1-[alkyl], 1-[(heteroaryl)alkyl] and 1-[(aryl)alkyl]-7pyridinyl-imidazo[1,2-alpha]pyrimidin-5(1H)-one derivatives

1. An imidazo[1,2-a]pyrimidone compound represented by formula (I) or a salt thereof, or a hydrate thereof;

wherein:

X represents a bond, an ethenylene group, an ethynylene group, a methylene group optionally substituted by one or two groups selected from a C 1-6 alkyl group, a hydroxy group and a C 1-4 alkoxy group; a carbonyl group, an oxygen atom, a sulfur atom, a sulfonyl group, a sulforide group or a nitrogen atom being optionally substituted by a C 1-6 alkyl group;

R 1 represents a 2, 3 or 4-pyridyl group optionally substituted by a C 1-4 alkyl group, C 1-4 alkoxy group or a halogen atom;

R 2 represents a C 1-6 alkyl group, a C 1-2 perhalogenated alkyl group, a C 1-3 halogenated alkyl group, a benzyl group, a phenyl ring, a naphthyl ring, 5,6,7,8-terahydronaphtyl ring, a pyridyl ring, an indole ring, a pyrrole ring, a thiophene ring, a furan ring or an imidazole ring, the benzyl group and the rings being optionally substituted by 1 to 4 substituents selected from a C 1-6 alkyl group, a phenyl ring, a halogen atom, a C 1-2 perhalogenated alkyl group, a C 1-3 halogenated alkyl group, a hydroxyl group, a C 1-4 alkoxy group, a nitro, a cyano, an amino, a C 1-6 monoalkylamino group or a C 2-10 dialkylamino group;

and n represents 0 to 3.

2. An imidazo[1,2-a]pyrimidone compound or a salt thereof, or a hydrate thereof according to claim 1 , wherein R1 represents an unsubstituted 4-pyridyl group or 3-pyridyl group.

3. An imidazo[1,2-a]pyrimidone compound or a salt thereof, or a hydrate thereof according to claim 1 , wherein R2 represents a trifluorornethyl group, a 2,2,2-trifluoroethyl, a phenyl ring, a naphthyl ring, a 5,6,7,8-telrahydronaplithyl ring or an indole ring, the rings being optionally substituted.

4. An imidazo[1,2-a]pyrimidone compound which is selected from the group consisting of:

1: 1-[2-(phenyl)ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

2: 1-[2-(1H-indol-3-yl)ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

3: 1-[3-(phenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

4: 1-[3-(1H-indol-3-yl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

5: 1-[3-(4-methoxyphenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

6: 1-[2-(phenoxy)ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

7: 1-[3-(2-methoxyphenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

8: 1-[3-(2-chlorophenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

9: 1-[3-(2-methylphenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

10: 1-[2-(phenylthio)ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

11: 1-[3-(2,5-dimethoxyphenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

12: 1-[3-(4-methylphenyl)propyl]7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

13: 1-[3-(4-trifluoromethylphenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

14: 1-[4-(phenyl)butyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

15: 1-[3-(phenyl)propyl]-7-pyridin-3-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

16: 1-(2-phenyl)-2-oxo-ethyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

17: (S)-1-(4,4,4-trifluoro-3-hydroxybutyl)-7-pyridin-4-yIimidazo[1,2-a]pyrimidin-5(1H)-one,

18: 1-(4,4,4-trifluorobut-2-enyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

19: (R)-1-(4,4,4-trifluoro-3-hydroxybutyl)-7-pyridin4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

20: 1-(4,4,4-trifluorobut-1-enyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

21: 1-[2-(2,5-dimethoxyphenyl)ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

22: 1-[3-(2-fluorophenyl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

23: 1-(3-phenyl-3-oxo-propyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

24: 1-[3-(pyridin-3-yl)propyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

25: (S)-1-(4,4,4-trifluoro-butyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

26: 1-[2-(2-methoxyphenyl)ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

27: 1-[2-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphth-2-yl)-2-oxo-ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

28: 1-[2-(4-phenyl-phenyl)-2-oxo-ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

29: 1-[2-(3-methoxyphenyl)-2-oxo-ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

30: 1-[2-(2-naphthyl)-2-oxo-ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

31: 1-[2-(4-methylphenyl)-2-oxo-ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

32: 1-[2-(4-fluorophenyl)-2-oxo-ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

33: 1-[2-(4-chlorophenyl)-2-oxo-ethyl]-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

34: 1-(2-(4-fluorophenyl)-2-hydroxyethyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

35: 1-(2-naphthyl-2-hydroxyethyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one,

36: 1-(2-(1,1,4,4,-tetramethyl-1,2,3,4-tetrahydronaphth-6-yl)-2-hydroxyethyl)-7-pyridin-4-ylimidazo[1,2-a]pyrimidin-5(1H)-one, or a salt thereof, or a hydrate thereof.

5. An imidazo[1,2-a]pyrimidone compound or a salt thereof, or a hydrate thereof according to claim 2 , wherein R2 represents a trifluoromethyl group, a 2,2,2-trifluoroethyl, a phenyl ring, a naphthyl ring, a 5,6,7,8-tetrahydronaphthyl ring or an indole ring, the rings being optionally substituted.

6. A pharmaceutical composition which comprises a compound according to claim 1 together with one or more pharmaceutically acceptable additives.

7. A pharmaceutical composition which comprises a compound according to claim 2 together with one or more pharmaceutically acceptable additives.

8. A pharmaceutical composition which comprises a compound according to claim 3 together with one or more pharmaceutically acceptable additives.

9. A pharmaceutical composition which comprises a compound according to claim 4 together with one or more pharmaceutically acceptable additives.

10. A pharmaceutical composition which comprises a compound according to claim 5 together with one or more pharmaceutically acceptable additives.