FR2551748A1 - New dimethylated nitroparaphenylenediamines, process for preparing them and their use for dyeing keratinous fibres - Google Patents

Abstract

The invention relates to dimethylated derivatives of nitroparaphenylenediamine of formula: in which CH3 is in position 2 or 5 of the benzene ring, or to the cosmetically acceptable salts of these compounds, as well as the process for preparing them and their use in dyeing compositions, in particular for the hair, both for direct dyeing and for oxidative dyeing.

Description

New nitroparaphenylenediamine diethyls, process for their preparation and their use in dyeing keratin fibers.

 The present invention relates to novel dimethyl derivatives of nitroparaphenylenediamine X in their process of preparation and their use in dyeing keratinous fibers, and in particular human hair.

 It is well known that to give the hair a direct coloration or complementary reflections in the case of oxidation dyeing, it is possible to use nitro derivatives of the benzene series. It has already been advocated the use of nitroparaphenylenediamines such as more particularly nitroparaphenylenediamine and 2-methyl-5-nitro paraphenylenediamine both in direct dyeing and oxidation dyeing.

 The perfect safety of these nitroparaphenylenediamines has, however, been questioned in recent years and it was sought thereby to replace these dyes in hair dye compositions.

 Furthermore, it has generally been found that nitroparaphenylenediamines are poorly preserved in the reducing alkaline medium, especially comprising sodium bisulfite, which is usually used in oxidation dyeing compositions. Nitroparaphenylenediamines having a good preservation in a reducing alkaline medium have therefore also been sought.

 As a result of these investigations, the Applicant has discovered new dimethyl nitroparaphthylenediamines having both a very low toxicity and a very good stability in solution, especially when they are used in an oxidation dyeing composition in the presence of an agent. alkali and a reducing agent such as sodium bisulfite.

 The Applicant has also found that the hair dyes obtained using these new nitroparaphenylenediamines have good weatherability, light and washing.

 The subject of the present invention is therefore new dimethyl nitroparaphenylenediamines and their process of preparation.

 The invention also relates to dye compositions for keratinous fibers, and in particular for human hair, containing these dimethylated nitro paraphenylenediamines, dyeing compositions which can be used both for direct hair dyeing and for dyeing by oxidation.

 Other objects and advantages of the present invention will become apparent on reading the description and examples which follow.

dans laquelle le radical CH3 à position variable peut se trouver en position 2 ou 5 du cycle benzénique, et peuvent exister sous forme de sels cosmétiquement acceptables des composés de formule (I).The dimethyl nitroparaphenylenediamines according to the invention correspond to the following formula (I)

in which the variable-position CH3 radical can be in position 2 or 5 of the benzene ring, and can exist in the form of cosmetically acceptable salts of the compounds of formula (I).

 The compounds which are the subject of the invention are, on the one hand, 2,6-dimethyl-3-nitro-para-phenylenediamine and, on the other hand, 5-dimethyl-3-nitro-para-phenylenediamine.

 The 2,5-dimethyl-3-nitro-para-phenylenediamine also synthesized has dye properties but does not exhibit the significant advantages of the preferred compounds. Their interesting properties seem to be due without this interpretation being limited to the presence of a methyl radical para para group NO2.

dans laquelle Ri désigne un atome d'hydrogène lorsque CH3 est en position 2 et R1 désigne le groupe acétyle(-COCH3) lorsque CH3 est en position 5.The compounds of formula (I) may be prepared by nitration of the compounds of formula (II) below

wherein R 1 is hydrogen when CH 3 is in the 2-position and R 1 is acetyl (-COCH 3) when CH 3 is in the 5-position.

 When the radical CR 3 is in the 5-position with R 1 denoting -COCH 3, it is the N, N'-diacetyl derivative of dimethyl-5,6-paraphenylenediamine which is a known compound.

