GB2168369A - New 2,4-dinitro anilines useful as hair dyes - Google Patents

Abstract

2,4-Dinitro-6-hydroxyalkylanilines of formula (I> <IMAGE> wherein: X is an unsubstituted or a mono- or polyhydroxy substituted branched or unbranched alkylene of 2 to 6 carbon atoms; R is hydrogen, (C1-4)-alkyl, mono- or polyhydroxy-(C1-4)-alkyl, amino-(C1-4)-alkyl or mono- or disubstituted amino-(C1-4)-alkyl wherein each substituent is (C1-4)-alkyl, mono- or polyhydroxy (C1-4)-alkyl or the nitrogen atom and at least one substituent form part of a heterocyclic system; R' is hydrogen or (C1-4)-alkyl; or cosmetically acceptable salts of such compounds containing a salifiable amine group are useful as direct dyes for human hair.

Description

SPECIFICATION New 2,4-dinitro anilines The present invention relates to new 2,4-dinitro-6-hydroxyalkylanilines, the process for preparation thereof and their use in dyeing keratinous fibres, and especially human hair, both by direct dyeing and by so-called oxidation dyeing.

It is well known that, to perform direct dyeing on hair or endow the latter with complementary glints in the case of oxidation dyeing, nitro derivatives of the benzene series can be used.

The use has already been recommended of N-substituted 2,4-dinitroanilines, which are obtained by reaction of a primary amine with 2,4-dinitro-1-chlorobenzene, both in direct dyeing and in oxidation dyeing.

Nevertheless said compounds, when used as direct dyes for dyeing keratinous fibres, and more especially human hair, give rise to shades which are insufficiently stable to light, adverse weather conditions and washing.

Consequently, the Applicant has sought other nitro-aminobenzene dyes which enable shades to be obtained which are more resistant to light, adverse weather conditions and washing, and has in this manner discovered the compounds of formula:

in which X denotes a branched or unbranched alkylene radical containing 2 to 6 carbon atoms, one of these atoms optionally being able to be substituted with one or more hydroxyl radicals; R denotes a hydrogen atom, an alkyl or a mono- or polyhydroxylalkyl radical or an aminoalkyl radical in which the amine group can be mono- or disubstituted with an alkyl or a mono- or polyhydroxyalkyl radical, the nitrogen atom also being able to form part of a heterocyclic system, and the alkyl radical containing 1 to 4 carbon atoms; R' denotes a hydrogen atom or a C, to C4 alkyl radical.

The subject of the present invention is hence the new, 2,4-dinitro-6-hydroxyalkylanilines of formula (I), as well as the cosmetically acceptable salts of the compounds containing 1 salifiable amine group.

By way of preferred radicals X, ethylene, propylene, 1,1- dimethylethylene, 1,2-dimethylethylene and 1,1 ,2-trimethylethylene radicals may be mentioned.

By way of preferred radicals R, hydrogen and methyl, ethyl, n-propyl, p-hydrnxyethyl, Fy-hydroxypropyl, P,y-dihyd roxypropyl, p-aminoethyl and p-diethylaminoethyl radicals may be mentioned.

By way of preferred radicals R', hydrogen and the methyl radical may be mentioned.

Preferred compounds of formula (I) according to the invention are the following: - 2-(2-amino-3,5-dinitrophenyl)ethanol; - 2-[2-(ss-hydroxyethyl)amino-3,5-dinitrophenyl]-ethanol; - 1 -(2-amino-3,5-dinitrophenyl)-2-propanol; - 1-(2-methylamino-3,5-dinitrophenyl)-2-propanol; - 1-[2-(ss-aminoethyl)amino-3,5-dinitrophenyl]-2-propanol, as well as the salts thereof.

The subject of the invention is also the process for preparing the compounds of formula (I), which consists in reacting an aqueous ammonia solution or a primary aliphatic amine R-NH2, where R has the meaning given above, with the heterocyclic compounds of formula (II), according to the following reaction scheme:

R' and X having the meaning given above.

The opening of the heterocyclic ring by the primary amine or by ammonia is performed at a temperature between 20 and 1200C, optionally under pressure, in the presence or absence of polar protic solvents such as water, alcohols, glycols or glycols ethers, or polar aprotic solvents such as formamide, dimethylformamide, dioxane or tetrahydrofuran.

