,3-oxazolidin-2-one;

2-({(3 S)-1-[(6-chloroimidazo[1,2-a]pyridin-8-yl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrazolo[4,3-c]pyridin-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrazolo[3,4-b]pyridin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[7-(trifluoromethyl)imidazo[1,2-a]pyridin-8-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(3-iodoimidazo[1,2-a]pyridin-8-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

3-(3-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-fluorophenyl)-1,3-oxazolidin-2-one;

1-(3-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-fluorophenyl)pyrrolidin-2-one;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[2,3-c]pyridin-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(7H-pyrrolo[2,3-d]pyrimidin-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-indol-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[2,3-b]pyridin-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-([1,2,3]triazolo[1,5-a]pyridin-7-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[3,2-c]pyridin-4-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

1-(3-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4,6-difluorophenyl)imidazolidin-2-one;

4-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-1,3-dihydro-2H-indol-2-one;

2-({(3S)-4,4-difluoro-1-[(5-methylpyrazolo[1, 5-a]pyrimidin-7-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-imidazo[4,5-c]pyridin-6-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-1-(1,3-benzothiazol-5-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-imidazo[4,5-b]pyridin-6-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(pyrazolo[1, 5-a]pyridin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-indazol-5-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-indazol-6-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-1-(2, 1-benzisothiazol-3-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-{[(3 S)-1-(2, 1-benzisoxazol-3-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-({4,4-difluoro-1-[(2-methyl-5-phenyl-1,3-thiazol-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[4,4-difluoro-1-([1,2,4]triazolo[4,3-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({4,4-difluoro-1-[(6-methylimidazo[2,1-b][1,3]thiazol-3-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-[(4,4-difluoro-1-{[4-(2H-1,2,3-triazol-2-yl)isothiazol-3-yl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-[(4,4-difluoro-1-{[3-methyl-5-(2H-1,2,3-triazol-2-yl)isothiazol-4-yl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-{[1-(1H-benzotriazol-5-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-[(4,4-difluoro-1-{[3-(1H-1,2,4-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-{[4,4-difluoro-1-(imidazo[1, 5-a]pyridin-5-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[4,4-difluoro-1-(pyrazin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[4,4-difluoro-1-(pyrimidin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[1-(biphenyl-2-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-[(4,4-difluoro-1-{[2-(trifluoromethoxy)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-{[4,4-difluoro-1-(1H-indol-7-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(pyrazolo[1, 5-a]pyrimidin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-([1,2,4]triazolo[1,5-a]pyrimidin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[3,2-b]pyridin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,5-b]pyridazin-7-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-b]pyridazin-2-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({(3 S)-4,4-difluoro-1-[(1-methyl-1H-benzimidazol-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({(3 S)-4,4-difluoro-1-[(1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-{[6-(trifluoromethyl)imidazo[1,2-a]pyridin-8-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1,2,4-oxadiazol-5-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-N,N-dimethylaniline;

2-[(4,4-difluoro-1-{[5-fluoro-2-(1,3-thiazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

4-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-5-phenyl-1,3-thiazol-2-amine;

2-[(4,4-difluoro-1-{[3-(1H-pyrrol-1-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline;

2-({4,4-difluoro-1-[(3-thiophen-3-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-({1-[(2,2-difluoro-1,3-benzodioxol-4-yl)carbonyl]-4,4-difluoropiperidin-3-yl}oxy)quinoline;

3-{[4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-N,N-dimethylaniline;

2-({(3S)-4,4-difluoro-1-[(3-thiophen-2-ylphenyl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S,4R)-4-fluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S,4R)-4-fluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[2-(trifluoromethyl)imidazo[1,2-a]pyridin-8-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-{[5-(trifluoromethyl)imidazo[1,2-a]pyridin-8-yl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-6-iodoquinoline;