 When the CH3 radical is in the X position, where R1 denotes hydrogen, it is 2,6-dimethyl-4-acetylamino aniline which is a new compound obtained by acetylation formed in water, at room temperature, in the presence of sulphite. sodium, 2,6-dimethyl-paraphenylenediamine dihydrochloride.

dans laquelle R1 a les mêmes significations que ci-dessus et CH3 les moles positions que celles indiquées ci-dessus. The nitration of the compounds II is carried out in a conventional manner. Compounds II, after having been placed in solution at room temperature, in 96% sulfuric acid, are treated at -5 ° to 0 ° C. with a sulphonitrile mixture resulting in the following compounds of formula III:

in which R 1 has the same meanings as above and CH 3 the same positions as those indicated above.

 The compounds of formula (III) thus obtained are then hydrolysed using hydrochloric acid.

 The dyeing compositions in accordance with the invention contain, in a solvent medium, at least one compound corresponding to formula (I) and may be used for the direct dyeing of keratinous fibers or for the oxidation dyeing of these fibers, in which case the compounds of formula (I) confer complementary reflections on the basic coloring obtained by oxidative development of oxidation dye precursors.

 These compositions contain the compounds according to the invention in proportions of between 0.001 and 1% by weight and preferably between 0.05 and 0.5% by weight relative to the total weight of the composition.

 The solvent medium is preferably a cosmetic vehicle generally consisting of water, but organic solvents can also be added to the compositions in order to solubilize 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-butoxy ethanol. ethoxy-2-ethanol, ethylene glycol, propylene glycol, diethylene glycol monoethyl ether and monomethyl ether and the like and mixtures thereof. These solvents are preferably present in proportions ranging from 1 to 75% by weight and in particular from 5 to 50% by weight. % by weight relative to the total weight of the composition.

 These compositions may contain anionic, cationic, nonionic or 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 may be thickened preferably with compounds selected from sodium alginate, gum arabic, cellulose derivatives such as methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose and various polymers having the thickener function such as more particularly derivatives of acrylic acid. It is also possible to use inorganic thickening agents such as bentonite. These thickening agents are preferably present in proportions of between 0.5 and 10% by weight and in particular between 0.5 and 3% by weight relative to the total weight of the composition.

 The compositions according to the invention may also contain various adjuvants usually used in hair dye compositions and in particular penetrating agents, dispersing agents, sequestering agents, film-forming agents, buffers and perfumes.

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

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

 When the compositions are intended to be used in a direct hair dyeing process, they may additionally contain compounds according to the invention other direct dyes such as azotic or anthraquinone dyes, such as tetraamino-1, 4,5,8-anthraquinone, nitro dyes of the benzene series different from the compounds of formula (I) and more particularly the compounds following the 2-methyl-6-nitroaniline, the 2-methyl-4-amino-5-nitro phenol, the 3-nitro N, N-hydroxyethylamino-N-methylaniline, 3-nitro N, N-hydroxyethyl-4-amino-N-methyl, N - (-hydroxyethylaniline), 1-amino-3-nitro-4-phenol, 2-amino-3-nitro-phenol, N-5-hydroxyethylamino-2-nitro-5-anisole, 2-methyl-5-nitro-N, N '(- ss-hydroxyethyl) para-phenylenediamine, nitroO 3 N-ss-aminoethylamino- N, N- (ss-hydroxyethyl) aniline.

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

 These compositions, implemented in a direct dyeing process, are applied to the keratinous fibers for a laying time ranging from 5 to 50 minutes, and then the fibers are rinsed, if necessary washed, rinsed again and dried. .

 The compositions according to the invention can also be used in the form of a hair styling lotion designed both to give the hair a slight coloration and to improve the holding of the setting. In this case, they are in the form of aqueous, alcoholic or aqueous-alcoholic solutions containing at least one cosmetic resin and their application is carried out on wet hair previously washed and rinsed which are optionally wound and dried.

 The cosmetic resins used in haircolour lotions may be in particular polyvinylpyrrolidone, crotonic acid-vinyl acetate copolymers, vinylpyrrolidone-vinyl acetate, maleic anhydride-butylvinyl ether, maleic anhydride-methylvinyl ether and any other cationic polymer. , anionic, nonionic or amphoteric usually used in this type of composition. These cosmetic resins are present in the compositions of the invention in amounts of from 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 are oxidation dyes involving the development with an oxidant, the compounds of formula (I) according to the invention are essentially used to give reflections to the final dyeing.

