SUBSTITUTED PIPERIDINE COMPOUND AND USE THEREOF

1 .- 20 . (canceled)

21 . A method of activating an orexin type 2 receptor in a subject, comprising administering an effective amount of the compound represented by the formula:

wherein

R 1 is an acyl group, or a hydrogen atom;

R 2 is an optionally substituted 3- to 6-membered saturated cyclic group; and

R 3 is an optionally substituted C 1-6 alkyl group, a mono- or di-C 1-6 alkylamino group or a C 3-6 cycloalkyl group, or a salt thereof.

22 . The method according to claim 21 , wherein R 3 is an optionally substituted C 1-6 alkyl group or a mono- or di-C 1-6 alkylamino group, or a salt thereof.

23 . The method according to claim 21 , which is represented by the formula:

wherein R 1 , R 2 and R 3 are as defined in claim 21 , or a salt thereof.

24 . The method according to claim 21 , wherein R 1 is an acyl group, or a salt thereof.

25 . The method according to claim 21 , wherein R 2 is a C 3-6 cycloalkyl group substituted by one optionally substituted phenyl group, or a salt thereof.

26 . The method according to claim 21 , wherein R 3 is an optionally substituted C 1-6 alkyl group, or a salt thereof.

27 . The method according to claim 21 , wherein R 1 is

(1) a hydrogen atom,

(2) an optionally substituted C 1-6 alkyl-carbonyl group,

(3) an optionally substituted C 3-10 cycloalkyl-carbonyl group,

(4) an optionally substituted C 1-6 alkoxy-carbonyl group,

(5) an optionally substituted C 3-10 cycloalkyloxy-carbonyl group,

(6) an optionally substituted C 6-14 aryl-carbonyl group,

(7) an optionally substituted C 6-14 aryloxy-carbonyl group,

(8) an optionally substituted 5- to 14-membered aromatic heterocyclylcarbonyl group,

(9) an optionally substituted 3- to 14-membered non-aromatic heterocyclylcarbonyl group,

(10) an optionally substituted mono- or di-C 1-6 alkyl-carbamoyl group,

(11) an optionally substituted mono- or di-C 3-10 cycloalkyl-carbamoyl group,

(12) an optionally substituted mono- or di-C 6-14 aryl-carbamoyl group,

(13) an optionally substituted C 1-6 alkylsulfonyl group,

(14) an optionally substituted C 3-10 cycloalkylsulfonyl group,

(15) an optionally substituted C 6-14 arylsulfonyl group,

(16) an optionally substituted heterocyclyl-sulfonyl group,

(17) an optionally substituted mono- or di-C 1-6 alkyl-sulfamoyl group or

(18) an optionally substituted C 1-6 alkyl-carbonyl-carbonyl group;

R 2 is a C 3-6 cycloalkyl group or a 3- to 6-membered saturated monocyclic non-aromatic heterocyclic group, each of which is optionally substituted by 1 to 3 substituents selected from

(1) deuterium,

(2) a halogen atom,

(3) a hydroxy group,

(4) an optionally substituted C 1-6 alkyl group,

(5) a C 3-10 cycloalkyl group,

(6) an optionally substituted C 1-6 alkoxy group,

(7) an optionally substituted C 6-14 aryl group,

(8) a C 6-14 aryloxy group,

(9) a tri-C 1-6 alkylsilyloxy group,

(10) an optionally substituted 5- to 14-membered aromatic heterocyclic group and

(11) an optionally substituted C 6-14 aryl-carbonyl group; and

R 3 is a C 1-6 alkyl group optionally substituted by 1 to 3 substituents selected from a halogen atom and a C 6-14 aryl group, or a mono- or di-C 1-6 alkylamino group, or a salt thereof.

