8-Substituted-6,7,8,9-tetrahydropyrimido [1,2-a] pyrimidin-4-one derivatives.

A compound of formula (III)

• wherein
• p+q=0-3;
• R1 represents a 2, 3 or 4-pyridine ring or a 2, 4 or 5-pyrimidine ring, the rings being optionally substituted by a C1-4 alkyl group, a C1-4 alkoxy group or a halogen atom;
• R3 represents a hydrogen atom or a C1-6 alkyl group;
• R4 represents a phenyl group, a naphthalene ring or a pyridinyl group, the groups and the ring being optionally substituted by 1 to 4 substituents selected from a C1-6 alkyl group, a methylenedioxy group, a halogen atom, a C1-2 perhalogenated alkyl group, a C1-3 halogenated alkyl group, a hydroxyl group, a C1-4 alkoxy group, a nitro, a cyano, an amino, a C1-5 monoalkylamino group or a C2-10 dialkylamino group;
• and
• R5 represents a hydrogen atom, a C1-6 alkyl group or a halogen atom.

A method of treating a disease in a patient, said disease selected from the group consisting of Alzheimer's disease, Parkinson's disease, taupathies, noninsulin dependent diabetes, obesity, manic depressive illness and schizophrenia, comprising administering to said patient a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof:

• wherein:
• X represents two hydrogen atoms, a sulfur atom, an oxygen atom or a C1-2 alkyl group and a hydrogen atom;
• Y represents a bond, a carbonyl group, a methylene group optionally substituted by one or two groups chosen from a C1-6 alkyl group, a hydroxyl group, a C1-4 alkoxy group, a C1-2 perhalogenated alkyl group or an amino group;
• R1 represents a 2, 3 or 4-pyridine ring or a 2, 4 or 5-pyrimidine ring, the rings being optionally substituted by a C1-4 alkyl group, a C1-4 alkoxy group or a halogen atom;
• R2 represents a phenyl group or a naphthalene ring;
• the phenyl group or the naphthalene ring being optionally substituted by 1 to 4 substituents selected from a C1-6 alkyl group, a methylenedioxy group, a halogen atom, a C1-2 perhalogenated alkyl group, a C1-3 halogenated alkyl group, a hydroxyl group, a C1-4 alkoxy group, a nitro, a cyano, an amino, a C1-5 monoalkylamino group, a C2-10 dialkylamino group, a phenyl group, a pyrrolidine ring, a piperidine ring or an azepine ring;
• R3 represents a hydrogen atom or a C1-6 alkyl group;
• R4 represents a phenyl group, a naphthalene ring or a pyridinyl group, the groups and the ring being optionally substituted by 1 to 4 substituents selected from a C1-6 alkyl group, a methylenedioxy group, a halogen atom, a C1-2 perhalogenated alkyl group, a C1-3 halogenated alkyl group, a hydroxyl group, a C1-4 alkoxy group, a nitro, a cyano, an amino, a C1-5 monoalkylamino group or a C2-10 dialkylamino group;
• R5 represents a hydrogen atom, a C1-6 alkyl group or a halogen atom;
• n represents 0 to 3;
• and p+q=0-3.