Pyrimidin-4-one compounds

A compound of formula (I):

• wherein:
• R1, R2, R3 and R4, which may be the same or different, each represent a hydrogen atom, a halogen atom or a group selected from linear or branched (C1-C6)alkyl, linear or branched (C1-C6)alkoxy, linear or branched (C1-C6)polyhaloalkyl, hydroxy, cyano, nitro and amino,
• or R1 with R2, R2 with R3, or R3 with R4, together with the carbon atoms carrying them, form an optionally substituted benzene ring or an optionally substituted heteroaromatic ring,
• X represents an oxygen atom or a methylene group,
• A represents a linear or branched (C1-C6)alkylene chain,
• represents an unsaturated nitrogen-containing heterocycle optionally substituted by one or two identical or different substituents selected from halogen atoms and linear or branched (C1-C6)alkyl, hydroxy, linear or branched (C1-C6)alkoxy, linear or branched (C1-C6)polyhaloalkyl, cyano, nitro, amino, optionally substituted phenyl, optionally substituted thienyl, optionally substituted furyl and optionally substituted pyrrolyl groups,
• and R5 represents a linear or branched (C1-C6)alkyl group,
• its enantiomers and diastereoisomers, and addition salts thereof with a pharmaceutically acceptable acid or base,
• it being understood that:
• the term “(C1-C6)alkyl” denotes a saturated hydrocarbon chain containing from one to six carbon atoms,
• the term “(C1-C6)alkoxy” denotes a (C1-C6)alkyl-oxy group containing from one to six carbon atoms,
• the term “(C1-C6)alkylene” denotes a bivalent hydrocarbon chain containing from one to six carbon atoms,
• the term (C1-C6)polyhaloalkyl denotes a carbon chain containing from one to six carbon atoms and from 1 to 9 halogen atoms,
• the term “heteroaromatic ring” denotes a 5- or 6-membered aromatic ring containing one, two or three hetero atoms selected from oxygen, nitrogen and sulphur,
• the term “unsaturated nitrogen-containing heterocycle” denotes a 5- to 7-membered unsaturated ring having one, two or three unsaturations and containing one, two or three hetero atoms, one of those hetero atoms being the nitrogen atom and the additional hetero atom(s) optionally present being selected from oxygen, nitrogen and sulphur atoms,
• the term “optionally substituted” applied to the expressions “benzene ring”, “heteroaromatic ring”, “phenyl”, “thienyl”, “furyl” or pyrrolyl”, and indicates that those groups are optionally substituted by one or two identical or different substituents selected from halogen atoms and linear or branched (C1-C6)alkyl, hydroxy, linear or branched (C1-C6)alkoxy, linear or branched (C1-C6)polyhaloalkyl, cyano, nitro and amino groups.