3-Substituted-4-pyrimidone derivatives

1. A pyrimidone derivative represented by formula (I) or a salt thereof:

wherein R 1 represents a C 1 -C 12 alkyl group which may be substituted;

R represents any one of groups represented by the following formulas (II) to (V):

wherein R 2 and R 3 independently represent a hydrogen atom or a C 1 -C 8 alkyl group;

R 4 represents a benzene ring which may be substituted, a naphthalene ring which may be substituted, an indan ring which may be substituted, a tetrahydronaphthalene ring which may be substituted, or an optionally substituted heterocyclic ring having 1 to 4 hetero atoms selected from the group consisting of oxygen atom, sulfur atom and nitrogen atom, and having 5 to 10 ring-constituting atoms in total;

R 5 represents a C 1 -C 8 alkyl group which may be substituted, a C 3 -C 8 cycloalkyl group which may be substituted, a benzene ring which may be substituted, a naphthalene ring which may be substituted, an indan ring which may be substituted, a tetrahydronaphthalene ring which may be substituted, or an optionally substituted heterocyclic ring having 1 to 4 hetero atoms selected from the group consisting of oxygen atom, sulfur atom, and nitrogen atom, and having 5 to 10 ring-constituting atoms in total;

R 6 represents a hydrogen atom, a C 1 -C 8 alkyl group which may be substituted, a benzene ring which may be substituted;

or R 5 and R 6 may bind to each other to form together with the carbon to which R 5 and R 6 are attached an optionally substituted spiro carbocyclic ring having 3 to 11 ring-constituting atoms in total;

R 7 and R 8 independently represent a hydrogen atom or a C 1 -C 8 alkyl group, or R 7 and R 8 may combine to each other to form a C 2 -C 6 alkylene group;

R 9 and R 10 represent a C 1 -C 8 alkyl group which may be substituted, a C 3 -C 8 cycloalkyl group which may be substituted, a benzene ring which may be substituted, a naphthalene ring which may be substituted, an optionally substituted heterocyclic ring having 1 to 4 hetero atoms selected from the group consisting of oxygen atom, sulfur atom, and nitrogen atom, and having 5 to 10 ring-constituting atoms in total, or R 9 and R 10 represent —N(R 11 )(R 12 ) wherein R 11 represents a hydrogen atom, a C 1 -C 8 alkyl group; and R 12 represents a C 1 -C 8 alkyl group, a benzene ring which may be substituted, a naphthalene ring which may be substituted, or an optionally substituted heterocyclic ring having 1 to 4 hetero atoms selected from the group consisting of oxygen atom, sulfur atom, and nitrogen atom, and having 5 to 10 ring-constituting atoms in total; and X represents CH 2 , O or NR 13 wherein R 13 represents a hydrogen atom or a C 1 -C 8 alkyl group.

2. The pyrimidone derivative or the salt thereof, according to claim 1 , wherein R 1 is methyl group.

3. The pyrimidone derivative or the salt thereof, according to claim 1 , wherein R is the group represented by formula (II).

4. The pyrimidone derivative or the salt thereof, according to claim 3 , wherein each of R 2 and R 3 is hydrogen atom.

5. A pyrimidone derivative which is selected from the group consisting of:

3-methyl-2-(2-oxo-2-phenylethylamino)-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

3-methyl-2-(2-oxo-2-(3-fluorophenyl)ethylamino)-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

3-methyl-2-(2-oxo-2-(4-fluorophenyl)ethylamino)-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

3-methyl-2-(2-oxo-2-(3-chlorophenyl)ethylamino)-6-pyrimidin-4-yl-3H-pyrimidin-4-one and 3-methyl-2-(2-oxo-2-(3-methylphenyl)ethylamino)-6-pyrimidin-4-yl-3H-pyrimidin-4-one or a salt thereof.

6. The pyrimidone derivative or the salt thereof, according to claim 1 , wherein R is the group represented by formula (III).

