Derivatives of 2H-[1,2,4]triazine-3,5-dione and of H-pyrimidine-2,4-dione of formula I wherein: - W represents nitrogen or CH - R 1 and R 2 represent: • a hydrogen, provided that R 1 and R 2 are not simultaneously a hydrogen, or a linear or branched C 1 -C 7 alkyl or alkenyl radical or, • a C 1 -C 3 alkyl radical substituted with groups such as: - trifluoromethyle, nitrile, hydroxy, C 1 -C 3 alkoxy, C 3 -C 6 alkoxyalkoxy, indolyl, thiophenyl, oxothiophenyl, C 1 -C 3 N-alkyl or N-dialkylcarbamoyle groups or, - phenyl or aroyl or benzyloxy or N-arylcarbamoyl groups for which the phenyl ring is optionally substituted with one or more groups such as linear or branched C 1 -C 4 alkyl, nitro groups, halogen atoms, • a phenyl or pyridyl or naphthyl or thiophenyl group optionally substituted with one or more groups such as halogen atoms, nitro, nitrile, trifluoromethyl, vinyl, methylsulfanyl, linear or branched C 1 -C 4 alkyl, linear or branched C 1 -C 3 alkoxy, phenyl, C 1 -C 3 N-mono- or di-alkylcarbamoyl, C 1 -C 4 alkylcarboxamido groups, • a C 5 -C 6 2-oxocycloalkyl radical optionally fused with a phenyl group, - m,n are equal to 1 - V represents CH 2 - X-Y represents -N-(C=O)-, - -CH-CH 2 -, -CH-O-, -CH-(C=O)-, - Z represents a phenyl group substituted with one or more trifluoromethyl groups, halogen atoms, linear or branched C 1 -C 4 alkyl, linear or branched C 1 -C 3 alkoxy groups. - W represents nitrogen or CH - R 1 and R 2 represent: • a hydrogen, provided that R 1 and R 2 are not simultaneously a hydrogen, or a linear or branched C 1 -C 7 alkyl or alkenyl radical or, • a C 1 -C 3 alkyl radical substituted with groups such as: - trifluoromethyle, nitrile, hydroxy, C 1 -C 3 alkoxy, C 3 -C 6 alkoxyalkoxy, indolyl, thiophenyl, oxothiophenyl, C 1 -C 3 N-alkyl or N-dialkylcarbamoyle groups or, - phenyl or aroyl or benzyloxy or N-arylcarbamoyl groups for which the phenyl ring is optionally substituted with one or more groups such as linear or branched C 1 -C 4 alkyl, nitro groups, halogen atoms, • a phenyl or pyridyl or naphthyl or thiophenyl group optionally substituted with one or more groups such as halogen atoms, nitro, nitrile, trifluoromethyl, vinyl, methylsulfanyl, linear or branched C 1 -C 4 alkyl, linear or branched C 1 -C 3 alkoxy, phenyl, C 1 -C 3 N-mono- or di-alkylcarbamoyl, C 1 -C 4 alkylcarboxamido groups, • a C 5 -C 6 2-oxocycloalkyl radical optionally fused with a phenyl group, • a hydrogen, provided that R 1 and R 2 are not simultaneously a hydrogen, or a linear or branched C 1 -C 7 alkyl or alkenyl radical or, • a C 1 -C 3 alkyl radical substituted with groups such as: - trifluoromethyle, nitrile, hydroxy, C 1 -C 3 alkoxy, C 3 -C 6 alkoxyalkoxy, indolyl, thiophenyl, oxothiophenyl, C 1 -C 3 N-alkyl or N-dialkylcarbamoyle groups or, - phenyl or aroyl or benzyloxy or N-arylcarbamoyl groups for which the phenyl ring is optionally substituted with one or more groups such as linear or branched C 1 -C 4 alkyl, nitro groups, halogen atoms, - trifluoromethyle, nitrile, hydroxy, C 1 -C 3 alkoxy, C 3 -C 6 alkoxyalkoxy, indolyl, thiophenyl, oxothiophenyl, C 1 -C 3 N-alkyl or N-dialkylcarbamoyle groups or, - phenyl or aroyl or benzyloxy or N-arylcarbamoyl groups for which the phenyl ring is optionally substituted with one or more groups such as linear or branched C 1 -C 4 alkyl, nitro groups, halogen atoms, • a phenyl or pyridyl or naphthyl or thiophenyl group optionally substituted with one or more groups such as halogen atoms, nitro, nitrile, trifluoromethyl, vinyl, methylsulfanyl, linear or branched C 1 -C 4 alkyl, linear or branched C 1 -C 3 alkoxy, phenyl, C 1 -C 3 N-mono- or di-alkylcarbamoyl, C 1 -C 4 alkylcarboxamido groups, • a C 5 -C 6 2-oxocycloalkyl radical optionally fused with a phenyl group, - m,n are equal to 1 - V represents CH 2 - X-Y represents -N-(C=O)-, - -CH-CH 2 -, -CH-O-, -CH-(C=O)-, - Z represents a phenyl group substituted with one or more trifluoromethyl groups, halogen atoms, linear or branched C 1 -C 4 alkyl, linear or branched C 1 -C 3 alkoxy groups.