LU85679A1 - NOVEL DINOTRO-2,4, HYDROXYALKYL-6 ANILINES, PROCESS FOR THEIR PREPARATION AND THEIR USE IN DYEING KERATINIC FIBERS, AND IN PARTICULAR HUNAN HAIR - Google Patents

Description

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New 2,4-dinitro, 6-hydroxyalkyl anilines, process for their preparation and their use in dyeing keratin fibers, and in particular human hair.

The present invention relates to novel 2,4-dinitro-6-hydroxyalkyl-6 anilines, to their process of preparation and to their use in dyeing ineric kerat fibers, and in particular human hair, as well by direct dyeing. only by so-called oxidation coloring.

] £) It is well known that, to give the hair direct coloring or complementary reflections in the case of oxidation coloring, nitrous derivatives of the benzene series can be used. ♦

The use of dinitro-2,4 N-substituted anilines, which are obtained by reaction of a primary amine with dinitro-2,4 chlorobenzene, both in direct dye and in oxidation dye, has already been recommended.

However, these compounds, when used as direct dyes for dyeing keratin fibers, and more particularly human hair, give shades which are insufficiently stable to light, weathering and washing.

20 Consequently, the applicant has sought other nitroaminobenzene dyes which make it possible to obtain more solid shades in light, weathering and washing, and this is how it discovered the compounds of formula:

25 ON · - X-OH

Ί Γ

\ sy ^ '^ NH-R

no2 in which X denotes a branched or unbranched alkylene radical containing 2 to 6 carbon atoms, one of these atoms possibly being substituted by one or more hydroxyl radicals; R denotes a hydrogen atom, an alkyl, mono- or polyhydroxy-alkyl or aminoalkyl radical, the amine function of which can be mono- or disubstituted by an alkyl or mono- or polyhydroxyalkyl radical, the nitrogen atom possibly being also be part of a heterocycle, the alkyl radical 2 c carrying 1 to 4 carbon atoms; R ’denotes a hydrogen atom or an alkyl radical in â C ^.

The present invention therefore relates to the new 2,4-dinitro-2,4-hydroxyalkyl-6 anilines of formula (I), as well as the cosmetically acceptable salts of the compounds comprising 1 salifiable amine function.

Mention may be made, as preferred radicals X, of the ethylene, propylene, dimethyl-1.1 ethylene, 1,2-dimethyl ethylene and trimethyl-1,1.2 ethylene radicals.

As preferred radicals R, mention may be made of hydrogen, methyl, ethyl, n-propyl, ^ -hydroxyethyl, if -hydroxypropyl, ß, ÿ'-dihydtoxypropyl, y £> -aminoethyl, β - diethylaminoethyl.

As preferred R ’radicals, mention may be made of hydrogen and the methyl radical.

Preferred compounds of formula (I) according to the invention are: 15 - 1 ′ (2-amino, 3,5-dinitro) 2-phenyl-1-ethanol; - (^ -hydroxyethylamino-2, dinitro-3,5) phenyl-2 ethanol-1; - 1 ’(2-amino, 3,5-dinitro) phenyl-1 propanol-2; - (methylamino-2, dinitro-3,5) phenyl-l propanol-2; - £ (^ 3-aminoethyl) amino-2, dinitro-3,5] phenyl-1 propanol-2, as well as their salts.

A subject of the invention is also the process for the preparation of the compounds of formula (I) consisting in reacting an aqueous ammonia solution or a primary aliphatic amine R-NH2, or R with the meaning indicated above, on the compounds heterocyclics of formula (II) according to the following reaction scheme: R 'R'

+ RNH „-> --X-OH

I ir 30 N02 Tïo2 (II) (I) R * and X having the meaning indicated above, i The opening of the heterocycle by the primary amine or by the ammonia * is carried out at a temperature between 20 and 120 ° C., possibly under pressure, in the presence or absence of polar protic solvents such as water, alcohols, glycols or glycol ethers, or of 3 polar aprotic solvents such as formamide, dimethylformamide, dioxane, tetrahydrofuran.

The compounds of formula (II) are obtained by nitration of the compounds of formula (III):. 5 R ’

(HD

where R ’and X have the meaning indicated above, the nitration being effected by adding the compound (III) to the fuming nitric acid at a temperature between 30 and 35 ° C £ according to G. CHATELUS - Ann. Chem.

