WO2009077394A1

WO2009077394A1 - Azomethine direct dyes or reduced precursors of these dyes obtained from 5-(2-hydroxyethylamino)-2-methylphenol, and dyeing process using these dyes and precursors

Info

Publication number: WO2009077394A1
Application number: PCT/EP2008/067153
Authority: WO
Inventors: Stéphane SABELLE; Eric Metais; Christophe Rondot
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2007-12-14
Filing date: 2008-12-09
Publication date: 2009-06-25
Anticipated expiration: 2010-06-14
Also published as: FR2925055B1; FR2925055A1

Abstract

The invention relates to the dyeing of keratin fibres using azomethine direct dyes or reduced precursors of azomethine direct dyes obtained from 5-(2-hydroxyethylamino)-2- methylphenol of formula (I) or (II). The invention relates to a dye composition comprising at least one azomethine direct dye or a reduced precursor of an azomethine direct dye, to a process for dyeing keratin fibres, using the said composition, and to their uses in the dyeing of keratin fibres. This composition allows a particularly stable and fast coloration to be obtained.

Description

AZOMETHINE DIRECT DYES OR REDUCED PRECURSORS OF THESE

DYES OBTAINED FROM 5- (2-HYDROXYETHYLAMINO) -2- METHYLPHENOL, AND DYEING PROCESS USING THESE DYES AND

PRECURSORS

The invention relates to the dyeing of keratin fibres using azomethine direct dyes or reduced precursors of azomethine direct dyes obtained from 5- (2- hydroxyethylamino) -2-methylphenol .

It is known practice to dye keratin fibres, and in particular the hair, with dye compositions containing direct dyes, according to a "direct dyeing" process.

The process conventionally used in direct dyeing consists in applying to keratin fibres direct dyes, or colouring molecules, which have affinity for the said fibres, leaving them to stand on the fibres, and then rinsing the fibres. The direct dyes used hitherto are nitrobenzene dyes, anthraquinones, nitropyridines, dyes of azo, xanthene, acridine or azine type or triarylmethanebenzene-based dyes .

Other dyes are obtained from oxidation bases and couplers, which, once condensed, are applied onto the hair. For example, in documents FR 233 036, FR 2 262 022,

FR 2 262 024, US 4 221 729 and FR 2 261 750, diphenylamines such as leuco derivatives of indophenols, of indoamine and of indoaniline are used either alone or in combination with other dyes in dye compositions. Other compounds corresponding to oxidized derivatives of leuco derivatives such as those described in documents FR 2 254 557 and FR 2 234 277 are also known for dyeing keratin fibres.

The colorations that result from direct dyeing are temporary or semi-permanent colorations, since the nature of the interactions that bind the direct dyes to the keratin fibre, and their desorption from the surface and/or the core of the fibre, are responsible for their poor dyeing power and their poor fastness with respect to washing or to perspiration. These direct dyes are also generally sensitive to the action of oxidizing agents such as hydrogen peroxide, which makes them generally unusable in lightening direct dye compositions based on hydrogen peroxide and on a basifying agent, which would be similar to oxidation dyeing.

Direct dyes also have a certain lack of light stability, associated with the poor resistance of the chromophore to photochemical attack. In addition, their sensitivity to light is dependent on the distribution of their molecules, uniformly or in aggregates, in the substrate .

Consequently, there is a real need to find direct dyes for dyeing keratin fibres, which are light-stable, and which are also resistant to bad weather, washing and perspiration and sufficiently stable in the presence of oxidizing agents such as hydrogen peroxide to be able to obtain simultaneous lightening of the fibre with the advantages outlined above, while at the same time having a toxicological profile that is compatible with cosmetic use on keratin fibres.

These aims are achieved with the present invention, one subject of which is a process for dyeing keratin fibres using direct dyes of formula (I) :

(I) salts thereof with an organic or mineral acid, geometrical isomers thereof, tautomers thereof, and solvates thereof such as the hydrates; in which formula (I) :

• Ri represents: - a (Ci-C₃) alkyl radical optionally substituted with one or more hydroxyl groups; a (Ci-C₃) alkoxy radical optionally substituted with one or more hydroxyl groups;

• X represents: - a hydroxyl radical; a radical -NR₂R₃ with R₂ and R₃ representing, independently of each other: i) a hydrogen atom; ii) a Ci-C₅ alkyl radical optionally substituted with one or more groups chosen from hydroxyl, (Ci-C₃) alkoxy, amino, (Ci- C₃) alkylamino, di (Ci-C₃) alkylamino, aminocarbonyl, carboxylic -COOH, sulfonic -SO₃H, tri (Ci-C₃) alkylammonium and (Ci- C₃) alkylimidazolium; a pyrrolidinyl radical optionally substituted with a group chosen from hydroxyl, (Ci- C₃) alkoxy, amino, (Ci-C₃) alkylamino, di (Ci- C₃) alkylamino, tri (Ci-C₃) alkylammonium and (Ci- C₃) alkylimidazolium;

• n represents an integer between 0 and 3 inclusive; it being understood that: when X and/or R₂ and/or R₃ comprise a cationic group, the electrical neutrality of the compounds of formula (I) is achieved with an anionic counterion or a mixture of anionic counterions that are cosmetically acceptable, for instance chlorides, bromides and sulfates.

Another subject of the invention relates to a dyeing process using reduced precursors of colourless azomethine dyes, which, once oxidized, generate the compounds of formula (I) as defined above. These precursors correspond to the compounds of formula (II) :

(H) the salts thereof with an organic or mineral acid, the geometrical isomers thereof, the tautomers thereof, and the solvates thereof such as the hydrates; in which formula (II) Ri, X and n are as defined previously; it being understood that: when X and/or R₂ and/or R₃ comprise a cationic group, the electrical neutrality of the compounds of formula (II) is achieved with an anionic counterion or a mixture of anionic counterions that are cosmetically acceptable, for instance chlorides, bromides and sulfates; the compounds of formula (II) cannot represent the following compound:

Another subject of the invention is a compound of formula (I) or (II) , the compound of formula (I) or (II) not being able to represent the compounds:

Another subject of the invention is a dye composition for dyeing keratin fibres, comprising, in a cosmetic medium, at least one compound of formula (I) or (II) as defined previously, it being understood that the compound of formula (I) or (II) cannot represent the compounds :

or respectively.

