Amidopropoxyphenyl Orexin Receptor Antagonists

1 - 28 . (canceled)

29 . A compound of the formula I:

wherein:

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

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 —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 ,

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

(9) —(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 13 ,

(c) C 3-6 alkenyl, which is unsubstituted or substituted with R 13 ,

(d) cycloalkyl which is unsubstituted or substituted with R 13 ,

(e) phenyl, which is unsubstituted or substituted with R 13 , and

(f) heterocycle, which is unsubstituted or substituted with R 13 ,

(10) —S(O) 2 —NR 10 R 11 ,

(11) —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 ,

(12) —CO 2 H,

(13) —CN, and

(14) —NO 2 ;

R 2 is selected from the group consisting of:

(1) hydrogen,

(2) C 1-6 alkyl, which is unsubstituted or substituted with one or more substituents selected from R 13 ,

(3) —C 3-6 cycloalkyl, which is unsubstituted or substituted with one or more substituents selected from R 13 ,

(4) -phenyl which is unsubstituted or substituted with one or more substituents selected from R 13 , and

(5) -heteroaryl, which is unsubstituted or substituted with one or more substituents selected from R 13 ;

R 3 and R 4 are independently selected from the group consisting of:

(1) hydrogen,

(2) C 1-6 alkyl, which is unsubstituted or substituted with one or more substituents selected from R 13 ,

(3) —C 3-6 cycloalkyl, which is unsubstituted or substituted with one or more substituents selected from R 13 ,

(4) -phenyl which is unsubstituted or substituted with one or more substituents selected from R 13 , and

(5) -heteroaryl, which is unsubstituted or substituted with one or more substituents selected from R 13 ,

or R 3 and R 4 and the carbon to which they are attached form a C 3-6 cycloalkyl ring, which is unsubstituted or substituted with R 13 ;

R 5 and R 6 are independently selected from the group consisting of:

(1) hydrogen,

(2) halogen,

(3) hydroxyl,

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

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

(6) -phenyl, which is unsubstituted or substituted with one or more substituents selected from R 13 ,

(7) -heterocycle, which is unsubstituted or substituted with one or more substituents selected from R 13 , and

(8) —CN,

or R 5 and R 6 and the carbon to which they are attached form a C 3-6 cycloalkyl ring, which is unsubstituted or substituted with R 13 ;

R 7a , R 7b and R 7c 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 —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 ,

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

(9) —(C═O) m —NR 10 R 11 ,

(10) —S(O) 2 —NR 10 R 11 ,

(11) —S(O) q —R 12 ,

(12) —CO 2 H,

(13) —CN, and

(14) —NO 2 ;

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 —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 ,

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

(9) —(C═O) m —NR 10 R 11 ,

(10) —S(O) 2 —NR 10 R 11 ,

(11) —S(O) q —R 12 ,

(12) —CO 2 H,

(13) —CN, and

(14) —NO 2 ;

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 1-16 alkyl,

(7) —NH—C 1-16 alkyl,

(8) phenyl,

(9) heterocycle,

(10) —CO 2 H, and

(11) —CN;

or a pharmaceutically acceptable salt thereof.

30 . The compound of claim 29 wherein:

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

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

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

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

(7) C 2-4 alkenyl, which is unsubstituted or substituted with C 3-6 cycloalkyl or phenyl,

(8) phenyl or napthyl, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl, —SH, —S—C 1-6 alkyl, —NO 2 , —CO 2 H, —CN, or —NR 10 R 11 ,

(9) —O-phenyl, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl, —SH, —S—C 1-6 alkyl, —NO 2 , —CO 2 H, —CN, or —NR 10 R 11 ,

(10) heterocycle, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl, —SH, —S—C 1-6 alkyl, —NO 2 , —CO 2 H, —CN, or —NR 10 R 11 ,