 These compositions then contain, in combination with at least one nitro dye of formula (I), oxidation dye precursors.

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

 They may also contain para-aminophenols, for example: para-aminophenol, N-methyl-para-aminophenol, chloro-2-amino-4-phenol, 3-chloro-4-aminophenol, 2-methyl-4-aminophenol, and their salts .

 They may also contain heterocyclic derivatives, for example 2,5-diaminopyridine or 7-aminobenzomorpholine.

 The compositions according to the invention may contain, in combination with the oxidation dye precursors, couplers which are well known in the state of the art.

 As couplers, there may be mentioned in particular: meta-diphenols such as resorcinol, 2-methyl resorcinol, meta-aminophenols such as: meta-aminophenol, 2-methyl-5-aminophenol, 2-methyl-N-methylamino-5-phenol , 2-methyl-N - (- hydroxyethyl) amino-5-phenol, and their salts, meta-phenylenediamines such as: (2,4-diamino) phenoxyethanol, [N- (ss-hydroxyethyl) amino-2-amino-4 ] phenoxyethanol, (2,4-diaminophenyl) and di-hydroxypropyl ether and their salts, metaacylaminophenols, metauridophenols, metacarbalcoxyaminophenols such as: 2-methyl-5-acetylamino phenol, 2-methyl-5-ureido-phenol methyl 2 carbethoxy-5-amino phenol.

 Finally, other couplers that may be used in the compositions of the invention may be mentioned. α-naphthol, the couplers having an active methylene group such as diketone compounds and pyrazolones and heterocyclic couplers such as 2,4-diaminopyridine, 6-hydroxybenzomorpholine, 6-aminobenzomorpholine and as their salts.

 These compositions contain, in addition. oxidation dye precursors, reducing agents such as, more particularly, sodium bisulfite, sodium sulphite, thioglycolic acid, thiolactic acid, mercapto succinic acid, ascorbic acid and their salts, and hydrochloric acid. none. These reducing agents are present in proportions of between 0.05 and 3% by weight relative to the total weight of the composition.

 The oxidation dye precursors may 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 may 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 dyeing compositions is preferably from 7 to 31.5 and is adjusted using alkalinizing agents defined above.

 The Applicant has found that the compounds according to the invention were particularly stable in such compositions.

 The process for dyeing keratinous fibers, in particular human hair, using the revelation with an oxidant, consists in applying to the hair the dyeing 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 in the air, but preferably a chemical developer system is used which is most often chosen from hydrogen peroxide, urea peroxide and salts. In particular, a solution of hydrogen peroxide at 20 volumes is used.

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

 The examples which follow are intended to illustrate the invention without being limiting in nature.

PREPARATION EXAMPLE 1
Preparation of 2,6-dimethyl-3-nitro paraphenylenediamine

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First stage
Preparation of 2,6-dimethyl-4-acetylaminoaniline

 1.6 moles (334.6 g) of 2,6-dimethylparamphenylenediamine dihydrochloride are dissolved in 1600 ml of water. To this solution is added 3.36 moles (423.3 g) of sodium sulphite in solution in 1600 ml of water and then, little by little, with stirring, maintaining the temperature in the vicinity of 250C, 1.68 mol ( 174.8 g) of acetic anhydride. The addition is complete the reaction medium is left for 1 hour at room temperature. After cooling, the monoacetylated derivative which has precipitated is filtered off. It melts at 148 C.

Second step
Preparation of 2,6-dimethyl-3-nitro-4-acetylamino aniline

 0.226 mol (40.3 g) of the previously obtained monoacetyl derivative is added with good stirring to 230 ml of 96% sulfuric acid while maintaining the temperature between 18 and 20 ° C. The dissolution is complete after 30 minutes. This solution is then cooled to -30 ° C. and then added dropwise over 45 minutes, with good stirring and while maintaining the temperature between -2 ° and 0 ° C., the sulphonitric mixture prepared from 10.5 ml of nitric acid ( d = 1.5) and 40 ml of 96% sulfuric acid. The addition is complete, the reaction medium is maintained at 0 ° C. for 1 hour and then poured into 2 kg of crushed ice. After neutralization with ammonia, the expected product which has precipitated is filtered off and washed with water. and recrystallized from ethanol. It melts at 1970C.