The direct dyes of formula (I) make it possible to overcome the drawbacks of the direct dyes conventionally used previously, and lead to dyeing results by direct dyeing that show very good resistance to light, bad weather, perspiration and rubbing. Their good stability with respect to oxidizing agents such as hydrogen peroxide also allows them to be used in a process of lightening direct dyeing.

Furthermore, it has been discovered that the reduced form of the azomethine derivatives obtained from 5- (2- hydroxyethylamino) -2-methylphenol derivatives of formula (II) , used under oxidizing conditions, may also lead to colorations that show very good resistance to light, bad weather, washing, perspiration and rubbing.

For the purposes of the present invention, and unless otherwise indicated: a "salt of an organic or mineral acid" is chosen, for example, from a solvent derived from i) hydrochloric acid HCl, ii) hydrobromic acid HBr, iii) sulfuric acid H₂SO₄, iv) alkylsulfonic acids: AIk-S(O)₂OH such as methanesulfonic acid and ethanesulfonic acid; v) arylsulfonic acids: Ar-S(O)₂OH such as benzenesulfonic acid and toluenesulfonic acid; vi) citric acid; vii) succinic acid; viii) tartaric acid; ix) lactic acid; x) alkoxysulfinic acids: AIk-O-S(O)OH such as methoxysulfinic acid and ethoxysulfinic acid; xi) aryloxysulfinic acids such as tolueneoxysulfinic acid and phenoxysulfinic acid; xii) phosphoric acid H₃PO₄; xiii) acetic acid CH₃C(O)OH; xiv) triflic acid CF₃SO₃H; and xv) tetrafluoroboric acid HBF₄; an "anionic counterion" is an anion or an anionic group associated with the cationic charge of the dye; more particularly, the anionic counterion is chosen from: i) halides such as chloride or bromide; ii) nitrates; iii) sulfonates, including C₁-C₆ alkylsulfonates: AIk-S(O)₂O^" such as methanesulfonate or mesylate and ethanesulfonate; iv) arylsulfonates : Ar-S(O)₂O^" such as benzenesulfonate and toluenesulfonate or tosylate; v) citrate; vi) succinate; vii) tartrate; viii) lactate; ix) alkyl sulfates: AIk-O-S(O)O^" such as methyl sulfate and ethyl sulfate; x) aryl sulfates: Ar-O-S(O)O^" such as benzene sulfate and toluene sulfate; xi) alkoxy sulfates: AIk-O-S(O)₂O^" such as methoxy sulfate and ethoxy sulfate; xii) aryloxy sulfates: Ar-O-S(O)₂O^"; xiii) phosphate; xiv) acetate; xv) triflate; and xvi) borates such as a tetrafluoroborate; an "alkyl" radical is a saturated, linear or branched hydrocarbon-based radical, containing from 1 to 6 carbon atoms and particularly from 1 to 3 carbon atoms, such as the methyl or ethyl radical; an "alkoxy" radical is an "alkyl-oxy" alkyl-O- radical in which the alkyl part is as defined previously; - the alkyl, alkoxy or heterocycloalkyl radicals followed by "optionally substituted with..." means that the said radicals may have one or more hydrogen atoms replaced with one or more substituents in question, particularly one or two substituents in question.

One subject of the invention is a direct dye of formula (I) or a dye precursor of formula (II) for dyeing keratin fibres, especially human keratin fibres such as the hai r .

One particular mode of the invention concerns compounds of formula (I) or (II) in which, when n is greater than or equal to 2, at least two groups Ri are identical.

The groups Ri that are identical are either in position

2,6 or in position 3,5 on the phenyl radical. More particularly, when n is 2, the groups are identical and are in position 2,6 or in position 3,5 on the phenyl radical and represent alkyl groups such as a methyl radical .

One particular embodiment of the invention concerns the compounds of formula (I) or (II) for which n is zero.

One variant concerns compounds of formula (I) or (II) for which X represents a hydroxyl radical.

Another variant of the invention involves compounds of formula (I) or (II) for which X represents a radical -NR₂R₃ with R₂ and R₃ representing, independently of each other, i) a hydrogen atom or ii) a Ci-C₅ alkyl radical optionally substituted with one or more groups chosen from hydroxyl, (Ci-C₃) alkoxy, amino, (Ci- C₃) alkylamino, di (C₁-C₃) alkylamino, aminocarbonyl, carboxylic -COOH, sulfonic -SO₃H, tri (Ci-C₃) alkylaminonium and (Ci-C₃) alkylimidazolium_. More particularly, X represents a group chosen from: i) (di) (Ci- C₃) (alkyl) amino; ii) (di) [hydroxy (Ci-C₃) alkyl] amino; iii) (Ci-C₃) akylimidazolium (Ci-C₃) alkylamino; iv) [JV-(Ci- C₃) alkyl, JV- (Ci-C₃) akylimidazolium (Ci-C₃) alkyl] amino; v) tri (Ci-C₃) alkylammonium (Ci-C₅) alkylamino and vi) (di) [tri (Ci-C₃) alkylammonium (Ci-C₅) alkyl] amino .

According to another particular embodiment of the invention, the compounds of formula (I) or (II) are such that X represents a pyrrolidinyl group optionally substituted with a tri (Ci-C₃) alkylammonium or (Ci- C₃) alkylimidazolium group. More particularly, X represents a pyrrolidino radical optionally substituted with a tri (C₁-C₃) alkylammonium or (C₁-C₃) alkylimidazolium group.