The compounds of formula (II) are obtained by nitration of the compounds of formula (III):

where R' and X have the meaning given above, the nitration being performed by adding the compound (III) to 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 mixture of concentrated sulphuric and nitric acids at a temperature in the region of 5"C [according to Charles D. HURD, Rostyslaw DOWBENKO, J.A.C.S. 80, 4711-14 (1958)]; the compound (II) is then isolated after dilution of the reaction medium with water.

Compounds of formula (II) are known, and most of the compounds of formula (II) are also known.

Among the known compounds of formula (it), the following may be mentioned: 5,7-dinitrocoumaran (or 2,3-di hydro-5,7-dinitrobenzof uran), 2-methyl-5,7-dinitrocoumaran, 2,2-dimethyl-5,7-dinitrocoumaran, 2,3-dimethyl-5,7-dinitrocoumaran and 2,2,3-trimethyl-5,7-dinitrocoumaran.

The process for preparing the compounds of formula (I) according to the invention enable excellent yields of these compounds to be obtained.

A further subject of the present invention consists of a dyeing composition for keratinous fibres, and more especially for human hair, containing at least one 2,4-dinitro-6-hydroxyalkylaniline of formula (I) above, or one of its cosmetically acceptable salts, in a solvent medium.

The present invention also relates to a process for dyeing keratinous fibres, and more especially human hair, by direct dyeing or by oxidation dyeing involving development with an oxidising agent.

The dyeing compositions according to the invention contain, in a solvent medium, at least one compound corresponding to the formula (I), or one of its cosmetically acceptable salts, and can be used for direct dyeing of keratinous fibres or for oxidation dyeing of these fibres, in which case the compounds of formula (I) confer glints which are complementary to the basic coloration obtained by oxidative development of precursors of oxidation dyes.

These compounds 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 organic solvents can also be added into the compositions to solubilise compounds which would not be sufficiently soluble in water. Among these solvents, there may be mentioned 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 of 2-ethoxyethanol, ethylene glycol and propylene glycol, diethylene glycol monomethyl ether and monoethyl ether and also similar products and mixtures thereof. These solvents are preferably present in proportions ranging from 1 to 75% by weight, and especially from 5 to 50% by weight, relative to the total weight of the composition.

These compositions can contain anionic, cationic, nonionLor 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 be thickened, preferably with compounds chosen from sodium alginate, gum arabic, cellulose derivatives such as methylcel lulose, hydroxyethylceilulose, hydroxypropylmethylcellulose and carboxymethylcellulose and various polymers which have the function of a thickener such as, more especially, acrylic acid derivatives. 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 especially between 0.5 and 2% by weight, relative to the total weight of the composition.

The compositions according to the invention can also contain various adjuvants customarily used in dyeing compositions for the hair, and especially penetrants, dispersants, sequestering agents, film-forming agents, buffers and perfumes.

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

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

When the compositions are intended for use in a process for direct dyeing of hair, they can contain, in addition to the compounds according to the invention, other direct dyes such as azo or anthraquinone dyes, for example 1,4,5,8-tetraaminoanthraquinone, indophenols, indoanilines and nitro dyes of the benzene series other than 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, employed in a direct dyeing process, are applied on the keratinous fibres for an exposure time which varies from 5 to 50 minutes, the fibres are then rinsed, optionally washed with shampoo, rinsed again and dried.

The compositions according to the invention can also be employed in the form of hair setting lotions intended at one and the same time to endow the hair with a light coloration or with glints, and to improve the shape-retention of the set. In this case, they take the form of aqueous, alcoholic or hydroalcoholic solutions containing at least one cosmetic resin, and they are applied on damp hair which has been washed and rinsed beforehand and which is optionally coiled and then dried.

The cosmetic resins which are used in the setting lotions can be, in particular, polyvinylpyrrolidone, crotonic acid/vinyl acetate, vinylpyrrolidonelvinyl acetate, maleic anhydride/butyl vinyl ether and maleic anhydride/ methyl vinyl ether copolymers, as well as any other cationic, anionic, nonionic or amphoteric polymer customarily used in this type of composition. These cosmetic resins participate in the compositions of the invention in the proportion 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 development with an oxidizing agent, the compounds of formula (I) according to the invention are mainly used for the purpose of contributing glints to the final dyeing.

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

The compositions can contain, for example, paraphenylenediamines such as: para-phenylenediamine, para-tolylenediamine, 2-chloro-para-phenylenediamine, 2,6-dimethyl-para-phenylenediamine, 2,6-dimethyl-3-methoxy-para-phenylenediamine, N-(ss-methoxyethyl)-para-phenylenediamine, N,N-bis(p-hy- droxyethyl)-para-phenylenediamine, 4-[N-ethyl-N-(carbamylmethyl)amino]aniline and also the salts thereof.