2-1 [(3 S)-4,4-difluoro-1-(5,6,7, 8-tetrahydroimidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[2,3-c]pyridin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({4,4-difluoro-1-[(3-methyl[1,2,4]triazolo[4,3-a]pyridin-8-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-1-(1H-benzimidazol-2-ylcarbonyl)-4,4-difluoropiperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(1H-pyrrolo[3,2-c]pyridin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-({(3S)-4,4-difluoro-1-[(1-methyl-1H-pyrazolo[3,4-b]pyridin-3-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[4,4-difluoro-1-([1,2,3]triazolo[1, 5-a]pyridin-3-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{(4,4-difluoro-1-[(1-methyl-1H-indol-5-yl)carbonyl]piperidin-3-yl}oxy)quinoline;

2-{[(3 S)-4,4-difluoro-1-(5H-pyrrolo[2,3-b]pyrazin-6-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

7-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-1,2-dihydro-3H-indazol-3-one;

4-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-1,3-benzoxazol-2(3H)-one;

6-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-2,3-dihydro-1H-isoindol-1-one;

6-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-1,3-benzoxazol-2(3H)-one;

5-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-1,3-dihydro-2H-benzimidazol-2-one;

(3 S,4R)-4-fluoro-3-(quinolin-2-ylamino)piperidin-1-yl](imidazo[1,2-a]pyridin-8-yl)methanone;

[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl][3-(1,3-thiazol-4-yl)phenyl]methanone;

(6-chloro-1H-imidazo[4,5-c]pyridin-4-yl)[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]methanone;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinazoline

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoxaline

6-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]thieno[2,3-b]pyridine;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]-1,3-benzothiazole

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-6-fluoroquinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}-1,3-benzothiazole;

5-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}thieno[3,2-b]pyridine;

6-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}thieno[2,3-b]pyridine;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]quinoline; -3-carbonitrile;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}-6-fluoroquinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}-8-methylquinoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}-8-fluoroquinoline;

8-chloro-2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]-6,7-dihydro-5H-cyclopenta[b]pyridine;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]-5-(trifluoromethyl)pyridine;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}quinoline; -3-carbonitrile;

8-{[(3 S)-3-{[6-chloro-5-(trifluoromethyl)pyridin-2-yl]oxy}-4,4-difluoropiperidin-1-yl]carbonyl}imidazo[1,2-a]pyridine;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-1,3-benzothiazole;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-8-methylquinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-8-fluoroquinoline;

8-chloro-2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}quinoline;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-4,6-difluoro-1,3-benzothiazole;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-4,5,6-trifluoro-1,3-benzothiazole;

8-{[(3 S)-3-(6,7-dihydro-5H-cyclopenta[b]pyridin-2-yloxy)-4,4-difluoropiperidin-1-yl]carbonyl}imidazo[1,2-a]pyridine;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]-4-(trifluoromethyl)-5,6,7, 8-tetrahydroquinazoline;

2-{[(3 S)-4,4-difluoro-1-{[3-(1H-1,2,3-triazol-1-yl)phenyl]carbonyl}piperidin-3-yl]oxy}-5,6,7,8-tetrahydroquinazoline;

5-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]pyrazolo[1,5-a]pyrimidine;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]-1,3-benzoxazole;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy][1,3]thiazolo[5,4-b]pyridine;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy][1,3]thiazolo[5,4-c]pyridine;

2-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]-7,8-dihydro-5H-pyrano[4,3-d]pyrimidine;

2-{[(3 S)-4,4-difluoro-1-(imidazo[1,2-a]pyridin-8-ylcarbonyl)piperidin-3-yl]oxy}-4-(trifluoromethyl)-1,3-benzothiazole;

3-[(4,4-difluoro-1-{[2-(2H-1,2,3-triazol-2-yl)phenyl]carbonyl}piperidin-3-yl)oxy]isoquinoline;

1-(3-{[(3 S)-4,4-difluoro-3-(quinolin-2-yloxy)piperidin-1-yl]carbonyl}-4-fluorophenyl)-3-methylimidazolidin-2-one; and

[(3 S)-4,4-difluoro-3-{[6-methyl-5-(trifluoromethyl)pyridin-2-yl]oxy}piperidin-1-yl](imidazo[1,2-a]pyridin-8-yl)methanone;

or a pharmaceutically acceptable salt thereof.

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

12. 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.