4_, 505-547 (1949)] or by adding the compound (III) to a sulfonic mixture, at a temperature close to 5 ° C. according to Charles D. HÜRD, Rostyslaw DOWBENKO, J.A.C.S. 80, 4711-14 (1958)]; the compound (II) is then isolated after dilution of the reaction medium with water.

The compounds of formula (III) are known and most of the compounds of formula (II) are also known.

Among the compounds of formula (II) known, there may be mentioned: 2o dinitro-5,7 coumaranne (or dihydro-2,3, dinitro-5,7 benzofurane), methyl-2; d in itro-5.7 coumaranne, dimethyl-2,2, dinitro-5,7 coumaranne, dimethyl1-2,3, dinitro-5,7 coumaranne and trimithyl-2,2,3 dinitro-- 5, 7 coumaranne.

The process for preparing the compounds of formula (I) according to in-2Ç. vention provides excellent yields of these compounds.

Another object of the present invention consists of a dye composition for keratin fibers, and more particularly for human hair, containing in a solvent medium, at least one 2,4-dinitro-6, 6-hydroxyalkyl aniline of formula (I) below. above or one of its cosmetically acceptable salts.

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The present invention also relates to a process for dyeing keratin fibers, and more particularly human hair, by direct dyeing or by oxidation dyeing involving revelation by an oxidant.

* The dye compositions in accordance with the invention contain, in a solvent medium, at least one compound corresponding to formula (I) //! 4 or one of its cosmetically acceptable salts, and can be used for the direct dyeing of keratin fibers or for the oxidation dyeing of these fibers, in which case the compounds of formula (1) confer reflections complementary to the dyeing of base obtained by oxidative development of oxidation dye precursors.

These compositions contain the compounds according to the invention in proportions of between 0.001 and 5% by weight and preferably between 0.05 and 2% by weight relative to the total weight of the composition.

The solvent medium is preferably a cosmetic vehicle generally consisting of water, but it is also possible to add, in the compositions, organic solvents to dissolve compounds which are not sufficiently soluble in water. Among these solvents, mention may be made of lower alkanols such as ethanol and isopropanol, aromatic alcohols such as benzyl alcohol, polyols such as glycerol, glycols or glycol ethers such as 2-butoxyethanol or 2-ethoxyethanol, ethylene glycol, pro-pylene glycol, monethylethyl ether and monoethyl ether of diethylene glycol as well as analogues and their mixtures. These solvents are preferably present in proportions ranging from 1 to 75% by weight and in particular from 5 to 50% by weight relative to the total weight of the composition.

These compositions can contain anionic, cationic, nonionic, amphoteric surfactants or mixtures thereof. These surfactants are present in the compositions of the invention in proportions of between 0.5 and 55% by weight and preferably between 4 and 40% by weight relative to the total weight of the composition.

The compositions can preferably be thickened with layered compounds chosen from sodium alginate, gum arabic, cellulose derivatives such as methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose and various polymers. having the function of thickener such as more particularly derivatives of acrylic acid. It is also possible to use mineral thickening agents such as bentonite. These thickening agents are preferably present in the proportions of between 0.5 and 10% by weight and in particular between 0.5 and 2% by weight relative to the total weight of the composition.

\ 5

The compositions according to the invention can also contain various adjuvants usually used in hair dye compositions and in particular penetration agents, dispersing agents, sequestering agents, filmpgene agents, buffers and perfumes.

These compositions can be in various forms such as liquid, cream, gel or any other form suitable for dyeing the hair. They can also be packaged in aerosol bottles in the presence of a propellant.

The pH of these dye compositions can be between 3 and 11.5, preferably between 5 and 11.5. It is adjusted to the desired value using an alkalizing agent such as ammonia, sodium, potassium or ammonium carbonate, sodium or potassium hydroxides, alkanolamines such as mono, di- or triethanolamine, 2-amino-2-methyl-propanol-1, 2-amino-2-methylpropanediol-1,3, alkylamines such as ethylamine or tri-thylamine or using an acidifying agent such as phosphoric, hydrochloric, tartaric, acetic, lactic or citric acids.

When the compositions are intended to be used in a direct hair coloring process, they may contain, in addition to the compounds according to the invention, other direct dyes such as azo or anthraquinone dyes, such as for example - tetra-amino-1,4,5,8 anthraquinone, indophenols, indoanilines and nitrous dyes of the benzene series different from the compounds of formula (I).

