Piperidine derivatives as orexin receptor antagonist

1. A compound of formula (I), or a pharmaceutically 2 acceptable salt thereof,

wherein:

A is selected from an optionally substituted 3-12 membered cyclohydrocarbyl or heterocyclohydrocarbyl or cyclic heterohydrocarbyl;

B is selected from C(═O);

X is a single bond of linkage;

D and L are independently selected from CH 2 ,

T is C;

M is selected from C(Y)(R 1a ) when Q is selected from C(R 1b )(R 1c ), or M is selected from C(R 1b )(R 1c ) when Q is selected from C(Y)(R 1a );

Y is selected from —(CH 2 ) r4 (G) r5 (CH 2 ) r6 —Y 1 , wherein Y 1 is selected from —O-E or a structure of formula Y 22 which is optionally substituted,

wherein the substituent is selected from F, Cl, Br, halogen-substituted or unsubstituted C 1-6 alkyl;

G is unsubstituted CH 2 ;

r 4 and r 6 are independently selected from 0, r 5 is selected from 0 or 1, and when r 4 , r 5 and r 6 are all 0, it means the corresponding structure is a single bond of linkage;

E is selected from a structure unit of formula (Ea):

wherein:

the structure unit

is defined as phenyl or pyridyl;

R 8 and R 9 are independently selected from H, F, Cl, Br, halogen-substituted or unsubstituted C 1-6 alkyl;

each of R 1a , R 1b , R 1c , R 2 , and R 3 is independently selected from H, F, Cl, halogen-substituted and

the compound or the pharmaceutically acceptable salt thereof comprises one or more chiral center;

wherein A is selected from a structure unit as shown in formula (A 1 ) or (A 2 ):

wherein:

the structure unit

is phenyl;

formula (A 2 ) is of formula (A 22 ):

n 6a is selected from 0 or 1;

R 4 and R 6 are independently selected from H, F, Cl, Br, halogen-substituted, or unsubstituted C 1-6 alkyl;

R 5 and R 7 are independently selected from optionally substituted 5-6 membered cyclohydrocarbyl or heterocyclic group, while the substituent is selected from F, Cl, Br, CN, halogen-substituted or unsubstituted C 1-6 alkyl wherein the 5-6 membered cyclohydrocarbyl or heterocyclic group are each independently selected from phenyl, pyridyl, furyl, thienyl, thiazolyl, pyrimidinyl, pyrazolyl, 1,2,3-triazolyl or 1,2,5-triazolyl;

n 4 is selected from 0, 1, 2, 3, 4; and

C 1-6 alkyl is selected from methyl, ethyl, propyl, butyl, pentyl, or hexyl.

2. The compound of claim 1 or the pharmaceutically acceptable salt thereof, wherein A is selected from:

3. The compound of claim 1 or the pharmaceutically acceptable salt thereof, wherein Y is selected from —CH 2 —O-E or —O-E, wherein E is defined as in claim 1 .

4. The compound of claim 1 or the pharmaceutically acceptable salt thereof, wherein the structure unit

is defined as pyridyl.

5. The compound of claim 3 or the pharmaceutically acceptable salt thereof, wherein Y is selected from:

6. The compound of claim 1 or the pharmaceutically acceptable salt thereof, wherein R 1a , R 1b , and R 1c are independently selected from H, methyl, or fluoro.

7. The compound of claim 1 or the pharmaceutically acceptable salt thereof, wherein R 2 and R 3 are independently selected from H, methyl or fluoro.

8. The compound of claim 1 or the pharmaceutically acceptable salt thereof, which has any of the following structures:

9. A pharmaceutical composition comprising a therapeutically effective amount of the compound of claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

10. A method for treating insomnia, chronic obstructive pulmonary disease, obstructive sleep apnea, hypersomnia, anxiety, obsessive-compulsive disorder, panic attack, nicotine addiction, or binge eating disorder wherein comprises the following step: administrating treatment effective dose of a compound of claim 1 or a pharmaceutically acceptable salt thereof to the subjects in need.