As examples of compounds of formula (I) or (II) contained in the composition according to the invention, mention may be made of the dyes (a) to (p) and precursors (q) to (al) below, and also the salts thereof with an organic or mineral acid, geometrical isomers thereof, tautomers thereof and solvates thereof such as the hydrates:

Dyes of formula (I) :

with An , which may be identical or different, representing an anionic counterion such as halide, An^" particularly representing a chloride.

More particularly, the dyes are chosen from the preceding dyes (b) , (c) , (e) , (g) , (j) , (h) , (k) , (m) , (1) and (n) , and the dye precursors are chosen from the preceding precursors (q) , (r) , (s) , (z) , (al) and (bl) and the salts thereof with an organic or mineral acid, geometrical isomers and tautomers thereof, and solvates thereof such as the hydrates.

The compounds included in the invention are prepared according to the following general synthetic routes: 1- Access to the compounds corresponding to formula (I) :

The compounds corresponding to formula (I) are generally obtained by reacting 5- (2-hydroxyethylamino) - 2-methylphenol with a para-aminophenol derivative (X=OH) or a para-phenylenediamine derivative (X= - NR₂R3) , preferably in basic medium in the presence of an oxidizing agent. The base used is preferentially an aqueous solution of ammonia or of sodium hydroxide and the oxidizing agent is preferentially chosen from hydrogen peroxide, potassium ferricyanide, air, ammonium persulfate and manganese oxide.

The compounds of the invention may also be obtained by reacting 5- (2-hydroxyethylamino) -2-methylphenol with a para-nitrosophenol derivative (X = OH) or a para- nitrosoaniline derivative (X= -NR2R3) according to the following scheme:

2- Access to the compounds corresponding to formula

(II) :

The compounds corresponding to formula (II) are generally obtained by reacting the compounds of formula (I) with a reducing agent. This reducing agent may be preferentially chosen from sodium hydrosulfite .

reducing agent

Similar synthetic approaches are described in patents FR 2 056 799, FR 2 047 932, FR 2 165 965 and FR 2 262 023.

One subject of the invention relates to a cosmetically acceptable composition for dyeing keratin fibres, especially human keratin fibres such as the hair, comprising at least one direct dye of formula (I) or a dye precursor of formula (II) . The dye composition that is useful in the invention generally contains an amount of dye of formula (I) or of precursor of formula (II) of between 0.001% and 30% relative to the total weight of the composition. Preferably, this amount is between 0.005% and 10% by weight and even more preferentially between 0.01% and 6% by weight relative to the total weight of the composition .

The dye composition containing the dye of formula (I) or the precursor of formula (II) may also contain an oxidizing agent such as hydrogen peroxide, urea peroxide, alkali metal bromates, persalts, peracids and oxidase enzymes.

The dye composition may also contain additional direct dyes. These direct dyes are chosen, for example, from neutral, acidic or cationic nitrobenzene direct dyes, neutral, acidic or cationic azo direct dyes, tetraazapentamethine dyes, neutral, acidic or cationic quinone and in particular anthraquinone dyes, azine direct dyes, triarylmethane direct dyes, indoamine direct dyes and natural direct dyes.

Among the nitrobenzene direct dyes that may be mentioned, in a non-limiting manner, are the following compounds : 1, 4-diamino-2-nitrobenzene, l-amino-2-nitro-4-β- hydroxyethylaminobenzene, l-amino-2-nitro-4-bis ( β- hydroxyethyl) aminobenzene, 1, 4-bis ( β-hydroxyethyl- amino) -2-nitrobenzene, l-β-hydroxyethylamino-2-nitro-4- bis ( β-hydroxyethylamino) benzene, 1-β-hydroxyethylamino- 2 -nitro-4 -aminobenzene, l-β-hydroxyethylamino-2-nitro- 4- (ethyl) (β-hydroxyethyl) aminobenzene, l-amino-3- methyl-4- β-hydroxyethylamino- 6-nitrobenzene, l-amino-2- nitro-4-β-hydroxyethylamino-5-chlorobenzene, 1, 2- diamino-4 -nitrobenzene, l-amino-2-β-hydroxyethylamino- 5-nitrobenzene, 1 , 2-bis ( β-hydroxyethylamino) -4-nitro- benzene, l-amino-2-tris (hydroxymethyl) methylamino-5- nitrobenzene, l-hydroxy-2-amino-5-nitrobenzene, 1- hydroxy-2 -amino-4 -nitrobenzene, 1 -hydroxy-3-nitro-4- aminobenzene, l-hydroxy-2-amino-4, 6-dinitrobenzene, 1- β-hydroxyethyloxy-2-β-hydroxyethylamino-5-nitrobenzene, 1 -methoxy-2-β-hydroxyethylamino-5-nitrobenzene, 1-β- hydroxyethyloxy-3-methylamino-4 -nitrobenzene, l~β/ Y~ dihydroxypropyloxy-3-methylamino-4 -nitrobenzene, 1-β- hydroxyethylamino-4-β, γ-dihydroxypropyloxy-2-nitro- benzene, 1-β, γ-dihydroxypropylamino-4-trifluoromethyl- 2 -nitrobenzene, l-β-hydroxyethylamino-4-trifluoro- methyl-2 -nitrobenzene, l-β-hydroxyethylamino-3-methyl- 2 -nitrobenzene, l-β-aminoethylamino-5-methoxy-2 -nitrobenzene, l-hydroxy-2-chloro-6-ethylamino-4-nitro- benzene, l-hydroxy-2-chloro-6-amino-4-nitrobenzene, 1- hydroxy-6-bis (β-hydroxyethyl) amino-3-nitrobenzene, 1-β- hydroxyethy1amino-2 -nitrobenzene, l-hydroxy-4-β- hydroxyethy1amino-3-nitrobenzene .