The concentrations of these direct dyes other than the dyes of formula (I) can be between 0.001 and 5% by weight relative to the total weight of the composition.

These compositions, used in a dyeing process by 3q direct coloration, are applied to the keratin fibers for an exposure time varying from 5 to 50 minutes, then the fibers are rinsed, optionally washed with shampoo, rinsed again and dried.

The compositions according to the invention can also be used in the form of ‘hair styling lotions intended both to give the hair a slight coloration or reflections.

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6 and to improve the holding of the styling. In this case, they are in the form of aqueous, alcoholic or hydroalcoholic solutions containing at least one cosmetic resin and their application is carried out on damp hair previously washed and rinsed which are optionally coiled and then dried.

The cosmetic resins used in the setting lotions can be in particular polyvinylpyrrolidone, crotonic acid-vinyl acetate, vinylpyrrolidone-vinyl acetate, maleic anhydride-butylvinyl ether, maleic anhydride-methyl vinyl ether as well as any other cationic, anionic, nonionic or amphoteric polymer usually used in this type of composition. These cosmetic resins fall within the limits of the invention in an amount of 0.5 to 4% by weight, and preferably from 1 to 3% by weight based on the total weight of the composition.

When the compositions according to the invention constitute oxidation dyes involving revelation by an oxidizing agent, the compounds of formula (I) in accordance with the invention are essentially used with a view to bringing reflections to the final dye.

These compositions then contain, in association with at least one 2o nitrated dye of formula (I) and optionally other direct dyes, dye precursors by oxidation.

They may contain, for example, para-phenylenediamines such as: para-phenylenediamine, paratoluylenediamine, 2-chloro-para-phenylenediamine, 2,6-dimethyl para-phenylenediamine, 2,6-dimethyl-2,6-methoxy-3-para-phenylenediamine, N- (yô- methoxyethy 1) paraphenylenediamine, N, N- (ß-hydroxyethyl) paraphenylenediamine, N, N- (ethyl, carbamylmethyl) 4-amino aniline, as well as their salts.

They can also contain paraaminophenols, for example: s paraaminqphenol, N-methyl paraaminqphenol, chloro-2 amino-4 3q phenol, chloro-3 amdno-4 phenol, methyl-2 amino-4 phenol, and their salts.

They may also contain orthoaminophenol.

They can also contain heterocyclic derivatives, for example: 2,5-diamino pyridine, 7-amino benzomorpholine.

The compositions according to the invention may contain, in combination with the dye precursors by oxidation, couplers \A / 7 well known in the state of the art.

As couplers, there may be mentioned in particular: metadiphenols, metaaminophenols and their salts, metaphenylenediamines and their salts, metaacylaminophenols, metaurideophenols, 5-metacarbal coxyaminophenols.

Finally, mention may be made, as other couplers which can be used in the compositions of the invention, of o-naphthol, -couplers having an active methylene group such as diketonic compounds and pyrazolones and heterocyclic couplers derived from pyridine and 10 benzomorpholine.

These compositions contain, in addition to dye precursors by oxidation, reducing agents present in proportions of between 0.05 and 3% by weight relative to the total weight of the composition.

The oxidation dye precursors can be used, in the compositions of the invention, at concentrations of between 0.001 and 5% by weight and preferably between 0.03 and 2% by weight based on the total weight of the composition. The couplers can also be present in proportions of between 0.001 and 5% by weight, preferably between 0.015 and 2% by weight. The pH of these oxidation dye compositions is preferably between 7 and 11.5 and is adjusted using basifying agents defined above.

The process for dyeing keratin fibers, in particular human hair, using revelation by an oxidant, consists in applying to the hair the dye composition comprising both a dye according to the invention and the dye precursors. The development of the coloration can then be carried out slowly in the presence of oxygen from the air, but preferably a chemical developing system is used which is most often chosen from hydrogen peroxide, 2q urea peroxide and parsley ·. In particular, a 20-volume hydrogen peroxide solution is used.

Once the composition with the oxidizing agent has been applied to the keratin fibers, it is left to stand for 10 to 50 minutes, preferably 15 to 30 minutes, after which the keratin fibers are rinsed and washed. possibly with shampoo, they are rinsed again and dried.