They can also contain para-aminophenols, for example: para-aminophenol, N-methyl-para-aminophenol, 2-chloro-4-aminophenol, 3-chloro-4-aminophenol, 2-methyl-4-aminophenol and the salts thereof.

They can also contain ortho-aminophenol.

They can also contain heterocyclic derivatives, for example: 2,5-diaminopyridine and 7-aminobenzomorpholine.

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

By way of couplers, there may be mentioned, in particular: meta-diphenols, meta-aminophenols and the salts thereof, meta-phenylenediamines and the salts thereof, meta-acylaminophenols, meta-ureidophenols and meta-carbalkoxyaminophenols.

As other couplers which can be used in the compositions according to the invention, there may finally be mentioned: a-naphthol, couplers possessing an active methylene group such as diketo compounds and pyrazolones, and heterocyclic couplers derived from pyridine and benzomorpholine.

These compositions contain, in addition to the oxidation dye precursors, 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, and preferably between 0.015 and 2% by weight. The pH of these oxidation dyeing compositions is preferably between 7 and 11.5, and is adjusted using alkalinising agents defined above.

The process of dyeing the keratinous fibres, especially human hair, employing development by an oxidising agent, consists in applying on the hair the dyeing composition containing both a dye according to the invention and dye precursors. The development of the coloration can then be accomplished slowly in the presence of the oxygen in the air, but a chemical development system is preferably used, this most frequently being chosen from hydrogen peroxide, urea peroxide and persalts. A solution of "20 volumes" hydrogen peroxide is used in particular.

When the composition with the oxidising agent has been applied on the keratinous fibres, it is left in place for 10 to 50 minutes, preferably 15 to 30 minutes, after which the keratinous fibres are rinsed, optionally washed with shampoo, rinsed again and dried.

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

Example 1

Preparation of 2-(2-amino-3,5-dinitrnphenyl)ethanol 0.17 Mole (35.7 g) of 2,3-dihydro-5,7-dinitrobenzofuran, prepared according to Chatelus Ann. Chim.

[12], 4, 505-547 (1949), is suspended in 350 ml of 20% strength ammonia solution and 220 ml of formamide. After 8 hours' heating at 110"C, a further 100 ml of 20% strength ammonia solution are added. Heating is maintained for 4 hours. When the reaction medium is cooled, the expected product precipitates.

After being drained, washed with ice-cold water until neutral and dried under vacuum, 0.13 mole (30.3 g) of a product melting at 151"C is obtained, and this is recrystallized from dioxane.

Analysis of the product gives the following results: Analysis Calculated for Found C8H9N3O5 %C 42.29 42.24 %H 3.99 3.91 %N 18.50 18.60 35.21 35.14 Example 2

Preparation of 2[2-(ss-hydroxyethyl)amino-3,5-dinitrophenyl]ethanol 0.29 Mole (60.9 g) of 2,3-dihydro-5,7-dinitrobenzofuran is added in small portions at room temperature to 122 ml of 2-aminoethanol. After the addition is complete, the reaction medium is brought for 15 minutes to 95 C. 500 ml of water are added; after the mixture is cooled, the expected product is drained, and this, after being made into a paste in water and recrystallized from 75 ml of 96" strength ethanol, melts at 115 C.

Analysis gives the following results: Analysis Calculated for Found CioHiaNsOs %C 44.28 44.38 %H 4.83 4.74 %N 15.49 15.48 35.39 35.60 Example 3

Preparation of 1-(2-amino-3,5-dinitronphenyl)-2-propanol 0.39 Mole (88 9) of 2,3-dihydro-5,7-dinitro-2-methylbenzofuran, prepared according to J.A.C.S. 80, p.

4711-4714 (1958), is suspended in 1.11 of 20% strength ammonia solution and 600 ml of Methyl Cellosolve. After 18 hours' heating at 70 C, the reaction mixture is cooled The precipitate formed is drained and, after being made into a paste in water until neutral and then dried under vacuum, is recrystallized from 170 ml of dioxane. After being dried under vacuum, 0.30 mole (72 9) of the expected product is obtained; it melts at 177 C.