Among the azo direct dyes, mention may be made of the cationic azo dyes described in patent applications WO-95/15144, WO-95/01772 and EP-714 954, the content of which forms an integral part of the invention.

Among these compounds, mention may be made most particularly of the following dyes: 1, 3-dimethyl-2- [ [4-

(dimethylamino) phenyl ] azo] -lH-imidazolium chloride,

1, 3-dimethyl-2- [ (4-aminophenyl) azo] -lH-imidazolium chloride, l-methyl-4- [ (methylphenylhydrazono) methyl] - pyridinium methyl sulfonate.

Among the azo direct dyes, mention may also be made of the following dyes, described in the COLOUR INDEX INTERNATIONAL 3rd edition: Disperse Red 17, Acid Yellow 9, Acid Black 1, Basic Red 22, Basic Red 76, Basic Yellow 57, Basic Brown 16, Acid Yellow 36, Acid Orange 7, Acid Red 33, Acid Red 35, Basic Brown 17, Acid Yellow 23, Acid Orange 24, Disperse Black 9. Mention may also be made of 1- (4' -aminodiphenylazo) -2- methyl-4-bis (β-hydroxyethyl) aminobenzene and 4-hydroxy- 3- (2-methoxyphenylazo) -1-naphthalenesulfonic acid.

Among the quinone direct dyes, mention may be made of the following dyes:

Disperse Red 15, Solvent Violet 13, Acid Violet 43, Disperse Violet 1, Disperse Violet 4, Disperse Blue 1, Disperse Violet 8, Disperse Blue 3, Disperse Red 11, Acid Blue 62, Disperse Blue 7, Basic Blue 22, Disperse Violet 15, Basic Blue 99, and also the following compounds : l-N-methylmorpholiniumpropylamino-4-hydroxy- anthraquinone, l-aminopropylamino-4-methylaminoanthra- quinone, 1-aminopropylaminoanthraquinone, 5-β-hydroxy- ethyl-1, 4-diaminoanthraquinone, 2-aminoethylamino- anthraquinone, 1 , 4 -bis ( β, γ-dihydroxypropylamino) - anthraquinone .

Among the azine dyes, mention may be made of the following compounds: - Basic Blue 17 and Basic Red 2.

Among the triarylmethane dyes, mention may be made of the following compounds: Basic Green 1, Acid Blue 9, Basic Violet 3, Basic Violet 14, Basic Blue 7, Acid Violet 49, Basic Blue 26, Acid Blue 7.

Among the indoamine dyes, mention may be made of the following compounds:

2-β-hydroxyethlyamino-5- [bis (β-4' -hydroxyethyl) amino] - anilino-1, 4-benzoquinone;

2-β-hydroxyethylamino-5- (2' -methoxy-4' -amino) anilino- 1, 4-benzoquinone; - 3-N- (2' -chloro-4' -hydroxy) phenylacetylamino-6-methoxy- 1, 4-benzoquinoneimine;

3-N- (3' -chloro-4 ' -methylamino) phenylureido-6-methyl- 1, 4-benzoquinoneimine;

3- [ 4 ' -N- (ethyl, carbamylmethyl) amino] phenylureido-6- methyl-1 , 4-benzoquinoneimine .

Among the natural direct dyes, mention may be made of lawsone, juglone, alizarin, purpurin, carminic acid, kermesic acid, purpurogallin, protocatechaldehyde, indigo, isatin, curcumin, spinulosin and apigenidin. Extracts or decoctions containing these natural dyes, and especially henna-based poultices or extracts, may also be used.

The dye composition may contain one or more oxidation bases and/or one or more couplers conventionally used for the dyeing of keratin fibres.

Among the oxidation bases, mention may be made of para- phenylenediamines, bis (phenyl) alkylenediamines, para- aminophenols, bis-para-aminophenols, ortho-aminophenols and heterocyclic bases, and the addition salts thereof.

Among the couplers, mention may be made especially of meta-phenylenediamines, meta-aminophenols, meta- diphenols, naphthalene-based couplers and heterocyclic couplers, and the addition salts thereof.

The coupler (s) is (are) each generally present in an amount of between 0.001% and 10% by weight and preferably between 0.005% and 6% by weight relative to the total weight of the dye composition.

The oxidation base(s) present in the dye composition is (are) each generally present in an amount of between 0.001% and 10% by weight and preferably between 0.005% and 6% by weight relative to the total weight of the dye composition.

In general, the addition salts of the oxidation bases and couplers used in the context of the invention are especially chosen from the salts of addition with an acid, such as the hydrochlorides, hydrobromides, sulfates, citrates, succinates, tartrates, lactates, tosylates, benzenesulfonates, phosphates and acetates, and the salts of addition with a base, such as alkali metal hydroxides, for instance sodium hydroxide, potassium hydroxide, ammonia, amines or alkanolamines .

The medium that is suitable for dyeing, also known as the dye support, is a cosmetic medium generally comprising water or a mixture of water and of at least one organic solvent. Examples of organic solvents that may be mentioned include lower Ci-C₄ alkanols, such as ethanol and isopropanol; polyols and polyol ethers, for instance 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether and diethylene glycol monomethyl ether and monomethyl ether, and also aromatic alcohols, for instance benzyl alcohol or phenoxyethanol, and mixtures thereof.

When they are present, the solvents are preferably present in proportions preferably of between 1% and 40% by weight approximately, and even more preferentially between 5% and 30% by weight approximately, relative to the total weight of the dye composition.

The dye composition may also contain various adjuvants conventionally used in hair dye compositions, such as anionic, cationic, nonionic, amphoteric or zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic polymers or mixtures thereof, mineral or organic thickeners, and in particular anionic, cationic, nonionic and amphoteric polymeric associative thickeners, antioxidants, penetrants, sequestrants, fragrances, buffers, dispersants, conditioning agents, for instance volatile or non-volatile, modified or unmodified silicones such as amino silicones, film-forming agents, ceramides, preserving agents, opacifiers and conductive polymers.

