The subject of the present invention is compounds of the following formula (I): wherein R 1 and R "1 represent -CH 3； -CH 2 O 2； -CHO； -COOR 10, R 10: H, aklyl； -CONR 11 R 12, R 11, R 12: H, W； at least one of the radicals being different from H； -CH 2 NR 13 R 14, R 13, R 14: H, W, at least one of the radicals being different from H； -COR 15, R 15: alkyl, R 2 and R "2 represent H； -CH3； -CH2OZ； -COR20, R20: alkyl； -COOR21, R21: H, alkyl； -CONR22R23, R22, R23: H, W, at least one of which is different from H； -CH2NR24R25, R24 and R25: H, W, at least one of which is different from H； - C (OH) R 26 R 27, R 26, R 27: alkyl, phenyl, unsubstituted benzyl； R3 and R "3 represent: -OZ； -CH3； -NR31R32, R31 and R32: H, W, at least one of which is different from H； alkylthio； R'3 may additionally be H； R4 and R； "4 represent H； an alkyl； a sugar pattern； -COR40, R40: alkyl； -COOR41, R41: alkyl； -CONR42R43, R42, R43: H, W； -Si (R44) 3 R44: alkyl； Z is H； alkyl； sulfonic, alkylsulphonate, phenylsulphonate or alkylphenylsulphonate group； a -COR 2 group with R 2: alkyl, sugar unit； W represents a hydrocarbon radical C1-C40, linear, branched and / or cyclic, saturated, unsaturated, aromatic or otherwise, optionally substituted； and / or optionally interrupted by one or more heteroatoms and / or groups comprising； n integer varies from 0 to 5； Exclusions of formula (I): * when R4 represents a sugar unit, a (C1-C4) alkylcarbonyl, a mono- or di (C1-C4) alkylaminocarbonyl, then R2 does not represent an alkoxy (C1- C2) carbonyl, hydroxycarbonyl, -CH2OH, R2 also does not represent H when R4 is a sugar； when R4 is H and R1 is -CH3, -CH2OH, then R2 is not H, -CH3, -COOH, -COOCH3. The invention also relates to a composition comprising such compounds and a process for dyeing keratinous fibers implementing it. La présente invention a pour objet des composés de formule (I) suivante : où R et R" représentent -CH ； -CH OZ ；-CHO ； -COOR , R : H, aklyle ； -CONR R , R , R : H,