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

C 1-6 alkyl,

(12) —S(O) 2 —NR 10 R 11 ,

(13) —S(O) q —R 12 , where q is 0, 1 or 2 and where R 12 is C 1-6 alkyl, C 3-6 cycloalkyl, or phenyl which is unsubstituted or substituted with halogen, hydroxyl, phenyl or —O—C 1-6 alkyl,

(14) —CO 2 H,

(15) —CO 2 —R 12 ,

(16) —CN, and

(17) —NO 2 ;

R 2 is selected from the group consisting of:

(1) hydrogen,

(2) C 1-6 alkyl, which is unsubstituted or substituted with halogen, C 3-6 cycloalkyl or phenyl,

(3) —C 3-6 cycloalkyl, which is unsubstituted or substituted with halogen, C 1-6 alkyl or phenyl, and

(4) phenyl, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl or —NO 2 ;

R 3 and R 4 are independently selected from the group consisting of:

(1) hydrogen,

(2) C 1-6 alkyl, which is unsubstituted or substituted with halo, C 3-6 cycloalkyl or phenyl, and

(3) C 3-6 cycloalkyl, which is unsubstituted or substituted with halo, C 3-6 cycloalkyl or phenyl,

or R 3 and R 4 and the carbon to which they are attached form a C 3-6 cycloalkyl ring;

R 5 and R 6 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, phenyl or —O—C 1-6 alkyl,

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

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

(7) phenyl, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl or —NO 2 ,

or R 5 and R 6 and the carbon to which they are attached form a C 3-6 cycloalkyl ring, which is unsubstituted or substituted with halogen, hydroxyl or phenyl;

R 7a , R 7b and R 7c 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, phenyl or —O—C 1-6 alkyl,

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

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

(7) phenyl or napthyl, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl or —NO 2 ,

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

(9) —S(O) 2 —NR 10 R 11 ,

(10) —S(O) q —R 12 , and

(11) —CN;

or a pharmaceutically acceptable salt thereof.

31 . The compound of claim 29 wherein A is selected from the group consisting of:

(1) phenyl,

(2) oxazolyl,

(3) isoxazolyl,

(4) thiazolyl,

(5) thiadiazolyl,

(6) pyrazolyl, and

(7) pyridyl.

32 . The compound of claim 31 of the formula Ib:

or a pharmaceutically acceptable salt thereof.

33 . The compound of claim 31 of the formula Ie:

or a pharmaceutically acceptable salt thereof.

34 . The compound of claim 33 of the formula If:

or a pharmaceutically acceptable salt thereof.

35 . The compound of claim 29 wherein R 1b is hydrogen, R 1c is hydrogen and R 1a is independently selected from the group consisting of:

(1) hydrogen,

(2) halogen,

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

—O—C 1-6 alkyl,

(4) C 2-4 alkenyl, which is unsubstituted or substituted with C 3-6 cycloalkyl or phenyl,

(5) phenyl which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-6 alkyl, —SH, —S—C 1-6 alkyl, —NO 2 , —CO 2 H, or —CN,

(6) —O-phenyl, which is unsubstituted or substituted with halogen, hydroxyl, C 1-6 alkyl, —O—C 1-16 alkyl, —SH, —S—C 1-6 alkyl, —NO 2 , —CO 2 H, —CN,

(7) —NR 10 R 11 , wherein R 10 and R 11 are independently selected from hydrogen and

C 1-16 alkyl,

(8) tetrazolyl,

(9) thienyl,

(10) triazolyl,

(11) benzothienyl,

(12) pyrazolyl,

(13) imidazolyl,

(14) —NO 2 , and

(15) —CN.

36 . The compound of claim 29 wherein R 2 is selected from the group consisting of:

(1) hydrogen,

(2) CH 3 ,

(3) CH 2 CH 3 ,

(4) CH 2 CH 2 F,

(5) CH 2 -phenyl,

(6) CH 2 -cyclopropyl,

(7) CH 2 -cyclobutyl,

(8) cyclopropyl,

(9) cyclobutyl, and

(10) CH 2 CH 2 CH 3 .

37 . The compound of claim 36 wherein R 2 is CH 3 , CH 2 CH 3 , cyclopropyl or cyclobutyl.