Analysis gives the following results: Analysis Calculated for Found CgHttN305 %C 44.81 44.87 %H 4.60 4.62 %N 17.42 17.45 33.17 33.08 Example 4

Preparation of l-(2-methylamino-3, 5-dinitrophenyl)-2-propanol 0.056 Mole (12.5 g) of 2,3-dihydro-5,7-dinitro-2-methyl-benzofuran is suspended in 100 ml of a 33% strength solution of methylamine in ethanol. After 10 hours' stirring at room temperature in a sealed Erlenmeyer, the reaction mixture is brought for 30 minutes to the refluxing temperature of the alcohol.

After the mixing is cooled, the expected product precipitates. It is drained, washed with alcohol and then recrystallized from 50 ml of 96" strength ethanol. After being dried, 0.047 mole (12 g) is obtained of a product which melts at 132"C.

Analysis gives the following results: Anaylsis Calculated for Found C,oH,3N305 %C 47.06 47.11 %H 5.13 5.03 %N 16.47 16.52 31.34 31.25 Example 5

Preparation of 1-[2-(ss-aminoethyl)amino-3,5-dinitrophenyl]-2-propanol 0.089 Mole (20 g) of 2,3-dihydro-5,7-dinitro-2-methylbenzofuran is added with stirring at room temperature to 40 ml of ethylenediamine. When the addition is complete, the reaction medium is poured into 500 ml of water. The expected product precipitates. After being drained and made into a paste in water, it is recrystallized from 210 ml of 96" strength ethanol. 0.074 mole (20.9 g) of a product is obtained which melts at 140"C.

Molecular mass calculated for C1,H16N4Os: 284.

Molecular mass found by potentiometric assay in acetic acid using perchloric acid: 293.

Analysis of the product obtained gives the following results: Analysis Calculated for Found C"H,6N40s %C 46.47 46.40 %H 5.67 5.68 %N 19.71 19.82 0% 28.14 27.95 Example 6 The following dyeing composition is prepared: 2-(2-Amino-3,5-dinitrophenyl)ethanol 0.2 g 96 strength alcohol 15 g ALFOL C1S,8 89 Lanette Wax E 0.5 g CEMULSOL B Oleic diethanolamide 1.5 g Triethanolamine, 1% concentration by weight 1g Water q.s 100g pH 8.4 When applied for 30 minutes at 28"C on hair which has been bleached white, this mixture endows it, after shampooing and rinsing, with a coloration 6.25 Y 8.5/6, according to Munsell's notation.

Example 7 The following dyeing composition is prepared: 2-[2-(,-Hydroxyethyl)amino-3,5-dinitrophenyl]ethanol 0.36 g 2-Butoxyethanol 10 g ALFOL C18 89 Lanette Wax E 0.5 g CEMULSOL B 1g Oleic diethanolamide 1.5 g Triethanolamine, 1% concentration by weight . 1 9 Water q.s. 100 g pH 7.8 When applied on hair for 20 minutes at 28oC, this mixture endows it, after shampooing and rinsing, with a coloration: 5 Y 8.5/7 on hair which has been bleached white; 5 Y 8/5 on hair which is naturally 90% white, these colors being expressed according to Munsell's notation.

Example 8 The following dyeing composition is prepared: 1 -(2-Amino-3,5-dinitrophenyl)-2-propanol 0.24 g Propylene glycol 10 g COMPERLAN KD 2.2 g Lauric acid 0.8 g 2-Ethoxyethanol 2 g Monoethanolamine 1g Water q.s. 100 g pH 8.4 When applied for 30 minutes at 28"C on hair which has been bleached white, this mixture endows it, after shampooing and rinsing, with a coloration 3.75 Y 8.5/5 according to Munsell's notation.

Example 9 The following dyeing composition is prepared: 1-(2-Methylamino-3,5-dinitrophenyl)-2-propanol 0.36 g 96 strength alcohol 12 g COMPERLAN KD 2.2 g Lauric acid 0.8 g 2-Ethoxyethanol 2g Monoethanolamine 1g Water q.s. 100g pH 8 When applied for 20 minutes at 30 C on hair which has been bleached white, this mixture endows it, after shampooing and rinsing, with a coloration 7 Y 8.5/4 according to Munsell's notation.

Example 10 The following dyeing composition is prepared: 1-[2-(ss-Aminoethyl)amino-3,5-dinitro-phenyl]-2-propanol 0.12 9 2-Butoxyethanol 8 g CARBOPOL 934 2g 2-Amino-2-methyl-1-propanol in 25% strength solution in water 2g Water q.s. 100 g pH 5 When applied for 30 minutes at 30 C on hair which has been bleached white, this mixture endows it, after shampooing and rinsing, with a coloration 5 Y 8.5/7 according to Munsell's notation.