28 . The method according to claim 21 , wherein R 1 is

(1) a hydrogen atom,

(2) a C 1-6 alkyl-carbonyl group optionally substituted by 1 to 7 substituents selected from (i) a halogen atom, (ii) a cyano group, (iii) a hydroxy group, (iv) a C 3-10 cycloalkyl group, (v) a C 1-6 alkoxy group, (vi) a C 6-14 aryl group, (vii) a C 6-14 aryloxy group, (viii) a pyrazolyl group, a thiazolyl group, a pyrimidinyl group or a pyridazinyl group, each of which is optionally substituted by an oxo group, (ix) a pyrazolyloxy group optionally substituted by 1 to 3 C 1-6 alkyl groups, (x) a C 1-6 alkyl-carbonyl group, (xi) a C 1-6 alkoxy-carbonyl group, (xii) a C 1-6 alkyl-carbonyloxy group, (xiii) a C 1-6 alkylsulfonyl group, (xiv) a mono- or di-C 1-6 alkylamino group, (xv) a C 1-6 alkyl-carbonylamino group and (xvi) a (C 1-6 alkyl) (C 1-6 alkyl-carbonyl)amino group,

(3) a C 3-10 cycloalkyl-carbonyl group optionally substituted by 1 to 3 substituents selected from a halogen atom, a cyano group, a hydroxy group, an oxo group and a C 1-6 alkyl group,

(4) a C 1-6 alkoxy-carbonyl group optionally substituted by 1 to 6 substituents selected from deuterium, a halogen atom and a C 6-14 aryl group,

(5) a C 3-10 cycloalkyloxy-carbonyl group optionally substituted by 1 to 3 substituents selected from a C 1-6 alkyl group,

(6) a C 6-14 aryl-carbonyl group optionally substituted by 1 to 3 substituents selected from a halogen atom and a C 6-14 aryl group,

(7) a C 6-14 aryloxy-carbonyl group,

(8) a furylcarbonyl group, a thienylcarbonyl group, a pyrazolylcarbonyl group, an isoxazolylcarbonyl group or a pyridylcarbonyl group, each of which is optionally substituted by 1 to 3 substituents selected from a C 1-6 alkyl group,

(9) an azetidinylcarbonyl group, an oxetanylcarbonyl group, a pyrrolidinylcarbonyl group, a tetrahydrofuranylcarbonyl group, a tetrahydropyranylcarbonyl group or a morpholinylcarbonyl group, each of which is optionally substituted by 1 to 3 substituents selected from an oxo group, a C 1-6 alkyl-carbonyl group, a C 1-6 alkoxy-carbonyl group and a C 1-6 alkylsulfonyl group,

(10) a mono- or di-C 1-6 alkyl-carbamoyl group optionally substituted by 1 to 3 substituents selected from a halogen atom, a cyano group, a hydroxy group and a C 1-6 alkoxy group,

(11) a mono- or di-C 3-10 cycloalkyl-carbamoyl group,

(12) a mono- or di-C 6-14 aryl-carbamoyl group,

(13) a C 1-6 alkylsulfonyl group,

(14) a C 3-10 cycloalkylsulfonyl group,

(15) a C 6-14 arylsulfonyl group optionally substituted by 1 to 3 halogen atoms,

(16) a thienylsulfonyl group, a pyrazolylsulfonyl group, an imidazolylsulfonyl group, a pyridylsulfonyl group or a dihydrochromenylsulfonyl group, each of which is optionally substituted by 1 to 3 substituents selected from a C 1-6 alkyl group,

(17) a mono- or di-C 1-6 alkyl-sulfamoyl group or

(18) a C 1-6 alkyl-carbonyl-carbonyl group;

R 2 is a C 3-6 cycloalkyl group, a pyrrolidinyl group, a piperidinyl group or a dioxanyl group, each of which is optionally substituted by 1 to 3 substituents selected from

(1) deuterium,

(2) a halogen atom,

(3) a hydroxy group,

(4) a C 1-6 alkyl group optionally substituted by 1 to 3 substituents selected from a halogen atom and a C 6-14 aryl group,

(5) a C 3-10 cycloalkyl group,

(6) a C 1-6 alkoxy group optionally substituted by a C 3-10 cycloalkyl group,

(7) a C 6-14 aryl group optionally substituted by 1 to 3 substituents selected from a halogen atom, a cyano group, a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms, a C 1-6 alkoxy group optionally substituted by 1 to 3 halogen atoms and a hydroxy group,

(8) a C 6-14 aryloxy group,

(9) a tri-C 1-6 alkylsilyloxy group,

(10) a pyrazolyl group, a thiazolyl group, a pyridyl group, a pyrimidinyl group, a quinazolinyl group, a benzothiazolyl group or an isoquinolinyl group, each of which is optionally substituted by 1 to 3 substituents selected from a halogen atom, a C 1-6 alkyl group and a C 1-6 alkoxy group, and

(11) a C 6-14 aryl-carbonyl group; and

R 3 is a C 1-6 alkyl group, or a mono- or di-C 1-6 alkylamino group, or a salt thereof.

