Process for dyeing keratinous fibres with indole derivatives associated with nitrite, and compositions therefor.

摘要

The invention relates to a process for dyeing keratinous fibres, comprising the application of a composition (A) containing an indole derivative corresponding to the formula (I): <IMAGE> in which R1 represents hydrogen, alkyl or -SiR9R10R11; R2 and R3 represent hydrogen, alkyl, carboxyl, alkoxycarbonyl or -COOSiR9R10R11; R4 and R5 represent hydrogen, alkyl, formyl, acyl, alkenoyl, -SiR9R10R11, -P(O)(OR6)2, R6OSO2-, or alternatively R4 and R5, together with the oxygen atoms to which they are attached, form a ring; R6 and R7 represent hydrogen or alkyl, R8 representing an alkoxy or mono- or dialkylamino, R9, R10 and R11 representing alkyl, at least one of the radicals R1 to R5 being other than hydrogen; and the salts, the application of the composition (A) being followed by the application of the composition (B) consisting of an aqueous composition possessing an acid pH, the composition (A) or (B) containing at least one nitrite.