Calculated Analysis for Found
C10H13N3O3
C% 53.80 53.83
H% 5.87 5.92
N% 18.83 18.93 0% 21.50 21.35
Third step
Preparation of 2,6-dimethyl-3-nitro paraphenylenediamine

 0.04 mole (8.9 g) of 2,6-dimethyl-3-nitro-4-acetylamino aniline are introduced into 25 ml of 36% hydrochloric acid plus 10 ml of acetic acid. After 1 1/2 hours of heating in a boiling water bath, the expected product is wrung as hydrochloride. This hydrochloride is dissolved in 40 ml of water. By addition of ammonia 2,6-dimethyl-3-nitro-para-phenylenediamine is precipitated. The product is drained, washed with water, dried and recrystallized from benzene. I1 melts at 124 C.

Calculated Analysis for Found
C8H11N3O2
C% 53.03 53.23
H% 6.12 6.14
N% 23.19 23.22 0% 17.66 17.58
EXAMPLE OF PREPARATION 2
Preparation of dimethyl-5,6-nitro-3-paraphenylenediamine

First stage
Preparation of dimethyl-5,6-nitro-3N, N'-diacetylparaphenylenediamine,
0.085 mol (18.3 g) of dimethyl-2,6-N, N'-diazetyl-para-phenylenediamine were added slowly with vigorous stirring to 85 ml of 96% sulfuric acid while maintaining the temperature between 18 and 20 ° C. The dissolution is complete after 30 minutes. This solution is cooled to -5 ° C. and is then added dropwise in 20 minutes, while keeping the temperature in the vicinity of -20 ° C., the sulphonitric mixture prepared according to the usual method, starting from 15 ml of sulfuric acid. 96% and 4 ml of mitric acid d = 1.5. After the addition, the stirring is maintained for 1 hour in the vicinity of 0 C and the reaction medium is poured onto 0.8 kg of crushed ice. The desired product which has precipitated is filtered off with suction, washed with water and dried under vacuum at 50 ° C.

After recrystallization from ethanol, it melts above 260 C.
Calculated Analysis for Found
C12H15N3O4
C, 54.33, 54.36
H% 5.70 5.70
N% 15.84 15.93 0% 24.13 24.30
Second step
Preparation of 5,6-dimethyl-3-nitro paraphenylenediamine

 The diacetyl derivative prepared according to the method of the first step is heated for 1 hour and a half in a steam bath of 0.075 mole (19.9 g) in 75 ml of 36% hydrochloric acid.

 After cooling the medium, the expected product is filtered off in the hydrochloride form. This hydrochloride is dissolved in 150 ml of ean and basified with ammonia to precipitate the dimethyl-5,6-nitro-3-paraphenylenediamine. The product is drained, washed with water and recrystallized with ethyl acetate; it melts at 159 C.

Calculated Analysis for Found
C8H11N3O2 53.03 52.96 6.12 6.08
N% 23.19 23.14 0% 17.66 17.71
EXAMPLE 1
The following dye composition is prepared Dimethyl-5,6-nitro-3-paraphenylenediamine 0.15 g
2-Butoxy ethanol 15 g Coconut fatty acid amintamines 2.2 g
Lauric acid 0.8 g
Ethylene glycol ethyl ether monether 2 g
Monoethanolamine 1 g
Water qs 100 g pH - 7.0.

 This mixture applied for 25 minutes at 28 ° C. on white-bleached hair gives them, after rinsing and shampooing, a pink salmon coloration.

EXAMPLE 2
The following dye composition is prepared Dimethyl-2,6-nitro-3-para-phenylenediamine 0.1 g
Butoxy-2 ethanol 10 g
Hydroxyethylcellulose 2 g
5 g ammonium lauryl sulphate
Triethanomamine solution 1% 2 g
Water qs 100 g pH = 8.4.

 This mixture applied for 20 minutes at 280 ° C. on bleached white hair gives them, after rinsing and shampooing, a rosy champagne coloring.

