Patent ID: 7303588

Claim:
A composition for dyeing a keratinous fiber comprising: a) at least one oxidation base or direct dye or a mixture thereof; b) at least one compound of formula (I) R—N—(CH(R′)CO 2 X) 2 (I) wherein R represents a hydrogen atom or a CH(CO 2 X)—(CH 2 ) 2 CO 2 X, CH 2 —CH 2 —OH; CH(CH 3 )—CO 2 X or (CH 2 ) 2 —N(COR″)—CH 2 —CO 2 X group; R″ represents a linear or branched alkyl group containing from 1 to 30 carbon atoms or a cyclic group containing from 3 to 30 carbon atoms; R′ represents either a CH 2 CO 2 X group when R is a hydrogen atom or a hydrogen atom when R is other than a hydrogen atom; and X represents a hydrogen atom or a monovalent or divalent cation chosen from an alkali metal, alkaline-earth metal, transition metal, organic amine or ammonium ion, c) a suitable medium.