The above adjuvants are generally present in an amount for each of them of between 0.01% and 20% by weight relative to the weight of the composition.

Needless to say, a person skilled in the art will take care to select this or these optional additional compounds such that the advantageous properties intrinsically associated with the dye composition in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition (s) .

The pH of the dye composition is generally between 3 and 14 approximately, and preferably between 5 and 12 approximately. It may be adjusted to the desired value by means of acidifying or basifying agents usually used in the dyeing of keratin fibres, or alternatively using standard buffer systems.

According to one particular mode of the invention, when the dye composition comprises at least one dye of formula (I) , the composition has a pH of between 6 and

11. According to another particular mode of the invention, when the composition comprises at least one dye precursor of formula (II) , the composition has pH of between 6 and 11.

Among the acidifying agents, examples that may be mentioned include mineral or organic acids, for instance hydrochloric acid, orthophosphoric acid, sulfuric acid, carboxylic acids, for instance acetic acid, tartaric acid, citric acid or lactic acid, and sulfonic acids.

Among the basifying agents, examples that may be mentioned include aqueous ammonia, alkali metal carbonates, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, and also derivatives thereof, sodium hydroxide, potassium hydroxide and the compounds of formula (γ) below: ^R^1 f ^Ra2

N-W -N

^Ra4 ^XRa3 _{( γ )} in which W_a is a propylene residue optionally substituted with a hydroxyl group or a Ci-C₄ alkyl radical; R_ai, R_a2, R_a3 and R_a4, which may be identical or different, represent a hydrogen atom or a Ci-C₄ alkyl or Ci-C₄ hydroxyalkyl radical.

The dye composition may be in various forms, such as in the form of a liquid, a cream or gel, or in any other form that is suitable for dyeing keratin fibres, and especially the hair.

Another subject of the invention is a process for dyeing keratin fibres, in particular the hair, which consists in applying to keratin materials, in the presence or absence of an oxidizing agent, a dye composition comprising, in a cosmetic medium, at least one azomethine dye of formula (I) or a dye precursor of formula (II) as defined previously.

After a leave-in time, the keratin fibres are rinsed to reveal dyed fibres. The leave-in time is generally between 3 and 50 minutes approximately and preferably 5 to 40 minutes approximately.

The application of the dye composition according to the invention is generally performed at room temperature. However, it may be performed at temperatures ranging from 20 to 80⁰C.

The examples that follow serve to illustrate the invention without, however, being limiting in nature. The dyes of the examples below were fully characterized via the standard spectroscopic and spectrometric methods . EXAMPLES

EXAMPLES OF SYNTHESIS

Example 1: synthesis of 5- (2-hydroxyethylamino) -4- (4- hydroxyphenylimino) -2-methylcyclohexa-2, 5- dienone (b)

A solution containing 100 g (0.6 mol) of 5-(2- hydroxyethylamino) -2-methylphenol in 3 1 of water and

1.3 1 of 20% aqueous ammonia is prepared. 65.3 g

(0.6 mol) of para-aminophenol in 0.6 1 of water, 60 ml of 12N hydrochloric acid and 395 g (1.2 mol) of potassium ferricyanide in 1.2 1 of water are added with stirring, while keeping the temperature at about 15°C. 2 1 of ice-cold water and then 1.5 1 of 20-volumes aqueous hydrogen peroxide solution are then added. The reaction medium is stirred for 2 hours at 20⁰C.

After neutralization with acetic acid, the solid formed is filtered off, washed with water and with acetone and then dried. 75 g of 5- (2-hydroxyethylamino) -4- (4- hydroxyphenylimino) -2-methylcyclohexa-2, 5-dienone are obtained.

Example 2: synthesis of 4- (4-aminophenylimino) -5- (2- hydroxyethylamino) -2-methylcyclohexa-2, 5- dienone (e)

To a solution containing 28.4 g (0.2 mol) of sodium hydrogen phosphate in 2 1 of water are added with stirring 21.6 g (0.2 mol) of para-phenylenediamine and 33.4 g (0.2 mol) of 5- (2-hydroxyethylamino) -2- methylphenol . Air is bubbled through the reaction medium for 48 hours at room temperature. The solid formed is filtered off, washed with water, dissolved in dimethyl sulfoxide and then precipitated from water.

After filtering off, washing with water and drying, 10.3 g of 4- (4-aminophenylimino) -5- (2-hydroxyethylamino) -2-methylcyclohexa-2, 5-dienone are obtained.

Example 3: synthesis of 4- (4-aminomethylphenylimino) -5- (2-hydroxyethylamino) -2-methylcyclohexa-2, 5- dienone (c)

A solution containing 50.1 g (0.3 mol) of 5- (2- hydroxyethylamino) -2-methylphenol and 58.5 g of para- toluenediamine dihydrochloride in 600 ml of acetone, 200 ml of water and 500 ml of 20% aqueous ammonia is prepared with stirring.

A solution containing 150 ml of 200-volumes aqueous hydrogen peroxide solution and 1150 ml of water is added slowly, while keeping the temperature below 45°C.

The reaction medium is stirred for 2 hours 45 minutes at room temperature.

After cooling to 0⁰C, the solid is filtered off, washed with water and then dried. 40 g of 4- (4-aminomethylphenylimino) -5- (2-hydroxyethylamino) -2-methyl- cyclohexa-2, 5-dienone are obtained.

Example 4: synthesis of 4- { 4- [bis (2-hydroxyethyl) - amino] phenylimino } -5- (2-hydroxyethylamino) -2-

A solution containing 29.4 g (0.176 mol) of 5- (2- hydroxyethylamino) -2-methylphenol dissolved in 150 ml of IN sodium hydroxide and 200 ml of ethanol is prepared with stirring. This mixture is then added slowly to a solution containing 39.44 g of 2- [ (2- hydroxyethyl) (4-nitrosophenyl) amino] ethanol in 360 ml of water. The resulting medium is stirred for 1 hour 30 minutes and the solid formed is then filtered off, washed with water and dried.

