Substituted pyridazin-4(1H)-ones as phosphodiesterase 10A inhibitors

1. A compound represented by formula (1),

W 1 -W 2 (1),

wherein:

(i) W 1 is

wherein

ring A d is

(A) C 3-8 cycloalkane,

(B) a tetrahydronaphthalene ring,

(C) a tetrahydropyridine ring optionally substituted by substituent(s) selected from the group consisting of (a) a C 1-6 alkyl group, (b) a C 1-6 alkyl group, (c) a C 1-6 alkyl group substituted by a phenyl group optionally substituted by a C 1-6 alkoxy group, and (d) a pyridyl group substituted by a halogen atom,

(D) a piperidine ring optionally substituted by substituent(s) selected from the group consisting of (a) a naphthyl group, (b) a thiazolyl group, (c) a benzofuranyl group, (d) a dihydrobenzofuranyl group, (e) a tetrahydropyranyl group, (f) a thienyl group substituted by a halogen atom or a C 1-6 alkylcarbonyl group, (g) a methylenedioxyphenyl group substituted by a halogen atom, (h) a benzothiazolyl group optionally substituted by a C 1-6 alkyl group, (i) a C 1-6 alkylcarbonyl group, (j) a C 1-6 alkoxycarbonyl group substituted by a C 1-6 alkyl group, (k) a C 1-6 alkyl group optionally substituted by a phenyl group, (1) a phenylcarbonyl group optionally substituted by a halogen atom, (m) a carbamoyl group mono-substituted by a phenyl group, (n) a pyridyl group optionally substituted by substituent(s) selected from the group consisting of a halogen atom, a cyano group, and a C 1-6 alkyl group substituted by a halogen atom, and (o) a phenyl group optionally substituted by substituent(s) selected from the group consisting of a halogen atom, a C 1-6 alkyl group optionally substituted by a halogen atom, C 1-6 alkoxy optionally substituted by a halogen atom, a cyano group, a C 1-6 alkylcarbonyl group, a C 1-6 alkylsulfonyl group, a sulfur atom substituted by 1-5 halogen atoms, and an amino group di-substituted by a C 1-6 alkyl group, or (E) an azetidine ring substituted by substituent(s) selected from the group consisting of (a) a phenyl group, (b) a phenylcarboxy group, (c) a pyridyl group substituted by a C 1-6 alkyl group substituted by a halogen atom, and (d) a C 1-6 alkyl group di-substituted by a phenyl group, and

R 1d is a hydrogen atom or a C 1-6 alkoxy group; and

W 2 is

wherein

ring B d is a pyrazole ring, and

R 2d is a phenyl group, or

(ii) W 1 is

wherein R 1e is a C 1-6 alkoxy group,

R 3e is

(a) a C 1-6 alkyl group substituted by a halogen atom,

(b) a C 3-7 cycloalkyl group,

(c) a tetrahydropyranyl group,

(d) a piperidyl group,

(e) a tetrahydrofuranyl group,

(f) a pyrrolidyl group,

(g) a morpholinyl group,

(h) a quinolinyl group,

(i) an isoquinolinyl group,

(j) an oxetanyl group substituted by a C 1-6 alkyl group,

(k) a phenyl group optionally substituted by 1 to 3 substituents selected from the group consisting of a C 1-6 alkyl group substituted by a halogen atom, a C 1-6 alkoxy group, a C 1-6 alkoxycarbonyl group, a cyano group, and a phenyl group,

(l) a pyridyl group optionally substituted by 1 to 3 substituents selected from the group consisting of a C 1-6 alkoxycarbonyl group and a C 1-6 alkoxy group substituted by a halogen atom, or

(m) a furyl group substituted by substituent(s) selected from the group consisting of a C 1-6 alkyl group substituted by a halogen atom and a C 1-6 alkoxycarbonyl group, and L e is a C 1-3 alkylene group optionally substituted by an oxo group or a sulfonyl group; and

W 2 is

wherein

ring A e is a pyrazole ring, and

R 2e is a phenyl group,

or a pharmaceutically acceptable salt thereof.

2. A pharmaceutical composition comprising the compound or pharmaceutically acceptable salt according to claim 1 , and a pharmaceutically acceptable carrier.

3. A method for treating schizophrenia in a mammal, which comprises administering to said mammal an effective amount of the compound according to claim 1 , or a pharmaceutically acceptable salt thereof.

4. A compound of 1-(1-Benzyl-1,2,3,6-tetrahydropyridin-4-yl)-5-methoxy-3-(1-phenyl-1H-pyrazol-5-yl)pyridazin-4(1H)-one, or a pharmaceutically acceptable salt thereof.

5. A pharmaceutical composition comprising the compound or pharmaceutically acceptable salt according to claim 4 , and a pharmaceutically acceptable carrier.

6. A method for treating schizophrenia in a mammal, which comprises administering to said mammal an effective amount of the compound according to claim 4 , or a pharmaceutically acceptable salt thereof.

7. A compound of 2-{4-[5-Methoxy-4-oxo-3-(1-phenyl-1H-pyrazol-5-yl)pyridazin-1 (4H)-yl]piperidin-1-yl}pyridine-3-carbonitrile, or a pharmaceutically acceptable salt thereof.

8. A pharmaceutical composition comprising the compound or pharmaceutically acceptable salt according to claim 7 , and a pharmaceutically acceptable carrier.

9. A method for treating schizophrenia in a mammal, which comprises administering to said mammal an effective amount of the compound according to claim 7 , or a pharmaceutically acceptable salt thereof.