8

The following examples are intended to illustrate the invention without being limiting in nature. PREPARATION EXAMPLE 1

° 2Îi ^ ° 2'V ^ y ^ CWH

p — 3 χτ N02 N02

Preparation of 1 ’(amiao-2.dlnitro-3,5) phenyl-2 ethanol-1

Is suspended in 350 ml of 20% ammonia and 220 ml of jq formamide, 0.17 mole (35.7 g) of 2,3-dihydro, 5,7-dinitro benzofuran prepared according to Chatelus Ann. Chlm. 505-547 (1949). After 8 hours of heating at 110 ° C., 100 ml of 20% ammonia are added. Heating is maintained for 4 hours. By cooling the reaction medium, the expected product precipitates.

^ After wringing, washing with ice water until neutral and drying under vacuum, 0.13 mol (30.3 g) of a product melting at 151 ° C. is obtained, which is recrystallized from dioxane.

The analysis of the product gives the following results:

Analysis Calculated for Found 20 C8H9N3 ° 5% C 42.29 42.24% H 3.99 3.91% N 18.50 18.60% 0 35.21 35.14 25 PREPARATION EXAMPLE 2 ° 2N ^ ^ 1 I HOCH CH9NH9] | ~ ^ —Nhch9ch „oh

To2 k2

Preparation of (β-hydroxyethylamlno-2, dlnltro-3,5) phenyl-2 and ethanol-1 3! 0.29 mole (60.9 g) of 2,3-dihydro-5,7-dinitro-5,7 benzofuran is added in portions at room temperature to 122 ml of 2-amino-ethanol.

After the end of the addition, the reaction medium is brought 15 minutes 35 to 95 ° C. 500 ml of water are added; after cooling, the i i t i i i, i / 9 is drained, the expected product which, after re-pasting in water and recrystallization from 75 ml of ethanol at 96 °, melts at 115 ° C.

The analysis gives the following results:

Analysis Calculated for Found. 5 C10H13N3 ° 6% C 44.28 44.38% H 4.83 4.74% N 15.49 15.48% 0 35.39 35.60 i0 PREPARATION EXAMPLE 3 ° ^ V ^ r- ^ CH2CHOHCH3

It η I NH, / CHo0CH9CH90H I Γ. - nh2 no2 no2

Preparation of 1 * (amino-2, dinitro-3,5) phenyl-1 propanol-2 Suspended in 1.1 l of 20% ammonia and 600 ml of methylcellosolve 0.39 mole (88 g) of dihydro “2,3, dinitro-5,7, 2-methyl benzofuran prepared according to J.À.CS 80, p. 4711-4714 (1958). After 18 hours of heating at 70 ° C., the reaction medium is cooled. 2q is filtered off the precipitate formed which, after repasting in water to neutral, then drying under vacuum, is recrystallized from 170 ml of dioxane.

After drying under vacuum, 0.30 mol (72 g) of the expected product is obtained; ; it melts at 177 ° C.

The analysis gives the following results: 2g Analysis Calculated for Found C9H11N3 ° 5% C 44.81 44.87% H 4.60 4.62% N 17.42 17.45 3Q% 0 33.17. 33.08 PREPARATION EXAMPLE 4

°? N OJJ CHCHOHCH

Y ^ l — 1 w-t * "Yf2 35 K \ I / / 10

Preparation of (methylamino-2, dinitro-3> 5) phenyl-l propanol-2

0.056 mol (12.5 g) of 2,3-dihydro, 5,7-dinitro, 2-methyl-benzofuran is suspended in 100 ml of a 33% methylamine solution in ethanol. After stirring for 10 hours at room temperature 5 in a stoppered Erlenmeyer flask, the reaction medium is brought to reflux of the alcohol for 30 minutes. After cooling, the expected product precipitates. It is wrung, washed with alcohol and then recrystallized from 50 ml of 96 ° ethanol. After drying, 0.047 mol (12 g) of a product melting at 132 ° C. is obtained.