38 . The compound of claim 29 wherein R 3 is hydrogen and R 4 is hydrogen.

39 . The compound of claim 29 wherein R 3 is cyclopropyl and R 4 is hydrogen.

40 . The compound of claim 29 wherein R 5 is hydrogen and R 6 is hydrogen.

41 . The compound of claim 29 wherein R 5 and R 6 and the carbon to which they are attached form a cyclopropyl or cyclobutyl ring.

42 . The compound of claim 29 wherein R 7a , R 7b and R 7c are independently selected from the group consisting of:

(1) hydrogen,

(2) fluoro,

(3) chloro, and

(4) bromo.

43 . The compound of claim 29 wherein R 7a is fluoro, R 7b is hydrogen and R 7c is hydrogen.

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

N-[3-(4-Fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-[3-(4-Fluorophenoxy)propyl]-N,2-dimethyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-(Cyclobutylmethyl)-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-(Cyclopropylmethyl)-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-Benzyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-[3-(4-Fluorophenoxy)propyl]-N-methyl-1,1′-biphenyl-2-carboxamide;

N-(2-Fluoroethyl)-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-[3-(4-Fluorophenoxy)propyl]-2-methyl-5-phenyl-N-propyl-1,3-thiazole-4-carboxamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-1,1′-biphenyl-2-carboxamide;

N-(Cyclopropylmethyl)-N-[3-(4-fluorophenoxy)propyl]-1,1′-biphenyl-2-carboxamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-pyrrol-1-yl)benzamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-pyrazol-1-yl)benzamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-5-phenyl-1,3-oxazole-4-carboxamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-tetraazol-1-yl)benzamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-4-phenyl-1,2,3-thiadiazole-5-carboxamide;

3-(2-Chlorophenyl)-N-ethyl-N-[3-(4-fluorophenoxy)propyl]-5-methylisoxazole-4-carboxamide;

2-(Dimethylamino)-N-ethyl-N-[3-(4-fluorophenoxy)propyl]benzamide;

N-Ethyl-2-fluoro-N-[3-(4-fluorophenoxy)propyl]benzamide;

2-Chloro-N-ethyl-N-[3-(4-fluorophenoxy)propyl]benzamide;

2-Bromo-N-ethyl-N-[3-(4-fluorophenoxy)propyl]benzamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-2-phenoxybenzamide;

3-Chloro-N-ethyl-N-[3-(4-fluorophenoxy)propyl]benzamide;

4-Chloro-N-ethyl-N-[3-(4-fluorophenoxy)propyl]benzamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-4′-methoxy-1,1′-biphenyl-2-carboxamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-4′-nitro-1,1′-biphenyl-2-carboxamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-3′-methyl-1,1′-biphenyl-2-carboxamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-2-thien-3-ylbenzamide;

4′-Cyano-N-ethyl-N-[3-(4-fluorophenoxy)propyl]-1,1′-biphenyl-2-carboxamide;

2-[(E)-2-Cyclohexylethenyl]-N-ethyl-N-[3-(4-fluorophenoxy)propyl]benzamide;

N-Ethyl-N-[3-(4-fluorophenoxy)propyl]-2-(2-naphthyl)benzamide;

2-(1-Benzothien-3-yl)-N-ethyl-N-[3-(4-fluorophenoxy)propyl]benzamide;

(±)-N-[1-Cyclopropyl-3-(4-fluorophenoxy)propyl]-N-ethyl-1,1′-biphenyl-2-carboxamide;

(±)-N-[1-Cyclopropyl-3-(4-fluorophenoxy)propyl]-N,2-dimethyl-5-phenyl-1,3-thiazole-4-carboxamide;

(±)-N-[1-Cyclopropyl-3-(4-fluorophenoxy)propyl]-N-ethyl-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

(±)-N-[1-Cyclopropyl-3-(4-fluorophenoxy)propyl]-N-methyl-1,1′-biphenyl-2-carboxamide;

