Patent ID: 7179306

Claim:
A process for dyeing keratin materials, comprising applying to the keratin materials a composition comprising, in a medium appropriate for dyeing, at least one ninhydrin compound of formula (I): wherein R 1 , R 2 , R 3 and R 4 , which may be identical or different, are chosen from hydrogen atoms; carboxy(C 1-6 alkyl)radicals; (C 1-6 alkyl)carboxy(C 1-6 alkyl) radicals; 6-membered aryloxy radicals; 5-membered heteroaryloxy radicals comprising at least one heteroatom chosen from N, O, S and P; aryl radicals comprising at least 5 members, which may be monocyclic or polycyclic, fused or non-fused, optionally comprising at least one heteroatom chosen from N, O, S and P; wherein the aryloxy, heteroaryloxy, aryl and heteroaryl groups optionally bear at least one substituent chosen from halogen atoms, C 1-9 alkyl radicals, hydroxyl radicals, C 1-6 alkoxy radicals, amino radicals, mono- and di(C 1-6 alkyl)amino radicals, mono- and di(C 1-6 hydroxyalkyl)amino radicals, thio radicals, C 1-6 alkylthio radicals, C 1-6 thioalkyl radicals, (C 1-6 alkyl)carbonyl radicals, hydrogenocarbonyl radicals, hydroxycarbonyl radicals, (C 1-6 alkoxy)carbonyl radicals, nitro radicals, sulphonato radicals, tri(C 1-6 alkyl)ammonio radicals, imidazolyl radicals, pyridinyl radicals, and the corresponding protonated radicals; and two adjacent substituents may together comprise the group —O—CH 2 —O—; with the proviso that at least one of the radicals R 1 , R 2 , R 3 , and R 4 is not a hydrogen atom, or R 1 and R 2 , R 2 and R 3 or R 3 and R 4 are together form the group —O—CH 2 —O—.