The present invention relates to compounds of formula (I) and (II) below, in which R1 and R"1 are -CH3 -CH2OZ -CHO -COOR10, R10: H, alkyl -CONRn R-12, Ru, R12: H, W, at least one of the radicals being other than H -CH2NR13R14, R13, R14: H, W, at least one of the radicals being other than H -COR15, R15: alkyl, R2 and R"2 are H -CH3 -CH2OZ -COR20, R20: alkyl -COOR21, R21: H, alkyl -CONR22R23, R, R23: H, W, at least one of the two being other than H -CH2NR24R25, R24 and R25: H, W, at least one of the two being other than H - C(OH)R26R27, R26, R27: non-substituted alkyl, phenyl, benzyl R3 and R"3 are: -OZ -CH3 -NR31 R32, R31 and R32: H, W, at least one of the two being other than H alkylthio R"3 also optionally being H R4 and R"4 are H an alkyl a sugar unit -COR40, R40: alkyl -COOR41 R41: alkyl -CONR42R43, R42, R43: H, W -Si(R44)3 R44: alkyl Z is H alkyl a sulphonic, alkyl sulphonate, phenyl sulphonate or alkylphenyl sulphonate group a -CORz group with Rz: alkyl, sugar unit W is a hydrocarbon radical at CrC40, which is straight, branched and/or cyclic, saturated, unsaturated, aromatic or not, optionally substituted and/or optionally interrupted by one or more heteroatoms and/or groups including same n integer varies from 0 to 5. Exclusions from the formula (I): * when R4 is a sugar unit, an alkyl(d-C4)carbonyl, a mono- or di- alkyl(C1-C4)aminocarbonyl, then R2 is not an alkoxy(d-C2)carbonyl, hydroxycarbonyl, -CH2OH, R2 also is not H when R4 is a sugar ** when R4 is H and R-\ is -CH3, -CH2OH, then R2 is not H, -CH3, -COOH or -COOCH3. The invention also relates to a composition including such compounds as well as to a method for dying keratin fibres implementing same.La présente invention a pour objet des composés de formule (I) et (II) suivante où R1 et R"1 représentent -CH3 -CH2OZ-CHO -COOR10, R10 : H, aklyle -CONRn R-12, Ru, R12 : H, W, au moins un des radicaux étant différents de H -CH2NR13R14, R13, R14 :H, W, au moins un des radicaux étant différents de H -CORis, Ris