Example 71 The following dyeing composition is prepared: 1-[2-(ss-Aminoethyl)amino-3,5-dinitrophenyl]-2-propanol 0.415 9 3-Nitro-4-methylamino-N,N-bis(ss-hydroxy- ethyl)aniline 0.155 g 2-Methyl-4-a m ino-3-n itro-N-(ss-hydroxy- ethyl)aniline 0.08 g 96 strength alcohol 12 9 ALFOL C,e,18 8 g Lanette Wax E 0.5 g CEMULSOL B 1g Oleic diethanolamide 1.5 g Monoethanolamine in 20% strength solution in water 0.25 g Water q.s. 100g pH 9.4 When applied for 20 minutes at 280C on bleached hair, this mixture endows it, after shampooing and rinsing with a hazel coloration.

Example 12 The following dyeing composition is prepared: 2-[2-(p-hydroxyethyl)amino-3,5- dinitrophenyljethanol 0.47 g 3-Nitro-4-( p-hydroxyethyl)aminophenol 0.13 g 1,4,5,8-Tetraaminoanthraquinone (Cibacete microdisperse blue) 0.08 g 2-Butoxyethanol 10 g CELLOSIZE WP 03 29 (Tallow alkyl)dimethylhydroxyethylammonium chloride 2g 5% strength ammonia solution 0.15 g Water q.s. 100 g pH 8 When applied for 25 minutes at 28"C on bleached hair, this mixture endows it, after shampooing and rinsing, with a golden dark blonde coloration.

Example 13 The following dyeing composition is prepared: 2-[2-(ss-hydroxyethyi)amino-3,5-dinitro- phenyl]ethanol 0.205 g Paraphenylenediamine 0.08 g Para-aminophenol 0.06 g Resorcinol 0.085 g Meta-aminophenol 0.06 g 3-(p-Hydroxyethyl)amino-6-methylphenol 0.05 g Polyglycerolated oleic alcohol (2 moles of glycerol) 4.5 g Polyglycerolated oleic alcohol (4 moles of glycerol) 4.5 g ETHOMEEN TO 12 4.5 g COMPERLAN KD 9g Propylene glycol 4g 2-Butoxyethanol 89 96 ethanol 6g MASQUOL DTPA 29 Thioglycolic acid 0.6 g Ammonia solution, 22 Bé 10 g Water q.s. 100 g pH 10.5 At the time of use, 100 g of "20 volumes" hydrogen peroxide are added.

When applied for 25 minutes at 30"C on bleached hair, the mixture endows it, after shampooing and rinsing, with a golden chestnut coloration.

The various trade names used in the above examples are clarified in greater detail below: CARBOPOL 934 Acrylic acid polymer of M.W. 2 to 3 million, sold by Goodrich Chemical Company.

ALFOL C1611, Cetyl/stearyl alcohol, sold by Condéa.

(50/50) Lanette Wax E Partially sulphated cetyl/stearyl alcohol, sold by Henkel.

CEMULSOL B Ethoxylated castor oil, sold by Rhône-Poulenc.

COMPERLAN KD Coconut fatty acid diethanolamide, sold by Henkel.

CELLOSIZE WP 03 Hydroxyethylcellulose, sold by Union Carbide.

ETHOMEEN TO 12 Oxyethylenated oleylamine (12 moles of ethylene oxide), sold by ARMAK.

MASQUOL DTPA Diethylenetriaminepentaacetic acid pentasodium salt, sold by PROTEX.

Claims (29)

1. A2,4-dinitro-6-hydroxyalkylaniline of formula

wherein: X is an unsubstituted or a mono- or polyhydroxy substituted branched or unbranched alkylene of 2 to 6 carbon atoms; R is hydrogen, (C1.4) alkyl, mono- or polyhydroxy (C14) alkyl, amino (C1.4) alkyl or mono- or disubstituted amino (C, 4) alkyl wherein each substituent is (via) alkyl, mono- or polyhydroxy (C1.4) alkyl or the nitrogen atom and at least one substituent form part of a heterocyclic system; R' denotes hydrogen or (C,.4) alkyl; or a cosmetically acceptable salt of such a compound containing a salifiable amine group.