EXAMPLE 3
The following dye composition is prepared Dimethyl-5,6-nitro-3-paraphenylenediamine 0.35 g
Amino-2-nitro-3-phenol 0.12 g
Nitro-3-N, N-aminoethylamino-4 N, N (ss-hydroxyethyl) aniline dihydrochloride aniline 0.15 g
Butoxy-2 ethanol 10 g
Alfol C16 / 18E 8 g (cetylstearyl alcohol sold by Condéa)
Wax of E 0.5 g (sodium cetylstearyl sulfate sold by Henkel)
Cemulsol B lg (ethoxylated castor oil sold by Rhône Poulenc)
Oleic diethanolamide 1.5 g
Ammonia at 220Bé 2 g
Water qs 100 g pH = 10.0
This mixture applied on hair discolored for 15 minutes at 250C gives them, after rinsing and shampooing, a red copper color.

EXAMPLE 4
The following dye composition is prepared
Dimethyl-5,6-nitro-3-paraphenylenediamine 0.16 g
2,6-Dimethyl-3-nitro-para-phenylenediamine 0.3 g Methyl-2-amino-4-nitro-5-phenol 0.2 g
2-Methyl-5-nitro N, N '(ss-hydroxyethyl) paraphenylenediamine 0.08 g
1,4,5,8-Tetraamino anthraquinone 0.25 g
Butoxy-2 ethanol 10 g
Alfol C16 / 18E (cetylstearyl alcohol sold by the Company
Condéa) 8g
Wax of E 0.5 g (sodium cetylstearyl sulfate sold by Henkel)
Cemulsol B lg (ethoxylated castor oil sold by RhSne Poulenc)
Oleic diethanolamide 1.5 g
Solution of 2-methyl-2-amino-1-propanol-25% 1 g
Water qs 100 g pH 9.8
This mixture applied for 20 minutes at 280 ° C. on white hair at 90% permonent gives them, after rinsing and shampooing, a medium coppery brown coloration.

EXAMPLE 5
The following dye composition is prepared
Dimethyl-5,6-nitro-3-paraphenylenediamine 0.25 g
Methyl-2, 6-nitroaniline 0.1 g
1,4,5,8-tetraamino anthraquinone 0.25 g
Alcohol with 96 20 g Hydroxyethylcel lulose 2g
5 g ammonium lauryl sulphate
5% Ammonia 0.5 g
Water qs 100 g pH = 8.

 This mixture is applied for 15 minutes at 30 ° C. on 95% white permed hair; after rinsing and shampooing, it gives them a copper coloring.

EXAMPLE 6
The following dye composition is prepared: 2,6-Dimethyl-3-nitro-paraphenylenediamine 0.15 g 0.25 g
Nitro-3 N-ss-hydroxyethylamino-2
N-α-hydroxyethylamino-2-nitroanisole 0.08 g
Butoxy-2 ethanol 10 g
Lauramide 1.5 g (lauric acid monoethanolamide sold by Witco)
Lauric acid 1 g
Hydroxyethylcellulose 5 g Nonoethanolamine 2g
Water qs 100 g pH = 9.5.

 This mixture applied for 20 minutes at 28 ° C on 90% naturally white hair gives them after rinsing and shampooing, a coppery light brown coloring.

EXAMPLE 7
The following dye composition is prepared:
phenylenediamine
Resorcin 0.1 g
Metaaminophenol 0.05 g
2,4-Diamino-phenoxyethanol dihydrochloride 0.03 g Dimethyl-5,6-nitro-3-paraphenylenediamine 0.16 g 0.35 g
2-Methyl-5-nitro N, N '- (s-hydroxyethyl) para-phenylenediamine 0.08 g
Oleic alcohol oxyethylenated with 2 moles of ethylene oxide 4.5 g
Oleyl alcohol oxyethylenated with 4 moles of ethylene oxide 4.5 g
Ethomeen T012 (oleylstearylamine oxyethylenated with 12 moles of ethylene oxide sold by Armak) 4.5 g
9% coconut fatty acid ethanomamides
Propylene Glycol 4g
Butoxy-2 ethanol 8 g
Ethanol 960 g
Masquol DTPA (sodium salt of diethylene triamine pentacetic acid) 2 g
Hydroquinone 0.15 g
Sodium bisulphite solution at 350Be 1.3 g
Ammonia at 220Bé 10 g
Water qs 100 g pH = 10.5.