10 The analysis gives the following results:

Analysis Calculated for Found C10H13N3 ° 5% C 47.06 47.11% H 5.13 5.03 15% N 16.47 16.52% 0 31.34 31.25 PREPARATION EXAMPLE 5 ° 2 ^ ^ ° 2N ^^^ ÏÏ2Œ0HCH3 1 I iy 1 1 20 7 --- NHCH2CH2NH2 N02 N02

DurCfi-amlnoethyl) amino-2, 3,5-dinitro-3,51-phenyl-propanol-2 preparation To 40 ml of ethylenedlamine, 0.089 mol (20 g) of 2,3-dihydro-dinitro is added with stirring at room temperature -5.7, 2-methylbenzofuran. At the end of the addition, the reaction medium is poured into 500 ml of water. The expected product precipitates. After wringing and re-pasting in water, it is recrystallized from 210 ml of 96 ° ethanol. 0.074 mole (20.9 g) of a product melting at 140 ° C. is obtained.

30 Molecular mass calculated for Ο ,, Η ,, Ν.Ογ: 284.

11 16 4 5

Molecular mass found by potentianetric determination in acetic acid by perchloric acid: 293.

The analysis of the product obtained gives the following results: • 11

Analysis Calculated for Found C11H16N4 ° 5% C 46.47 46.40% H 5.67 5.68 5% N 19.71 19.82% 0 28.14 27.95 EXAMPLE 1

The following dye composition is prepared: IQ (2-amino, 3,5-dinitro) 2-phenyl ethanol-0.2 g

96 ° alcohol 15 g ALFOL C16 / 18 8 g _ Lanette wax E 0.5 g CEMULSOL B 1 g ^ 5 Oleic diethanolamide 1.5 g

Triethanolamine at 1% by weight 1 g

Water qs 100 g pH * = 8.4

This mixture, applied for 30 minutes at 28 ° C on bleached hair 20 to white, gives them, after shampooing and rinsing, a coloration: 6.25 Y 8.5 / 6 according to the Munsell notation.

EXAMPLE 2

The following dye composition is prepared: (^ -hydroxyethylamino-2, dinitro-3,5) phenyl-2, 25 ethanol-1 0.36 g

Butoxy-2 ethanol 10 g ALFOL C16 / 18 8 g

Lanette wax E 0.5 g CEMULSOL B 1 g 30 Oleic diethanolamide 1.5 g

Triethanolamine at 1% by weight 1 g

Water qs 100 g pH = 7.8

This mixture, applied 20 minutes at 28 ° C. to the hair, gives them, after shampooing and rinsing, a coloring: / / • 12 5 Y 8.5 / 7 on hair bleached with white; 5 Y 8/5 on naturally white hair at 90%, these colors being expressed according to the Munsell notation.

EXAMPLE 3 The following dye composition is prepared: (2-amino, 3,5-dinitro) 2-phenyl-2-propanol 0.24 g

Propylene glycol 10 g CCMPERLAN KD 2.2 g

Lauric acid 0.8 g 10 Ethoxy-2 ethanol 2 g

Monoethanolamine 1 g

Water qs 100 g _pH = 8.4

This mixture, applied for 30 minutes at 28 ° C. to hair bleached in white, gives them, after shampooing and rinsing, a coloration: 3.75 Y 8.5 / 5 according to the Munsell rating.

EXAMPLE 4

The following dye composition is prepared; (methylamino-2, dinitro-3,5) phenyl-1 propanol-2 0.36 g 20 Alcohol at 96 ° 12 g CCMPERLAN KD 2.2 g

Lauric acid 0.8 g 'Ethoxy-2 ethanol 2 g

Monoethanolamine 1 g 25 Water qs 100 g pH = 8

This mixture, applied 20 minutes at 30 ° C to hair bleached in white, gives them, after shampooing and rinsing, a coloration: 7 Y 8.5 / 4 according to the Munsell rating.

30 EXAMPLE 5

The following dye composition is prepared: / ^ "- aminoethyl 1) amino-2, d initr o-3,5 ^ phenyl-1 propanol-2 0.12 g

Butoxy-2 ethanol ‘8 g 35 CARBOPOL 934 2 g i i» i i 13 «

Amin o-2, methyl 1-2 propanol-1 in 25% solution in water 2 g

Water qs 100 g pH - 5 5 This mixture, applied 30 minutes at 30 ° C on hair bleached with white, gives them, after shampooing and rinsing, a coloring: 5 Y 8.5 / 7 according to the Munsell rating.