2. A compound according to claim 1, wherein R' is hydrogen or methyl, X is ethylene, propylene, 1,1dimethylethylene, 1,2-dimethylethylene or 1,1,2-trimethylethylene and R is hydrogen or methyl, ethyl, npropyl, p-hydroxyethyl, y-hydroxypropyl, ss,-dihydroxypropyl, ss-aminoethyl or p-diethylamino.

3. A compound according to claim 1 or claim 2, selected from 2-(2-amino-3,5-dinitrophenyl)ethanol, 2 [2-(p-hydroxyethyl)-amino-3,5-dinitrnphenyl]-ethanol, 1-(2-amino-3,5-dinitrophenyl)-2-propanol, 1-(2-meth- ylamino-3,5-dinitrophenyl)-2-propanol, 1-[2-(ss-aminoethyl)amino-3,5-dinitrophenyl]-2-propanol and the salts of these compounds.

4. A compound according to claim 1, and substantially as hereinbefore described with reference to any one of Examples 1 to 5.

5. A process for preparing a 2,4-dinitro-6-hydroxyalkyl-aniline of formula (I) as defined in claim 1, comprising reacting an aqueous solution of a compound RNH2, wherein R is as defined in claim 1, with the heterocyclic compound of formula (ill):

wherein R' and X are each as defined in claim 1, at a temperature from 20 to 120"C.

6. A process according to claim 5, wherein the reaction is conducted under pressure.

7. A process according to claim 5 or claim 6, wherein the reaction is conducted in the presence of a polar protic solvent or a polar aprotic solvent.

8. A process according to claim 5, and substantially as hereinbefore described with reference to any one of Examples 1 to 5.

9. A composition for dyeing keratinous fibres comprising at least one compound as defined in one of claims 1 to 4 or as produced according to any one of claims 5 to 8 in a solvent medium.

10. A composition according to claim 9, containing from 0.001 to 5% by weight, of at least one compound of formula (I), relative to the total weight of the composition.

11. A composition according to claim 10, containing from 0.05 to 2% by weight of at least one compound of formula (I), relative to the total weight of the composition.

12. A composition according to any one of claims 9 to 11, having a pH of from 3 to 11.5.

13. A composition according to claim 12, having a pH of from 5 to 11.5.

14. A composition according to any one of claims 9 to 13, wherein the solvent medium comprises one or more lower alkanol, aromatic alcohol, polyol, glycol or glycol ether, or water or mixture thereof.

15. A composition according to any one of claims 9 to 14, further comprising one or more cosmetic adjuvant selected from anionic, cationic, nonionic and amphoteric surfactants and mixtures thereof, thickeners, dispersants, penetrants, sequestering agents, film-forming agents, buffers, perfumes and alkalinising and acidifying agents.

16. A composition according to any one of claims 9 to 15, formulated as a direct dye for human hair, comprising at least one compound of formula (I) and at least one other direct dye selected from azo dyes, anthraquinone dyes, indophenols, indoanilines and nitro derivatives of the benzene series.

17. A composition according to any one of claims 9 to 15, formulated as a hair setting lotion and comprising an aqueous, alcoholic or hydroalcoholic solution containing at least one cosmetic resin.

18. A composition according to any one of claims 9 to 15, formulated as an oxidation dye and comprising at least one oxidation dye precursor.

19. A composition according to claim 18 having a pH of from 7 to 11.5, and further comprising a reducing agent.

20. A composition according to claim 9, and substantially as hereinbefore described with reference to any one of Examples 4 to 13.

21. A process for dyeing keratinous fibres comprising applying a composition as defined in any one of claims 9 to 16 to the fibres, leaving the composition on the fibres for 5 to 50 minutes, then rinsing and drying the fibres.

22. A process according to claim 21 wherein after rinsing, the fibres are washed with shampoo and rinsed again then dried.

23. A process for dyeing keratinous fibres comprising applying a composition as defined in claim 17 to fibres which have previously been washed and rinsed, then drying the fibres.

24. A process according to claim 23 wherein before drying the fibres are coiled.

25. A process for dyeing keratinous fibres, comprising applying a composition as defined in claim 18 or claim 19, to the fibres, leaving the composition on the fibres for 10 to 50 minutes, then rinsing and drying the fibres.

26. A process according to claim 25, wherein an oxidizing agent is added to the composition applied to the fibres.

27. A process according to claim 25 or claim 26, wherein after rinsing the fibres are washed with shampoo, rinsed again and then dried.

28. A process according to any one of claims 21 to 27, wherein the keratinous fibres are human hairs.

29. A process according to claim 21 and substantially as hereinbefore described with reference to any one of Examples 4 to 13.