After dissolving the solid obtained in dimethylformamide and precipitating from water, filtering off, washing with water and drying, 33.5 g of 4- { 4- [bis (2-hydroxyethyl) amino] phenylimino} -5- (2-hydroxyethylamino) -2-methylcyclohexa-2, 5-dienone are obtained.

Example 5: synthesis of 4- { 4- [bis (2-hydroxyethyl) - amino] -2, 6-dimethylphenylimino } -5- (2- hydroxyethylamino) -2-methylcyclohexa-2, 5-

(j) A solution of 6.7 g (0.04 mol) of 5- (2- hydroxyethylamino) -2-methylphenol in 40 ml of acetone is added to a solution of 11.9 g (0.04 mol) of 2-[(4- amino-3, 5-dimethylphenyl) (2-hydroxyethyl) amino] ethanol in 150 g of water. 100 ml of 20% aqueous ammonia solution are then added, followed by addition over 15 minutes of a solution of 18.6 g (0.08 mol) of ammonium persulfate in 60 ml of water.

After stirring for 1 hour, the solid formed is filtered off and washed with water, with acetone and with petroleum ether. 12 g of 4- { 4- [bis (2-hydroxyethyl) - amino] -2, 6-dimethylphenylimino } -5- (2-hydroxyethyl- amino) -2-methylcyclohexa-2, 5-dienone are obtained.

Example 6: synthesis of 2- (ethyl { 4- [2- (2-hydroxyethyl- amino) -5-methyl-4-oxocyclohexa-2, 5-dienyl- ideneamino] phenyl } amino) acetamide (h)

To a solution containing 400 ml of acetone, 400 ml of water and 1 1 of 20% aqueous ammonia solution are added 133.6 g (0.8 mol) of 5- (2-hydroxyethylamino) -2- methylphenol and 154.5 g (0.8 mol) of 2- [ (4-amino- phenyl) ethylamino] acetamide . After cooling to 5°C, a solution containing 184 g (0.8 mol) of ammonium persulfate in 800 ml of water is then added over 1 hour 10 minutes. The medium is stirred for 30 minutes at 5°C, and the solid formed is then drained off, washed with water and then dried. 67 g of 2- (ethyl { 4- [2- (2- hydroxyethylamino) -5-methyl-4-oxocyclohexa-2, 5-dienyl- ideneamino] phenyl } amino) acetamide are obtained. Example 7: synthesis of 4- [ (4-aminophenyl) amino] -5- [ (2- hydroxyethyl) amino] -2-methylphenol (r)

To a solution containing 2.2 g of sodium hydrosulfite in 3.3 ml of ethanol and 22 ml of aqueous IN sodium hydroxide solution are added portionwise at 25°C 1.1 g of 4- (4-aminophenylimino) -5- (2-hydroxyethylamino) -2- methylcyclohexa-2, 5-dienone . After stirring for 30 minutes, the reaction medium is neutralized with acetic acid, under an atmosphere of carbon dioxide, filtered off still under an atmosphere of carbon dioxide, washed with water and then dried. The solid obtained is then recrystallized from a dimethylformamide/water mixture. 0.26 g of 4-[(4- aminophenyl) amino] -5- [ (2-hydroxyethyl) amino] -2- methylphenol is obtained.

Example 8: synthesis of 4- { 4- [bis (2-hydroxyethyl) amino] -2, 6-dimethylphenylamino } -5- (2-hydroxy- ethylamino) -2-methylphenol (z)

(Z)

38.7 g (0.1 mol) of 4- { 4- [bis (2-hydroxyethyl) amino] - 2, 6-dimethylphenylimino } -5- (2-hydroxyethylamino) -2- methylcyclohexa-2 , 5-dienone 5 in 100 ml of ethanol are added to a solution heated to 90⁰C containing 120 g of sodium hydrosulfite and 800 ml of aqueous IN sodium hydroxide solution. After stirring for 20 minutes, 20 ml of aqueous ION sodium hydroxide solution are added and the medium is then cooled to 0⁰C and neutralized with acetic acid. The solid formed is filtered off, washed with water and then dried. 34 g of 4- { 4- [bis (2-hydroxyethyl) amino] -2, 6-dimethylphenylamino} - 5- (2-hydroxyethylamino) -2-methylphenol are obtained.

Example 9: synthesis of 4- [ (4-aminomethylphenyl) amino] - 5- [ (2-hydroxyethyl) amino] -2-methylphenol (q)

To a solution containing 3 g of sodium hydrosulfite in 8 ml of ethanol and 30 ml of aqueous IN sodium hydroxide solution is added portionwise at 25°C 1.0 g of 4- (4-aminomethylphenylimino) -5- (2-hydroxyethylamino) -2-methylcyclohexa-2, 5-dienone 3. After stirring for 20 minutes, the reaction medium is cooled to 5°C, neutralized with acetic acid, under an atmosphere of carbon dioxide, filtered off still under an atmosphere of carbon dioxide, washed with water and then dried. 0.85 g of 4- [ (4-aminomethylphenyl) amino] -5- [ (2-hydroxy- ethyl) amino] -2-methylphenol is obtained.

Example 10: synthesis of 2- (ethyl { 4- [4-hydroxy-2- (2- hydroxyethylamino) -5-methylphenylamino] - phenyl } amino) acetamide (al)

To a solution containing 4 g of sodium hydrosulfite in 2 ml of ethanol and 40 ml of aqueous IN sodium hydroxide solution are added portionwise at 25°C 2 g of 2- (ethyl- {4- [2- (2-hydroxyethylamino) -5-methyl-4-oxo- cyclohexa-2, 5-dienylideneamino] phenyl } amino) acetamide 6. After stirring for 1 hour, the reaction medium is cooled to 0⁰C, neutralized with acetic acid, filtered off, washed with water charged with CO₂, and then dried. 1.9 g of 2- (ethyl { 4- [4-hydroxy-2- (2-hydroxyethylamino) -5-methylphenylamino] phenyl } amino) acetamide are obtained.