 At the time of use, 100 g of hydrogen peroxide at 20 volumes are added.

 This mixture applied for 20 minutes at 250 ° C. on hair that is naturally 90% white gives them, after rinsing and shampooing, a red-brown coloring.

EXAMPLE 8
The following dye composition is prepared
Paraphenylenediamine 0.2 g
2,4-Diamino-phenoxyethanol dihydrochloride 0.07 g
Resorcin 0.2 g
Metaaminophenol 0.08 g
Methyl-2-NP-hydroxyethylamino-5-phenol 0.07 g
Paraaminophenol 0.08 g
2,6-Dimethyl-3-nitro-para-phenylenediamine 0.22 g
Cemulsol NP4 (nonylphenol with 4 moles of ethylene oxide sold by
Rhône Poulenc) 21 g
Cemulsol NP9 (nonylphenol 9 mol ethylene oxide sold by Rhne Poulenc) 24 g
Oleic acid 4: g
Butoxy-2 ethanol 3 g
Ethanol at 960 g
Masquol DTPA 2.5 g
Sodium bisulfite at 350Be 1 g
Ammonia at 220Bé 10 g
Water qs 100 g pH = 10.5.

 At the time of use, 100 g of hydrogen peroxide at 20 volumes are added.

 This mixture applied for 20 minutes at 300 ° C. on naturally white hair at 90 ° gives them, after rinsing and shampooing, a brown coloration with violet hues.

EXAMPLE 9
We prepare the following dye composition
Paratoluylenediamine dihydrochloride 0.23 g
Resorcinol 0.12 g
2-methyl-N-methylamino-5-phenol 0.08 g Paraaminophenol 0.05 g
2,6-Dimethyl-3-nitro-para-phenylenediamine 0.4 g
Alfol C16 / 18E 8g (cetylstearyl alcohol sold by Condea)
Wax of E 0.5 g (sodium cetylstearyl sulfate sold by Henkel)
Cemulsol B lg (ethoxylated castor oil sold by Rhône Poulenc)
Oleic diethanolamide 1.5 g
Masquol DTPA 2.5 g
Mercapto succinic acid 0.3 g
Ammonia at 220Be 11 g
Water qs 100 g pH = 10.5.

 At the time of use, 100 g of hydrogen peroxide at 20 volumes are added.

 This mixture applied for 25 minutes at 25 ° C. on white-bleached hair gives them, after rinsing and shampooing, a mahogany coloring.

EXAMPLE 10
The following dye composition is prepared
Dimethyl-5,6-nitro-3-paraphenylenediamine 0.045 g
Parahenylenediamine 0.03 g
Resorcinol 0.06 g
Paraaminophenol 0.02 g
Hydroxyethylcellulose 2-g
5 g ammonium lauryl sulphate
Butoxy-2 ethanol 15 g
960 alcohol 5 g
Ammonia 20% 10 g
Sidium bisulfite at 350Be 1 g
Hydroquinone 0.15 g
Water qs 100 g pH = 10.3.

 At the time of use, 75 g of hydrogen peroxide at 20 volumes are added.

 This mixture applied for 25 minutes at 200C on bleached hair gives them, after rinsing and shampooing, a golden sand coloring.

EXAMPLE 11
The following dye composition is prepared: Dimethyl-5,6-nitro-3-paraphenylenediamine 0.2 g
N, N-di- (6-hydroxyethyl) paraphenylenediamine dihydrochloride 0.08 g
Paraaminophenol 0.15 g
2-methyl-N-hydroxyethylamino-5-phenol 0.1 g
Resorcinol 0.16 g
N'-4-L-hydroxyethylamino-4-nitro-N-methyl N-ss hydroxyethylaniline 0.1 g
Hydroxyethylcellulose sold under the name Cellosize
WP 03 by Union Carbide 2 g
5 g ammonium lauryl sulphate
Butoxy-2 ethanol 15 g
960 alcohol 5 g
Masquol DTPA 2g
Hydroquinone 0.15 g
Sodium bisulphite solution d = 1.32 1.5 g
Monoethanolamine 8g
Water qs 100 g pH = 10.7
At the time of use, 80 g of hydrogen peroxide are added to 20 volumes.