N-({1-[(4-Fluorophenoxy)methyl]cyclopropyl}methyl)-N,2-dimethyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-Ethyl-N-({1-[(4-fluorophenoxy)methyl]cyclopropyl}methyl)-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-(Cyclopropylmethyl)-N-({1-[(4-fluorophenoxy)-methyl]cyclopropyl}methyl)-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-({1-[(4-Fluorophenoxy)methyl]cyclobutyl}methyl)-N,2-dimethyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-1,1′-biphenyl-2-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-iodobenzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(trifluoromethoxy)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-pyrrol-1-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-pyrazol-1-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-4′-methoxy-1,1′-biphenyl-2-carboxamide;

N-Cyclobutyl-2-(dimethylamino)-N-[3-(4-fluorophenoxy)propyl]benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-1-methyl-4-phenyl-1H-pyrazole-3-carboxamide;

N-Cyclobutyl-3′-fluoro-N-[3-(4-fluorophenoxy)propyl]-1,1′-biphenyl-2-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-2H-1,2,3-triazole-4-carboxamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-1,3-thiazole-4-carboxamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-1,1′-biphenyl-2-carboxamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-2-(trifluoromethoxy)benzamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-pyrrol-1-yl)benzamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-pyrazol-1-yl)benzamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-4′-methoxy-1,1′-biphenyl-2-carboxamide;

N-Cyclopropyl-2-(dimethylamino)-N-[3-(4-fluorophenoxy)propyl]benzamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-1-methyl-4-phenyl-1H-pyrazole-3-carboxamide;

N-Cyclopropyl-3′-fluoro-N-[3-(4-fluorophenoxy)propyl]-1,1′-biphenyl-2-carboxamide;

N-Cyclopropyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-phenyl-2H-1,2,3-triazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-imidazol-1-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-5-methyl-2-(1H-pyrazol-1-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(2H-1,2,3-triazol-2-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(4H-1,2,4-triazol-4-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-5-methyl-2-(2H-1,2,3-triazol-2-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluoro-3-methylphenoxy)propyl]-5-methyl-2-(2H-1,2,3-triazol-2-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluoro-3-methylphenoxy)propyl]-2-(2H-1,2,3-triazol-2-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(1-methyl-1H-pyrazol-4-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-(1H-pyrazol-4-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluoro-3-methylphenoxy)propyl]-2-(1H-pyrazol-4-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluoro-3-methylphenoxy)propyl]-5-methyl-2-(1H-pyrazol-4-yl)benzamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-(1H-pyrazol-4-yl)-1,3-thiazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-(1-methyl-1H-pyrazol-4-yl)-1,3-thiazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-pyridin-3-yl-1,3-thiazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluorophenoxy)propyl]-2-methyl-5-pyridin-4-yl-1,3-thiazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluoro-3-methylphenoxy)propyl]-2-methyl-5-(1H-pyrazol-4-yl)-1,3-thiazole-4-carboxamide;

N-Cyclobutyl-N-[3-(4-fluoro-3-methylphenoxy)propyl]-2-methyl-5-(1-methyl-1H-pyrazol-4-yl)-1,3-thiazole-4-carboxamide;

or a pharmaceutically acceptable salt thereof.

45 . A pharmaceutical composition which comprises an inert carrier and a compound of claim 29 or a pharmaceutically acceptable salt thereof.

46 . A method for disease or disorder in which orexin receptors are involved in a mammalian patient in need thereof which comprises administering to the patient a therapeutically effective amount of the compound of claim 29 or a pharmaceutically acceptable salt thereof.

47 . The method of claim 46 wherein the disease or disorder is selected from a sleep disorder, a sleep disturbance, decreased sleep maintenance, decreased quality of sleep, decreased REM sleep, decreased stage 2 sleep, increased fragmentation of sleep patterns, insomnia, decreased cognition, decreased memory retention, obesity, epilepsy, absence epilepsy, pain, neuropathic pain, Parkinson's disease, psychosis and schizophrenia.