EXAMPLE 6

The following dye composition is prepared: 10 BP -aminoethyl) amino-2, dinitr o-3,5 J phenyl-1 prqpanol-2 0.415 g

Nitro-3, N’-methylamino-4, N, N- (y & -hydroxyethyl) aniline 0.155 g Methyl-2, amino-4, nitro-3, N - (^ - hydroxyethyl) aniline 0.08 g

96 ° alcohol 12 g 15 ALFOL C16 / lg 8 g

Lanette wax E 0.5 g CEMULSOL B 1 g

Oleic diethanolamide 1.5 g

Monoethanolamine in 20% solution in water 0.25 g 20 Water qs 100 g pH = 9.4

This mixture, applied 20 minutes at 28 ° C to bleached hair, gives them, after shampooing and rinsing, a hazelnut color.

EXAMPLE 7 The following dye composition is prepared: (^ S ~ hydroxyethylamino-2, dinitro-3,5) phenyl-ethanol-1 - 0.47 g

Nitro-3, ^> - 4-hydroxyethylamino phenol 0.13 g Tetraamino-l, 4,5,8-anthraquinone (blue Cibacète 30 microdispersed) 0.08 g,

Butoxy-2 ethanol 10 g CELLOSIZE WP 03 2 g

Alkyl chloride (tallow) dimethyl hydroxyethyl ammonium 2 g

5% ammonia 0.15 g 35 Water qs 100 g pH = 8 i l t 14

This mixture, applied 25 minutes at 28 ° C on bleached hair, gives them, after shampooing and rinsing, a dark golden blonde coloring.

EXAMPLE 8 The following dye mixture is prepared: (^ -hydroxyethylamino-2, dinitro-3,5) phenyl-2, ethanol-1 0.205 g

Paraphenylenediamine 0.08 g

Paraaminophenol 0.06 g 10 Resorcin 0.085 g Metaaminophenol 0.06 g ^> - 3-hydroxyethylamino, 6-methyl phenol 0.05 g _ Polyglycerol oleic alcohol with 2 moles of glycerol 4.5 g

Polyglycerol oleic alcohol with 4 moles of glycerol 4.5 g 15 ETHOMEEN TO 12 4.5 g COMPERLAN KD 9 g

Propylene glycol 4 g

Butoxy-2 ethanol 8 g

Ethanol at 96 ° 6 g 20 MASQUOL DTPA 2 g

Thipglycolic acid 0.6 g

Ammonia at 22 ° Bë 10 g

Water qs 100 g pH = 10.5 25. At the time of use, 100 g of hydrogen peroxide is added to 20 volumes.

The mixture, applied 25 minutes at 30 ° C to bleached hair, gives them, after shampooing and rinsing, a golden brown color.

15

The different commercial nans used in the above examples are explained in more detail below: CARBOPOL 934: Polymer of acrylic acid of PM 2 to 3 million sold by Goodrich Chemical Company.

5 ALEOL C16 / 18 (50/50): Cetylstearyl alcohol sold by the Company

Condéa.

Lanette Wax E: Partially sulfated cetylstearyl alcohol sold by Henkel.

. 10 CEMULSOL B: Ethoxylated castor oil sold by Rhône

Poulenc.

COMPEBLAN KD: Diethanolamide of coconut fatty acid sold by Henkel.

CELLOSÏZE WP 03: Hydraxyethylcellulose sold by Union Carbide.

15 ETHQMEEN TO 12: Oxyethylenated oleylamine containing 12 moles of ethylene oxide sold by the company AEMAK.

MASQUOL DTPA: Pentasodium salt of diethylene triamine pentacetic acid sold by the company PROTEX.

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Claims (16)