 This mixture applied for 25 minutes at 25 C on bleached hair gives them, after rinsing and shampooing, a coral coloring.

EXAMPLE 12
The following dye composition is prepared Dimethyl-2,6-nitro-3-paraphenylenediamine 0.2 g
2,6-Dimethyl paraphenylenediamine dihydrochloride 0.1 g
2,4-Diamino-phenoxyethanol dihydrochloride 0.04 g
Resorcinol 0.11 g
Metaaminophenol 0.06 g
2-Methyl-N-ss-hydroxyethylamino-5-phenol 0.05 g
Paraaminophenol 0.05 g
Remccpal 334 (nonylphenol with 4 moles of ethylene oxide sold by Gerland) 21 g
Remcoal 349 (nonylphenol with 9 moles of ethylene oxide sold by Gerland) 24 g
Oleic acid 4 g
Butoxy-2 ethanol 3 g
Alcohol 960 10 g
Masquol DTPA 2.5 g
Sodium bisulfite at 350Be 1 g
Hydroquinone 0.12 g
Ammonia at 220Bé 10 g
Water qs 100 g pH = 10.6.

 At the time of use, 100 g of hydrogen peroxide at 20 volumes are added. This mixture applied for 20 minutes at 280C on bleached hair gives them, after rinsing and shampooing, a tin-gray color with pink highlights.

EXAMPLE 13
The following dye composition is prepared
Dimethyl -5,6-nitro-3-para-phenylenediamine 0.25 g
N- (ss-methoxyethyl) paraphenylenediamine dihydrochloride 1 g
Paraaminophenol 0.3 g
Resorcin 0.25 g Nétaamiaophénol 0.15 g
Hydroxy quinone 0.15 g
Nonylphenol oxyethylenated with 9 moles of ethylene oxide 3 g
Oleic alcohol 9 9g
Oleic diethanolamide 9 g
Hydrogenated tallow amide with 50 moles of ethylene oxide 2.5 g
Oleic acid 18 g
Cationic polymer having the repeating unit: 3 g

Ethyl alcohol 9g
Benzyl alcohol 11 g
Ethylenediaminetetraacetic acid 0.2 g
Ammonia at 220Bé 14 g
Monoethanolamine 6.5 g
Sodium bisulfite at 350Be 1.3g
Water qs 100 g
This liquid composition gives a creamy gel by dilution weight for weight with hydrogen peroxide at 20 volumes.

 If one applies 30 minutes this gel on a dark blonde hair and if one carries out finally a shampoo one obtains, after drying, a hair color light blonde red coppery.

 The nitro dye used, namely 2,3-dimethyl-5-nitro paraphenylenediamine, is stable in the liquid composition.

EXAMPLE 14
The following dye composition is prepared Dimethyl-2,6-nitro-3-paraphenylenediamine 0.4 g
Paraphenylenediamine 0.35 g
Chlo ro-2 paraphenylenediamine 0.10 g
Paraaminophenol 0.10 s
Resorcin 0.20 g
Metaaminophenol 0.30 g
Methyl-2 resorcinol 0.20 g
Hydroquinone 0.15 g
Glycerolated oleic alcohol with 2 moles of glycerol 5.g
Glycerolated oleic alcohol with 4 moles of glycerol 5 g
Oleic acid 5-g
Oleic diethanolamide 5 g
Oleic diethanolamine 12 g
Ethyl alcohol 10 g
Ethoxy-2 ethanol 12 g
Ethylene diaminotetracetic acid 0.2 g
Sodium bisulfite 350 Be 1.3 g
Ammonia at 220Bé 8 g
Monoethanolamine 3g
Water qs 100 g
This liquid is diluted at the time of use with an equal weight of an oxidizing milk containing 20 volumes of hydrogen peroxide. The gel obtained is applied for 30 minutes on chestnut hair and rinsed. Shampoo is performed and dried. We then obtain dyed hair in a dark coppery shade.

