Substituted bicyclic pyrimidone derivatives

A compound of formula (I) or a salt thereof:

• wherein:
• Y represents two hydrogen atoms, a sulfur atom, an oxygen atom or a C1-2 alkyl group and a hydrogen atom;
• Z represents a bond, an oxygen atom, a nitrogen atom substituted by a hydrogen atom or a C1-3 alkyl group, a sulfur atom, a methylene group optionally substituted by one or two groups chosen from a C1-6 alkyl group, a hydroxyl group, a C1-6 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 ring being optionally substituted by a C1-6 alkyl group, a C1-6 alkoxy group or a halogen atom;
• R2 represents a benzene ring or a naphthalene ring;
• the rings being optionally substituted by 1 to 4 substituents selected from a C1-6 alkyl group, C3-7 cycloalkyl group, a C3-7 cycloalkyl-C1-6 alkyl group, a halogen atom, a C1-2 perhalogenated alkyl group, a C1-3 halogenated alkyl group, a hydroxyl group, a C1-6 alkoxy group optionally substituted by a C3-5 cycloalkyl group, a C1-2 perhalogenated alkoxy group, a C1-6 alkylsulfonyl group, a nitro, a cyano, an amino, a C1-6 monoalkylamino group, a C2-12 dialkylamino group, an acetoxy group or an aminosulfonyl group;
• R3 represents a hydrogen atom, a C1-6 alkyl group or a halogen atom;
• R4 represents a hydrogen atom or a C1-6 alkyl group;
• R5 represents a hydrogen atom, a C1-6 alkyl group optionally substituted by 1 to 4 substituents selected from a halogen atom, a phenyl group, a hydroxyl group or a C1-6 alkoxy group;
• R6 represents a hydrogen atom, a C1-6 alkyl group or a halogen atom;
• R7 represents a hydrogen atom or a C1-6 alkyl group;
• and
• n represents 0 to 3;
• m represents 0 to 1;
• o represents 0 to 2.