29 . The method according to claim 21 , wherein R 1 is

(1) a hydrogen atom,

(2) a C 1-6 alkyl-carbonyl group optionally substituted by a hydroxy group,

(3) a cyclopropanecarbonyl group,

(4) a C 1-6 alkoxy-carbonyl group or

(5) a mono- or di-C 1-6 alkyl-carbamoyl group;

R 2 is

(A) a cyclohexyl group optionally substituted by 1 to 3 substituents selected from

(1) a C 1-6 alkyl group and

(2) a phenyl group optionally substituted by 1 to 3 substituents selected from a halogen atom, a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms and a C 1-6 alkoxy group or

(B) a piperidinyl group optionally substituted by 1 to 3 pyrimidinyl groups; and

R 3 is a C 1-6 alkyl group or a di-C 1-6 alkylamino group, or a salt thereof.

30 . The method according to claim 21 , wherein R 1 is

(1) a C 1-6 alkyl-carbonyl group optionally substituted by a hydroxy group,

(2) a C 1-6 alkoxy-carbonyl group or

(3) a mono- or di-C 1-6 alkyl-carbamoyl group;

R 2 is a cyclohexyl group optionally substituted by 1 to 3 substituents selected from

(1) a C 1-6 alkyl group and

(2) a phenyl group optionally substituted by 1 to 3 halogen atoms; and

R 3 is a C 1-6 alkyl group, or a salt thereof.

31 . The method of claim 21 , wherein the compound is methyl (2R,3S)-3-((methylsulfonyl)amino)-2-(((cis-4-phenylcyclohexyl)oxy)methyl)piperidine-1-carboxylate or a salt thereof.

32 . The method of claim 21 , wherein the compound is N-((2R,3S)-1-glycoloyl-2-(((cis-4-(2,3,6-trifluorophenyl)cyclohexyl)oxy)methyl)piperidin-3-yl)methanesulfonamide or a salt thereof.

33 . The method of claim 21 , wherein the compound is (2R,3S)—N-ethyl-2-(((cis-4-isopropylcyclohexyl)oxy)methyl)-3-((methylsulfonyl)amino)piperidine-1-carboxamide or a salt thereof.

34 . The method according to claim 21 , wherein the subject has narcolepsy, idiopathic hypersomnia, hypersomnia, sleep apnea syndrome, narcolepsy syndrome accompanied by narcolepsy-like symptoms, hypersomnia syndrome accompanied by daytime hypersomnia, Alzheimer, obesity, insulin resistance syndrome, cardiac failure, diseases related to bone loss, sepsis, disturbance of consciousness, and side effects and complications due to anesthesia.

35 . The method according to claim 21 , wherein the subject has narcolepsy, idiopathic hypersomnia, hypersomnia, or sleep apnea syndrome.

36 . The method according to claim 21 , wherein the subject has narcolepsy.

37 . A method for the prophylaxis or treatment of narcolepsy in a subject in need thereof, comprising administering to the subject an effective amount of the compound of a compound represented by the formula:

wherein

R 1 is an acyl group, or a hydrogen atom;

R 2 is an optionally substituted 3- to 6-membered saturated cyclic group; and

R 3 is an optionally substituted C 1-6 alkyl group, a mono- or di-C 1-6 alkylamino group or a C 3-6 cycloalkyl group, or a salt thereof.

38 . The method of claim 37 , wherein the compound is methyl (2R,3S)-3-((methylsulfonyl)amino)-2-(((cis-4-phenylcyclohexyl)oxy)methyl)piperidine-1-carboxylate or a salt thereof.

39 . The method of claim 37 , wherein the compound is N-((2R,3S)-1-glycoloyl-2-(((cis-4-(2,3,6-trifluorophenyl)cyclohexyl)oxy)methyl)piperidin-3-yl)methanesulfonamide or a salt thereof.

40 . The method of claim 37 , wherein the compound is (2R,3S)—N-ethyl-2-(((cis-4-isopropylcyclohexyl)oxy)methyl)-3-((methylsulfonyl)amino)piperidine-1-carboxamide or a salt thereof.