 It is found that in this composition, the nitro dye, namely 2,6-dimethyl-3-nitro paraphenylenediamine, is preserved.

Claims (17)

 1. Dimethyl derivative of nitroparaphenylenediamine, characterized in that it corresponds to the following formula (I)

 wherein the variable-position CH3 radical is in the 2- or 5-position of the benzene ring or the cosmetically acceptable salts of this compound.  2. Compound according to claim 1, characterized in that it consists of 2,6-dimethyl-3-nitro paraphenylenediamine.  3. Compound according to claim 1, characterized in that it consists of dimethyl-5,6-nitro-3-paraphenylenediamine.  4. Process for the preparation of the compounds according to any one of claims 1 to 3, characterized in that in a first step, the nitration of the mono or di-acetylated derivative of formula (II) is carried out:

 in which R 1 denotes a hydrogen atom when -CH 3 is in position 2 and R 1 denotes an acetyl group when CH 3 is in position 5, using a sulphonitric mixture, at a temperature between -5 and OOC, for obtain the mono- or diacetyl derivative of formula (III)

  and that in a second step, the compound of formula (III) above is hydrolyzed using hydrochloric acid.  5. Method according to claim 4, characterized in that the monoacetylated derivative of 2,6-dimethyl paraphenylenediamine of formula (II) is prepared in claim 4 wherein R1 denotes a hydrogen atom, CR3 being in position 2, by acetylation of 2,6-dimethyl paraphenylenediamine dihydrochloride using acetic anhydride in the presence of water and sodium sulphite at temperature amblante.  6. Dye composition for keratinous fibers, characterized in that it contains in a solvent medium at least one compound as defined in any one of claims 1 to 3.  7. Composition according to claim 6, intended for dyeing human hair, characterized in that it contains in a cosmetically acceptable medium at least one compound of formula (in the proportions of 0.001 to 1% by weight, and preferably between 0.05 and 0.5% by weight relative to the total weight of the composition.  8. Composition according to claim 6 or 7, characterized in that it has a pH of between 3 and 11.5.  9. Dye composition according to claim 6 or 7, characterized in that the solvents are selected from water lower alkanol, aromatic alcohols, polyols, and their ethers or mixtures thereof.  10. Composition according to claim 6 or 7, characterized in that it additionally contains cosmetic adjuvants chosen from anionic surfactants, cationic, nonionic. amphoteric or mixtures thereof, thickeners, dispersing agents, penetrating agents, sequestering agents, film-forming agents, buffers, perfumes, alkalinising agents or acidifying agents.  11. A composition according to claim 6 or 7, intended to be used for the direct dyeing of human hair, characterized in that it also contains other direct dyes chosen from azo dyes, anthraquinone dyes and nitro derivatives of the benzene series. other than those of formula (I).  12. Composition according to claim 6 or 7, intended to be used as a setting lotion, characterized in that it is in the form of an aqueous solution, alcoholic or aqueous-alcoholic, containing at least one cosmetic resin.  13. The composition of claim 6 or 7, intended to be used for oxidation dyeing, characterized in that it further contains at least one dye precursor by oxidation.  14. A composition according to claim 13, characterized in that it has a pH of between 7 and 11.5 and that it additionally contains a reducing agent.  15. A process for dyeing keratinous fibers, characterized in that a composition as defined in any one of claims 6 to 11 is applied to the fibers, allowed to set for 5 to 50 minutes, and rinsed, eventually washed, rinsed again and dried.  16. A process for dyeing keratinous fibers, characterized in that a composition as defined in claim 12 is applied to the washed and rinsed fibers, optionally wound up and dried.  17. A process for dyeing keratinous fibers, characterized in that a composition as defined in claims 13 or 14 is applied to the fibers, optionally supplemented with an oxidizing agent, it is left for 10 to 50 minutes, rinsed, washed optionally with shampoo, rinsed again and dried.