NOVEL AZOMETHINE DIRECT DYES BEARING AT LEAST ONE CATIONIC CHARGE, COSMETIC COMPOSITION COMPRISING AT LEAST ONE SUCH DYE, IMPLEMENTATION PROCESS THEREFOR AND USE THEREOF

Abstract

The present invention relates to novel cationic azomethine direct dyes of formula (I) and the leuco forms thereof of formula (II), and also to the use thereof for dyeing keratin fibres, in particular human keratin fibres such as the hair: (I) (II) in which formula (I) or (II) X.sub.1, X.sub.2, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, n and n are as defined in the description. The compounds of formula (I) according to the invention can give powerful, chromatic and sparingly selective colourings with good colour build-up, which are resistant to the various attacking factors to which keratin fibres may be subjected, such as inclement weather, light, washing and perspiration.

##STR00001##

Claims

1. Compound chosen from those of formulae (I) and (II) below, organic or mineral acid or base addition salts thereof, tautomeric forms, optical isomers or geometrical isomers thereof and/or solvates thereof: ##STR00034## in which formula (I) or (II): n and n, which may be identical or different, represent an integer equal to 0, 1, 2, 3 or 4; preferably, n and n represent 0; R.sub.1 and R.sub.2, which may be identical or different, represent: a halogen atom, a C.sub.1-C.sub.6 alkyl radical, a (C.sub.1-C.sub.6)alkyl radical substituted with one or more radicals chosen from the following radicals: i) hydroxyl, ii) amino NH.sub.2, iii) (C.sub.1-C.sub.6)alkylamino, and iv) di(C.sub.1-C.sub.6)alkylamino, a (C.sub.1-C.sub.6)alkoxy radical, and a (C.sub.1-C.sub.6)alkoxy radical substituted with one or more radicals chosen from the following radicals: i) hydroxyl, ii) amino, iii) (C.sub.1-C.sub.6)alkylamino, and iv) di(C.sub.1-C.sub.6)alkylamino, X.sub.1 and X.sub.2, which may be identical or different, represent: a hydrogen atom, a sulfonic radical SO.sub.3H or sulfonate radical SO.sub.3, a carboxyl radical CO.sub.2H, a carboxylate radical COO.sup., a C.sub.1-C.sub.4 alkoxycarbonyl radical, a carbamide radical CO.sub.2NH.sub.2, an aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, which is optionally substituted, especially with one or more identical or different radicals chosen from C.sub.1-C.sub.4 alkyl and C.sub.1-C.sub.4 hydroxyalkyl; an aromatic or non-aromatic, 5- to 6-membered non-cationic heterocycle, substituted with: an ammonium radical N.sup.+RRR with R, R and R, which may be identical or different, representing a (C.sub.1-C.sub.4)alkyl group optionally substituted with one or more hydroxyl groups, such as methyl, ethyl, propyl or 2-hydroxyethyl, and/or an aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, which is optionally substituted, especially with one or more identical or different radicals chosen from C.sub.1-C.sub.4 alkyl and C.sub.1-C.sub.4 hydroxyalkyl, and/or a hydroxyl, amino, C.sub.1-C.sub.4 alkylamino, di(C.sub.1-C.sub.4)alkylamino, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 hydroxyalkyl radical; an ammonium radical N.sup.+RRR, with R, R and R which may be identical or different, representing a (C.sub.1-C.sub.4)alkyl group optionally substituted with one or more hydroxyl groups, such as methyl, ethyl, propyl or 2-hydroxyethyl, and preferably R, R and R, which may be identical or different, represent a C.sub.1-C.sub.4 alkyl group such as methyl; or a radical WR.sub.8, in which: W represents: an oxygen or sulfur atom, a divalent group N(R.sub.9); or a linear or branched, saturated or unsaturated, preferably saturated, divalent hydrocarbon-based chain, comprising from 1 to 14 carbon atoms, said hydrocarbon-based chain being: optionally substituted with one or more radicals, which may be identical or different, chosen from the following radicals: i) hydroxyl, ii) C.sub.1-C.sub.4 alkoxy, iii) amino NH.sub.2, iv) mono- and/or (di)(C.sub.1-C.sub.6)(alkyl)amino, v) ammoniums N.sup.+RRR with R, R and R as defined previously, vi) aromatic or non-aromatic, optionally substituted, 5- to 10-membered cationic heterocycles, preferably a 5- or 6-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, vii) aromatic or non-aromatic, 5- or 6-membered non-cationic heterocycles, substituted with one or more radicals, which may be identical or different, chosen from the following radicals: a) ammonium N.sup.+RRR with R, R and R as defined previously, b) aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, optionally substituted especially with one or more identical or different radicals chosen from C.sub.1-C.sub.4 alkyl; preferably, the cationic heterocycle is a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and c) a hydroxyl, amino, C.sub.1-C.sub.4 alkylamino, di(C.sub.1-C.sub.4)alkylamino, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 hydroxyalkyl radical; and/or optionally interrupted and/or optionally terminating with one or more divalent heteroatoms or groups, which may be identical or different, chosen from: O, S, N(R.sub.10), S(O), S(O).sub.2 and C(X) with X representing an oxygen or sulfur atom or NR.sub.10 and R.sub.10 representing a hydrogen atom or a (C.sub.1-C.sub.6)alkyl group, and combinations thereof; preferably optionally interrupted and/or optionally terminating with: O, NH, OC(O), C(O)O, C(O)N(H), N(H)C(O), N(H)C(O)N(H), OC(O)N(H), N(H)C(O)O or N(H)C(NH)NH; R.sub.8 and R.sub.9, which may be identical or different, represent: a hydrogen atom, a linear or branched C.sub.1-C.sub.14, in particular C.sub.1-C.sub.8 and preferably C.sub.1-C.sub.6 alkyl group, said alkyl group being: optionally interrupted with one or more heteroatoms or groups, which may be identical or different, such as O, S, N(R.sub.10), S(O), S(O).sub.2 and C(X) with X and R.sub.10 as defined previously, or combinations thereof; and/or optionally substituted with one or more radicals, which may be identical or different, chosen from: i) hydroxyl, ii) C.sub.1-C.sub.4 alkoxy, iii) amino NH.sub.2, iv) mono- and/or (di)(C.sub.1-C.sub.6)(alkyl)amino, v) ammoniums N.sup.+RRR with R, R and R as defined previously, vi) aromatic or non-aromatic, optionally substituted, 5- to 10-membered cationic heterocycles, preferably a 5- or 6-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, vii) aromatic or non-aromatic, 5- or 6-membered non-cationic heterocycles, substituted with one or more radicals, which may be identical or different, chosen from the following radicals: a) ammonium N.sup.+RRR with R, R and R as defined previously, b) aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, optionally substituted especially with one or more identical or different radicals chosen from C.sub.1-C.sub.4 alkyl; preferably, the cationic heterocycle is a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and c) a hydroxyl, amino, C.sub.1-C.sub.4 alkylamino di(C.sub.1-C.sub.4)alkylamino, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 hydroxyalkyl radical; R.sub.3 and R.sub.4, which may be identical or different, representing: a hydrogen atom, a (C.sub.1-C.sub.6)alkyl radical optionally substituted with one or more radicals chosen from i) hydroxyl, ii) (C.sub.1-C.sub.4)alkoxy, iii) amino, iv) (C.sub.1-C.sub.6)alkylamino and v) di(C.sub.1-C.sub.6)alkylamino; R.sub.5 and R.sub.6, which may be identical or different, represent an atom or group chosen from: a hydrogen atom, a halogen atom, a C.sub.1-C.sub.6 alkyl radical, a (C.sub.1-C.sub.6)alkyl radical substituted with one or more radicals chosen from the following radicals: i) hydroxyl, ii) amino NH.sub.2, iii) (C.sub.1-C.sub.6)alkylamino, and iv) di(C.sub.1-C.sub.6)alkylamino, a (C.sub.1-C.sub.6)alkoxy radical, and a (C.sub.1-C.sub.6)alkoxy radical substituted with one or more radicals chosen from the following radicals: i) hydroxyl, ii) amino, iii) (C.sub.1-C.sub.6)alkylamino, and iv) di(C.sub.1-C.sub.6)alkylamino, it being understood that: X.sub.1 and/or X.sub.2 comprise at least one permanent cationic charge, and the compound of formula (I) or (II) optionally comprises one or more anions An.sup. and optionally one or more cations M.sup.+ to ensure the electrical neutrality of the molecule; with: An.sup. denotes an anion, preferably chosen from bromide, chloride, methylsulfate and toluenesulfonate ions or a mixture of these ions; M.sup.+ represents a cation, preferably chosen from sodium, potassium, magnesium, calcium and ammonium.

2. Compound of formula (I) or (II) according to claim 1, characterized in that R.sub.3 and R.sub.4 represent a hydrogen atom.

3. Compound of formula (I) or (II) according to claim 1, characterized in that R.sub.5 and R.sub.6 represent a hydrogen atom.

4. Compound of formula (I) or (II) according to claim 1, characterized in that n and n represent an integer equal to 0.

5. Compound of formula (I) or (II) according to claim 1, characterized in that X.sub.1 and X.sub.2, which may be identical or different, represent: a radical OR.sub.8; a radical SR.sub.8; a radical NR.sub.8R.sup.9; a linear or branched C.sub.1-C.sub.14, in particular C.sub.1-C.sub.8 and preferably C.sub.1-C.sub.6 alkyl radical, said alkyl radical being: optionally interrupted with one or more heteroatoms or groups, which may be identical or different, chosen from O, S, N(R.sub.10), S(O), S(O).sub.2, and C(X) with X representing an oxygen or sulfur atom or NR.sub.10 with R.sub.10 as defined in claim 1, or combinations thereof preferably chosen from: OC(O), C(O)O, C(O)N(H), N(H)C(O), N(H)C(O)N(H), OC(O)N(H), N(H)C(O)O, N(H)C(NH)NH; and/or optionally substituted with one or more radicals, which may be identical or different, chosen from the following radicals: i) hydroxyl, ii) C.sub.1-C.sub.4 alkoxy, iii) amino NH.sub.2, iv) mono- and/or di(C.sub.1-C.sub.6)alkylamino, v) ammoniums N.sup.+RRR, An.sup. with R, R and R as defined in claim 1, vi) optionally substituted, aromatic or non-aromatic, 5- to 10-membered cationic heterocycles, preferably a 5- or 6-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and vii) aromatic or non-aromatic, 5- or 6-membered non-cationic heterocycles, substituted with one or more radicals, which may be identical or different, chosen from the following radicals: ammoniums N.sup.+RRR with R, R and R as defined previously, and/or optionally substituted, aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, preferably a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium; a hydroxyl, amino, C.sub.1-C.sub.4 alkylamino, di(C.sub.1-C.sub.4)alkylamino, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 hydroxyalkyl radical. a linear or branched C.sub.1-C.sub.14, in particular C.sub.1-C.sub.8 and preferably C.sub.1-C.sub.6 alkoxy radical, said alkoxy radical being: optionally interrupted with one or more heteroatoms or groups, which may be identical or different, chosen from O, S, N(R.sub.10), S(O), S(O).sub.2 and C(X) with X and R.sub.10 as defined previously, or combinations thereof preferably chosen from: OC(O), C(O)O, C(O)N(H), N(H)C(O), N(H)C(O)N(H), OC(O)N(H), N(H)C(O)O, N(H)C(NH)NH; and/or optionally substituted with one or more radicals, which may be identical or different, chosen from the following radicals: i) hydroxyl, ii) C.sub.1-C.sub.4 alkoxy, iii) amino NH.sub.2, iv) mono- and/or di(C.sub.1-C.sub.6)alkylamino, v) ammoniums N.sup.+RRR with R, R and R as defined previously, vi) optionally substituted, aromatic or non-aromatic, 5- to 10-membered cationic heterocycles, preferably a 5- or 6-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and vii) aromatic or non-aromatic, 5- or 6-membered non-cationic heterocycles, substituted with one or more radicals, which may be identical or different, chosen from the following radicals: ammoniums N.sup.+RRR with R, R and R as defined previously, and/or optionally substituted, aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, preferably a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium; a hydroxyl, amino, C.sub.1-C.sub.4 alkylamino, di(C.sub.1-C.sub.4)alkylamino, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 hydroxyalkyl radical. with R.sub.8 and R.sub.9, which may be identical or different, represent an atom or group chosen from: a hydrogen atom, a (C.sub.1-C.sub.14)alkyl radical, optionally interrupted with one or more heteroatoms or groups, which may be identical or different, chosen from O, S, N(H), N(R.sub.10) with R.sub.10 as defined previously, S(O), S(O).sub.2, and C(X) with X representing an oxygen or sulfur atom or NR.sub.10 with R.sub.10 as defined previously, or combinations thereof preferably chosen from: OC(O), C(O)O, C(O)N(H), N(H)C(O), N(H)C(O)N(H), OC(O)N(H), N(H)C(O)O, N(H)C(NH)NH; and/or optionally substituted with one or more radicals, which may be identical or different, chosen from the following radicals: i) hydroxyl, ii) C.sub.1-C.sub.4 alkoxy, iii) amino NH.sub.2, iv) mono- and/or di(C.sub.1-C.sub.6)alkylamino, v) ammoniums N.sup.+RRR with R, R and R as defined previously, vi) optionally substituted, aromatic or non-aromatic, 5- to 10-membered cationic heterocycles, preferably a 5- or 6-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and vii) aromatic or non-aromatic, 5- or 6-membered non-cationic heterocycles, substituted with one or more radicals, which may be identical or different, chosen from the following radicals: ammoniums N.sup.+RRR with R, R and R as defined previously, optionally substituted, aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, preferably a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium; and a hydroxyl, amino, C.sub.1-C.sub.4 alkylamino, di(C.sub.1-C.sub.4)alkylamino, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 hydroxyalkyl radical.

6. Compound of formula (I) or (II) according to claim 1, characterized in that: X.sub.1 and X.sub.2, which may be identical or different, represent a radical NR.sub.8R.sub.9; in which R.sub.8 and R.sub.9, which may be identical or different, represent an atom or group chosen from: a hydrogen atom, a (C.sub.1-C.sub.8)alkyl radical, optionally interrupted with one or more heteroatoms or groups, which may be identical or different, chosen from O, S, N(H), N(R.sub.10) with R.sub.10 as defined previously, S(O), S(O).sub.2, and C(X) with X representing an oxygen or sulfur atom or NR.sub.10 with R.sub.10 as defined previously, or combinations thereof preferably chosen from: OC(O), C(O)O, C(O)N(H), N(H)C(O), N(H)C(O)N(H), OC(O)N(H), N(H)C(O)O, N(H)C(NH)NH; and/or optionally substituted with one or more radicals, which may be identical or different, chosen from the following radicals: i) hydroxyl, ii) C.sub.1-C.sub.4 alkoxy, iii) amino NH.sub.2, iv) mono- and/or di(C.sub.1-C.sub.4)alkylamino, v) ammoniums N.sup.+RRR with R, R and R as defined in claim 1, vi) optionally substituted, aromatic or non-aromatic, 5- to 10-membered cationic heterocycles, preferably a 5- or 6-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and vii) aromatic or non-aromatic, 5- or 6-membered non-cationic heterocycles, substituted with one or more radicals, which may be identical or different, chosen from the following radicals: ammoniums N.sup.+RRR with R, R and R as defined previously, optionally substituted, aromatic or non-aromatic, 5- to 6-membered cationic heterocycle, preferably a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium; and a hydroxyl, amino, C.sub.1-C.sub.4 alkylamino, di(C.sub.1-C.sub.4)alkylamino, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 hydroxyalkyl radical. n and n represent an integer equal to 0; R.sub.3 and R.sub.4, which may be identical or different, represent a hydrogen atom, a (C.sub.1-C.sub.6)alkyl radical, or a (C.sub.1-C.sub.6)alkyl radical substituted with one or more radicals chosen from hydroxyl and/or C.sub.1-C.sub.4 alkoxy; preferentially R.sub.3 and R.sub.4 represent a hydrogen atom; R.sub.5 and R.sub.6 represent a hydrogen atom; it being understood that: X.sub.1 and/or X.sub.2 comprise at least one permanent cationic charge, and the compound of formula (I) or (II) comprises one or more anions An.sup. to ensure the electrical neutrality of the molecule; An.sup. is an anion as defined previously, preferably chosen from bromide, chloride, methyl sulfate and toluene sulfonate ions or a mixture of these ions; more preferentially, An.sup. is a halide and even more preferentially a chloride.

7. Compound of formula (I) or (II) according to claim 1, characterized in that X.sub.1 and X.sub.2, which may be identical or different, represent a radical OR.sub.8 or a radical NR.sub.8R.sub.9, in which R.sub.8 and R.sub.9, which may be identical or different, represent an atom or group chosen from: a hydrogen atom, a (C.sub.1-C.sub.8)alkyl radical, optionally interrupted with one or more heteroatoms or groups, which may be identical or different, chosen from O, S, N(H), N(R.sub.10) with R.sub.10 as defined previously, S(O), S(O).sub.2, and C(X) with X representing an oxygen or sulfur atom or NR.sub.10 with R.sub.10 as defined previously, or combinations thereof preferably chosen from: OC(O), C(O)O, C(O)N(H), N(H)C(O), N(H)C(O)N(H), OC(O)N(H), N(H)C(O)O, N(H)C(NH)NH; and/or optionally substituted with one or more radicals, which may be identical or different, chosen from: hydroxyl radicals; aromatic or non-aromatic, 5- to 10-membered cationic heterocycles, said cationic heterocycles being optionally substituted, preferably an aromatic or non-aromatic, 5- or 6-membered cationic heterocycle, optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as imidazoliums, piperaziniums, pyrrolidiniums, morpholiniums and piperidiniums, preferably pyrrolidiniums and piperidiniums; ammoniums N.sup.+RRR, An.sup. with R, R and R as defined previously, such as trimethylammonium; and aromatic or non-aromatic, 5- or 6-membered non-cationic heterocycles, substituted with one or more radicals, which may be identical or different, chosen especially from ammonium radicals N.sup.+RRR with R, R and R as defined previously, and/or with an aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, said cationic heterocycle being optionally substituted, in particular optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups.

8. Compound of formula (I) or (II) according to claim 1, characterized in that X.sub.1 and X.sub.2 are different, preferably represent a radical NR.sub.8R.sub.9 in which R.sub.8 and R.sub.9, which may be identical or different, represent an atom or group chosen from a (C.sub.1-C.sub.8)alkyl radical, optionally substituted with one or more radicals, which may be identical or different, chosen from the following radicals: i) hydroxyl, ii) ammoniums N.sup.+RRR with R, R and R as defined previously, iii) aromatic or non-aromatic, 5- to 10-membered cationic heterocycles, preferably a 5-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and iv) non-aromatic, 5-membered non-cationic heterocycles, substituted with one radical, chosen from the following radicals: ammoniums N.sup.+RRR with R, R and R as defined previously, optionally substituted, aromatic or non-aromatic, 5- to 6-membered cationic heterocycle, preferably a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium; and n and n represent an integer equal to 0; it being understood that: X.sub.1 and/or X.sub.2 comprise at least one permanent cationic charge, and the compound of formula (I) or (II) comprises one or more anions An.sup. to ensure the electrical neutrality of the molecule.

9. Compound of formula (I) or (II) according to claim 1, characterized in that X.sub.1 and X.sub.2 are identical, preferably represent a radical NR.sub.8R.sub.9 in which R.sub.8 and R.sub.9, which may be identical or different, represent an atom or group chosen from a (C.sub.1-C.sub.8)alkyl radical, optionally substituted with one or more radicals, which may be identical or different, chosen from the following radicals: i) hydroxyl, ii) ammoniums N.sup.+RRR with R, R and R as defined previously, iii) aromatic or non-aromatic, 5- to 10-membered cationic heterocycles, preferably a 5-membered cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium, and iv) non-aromatic, 5-membered non-cationic heterocycles, substituted with one radical, chosen from the following radicals: ammoniums N.sup.+RRR with R, R and R as defined previously, optionally substituted, aromatic or non-aromatic, 5- to 6-membered cationic heterocycle, preferably a cationic heteroaryl optionally substituted with one or more (C.sub.1-C.sub.4)alkyl groups, such as (C.sub.1-C.sub.4)(alkyl)imidazolium; and n and n represent an integer equal to 0; it being understood that: X.sub.1 and/or X.sub.2 comprise at least one permanent cationic charge, and the compound of formula (I) or (II) comprises one or more anions An.sup. to ensure the electrical neutrality of the molecule.

10. Compound of formula (I) or (II) claim 1, characterized in that said cationic heterocycle(s) are chosen from imidazoliums, piperaziniums, pyrrolidiniums, morpholiniums and piperidiniums; optionally substituted with one or more radicals, which may be identical or different, chosen from (hydroxy)(C.sub.1-C.sub.4)alkyl radicals.

11. Compound of formula (I) or (II) according to claim 1, characterized in that said non-cationic heterocycle(s) are 5- or 6-membered and are preferably chosen from piperidines, piperazines, pyrrolidines, morpholines, thiazoles, imidazoles and pyridines, more preferentially chosen from piperidines, piperazines, pyrrolidines, morpholines and imidazoles, the 5- or 6-membered non-cationic heterocycles possibly being substituted especially with: an ammonium radical N.sup.+RRR, An with R, R and R, which may be identical or different, representing a (C.sub.1-C.sub.4)alkyl group optionally substituted with one or more hydroxyl groups, such as methyl, ethyl, propyl or 2-hydroxyethyl, and, more preferentially, the radical N.sup.+RRR denotes a trimethylammonium radical, and/or an aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, which is optionally substituted, especially with one or more identical or different radicals chosen from (hydroxy)(C.sub.1-C.sub.4)alkyl radicals; preferably, said non-cationic heterocycle(s) are 5- or 6-membered and are pyrrolidines substituted with: an ammonium radical N.sup.+RRR with R, R and R as defined previously, preferably a trimethylammonium radical, and/or an aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, which is optionally substituted with one or more (hydroxy)(C.sub.1-C.sub.4)alkyl groups.

12. Compound of formula (I) or (II) according to claim 1, characterized in that said non-cationic heterocycle(s) are 5- or 6-membered and aromatic, preferably chosen from imidazoles, pyridines, pyrimidines, benzimidazoles, benzothiazoles, oxazoles, benzotriazoles, pyrazoles, thiazoles, triazoles and benzoxazoles; said 5- or 6-membered non-cationic heterocycles possibly being substituted especially with: an ammonium radical N.sup.+RRR with R, R and R, which may be identical or different, representing a (C.sub.1-C.sub.4)alkyl group optionally substituted with one or more hydroxyl groups, such as methyl, ethyl, propyl or 2-hydroxyethyl, and, more preferentially, the radical N.sup.+RRR denotes a trimethylammonium radical, and/or an aromatic or non-aromatic, 5- to 10-membered cationic heterocycle, which is optionally substituted, especially with one or more identical or different radicals chosen from (hydroxy)(C.sub.1-C.sub.4)alkyl radicals.

13. Compound of formula (I) or (II) according to claim 1, characterized in that it is chosen from compounds (1) to (13) and (1) to (13), and also the geometrical or optical isomers thereof, the tautomers thereof, the organic or mineral acid or base addition salts thereof, and/or the solvates thereof such as hydrates: ##STR00035## ##STR00036## ##STR00037## ##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044## with An.sup. as defined in claim 1.

14. Cosmetic composition comprising one or more compounds of formula (I) and/or (II) as defined in claim 1.

15. Composition according to claim 14, characterized in that it does not comprise any chemical oxidizing agent.

16. Composition according to claim 14, comprising one or more compounds of formula (I) and/or (II), preferentially one or more compounds of formula (II), characterized in that it also comprises one or more chemical oxidizing agents, chosen in particular from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulfates, peracids, and oxidase enzymes (with the possible cofactors thereof), among which mention may be made of peroxidases, 2-electron oxidoreductases such as uricases, and 4-electron oxygenases, for instance laccases, and preferably, the chemical oxidizing agent is hydrogen peroxide.

17. Process for dyeing keratin fibres, in particular human keratin fibres such as the hair, in one or more steps, comprising the following steps: either the application to said keratin fibres of a composition as defined in claim 14, or the sequential application to said keratin fibres, in a first step a), of the composition, and then, in a second step b), of an oxidizing composition, which comprises one or more chemical oxidizing agents; it being understood that, between step a) and step b), said fibres may be rinsed, and/or washed and then optionally dried.

18. Process according to claim 17 for dyeing keratin fibres, in particular human keratin fibres such as the hair, in one or more steps, in which the composition is applied to said fibres, and the fibres are then optionally rinsed, and/or washed, and said fibres are dried or left to dry.

19. Process according to claim 17, in which a cosmetic composition comprising one or more compounds of formula (II) is applied to said fibres, and the fibres are then optionally rinsed, and/or washed, and said fibres are dried or left to dry.

20. Process for preparing compounds of formulae (I) and (II) as defined in claim 1, according to the following scheme: ##STR00045## which consists for the compounds (I): a) in a first stage, in reacting one molar equivalent of a nitrobenzene compound (i) comprising in position 2 a nucleofugal group Nu and in position 5 a hydroxyl group protected with a group Prot, with one molar equivalent of aniline compound (ii); Nu representing a nucleofugal group, such as a halogen atom, for instance a chlorine atom, a methoxide, tosylate, mesylate or sulfonate group, and Prot representing a protecting group for a hydroxyl function, such as a benzyl, tetrahydropyran or trialkylsilyl group. Preferably, this reaction is performed i) in a polar protic solvent such as in water or a mixture of water/C.sub.1-C.sub.10 alcohol such as ethanol or in a polar aprotic solvent such as in 1-methyl-2-pyrrolidinone, acetone, acetonitrile, pyridine or N,N-dimethylformamide, ii) and/or in the presence of one or more mineral or organic basifying agents, as defined below, chosen in particular from diisopropylethylamine, triethylamine, sodium hydroxide, potassium hydroxide, a mineral carbonate such as potassium carbonate, or an acetate, iii) and/or at a temperature of between 0 C. and 75 C., preferably at 75 C.; and then b) in a second stage, in maintaining the reaction medium under stirring for a time of between 5 minutes and 48 hours, more particularly between 30 minutes and 24 hours if the reaction is performed at room temperature; and then c) the reaction product (iii) is optionally purified via a standard technique such as recrystallization, filtration or chromatography; d) in a third stage, in performing a reduction reaction, and at the same time a reaction for the deprotection of the hydroxyl function according to a standard literature method, on compound (iii), preferably, the reduction of compound (iii) may be performed in the presence of hydrazine, of ammonium formate, or under a hydrogen atmosphere, and in the presence of a hydrogenation catalyst based especially on a metal, for example palladium, nickel or rhodium, the reduction preferentially being performed with palladium on charcoal (Pd/C) under a hydrogen atmosphere; preferentially, this reaction is performed in a solvent such as esters, in particular such as (C.sub.1-C.sub.6)alkyl acetates, in particular ethyl acetate, (C.sub.1-C.sub.6)alkanols (i.e. a compound of formula ROH with R(C.sub.1-C.sub.6)-alkyl) such as ethanol or methanol, and mixtures thereof; better still, the solvent is ethanol, methanol or a mixture of the two; to give compound (iv); advantageously, the reduction is performed at a temperature of between 20 and 25 C. in the presence of a catalytic amount of the hydrogenation catalyst, better still based on palladium such as Pd/C, and at a hydrogen pressure of greater than or equal to 1 bar, especially between 1 and 5 bar; the amount of catalyst is advantageously less than 10 mol % relative to the molar amount of the compound of formula (iii) to be hydrogenated; and then e) in a fourth stage, in reacting compound (iv) with one molar equivalent of aniline compound (v) to give compound (I). Compound (I) is a particular compound of formula (I) according to the invention, in which R.sub.3 and R.sub.4 represent a hydrogen atom. Preferably, this reaction is performed i) in a polar protic solvent such as in water or a mixture of water/C.sub.1-C.sub.10 alcohol such as ethanol or in a polar aprotic solvent such as in 1-methyl-2-pyrrolidinone, acetone, acetonitrile, pyridine or N,N-dimethylformamide, ii) and/or in the presence of one or more mineral or organic basifying agents, as defined below, chosen in particular from diisopropylethylamine, triethylamine, sodium hydroxide, potassium hydroxide, a mineral carbonate such as potassium carbonate, or an acetate, iii) and/or at a temperature of between room temperature, i.e. 25 C., and the reflux temperature of the solvent, preferably at room temperature; and then f) in a fifth stage, in maintaining the reaction medium under stirring for a time of between 5 minutes and 48 hours, more particularly between 30 minutes and 24 hours; and then g) the reaction product (I) is optionally purified via a standard technique such as recrystallization, filtration or chromatography; h) according to another variant, compound (iv) is not purified, and reacts with one molar equivalent of aniline compound (v) under the same conditions as steps e) and f), to give the product (I), which is optionally purified via a standard technique such as recrystallization, filtration or chromatography; i) compound (I) possibly being N-substituted with halogenated reagents R.sub.3-Hal and R.sub.4Hal with Hal representing a halogen atom, preferably Cl or I, preferably with heating at the reflux point of the solvent and in the presence of an alkaline agent, in particular in a polar aprotic solvent such as THF, to give compound (I) according to the invention after filtration, removal of the precipitate and optionally purification by chromatography or recrystallization; it being understood that in the formulae (i), (ii), (iii), (iv), (v), (I) and (II), the radicals X.sub.1, X.sub.2, R.sub.1 to R.sub.6, n and n are as defined in any one of claims 1 to 13.

21. Use of one or more compounds of formula (I) and/or (II) as defined according to claim 1, optionally in the presence of one or more chemical oxidizing agents, for dyeing keratin fibres, in particular human keratin fibres such as the hair.

22. Device comprising one or more compartments comprising a first compartment containing one or more compounds of formula (I) and/or (II) as defined in claim 1, and a second compartment comprising one or more chemical oxidizing agents.

Description

SYNTHESIS EXAMPLES

Synthesis of 3-[3-(4-{4-amino-3-[4-dimethylaminophenylimino]-6-oxocyclohexa-1,4-dienylamino}phenylamino)propyl]-1-methyl-3H-imidazol-1-ium chloride (a)

[0353] ##STR00020##

i) Synthesis of (4)-3-amino-4-{[4-(dimethylamino)phenyl]imino}cyclohexa-2,5-dien-1-one (1a)

[0354] ##STR00021##

[0355] 20 mmol of N,N-dimethylbenzene-1,4-diamine dihydrochloride (4.18 g, 1 equivalent) dissolved in 50 ml of water are placed in a 500 ml round-bottomed flask containing 20 mmol of 3-aminophenol dissolved in 14 ml of 1-pentanol and 50 ml of water. The reaction medium is stirred at room temperature, 60 ml of 20-volumes aqueous hydrogen peroxide solution are then added and the reaction is monitored by TLC. After 72 hours at room temperature, the solid formed is filtered off on a sinter, washed with 15 ml of N,N-dimethylformamide and 315 ml of water, suction-filtered and dried in a desiccator (P.sub.2O.sub.5, vacuum, 40 C.) to give compound (1a) in the form of a very dark purple solid.

[0356] The NMR and mass spectrometry analyses are in accordance with the expected structure (1a).

ii) Synthesis of 3-[3-(4-{4-amino-3-[4-dimethylaminophenylimino]-6-oxocyclohexa-1,4-dienylamino}phenylamino)propyl]-1-methyl-3H-imidazol-1-ium chloride (a)

[0357] ##STR00022##

[0358] 0.41 mmol of compound (1a) (100 mg, 1 equivalent), 0.41 mmol of 1-{3-[(4-aminophenyl)amino]propyl}-3-methyl-1H-imidazol-3-ium chloride dihydrochloride (141 mg, 1 equivalent) and 0.91 mmol of N,N-diisopropylethylamine (159 l, 2.2 equivalents) are placed in a 25 ml three-necked flask under an inert atmosphere containing 2 ml of ethanol. The reaction medium is stirred at room temperature and the reaction is monitored by HPLC. After 24 hours at room temperature, the reaction medium is concentrated on a rotavapor.

[0359] The viscous oil obtained is then taken up in 10 ml of acetonitrile and the insoluble black matter present in the solution is filtered off on a sinter, washed with 25 ml of acetonitrile, suction-filtered and then dried in a desiccator (P.sub.2O.sub.5, vacuum, 40 C.) to give compound (a) in the form of a black solid.

[0360] The NMR and mass spectrometry analyses are in accordance with the expected structure (a).

Synthesis of 1-(3-{[4-({2-amino-5-[(4-{[3-(3-methyl-1H-imidazol-3-ium-1-yl)propyl]amino}phenyl)amino]-4-oxocyclohexa-2,5-dien-1-ylidene}amino)phenyl]amino}propyl)-3-methyl-1H-imidazol-3-ium dichloride

[0361] ##STR00023##

i) Synthesis of 4-(benzyloxy)-1-fluoro-2-nitrobenzene (1b)

[0362] ##STR00024##

[0363] 63.65 mmol of 4-fluoro-3-nitrophenol (10.0 g, 1 equivalent) are placed in a 500 ml three-necked flask containing 150 ml of acetonitrile. The reaction medium is stirred at room temperature, and 66.84 mmol of potassium carbonate (9.23 g, 1.05 equivalents) and 66.84 mmol of benzyl bromide (7.95 ml, 1.05 equivalents) are then added. The solution is heated to 80 C. and the reaction is monitored by TLC (dichloromethane/methanol: 95/5). After 1 hour at 80 C., the reaction medium is poured onto ice. The precipitate formed is filtered off on a sinter to give, after washing with water, suction filtration and then drying (P.sub.2O.sub.5, vacuum, 40 C.), compound (1b) obtained in the form of a yellow powder.

[0364] The NMR and mass spectrometry analyses are in accordance with the expected structure (1b).

ii) Synthesis of 1-{3-[(4-{[4-(benzyloxy)-2-nitrophenyl]amino}phenyl)amino]propyl}-3-methyl-1H-imidazol-3-ium chloride (2b)

[0365] ##STR00025##

[0366] 4.04 mmol of compound (1b) (1.0 g, 1 equivalent), 4.04 mmol of 1-{3-[(4-aminophenyl)amino]propyl}-3-methyl-1H-imidazol-3-ium chloride dihydrochloride (1.37 g, 1.0 equivalent), 12.52 mmol of N,N-diisopropylethylamine (2.20 ml, 3.1 equivalents) and 10 ml of 1-butanol are placed in a 50 ml three-necked flask under an inert atmosphere. The reaction medium is heated to 110 C. and the reaction is monitored by HPLC. After 24 hours at 110 C., the heating is stopped and the reaction medium is then evaporated on a rotavapor.

[0367] The viscous oil obtained is then purified by chromatography on neutral alumina using an eluent constituted of a mixture of dichloromethane and methanol.

[0368] Compound (2b) is obtained in the form of a dark red solid.

[0369] The NMR and mass spectrometry analyses are in accordance with the expected structure (2b).

iii) Synthesis of 1-(3-{[4-({2-amino-5-[(4-{[3-(3-methyl-1H-imidazol-3-ium-1-yl)propyl]amino}phenyl) amino]-4-oxocyclohexa-2,5-dien-1-ylidene}amino)phenyl]amino}propyl) 3-methyl-1H-imidazol-3-ium dichloride

[0370] ##STR00026##

[0371] 2.83 mmol of compound (2b) (1.40 g, 1 equivalent) and 1.0 g of 5% palladium on charcoal are placed in a 100 ml three-necked flask under an inert atmosphere containing 20 ml of methanol. The reaction medium is heated to 65 C., 28.3 mmol of cyclohexene (2.9 ml, 10 equivalents) are then added dropwise and the reaction is monitored by HPLC. After 2 hours at 65 C., the reaction medium is filtered through a sinter packed with Celite. The filtrate is stirred at room temperature for 30 minutes and is then evaporated. The dark blue viscous oil obtained (1.05 g, 2.83 mmol, 1 equivalent), 2.83 mmol of 1-{3-[(4-aminophenyl)amino]propyl}-3-methyl-1H-imidazol-3-ium chloride dihydrochloride (959 mg, 1 equivalent) and 8.46 mmol of N,N-diisopropylethylamine (1.48 ml, 3 equivalents) are placed in a 100 ml three-necked flask under an inert atmosphere containing 15 ml of ethanol. The reaction medium is stirred at room temperature and the reaction is monitored by HPLC. After 48 hours at room temperature, the reaction medium is concentrated on a rotavapor.

[0372] The viscous oil obtained is then purified by chromatography on neutral alumina using an eluent constituted of a mixture of dichloromethane and methanol. Compound (b) is obtained in the form of a black solid.

[0373] The NMR and mass spectrometry analyses are in accordance with the expected structure (b).

Synthesis of 3-[3-(4-{4-amino-3-[4-(ethylisopropylamino)phenylimino]-6-oxocyclohexa-1,4-dienylamino}phenylamino)propyl]-1-methyl-3H-imidazol-1-ium chloride

[0374] ##STR00027##

i) Synthesis of N-[4-(benzyloxy)-2-nitrophenyl]-N-ethyl-N-(propan-2-yl)benzene-1,4-diamine (1c)

[0375] ##STR00028##

[0376] 40.45 mmol of compound (1b) (1.0 g, 1 equivalent), 42.47 mmol of N-ethyl-N-(propan-2-yl)benzene-1,4-diamine hydrochloride (9.12 g, 1.05 equivalents), 84.95 mmol of diisopropylethylamine (14.8 ml, 2.1 equivalents) and 100 ml of 1-butanol are placed in a 500 ml three-necked flask under an inert atmosphere. The reaction medium is heated to 110 C. and the reaction is monitored by HPLC. After 48 hours at 110 C., the heating is stopped and the reaction medium is then stirred at room temperature. After 3 hours at room temperature, the dark brown precipitate formed in the reaction medium is filtered off on a sinter, washed with 3200 ml of ethanol, suction-filtered and then dried in a desiccator (P.sub.2O.sub.5, vacuum, 40 C.) to give compound (1c) in the form of a dark red solid.

[0377] The NMR and mass spectrometry analyses are in accordance with the expected structure (1c).

ii) Synthesis of 3-[3-(4-{4-amino-3-[4-(ethylisopropylamino)phenylimino]-6-oxocyclohexa-1,4-dienylamino}phenylamino)propyl]-1-methyl-3H-imidazol-1-ium chloride (c)

[0378] ##STR00029##

[0379] 2.47 mmol of compound (1c) (1.0 g, 1 equivalent) and 0.5 g of 5% palladium on charcoal are placed in a 100 ml three-necked flask under an inert atmosphere containing 20 ml of methanol. The reaction medium is heated to 65 C., 24.7 mmol of cyclohexene (2.5 ml, 10 equivalents) are then added dropwise and the reaction is monitored by HPLC. After 2 hours at 65 C., the reaction medium is filtered through a sinter packed with Celite. The filtrate is stirred at room temperature for 30 minutes and is then evaporated. The dark blue viscous oil obtained (700 mg, 2.47 mmol, 1 equivalent), 2.47 mmol of 1-{3-[(4-aminophenyl)amino]propyl}-3-methyl-1H-imidazol-3-ium chloride dihydrochloride (839 mg, 1 equivalent) and 5.06 mmol of N,N-diisopropylethylamine (882 l, 2.1 equivalents) are placed in a 100 ml three-necked flask under an inert atmosphere containing 15 ml of ethanol. The reaction medium is stirred at room temperature and the reaction is monitored by HPLC. After 48 hours at room temperature, the reaction medium is evaporated on a rotavapor.

[0380] The viscous oil obtained is then purified by chromatography on neutral alumina using an eluent constituted of a mixture of dichloromethane and methanol.

[0381] Compound (c) is obtained in the form of a black solid.

[0382] The NMR and mass spectrometry analyses are in accordance with the expected structure (c).

Synthesis of 3-{3-[4-(4-amino-3-{(4-[bis(2-hydroxyethyl)amino]phenylimino}-6-oxocyclohexa-1,4-dienylamino)phenylamino]propyl}-1-methyl-3H-imidazol-1-ium chloride (d)

[0383] ##STR00030##

i) Synthesis of 2,2-[(4-{[4-(benzyloxy)-2-nitrophenyl]amino}phenyl)imino]diethanol (1d)

[0384] ##STR00031##

[0385] 40.45 mmol of compound (1b) (10.0 g, 1 equivalent), 40.45 mmol of 2,2-[(4-aminophenyl)imino]diethanol sulfate hydrate (12.63 g, 1.0 equivalent), 125.24 mmol of diisopropylethylamine (21.8 ml, 3.1 equivalents) and 75 ml of 1-butanol are placed in a 500 ml three-necked flask under an inert atmosphere. The reaction medium is heated to 110 C. and the reaction is monitored by HPLC. After 48 hours at 110 C., the heating is stopped and the reaction medium is then stirred at room temperature. After 4 hours at room temperature, the dark brown precipitate formed in the reaction medium is filtered off on a sinter, washed with 3200 ml of ethanol, suction-filtered and then dried in a desiccator (P.sub.2O.sub.5, vacuum, 40 C.) to give compound (1d) in the form of a dark red solid.