1. 2,4-Dinitro-6-hydroxyalkyl aniline of formula (I) below: IL 5 --110-11 ko2 in which: X denotes a branched or unbranched alkylene radical containing 2 to 6 carbon atoms, one of these atoms possibly being substituted by one or more hydroxyl radicals; R denotes a hydrogen atom, an alkyl, mono- or poly-hydroxyalkyl or aminoalkyl radical, the amine function of which can be my όση disubstituted by an alkyl radical or by a mono- or poly-hydroxyalkyl radical, the nitrogen atom can also be part of a hetero-ring, the alkyl radicals having 1 to 4 carbon atoms; R ′ denotes a hydrogen atom or a C 1 to C 4 alkyl radical; and the cosmetically acceptable salts of the compounds comprising a salifiable amine function. 2. Compound according to claim 1, characterized in that R 'is hydrogen or a methyl radical, X is an ethylene, propylene, 1,1-dimethyl ethylene, 1,2-dimethyl ethylene or trimethyl- radical. „1,1,2 ethylene and R is hydrogen or a methyl, ethyl, n-propyl, -hydroxyethyl, ^ -hydroxypropyl, - df-dihydroxypropyl, ^ 3-aminoethyl or β-diethylaminoethyl radical. 3. Compound according to Claim 1 or 2, characterized in that - "it is chosen from the group comprising: 1 '(2-amino, 3,5-dinitro) 2-phenyl-1-ethanol, the (^> -hydroxyethylamino-2, dinitro-3., 5) phenyl-2. I ethanol-1, 1 '(amino-2, dinitro-3,5) phenyl-l propanol-2, le (methylamino-2,> j dinitro -3.5) phenyl-l propanol-2, the £ "j ^ S-aminoethyl) amino-2, dinitro-3,5 ~]»! 1-phenyl-propanol-2, and the salts of these compounds, 4. Method for preparing a 2,4-dinitro-6-hydroxyalkyl aniline 'of formula (I) according to claim 1, characterized in that an aqueous ammonia solution or a primary amine is reacted RNH, R having the meaning given in claim 1, on the i L ·! 35 heterocyclic compound of formula (II):! \ /. / 17 R ’o2n --- X. (II) "5 to2 in which R * and X have the meanings indicated in claim 1, at a temperature between 20 and 120 ° C, optionally under pressure and optionally in the presence of polar protic or polar aprotic solvents. 5. Dye composition for ineric kërat fibers, and in particular for human hair, characterized in that it contains, in a solvent medium, at least one compound as defined in one of claims 1 to 3. 6. Composition according to claim 5, characterized in that it contains 0.001 to 5% by weight, and preferably 0.05 to 2% by weight, of at least one compound of formula (I), relative to the total weight of the composition. 7. Composition according to claim 5 or 6, characterized by the fact that it has a pH between 3 and 11.5, and preferably between 5 and 11.5. 8. Composition according to any one of claims 5 to 7, characterized in that the solvents are chosen from water, lower alkanols, aromatic alcohols, polyols, glycols or glycol ethers, or their mixtures. 9. Composition according to any one of claims 5 to 8, characterized in that it also contains cosmetic adjuvants chosen from anionic, cationic, nonionic, amphoteric surfactants or their mixtures, thickeners, Dispersing agents, penetrating agents, sequestering agents, film-forming agents, buffers, perfumes, alkalinizing or acidifying agents. 10. Composition according to any one of claims 5 'to 9, intended to be used for direct dyeing of human hair, - 18 t characterized in that it also contains other direct dyes chosen from azo dyes , anthraquinone dyes, indophenols, indoanilines and nitro derivatives of the benzene series other than those of formula (I). 11. Composition according to any one of claims 5 to 9, intended for use as a styling lotion, characterized in that it is in the form of an aqueous, alcoholic or hydroalcoholic solution, containing at least one . cosmetic resin. 12. Composition according to any one of claims 5 to 9, jo intended to be used for the oxidation dye, characterized in that it also contains at least one dye precursor by oxidation. - 13. Composition according to claim 12, characterized in that it has a pH between 7 and 11.5 and that it additionally contains a reducing agent. 14. Process for dyeing keratin fibers, and in particular human hair, characterized in that a composition as defined in any one of claims 5 to 10 is applied to the fibers, it is left to stand for 5 to 50 minutes, then rinse, optionally wash, rinse again and dry. 15. Process for dyeing keratinous fibers, and in particular (human hair, characterized in that a composition as defined in claim 11 is applied to the washed and rinsed fibers, optionally wound and we dry. 16. Process for dyeing keratin fibers, and in particular for human hair, characterized in that a composition as defined in claims 12 or 13 is applied to the fibers, optionally added with an oxidizing agent, leave on for 10 to 50 minutes, rinse, wash if necessary with shampoo, • 3o rinse again and dry. Drawings: ......... plates i. _jÂ3 __ .. pages of which ........ 4 ...... cover page * - AS. description pages ...... J. r s ‘- ;. üs ce demande / i t -. y ~ description Luxembourg i; aEC. 1se4 The manda ^ iiô: