It is known, for example, from WO 95/01772, WO 95/15144, EP 714 954 and EP 318 294 that cationic dyes can be used to dye organic material, for example keratin, silk, cellulose or cellulose derivatives, and also synthetic fibers, for example polyamides. Cationic dyes exhibit very brilliant shades. A disadvantage is their unsatisfactory fastness to hydrolysis and to light, their frequently inadequate stability under reducing or oxidizing conditions, and their frequently unsatisfactory storage stability (see: John F. Corbett:"The Chemistry of Hair-Care Products", JSCD August 1976, page 290).

The actual technical problem of the present invention was to provide brilliant dyes that are distinguished by deep dying having good fastness properties with respect to washing, light, shampooing and rubbing, and that preferably exhibit satisfactory stability under reducing or oxidizing dyeing conditions, for the dyeing of organic material.

Accordingly, the cationic dye of formula (1) has been discovered, wherein Ri and R7 are each independently of the other hydrogen, hydroxyl ; unsubstituted or substituted C-C6alkyl, aryl radical or C1-C6alkoxy ; or-NR3R4, wherein R3 and R4 are each independently of the other hydrogen, unsubstituted or substituted aryl radical or C1-C6alkyl, and R2 is hydrogen, hydroxyl, unsubstituted or substituted C1-C6alkyl, aryl radical or C1-C6alkoxy,-NR3R4, or an organic radical of formula (2) wherein Rs is hydrogen, unsubstituted or substituted aryl radical or Ci-Cealkyl, and 7C-is an anion.

Preferred is a cationic dye of formula (1), wherein Ri and R7 are each independently of the other hydrogen, unsubstituted C1-C6alkyl, -(C1- C6aikylen)-OH,-(C1-C6alkylen)-NR3R4 or-NR3R4 wherein R3 and R4 are each independently of the other hydrogen, unsubstituted C1-C6alkpi, and R2 is hydrogen, hydroxyl, unsubstituted C1-C6aklyl, -(C1-C6alkylen)-OH, -(C1-C6alkylen)- NR3R4 ; or-NR3R4, or an organic radical of formula (2).

Further, preference is given to a cationic dye of formula (1), wherein Ri, R2 and R7 are the same substituents, such as hydrogen, unsubstituted C1-C6alkyl, -(C1-C6alkylen)-OH, or -(C1- C6aklylen)-NR3R4.

More preferred is a cationic dye of formula (1), wherein R, and R7 are hydrogen.

In the present invention, substituents of Ci-C6alkyl, aryl or benzyl are, for example hydroxyl, NR3R4, wherein R3 and R4 are each independently of the other hydrogen, unsubstituted or substituted aryl radical or Ci-Cealkyl ; or C1-C8alkyl, C1-C8alkoxy, cyanide and/or halide.

The alkyl radical is, for example, Ci-Ceaikyi, Ci-C6alkyl and preferably C1-C4alkyi, and may be straight-chain, branched, substituted or unsubstituted, or, from Csalkyl upwards, monocyclic or polycyclic, and may be uninterrupted or interrupted by hetero atoms, such as O, S, N, NH ; for example -CH2CH2-O- CH2CH2-O- CH2CH3, or-CH2GH2-O-CH2CH3 or- CH2CH2-O-CH3, or - CH2-O-CH3.

Ci-Ceaiky ! is, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl, 3-pentyl, 2, 2'-dimethylpropyl, cyclopentyl, cyclohexyl, n-hexyl, n-octyl, 1,1', 3, 3'-tetramethylbutyl or2-ethylhexyl.

C1-C6alkyl is, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl, 3-pentyl, 2, 2'-dimethylpropyl, cyclopentyl, cyclohexyl, n-hexyl.

C1-C4-alkyl is, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl or tert-butyl.

CrCeatkoxy is O-C1-C6alkyl, preferably O-C1-C4aklyl.

Aryl radical is, for example, an unsubstituted or substituted phenyl, benzyl-or tolyl Halide is, for example, fluoride, chloride, bromide or iodide, especially chloride and fluoride.