[0386] The NMR and mass spectrometry analyses are in accordance with the expected structure (1d).

ii) Synthesis of 3-{3-[4-(4-amino-3-{(4-[bis(2-hydroxyethyl)amino]phenylimino}-6-oxocyclohexa-1,4-dienylamino)phenylamino]propyl}-1-methyl-3H-imidazol-1-ium chloride (d)

[0387] ##STR00032##

[0388] 35.42 mmol of compound (1d) (15.0 g, 1 equivalent) and 8.0 g of 5% palladium on charcoal are placed in a 500 ml three-necked flask under an inert atmosphere containing 150 ml of methanol. The reaction medium is heated to 65 C., 354.2 mmol of cyclohexene (35.9 ml, 10 equivalents) are then added dropwise and the reaction is monitored by HPLC. After 2 hours at 65 C., the reaction medium is filtered through a sinter packed with Celite. The filtrate is stirred at room temperature for 30 minutes and is then evaporated. The dark blue viscous oil obtained (10.67 g, 35.42 mmol, 1 equivalent), 35.42 mmol of 1-{3-[(4-aminophenyl)amino]propyl}-3-methyl-1H-imidazol-3-ium chloride dihydrochloride (12.03 g, 1 equivalent) and 74.38 mmol of N,N-diisopropylethylamine (12.96 ml, 2.1 equivalents) are placed in a 500 ml three-necked flask under an inert atmosphere containing 200 ml of ethanol. The reaction medium is stirred at room temperature and the reaction is monitored by HPLC. After 48 hours at room temperature, the reaction medium is concentrated on a rotavapor.

[0389] The viscous oil obtained is then purified by chromatography on neutral alumina using an eluent constituted of a mixture of dichloromethane and methanol.

[0390] Compound (d) is obtained in the form of a black solid.

[0391] The NMR and mass spectrometry analyses are in accordance with the expected structure (d).

Examples of Dyeing Evaluation

[0392] Cosmetic compositions 1 to 6 below were prepared:

TABLE-US-00002 Composi- Composi- Composi- Composi- tion 1 tion 2 tion 3 tion 4 Compound (a) 500 mg Compound (b) 500 mg Compound (c) 500 mg Compound (d) 500 mg Water 79.5 g 79.5 g 79.5 g 79.5 g Ethanol 15 g 15 g 15 g 15 g Benzyl alcohol 5 g 5 g 5 g 5 g

[0393] 2.0 g of compositions 1 to 4 are applied to a 1.0 g lock of grey hair containing 90% white hairs. After a leave-on time of 30 minutes at room temperature, the lock is rinsed, washed with a standard shampoo and then dried.

[0394] Spectrocolorimetric Evaluation:

[0395] The colour of the locks was evaluated in the CIE L* a* b* system using a Minolta Spectrophotometer CM3610D colorimeter. In this L* a* b* system, the three parameters respectively denote the intensity of the colour (L*), the green/red colour axis (a*) and the blue/yellow colour axis (b*).

[0396] Colour Build-Up:

[0397] The variation in colouration between the non-dyed and dyed locks of hair is defined by (E*) according to the following equation:

E*={square root over ((L*L.sub.0*).sup.2+(a*a.sub.0*).sup.2+(b*b.sub.0*).sup.2)}

[0398] In this equation, L*, a* and b* represent the values measured on locks of hair after dyeing and L.sub.0*, a.sub.0* and b.sub.0* represent the values measured on locks of hair before dyeing. The higher the value of E*, the greater the colour build-up.

[0399] Results:

[0400] The colours obtained on the lock thus treated are collated in the attached table:

TABLE-US-00003 Composition 1 Composition 2 Composition 3 Composition 4 L* = 24.08 L* = 25.67 L* = 30.47 L* = 26.90 a* = 1.10 a* = 0.66 a* = 0.04 a* = 0.36 b* = 2.16 b* = 3.17 b* = 1.76 b* = 0.41 E* = 36.81 E* = 38.70 E* = 31.25 E* = 36.91 Black Black Black Black

[0401] It is seen through these results that the compositions according to the invention give intense hair colourings and with good colour build-up.

Comparative Examples

[0402] The following dye compositions A (comparative) and B (invention) were prepared from the ingredients indicated in the table below. The contents are expressed as percentages of active material relative to the total weight of the composition.

##STR00033##

TABLE-US-00004 Composition A Composition B (comparative) (invention) Compound 1 0.5 Compound 2 0.5 Water 79.5 79.5 Pure ethyl alcohol 15 15 Benzyl alcohol 5 5

[0403] Process

[0404] 2 g of each of the compositions are applied to 1 g locks of natural Caucasian hair containing 90% white hairs. After 30 minutes, the locks are rinsed, shampooed and then dried. The colorimetric data of each of the locks are then measured with a Minolta CM-3610d spectrophotometer.

[0405] Results

[0406] The results are given in the table below.

TABLE-US-00005 Compositions tested L* a* b* E colour Composition A 60.19 1.05 13.98 2.52 Very very light (comparative) yellow-grey Composition B 24.08 1.1 2.16 36.81 Grey-black (Invention)

[0407] It is seen from the above table that the colour obtained with the comparative composition A is significantly lighter than that obtained with composition B according to the invention. It was not possible to obtain a black shade with the comparative composition A, whereas composition B according to the invention makes it possible to obtain a very intense grey-black colour.