Example 11: synthesis of 5- [ (2-hydroxyethyl) amino] -4- [ (4-hydroxyphenyl) amino] -2-methylphenol (bl)

To a solution containing 16 mg of sodium hydrosulfite in 500 μl of methanol and 5 μl of aqueous sodium hydroxide solution are added 10 mg of 5- [ (2-hydroxyethyl) amino] -4- [ (4-hydroxyphenyl) imino] -2-methylcyclo- hexa-2 , 5-dien-l-one . The solution is worked up according to the usual procedure and characterized. 5- [ (2-Hydroxyethyl) amino] -4- [ (4-hydroxyphenyl) amino] -2- methylphenol is thus obtained.

Example 12: synthesis of 4- ({ 4- [bis (2-hydroxyethyl) - amino] phenyl } amino) -5- [ (2-hydroxyethyl) amino] -2 -methy1- phenol (s)

To a solution containing 16 mg of sodium hydrosulfite in 500 μl of methanol and 5 μl of aqueous sodium hydroxide solution are added 13 mg of 4- ({ 4- [bis (2- hydroxyethyl) amino] phenyl } imino) -5- [ (2-hydroxyethyl) - amino] -2-methylcyclohexa-2, 5-dien-l-one.

The solution is worked up according to the usual procedure and characterized. 4- ({ 4- [Bis (2- hydroxyethyl) amino] phenyl } amino) -5- [ (2-hydroxyethyl) - amino] -2-methylphenol is thus obtained.

Example 13: synthesis of 3- { [4- ({ 2- [ (2-hydroxyethyl) - amino] -5-methyl-4-oxocyclohexa-2, 5-dien-l-ylidene } - amino) phenyl ] amino } -N, N, N-trimethylpropan-1-aminium bromide (pi)

To a solution of N-methylpyrrolidone containing 135,5 mg of 4- [ (4-aminophenyl) imino] -5- [ (2-hydroxyethyl) - amino] -2-methylcyclohexa-2 , 5-dien-l-one (e) , 138 mg of potassium carbonate and 130,5 mg of 3-bromo-N, N, N- trimethylpropan-1-aminium bromide are added. This mixture is stirred during 7 hours at 45°C. Then 15 ml of acetone are added into the reaction mixture and the obtained gum is washed with acetone and then the product is dried. 80 mg of the expected compound 3-{ [4- ( { 2- [ (2-hydroxyethyl) amino] -5-methyl-4-oxocyclohexa- 2 , 5-dien-l-ylidene } amino) phenyl ] amino } -N, N, N-trimethy1- propan-1-aminium bromide are obtained.

EXAMPLES OF DYEING

Dyeing in neutral medium

The dye compositions (A) to (D) below were prepared using compounds 1 to 4 synthesized previously.

Composition (A) (B) (C) (D) Compound (b) 10-3 mol - - -

Compound (e) - 10^"3 mol - -

Compound (C) - - 10 ^"3 mol -

Compound (g) - - - 10 ^"3 mol

Dye support (1) (* ) ⁽*⁾ ⁽*⁾ ⁽*⁾

Demineral ized

1 00 g 100 g 1 00 g 1 00 g water qs

(*) : dye support (1) pH=7 with the dye support constituted of:

96° ethyl alcohol 20.8 g

Pentasodium salt of diethylenetriaminepenta-

0.48 g AM acetic acid as an aqueous 40% solution

Cs-Cio alkyl polyglucoside as an aqueous 60%

3.6 g AM solution

Benzyl alcohol 2.0 g

Polyethylene glycol containing 8 units of

3.0 g ethylene oxide

Na₂HPO₄ 0.28 g

KH₂PO₄ 0.46 g

Compositions (A) to (D) are applied to locks of grey hair containing 90% white hairs. After a leave-on time of 30 minutes, the locks are rinsed, washed with a standard shampoo, rinsed again and then dried.

The shades obtained are given in the table below:

Dyeing in basic medium

The dye compositions (E) to (H) below are prepared from compounds 1 to 4 :

Compound (g) - - - 10^"3 mol

Dye support (2) ⁽*⁾ ⁽*⁾ ⁽*⁾ ⁽*⁾

Demineralized

100 g 100 g 100 g 100 g water qs

(*) : dye support (2) pH=9.5 with the dye support constituted of:

Compositions (E) to (H) are applied to locks of grey hair containing 90% white hairs. After a leave-on time of 30 minutes, the locks are rinsed, washed with a standard shampoo, rinsed again and then dried.

The shades obtained are given in the table below:

Claims

1. Compound of formula (I) or (II) :

(I) (H) salts thereof with an organic or mineral acid, geometrical isomers thereof, tautomers thereof, and solvates thereof such as the hydrates; in which formulae (I) and (II) :

• Ri represents: a (Ci-C3)alkyl radical optionally substituted with one or more hydroxyl groups; a (C1-C3) alkoxy radical optionally substituted with one or more hydroxyl groups;

• X represents: a hydroxyl radical; a radical -NR2R3 with R₂ and R3 representing, independently of each other: i) a hydrogen atom; ii) a C1-C5 alkyl radical optionally substituted with one or more groups chosen from hydroxyl, (C1-C3) alkoxy, amino, (Ci- C3) alkylamino, di (C1-C3) alkylamino, aminocarbonyl, carboxylic -COOH, sulfonic -SO3H, tri (C1-C3) alkylammonium and (Ci- C₃) alkylimidazolium; a pyrrolidinyl heterocycloalkyl radical optionally substituted with a group chosen from hydroxyl, (C1-C3) alkoxy, amino, (C1-C3) alkylamino, di (C1-C3) alkylamino, tri (C1-C3) alkylammonium and (C₁-C₃) alkylimidazolium; n represents an integer between 0 and 3 inclusive; it being understood that:

- when X and/or R₂ and/or R₃ comprise a cationic group, the electrical neutrality of the compounds of formula (I) or (II) is achieved with an anionic counterion or a mixture of anionic counterions that are cosmetically acceptable;

- the compounds of formula (I) or (II) cannot represent the compounds :

respectively.