"Anion"denotes, for example, an organic or inorganic anion, such as halide, preferably chloride and fluoride, sulfate, hydrogen sulfate, phosphate, boron tetrafluoride, carbonate, bicarbonate, oxalate or C1-C6alkyl sulfate, especially methyl sulfate or ethyl sulfate ; anion also denotes lactate, formate, acetate, propionate or a complex anion, such as the zinc chloride double salt.

The anion is especially a halide, preferably chloride or fluoride, sulfate, hydrogen sulfate, methylsulfate, phosphate, formate, acetate or lactate.

The anion is more especially chloride, methyl sulfate, formate or acetate.

Most preference is given to cationic dyes of formula (3), (4), (5), (6) or (7) wherein X is an anion.

The present invention relates also to a process for the preparation of the dyes of formula (1), preferably to a dye of formula (3), (4), (5), (6) or (7) and comprises reacting a compound of formula (8), which is obtainable according to methods known, such as described in T.

Deligeorgiev at al in"Dyes and Pigments", Vol. 31 (3), pages 219 to 224, from 1996, wherein R6 is d-Ceatkoxy or halide, preferred halides are chloride or fluoride, and X- is an anion, with an amine of formula (9) wherein Ri, Rs and R7are each independently of the other hydrogen, hydroxyl ; unsubstituted or substituted C-C6alkyl, aryl radical or C1-C6akloxy ; or-NR3R4, wherein R3 and R4 are each independently of the other hydrogen, Ci-Csalkyl, unsubstituted or substituted aryl radical, preferably R3 and R4 are each independently of the other hydrogen, C,-C6alkyl, preferably, wherein R, is hydrogen; and X'is an anion.

The reaction is generally initiated by bringing the compound of formula (8) and the amine of formula (9) into contact; for example by mixing together the starting compounds or by drop wise addition of one starting compound to the other.

Customary, the temperature is in the range of 290 to 300 K during the mixing of the starting compounds.

The molar ratio of compound of formula (8) to amine of formula (9) is generally selected in the range from 5: 1 to 1: 5, especially in the range from 3: 1 to 1: 3, more especially in the range from 2: 1 to 1: 1.

The duration of reaction is generally dependent on the reactivity of the starting compounds, on the reaction temperature chosen and on the desired conversion. The chosen duration of reaction is usually in the range from one hour to three days.

The reaction temperature for the reaction of the compound of formula (8) with the amine of formula (9) is advisable to select in the range from 293 to 363K, especially in the range from 323 to 355K, more especially in the range from 333 to 355K.

The reaction pressure chosen is generally in the range from 70 kPa to 10 MPa, especially from 90 kPa to 5 MPa, and is more especially atmospheric pressure.

It may by desirable to conduct the reaction of compound of formula (8) and amine of formula (9) in the presence of a catalyst.

The molar ratio of compound of formula (8) to the catalyst is generally selected in the range from 10: 1 to 1: 5, especially in the range from 10: 1 to 1 : 1.

Suitable catalysts are for example an alkali metal C1-C6alkyloxide, such as sodium-, potassium or lithium Ci-Ceaikyioxide, preferably sodium methoxide, potassium methoxide or lithium methoxide, or sodium ethoxide, potassium ethoxide or lithium ethoxide; or tertiary amines, for example, such as pyridine, trimethylamine, triethylamine, trioctyllamine, 1, 4-diazabicyclo [2.2. toctan, chinuclidine, N-methylpiperidine ; or alkalimetal acetate, for example such as sodium acetate, potassium acetate, or lithium acetate.

Preferred are potassium acetate, sodium methoxide, pyridine and 1,4-diaza- bicyclo [2.2. 2] octan.

It is recommended that the reaction mixture obtained be subsequently stirred in the selected temperature range from 293 to 363 K, especially in the range from 323 to 355K, more especially in the range from 333 to 355K. The duration chosen for the subsequent stirring is generally from 1 hour to 24 hours.

In addition, the reaction can be carried out with or without solvent, but is preferably carried out in a solvent. Preference is given to organic solvents or solvent mixtures.

Within the context of this invention, solvents are organic solvents and water, or a mixture of organic solvents or a mixture of organic solvents and water.