7. The pyrimidone derivative or the salt thereof, according to claim 6 , wherein R 6 is hydrogen atom.

8. The pyrimidone derivative or the salt thereof, according to claim 7 , wherein each of R 7 and R 8 is hydrogen atom.

9. The pyrimidone derivative or the salt thereof, according to claim 7 , wherein each of R 7 and R 8 is methyl group.

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

2-[2-(4-Fluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(4-Fluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Fluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2-Fluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Chlorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(3-Chlorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Chlorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2-Chlorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Bromophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(4-Bromophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(3-Bromophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(3-Bromophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Bromophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Methylphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(3-Methylphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Methylphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2-Methylphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Cyanophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(3-Cyanophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(3-Cyanophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Cyanophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(4-Methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(3-Methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(3-Methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one

2-[2-(2-Methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2-Methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Ethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Trifluoromethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(5-Fluoro-2-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Fluoro-2-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(4-Fluoro-2-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2,5-Dimethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,5-Dimethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Chloro-4,5-difluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2-Chloro-4,5-difluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Bromo-4-fluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2,4-Difluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,4-Difluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2,6-Dimethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,6-Dimethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4 -one;

2-[2-(2,4-Dimethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,4-Dimethoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2,6-Dichlorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,6-Dichlorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2,6-Difluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,6-Difluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Chloro-6-fluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2-Chloro-6-fluorophenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Fluoro-3-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(5-Cyano-2-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(5-Cyano-2-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Cyano-2-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(4-Cyano-2-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2,4-Difluoro-6-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,4-Difluoro-6-methoxyphenyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-(Pyrrolidin-1-yl-methyl)phenyl)morpholino-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(4-(Pyrrolidin-1-yl-methyl)phenyl)morpholino-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-( 1-Naphthyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Naphthyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2-Naphthyl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2,3-dihydrobenzofuran-7-yl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

(S)-2-[2-(2,3-dihydrobenzofuran-7-yl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(Benzofuran-2-yl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one; and

(S)-2-[2-(Benzofuran-2-yl)morpholin-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one

or a salt thereof.

11. The pyrimidone derivative or the salt thereof, according to claim 1 , wherein R is the group represented by formula (IV).

12. The pyrimidone derivative or the salt thereof, according to claim 11 , wherein R 9 is a benzene ring which may be substituted.

13. The pyrimidone derivative or the salt thereof, according to claim 11 , wherein X is CH 2 .

14. The pyrimidone derivative or the salt thereof, according to claim 11 , wherein X is O.

15. A pyrimidone derivative which is selected from the group consisting of:

2-[3-(4-Fluorobenzoyl)piperidin-1-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-(3-Benzoylpiperidin-1-yl)-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[3-(2-Methoxybenzoyl)piperidin-1-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[3-(4-Methoxybenzoyl)piperidin-1-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(4-Fluorobenzoyl)morpholine-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-(2-Benzoylmorpholine-4-yl)-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

2-[2-(2-Methoxybenzoyl)morpholine-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one; and

2-[2-(4-Methoxybenzoyl)morpholine-4-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

or a salt thereof.

16. The pyrimidone derivative or the salt thereof, according to claim 1 , wherein R is the group represented by formula (V).

17. The pyrimidone derivative or the salt thereof, according to claim 16 , wherein R 10 is a benzene ring which may be substituted.

18. The pyrimidone derivative or the salt thereof, according to claim 16 , wherein R 10 is a heterocyclic ring having 1 to 4 hetero atoms selected oxygen atom, sulfur atom and nitrogen atom, and having total ring-constituting atoms of 5 to I0 which may be substituted.

19. A pyrimidone derivative which is selected from the group consisting of:

2-[4-(4-Chlorobenzoyl)piperidin-1-yl]-3-methyl-6-pyrimidin-4-yl-3H-pyrimidin-4-one;

or a salt thereof.

20. A medicament composition as an active ingredient a substance selected from the group consisting of the pyrimidone derivative represented by formula (I) and a salt thereof, according to claim 1 .

21. A tau protein kinase 1 inhibitor selected from the group consisting of the pyrimidone derivative represented by formula (I) and a salt thereof, according to claim 1 .

22. A pyrimidone derivative represented by formula (VI) or a salt thereof:

wherein R 1 represents a C 1 -C 12 alkyl group which may be substituted.

23. pyrimidone derivative represented by formula (VII) or a salt thereof:

wherein R 1 represents a C 1 -C 12 alkyl group which may be substituted.