2. Compound of formula (I) or (II) according to Claim 1, for which, when n is greater than or equal to 2, at least two groups Ri are identical and are either in position 2,6 or in position 3,5 on the phenyl radical.

3. Compound of formula (I) or (II) according to Claim 1, for which n is zero.

4. Compound of formula (I) or (II) according to any one of the preceding claims, for which X represents a hydroxyl radical.

5. Compound of formula (I) or (II) according to any one of Claims 1 to 3, for which X represents a radical -NR₂R₃ with R₂ and R3 representing, independently of each other, i) a hydrogen atom or ii) a Ci-C₅ alkyl radical optionally substituted with one or more groups chosen from hydroxyl, (C1-C3) alkoxy, amino, (C1-C3) alkyl- amino, di (C₁-C₃) alkylamino, aminocarbonyl, carboxylic -COOH, sulfonic -SO₃H, tri (Ci-C₃) alkylammonium and (Ci- C₃) alkylimidazolium.

6. Compound of formula (I) or (II) according to any one of Claims 1 to 3, for which X represents a pyrrolidinyl group optionally substituted with a tri (C1-C3) alkylammonium or (C1-C3) alkylimidazolium group .

7. Compound of formula (I) or (II) according to any one of the preceding claims, chosen from:

1- [4- ({4-hydroxy-2- [ (2- hydroxyethyl) amino] -5- methylphenyl } amino) phenyl ] -

N, N, N-trimethylpyrrolidin-3- aminium chloride

1-{1- [4- ({4-hydroxy-2- [ (2- hydroxyethyl) amino] -5-methyl- phenyl } amino) phenyl ] pyrrolidin-

3-yl } -S-methyl-lH-imidazol-S- ium chloride

3-{ [4- ({4-hydroxy-2- [ (2-hydroxy- ethyl) amino] -5-methylphenyl } - amino) phenyl ] amino } -N, N, N- trimethylpropan-1-aminium chloride

1- (3-{ [4- ({4-hydroxy-2-[ (2- hydroxyethyl) amino] -5-methylphenyl } amino) phenyl] amino }propyl) ^■ 3-methyl-lH-imidazol-3-ium chloride

1- (2-{ethyl [4- ( { 4-hydroxy-2- [ (2-hydroxyethyl) amino] -5-methylphenyl } amino ) phenyl ] amino } ethyl ) - 3-methyl-lH-imidazol-3-ium chloride

3, 3' -{ [4- ({4-hydroxy-2- [ (2- hydroxyethyl) amino] -5-methylphenyl } amino) phenyl ] imino } - bis (N, N, N-trimethylpropan-1- aminium) dichloride

4-{4- [bis (2-hydroxyethyl) - amino] -2, 6-dimethylphenyl- amino}-5- (2-hydroxy-

ethylamino) -2-methylphenol

[Z) 2- (ethyl-{4- [4-hydroxy-2- (2- hydroxyethylamino) -5-methyl- phenylamino] phenyl } amino) -

(al) acetamide with An , which may be identical or different, representing an anionic counterion.

8. Dye composition for dyeing keratin fibres, comprising, in a cosmetic medium, at least one compound of formula (I) or (II) as defined in any one of the preceding claims.

9. Composition according to the preceding claim, in which the compound of formula (I) or (II) is present in an amount of between 0.001% and 30% by weight relative to the total weight of the composition.

10. Composition according to Claim 8 or 9, in which, when the composition comprises at least one compound of formula (I) , the composition has a pH of between 6 and 11.

11. Composition according to Claim 8 or 9, in which, when the composition comprises at least one compound of formula (II) , the composition has a pH of between 6 and 11.

12. Composition according to any one of Claims 5 to 8, which also comprises at least one oxidizing agent.

13. Composition according to the preceding claim, in which the oxidizing agent is chosen from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts, peracids and oxidase enzymes.

14. Process for dyeing keratin fibres, in which a suitable dye composition comprising: at least one compound of formula (II) as defined in any one of Claims 8 to 13, or at least one compound of formula (I) :

• X represents: a hydroxyl radical; a radical -NR2R3 with R2 and R3 representing, independently of each other: i) a hydrogen atom; ii) a C1-C5 alkyl radical optionally substituted with one or more groups chosen from hydroxyl, (C1-C3) alkoxy, amino, (Ci- C3) alkylamino, di (C1-C3) alkylamino, aminocarbonyl, carboxylic -COOH, sulfonic -SO3H, tri (C1-C3) alkylammonium and (Ci- C₃) alkylimidazolium; a pyrrolidinyl radical optionally substituted with a group chosen from hydroxyl, (Ci-

C3) alkoxy, amino, (C1-C3) alkylamino, di (Ci-

C3) alkylamino, tri (C1-C3) alkylammonium and (Ci-

C₃) alkylimidazolium;

• n represents an integer between 0 and 3 inclusive; it being understood that:

- when X and/or R2 and/or R3 comprise a cationic group, the electrical neutrality of the compounds of formula (I) is achieved with an anionic counterion or a mixture of anionic counterions that are cosmetically acceptable for instance chlorides, bromides and sulfates, is applied to keratin materials.

15. Process for dyeing according to the preceding claim, in which a suitable dye composition comprising at least one compound of formula (I) as defined in any one of Claims 8 to 13 is applied to keratin materials.

16. Use of a compound of formula (I) or (II) as defined in any one of Claims 1 to 7, for dyeing keratin fibres .