Organic solvents are, for example, protic or aprotic polare organic solvents, such as alcohols, for example methanol, ethanol, n-propanol, isopropanol, butanol or glycols, especially isopropanol, or nitrile, such as acetonitrile or propionitrile, or amide, such as dimethylformamide, dimethylacetamide or N-methylpyridine, or sulfoxide, such as dimethylsulfoxide, or mixtures thereof.

The ratio by weight of compound of formula (8) to the solvent is generally in the range from 20 to 90% by weight, especially in the range from 30 to 60% by weight.

The prepared product may be advantageously worked up and isolated, and if desired be purified.

Customary, the work up starts by decreasing the temperature of the reaction mixture in the range from 280 to 300 K, especially in the range from 290 to 300 K.

It may be of advantageous to decrease the temperature slowly, over a period of several hours.

In general, the reaction product is usually filtered and then washed with water or a salt solution and subsequently dried.

Filtration is normally carried out in standard filtering equipment, for example Bücher funnels, filter presses, pressurised suction filters, preferably in vacuo.

The temperature for the drying is dependent on the pressure applied. Drying is usually carried out in vacuo at 50-200 mbar.

The drying is usually carried out at a temperature in the range from 313 to 363 K, especially from 323 to 353 K, and more especially in the range from 328 to 348 K.

It has proved advantageous for the product to be purified by recrystallisation after it has been isolated.

Organic solvents and solvent mixtures are suitable for the recrystallisation. Preference is given to alcohols, for example methanol, ethanol, 2-propanol or butanol, especially 2- propanol.

The dyes of formula (1) according to the invention are suitable for dyeing organic material, such as keratin, wool, leather, silk, cellulose or polyamides, especially keratin-containing fibers, cotton or nylon, and preferably human hair.

Special preference is given to colouring compositions for the colouring of hair. Further additives that are suitable for such compositions include additives that are customary in hair- colouring, for example further dyes, surfactants, solvents, perfumes, polymeric adjuvants, thickeners and light stabilisers.

The diversity of shades and the colour fastness of the dye mixtures used in accordance with the invention can be increased by combination with other dyes used in the field of hair- colouring compositions. They can be combined very readily both with oxidation dyes and with direct dyes, it being possible for the latter to be of anionic or cationic nature or uncharged.

In all colouring compositions, it is also possible for a plurality of different colourants to be used together; likewise, it is possible for a plurality of different oxidation dye precursors from the group of the developer and coupler compounds to be used together, for example aromatic compounds having a primary or secondary amino group, nitrogen-containing heterocycles, aromatic hydroxy compounds or amino acids, as described, for example, in German Patent Application 197 17 224. 5.

The dye mixtures according to the invention produce colour shades in the range from yellow to blue, and the fastness properties are outstanding. Attention is drawn to the excellent fastness to light and fastness to washing properties and to their property that enables hair that has already been coloured a dark colour still to be distinctly altered in shade.

In a further embodiment, for the purpose of further modification of colour shades the colouring compositions according to the invention also comprise, in addition to the dye mixtures according to the invention, customary direct dyes, for example from the group of the nitroanilines, nitrophenylenediamines, nitroaminophenols, anthraquinones, indophenols, phenazines, phenothiazines and methines.

Also very suitable for combination with the dye mixtures according to the invention are cationised nitroaniline and anthraquinone dyes, for example those described in the following patent specifications: US-5 298 029, US-5 360 930, US-5 169 403, US-5 256 823, US-5 135 543, EP-A-818 193, US-5 486 629 and EP-A-758 547.

Also, cationic direct dyes such as cationic azo dyes, for example according to GB-A-2 319 776, as well as the oxazine dyes described in DE-A-299 12 327 and mixtures thereof with the other direct dyes mentioned therein, are likewise suitable for combination.

Cationic direct dyes, for example according to WO 95/01772, WO 95/15144, EP 714 954 and EP 318 294, are also suitable for combination.

In addition, the colouring compositions according to the invention may also comprise naturally occurring dyes, for example henna red, henna neutral, henna black, camomile blossom, sandalwood, black tea, Rhamnus frangula bark, sage, campeche wood, madder root, catechu, sedre and alkanet root. Such colouring methods are described, for example, in EP-A-404 868.

In respect of further customary dye components, reference is made expressly to the series "Dermatology", edited by Ch. Culnan, H. Maibach, Verlag Marcel Dekker Inc., New York, Basle, 1986, Vol. 7, Ch. Zviak, The Science of Hair Care, chapter 7, pages 248-250 (direct dyes), and chapter 8, pages 264-267 (oxidation dyes), and to"Europäisches Inventar der Kosmetikrohstoffe", 1996, published by The European Commission, obtainable in diskette form from the Bundesverband der deutschen Industrie-und Handelsunternehmen fur Arzneimittel, Reformwaren und Körperpflegemittel e. V. , Mannheim.

It is not necessary for the oxidation dye precursors, where present, or for the dyes each to be single compounds, but rather the colouring compositions according to the invention may additionally comprise, depending on the preparation procedures for the individual dyes, lesser amounts of further components, provided such components do not have an adverse effect on the colouring result or do not need to be excluded for other reasons, for example toxicological reasons.

The dye mixtures according to the invention may also readily be used in combination with other dyes and/or adjuvants used in the colouring of hair, for example with oxidising agents to achieve lightened colorations, as described in EP-A-810 851, oxidising agents in the form of permanent-wave fixing solution, as described in DE-A-197 13 698 or WO 99/40895, oxidation dyeing compositions, as described in EP-A-850 636, EP-A-850 637, EP-A-850 638 and EP-A-852 135, oxidation dyes in the presence of oxidoreductase enzyme, as described in WO 99/17730 and WO 99/36034, autooxidisable oxidation dyes, as described in WO 99/20234, or nitrobenzene derivatives, as described in WO 99/20235.

The colouring compositions according to the invention produce intense colorations even at physiological tolerable temperatures of less than 45°C. They are accordingly suitable especially for colouring human hair. For use on human hair, the colouring compositions can usually be incorporated into an aqueous cosmetic carrier. Suitable aqueous cosmetic carriers include, for example, creams, emulsions, gels and also surfactant-containing foaming solutions, e. g. shampoos or other preparations, that are suitable for use on keratin-containing fibres. Such forms of use are described in detail in Research Disclosure 42448 (August 1999). If necessary, it is also possible to incorporate the colouring compositions into anhydrous carriers, as described, for example, in US-3 369 970. The colouring compositions according to the invention are also outstandingly suitable for the colouring method described in DE-A-3 829 870 using a colouring comb or colouring brush.

The colouring compositions according to the invention may furthermore comprise any active ingredient, additive or adjuvant known for such preparations. The colouring compositions in many cases comprise at least one surfactant, there being suitable in principle anionic and also zwitterionic, ampholytic and non-ionic surfactants. In many cases, however, it has proved advantageous to select the surfactants from anionic and non-ionic surfactants.

Anionic surfactants suitable for use in preparations according to the invention include any anionic surface-active substance that is suitable for use on the human body. Such a substance is characterised by an anionic group that imparts water solubility, for example a carboxylate, sulfate, sulfonate or phosphate group, and a lipophilic alkyl group having approximately from 10 to 22 carbon atoms. In addition, glycol or polyglycol ether groups, ester, ether and amide groups and also hydroxy groups may be present in the molecule.

Examples of suitable anionic surfactants, each in the form of sodium, potassium or ammonium salts or mono-, di-or tri-alkanolammonium salts having 2 or 3 carbon atoms in the alkanol group, are: - linear fatty acids having from 10 to 22 carbon atoms (soaps), -ether carboxylic acids of formula R-O-(CH2-CH2-O), < CH 2 COOH, in which R is a linear alkyl group having from 10 to 22 carbon atoms and x = 0 or from 1 to 16, - acyl sarcosides having from 10 to 18 carbon atoms in the acyl group, -acyl taurides having from 10 to 18 carbon atoms in the acyl group, - acyl isothionates having from 10 to 18 carbon atoms in the acyl group, - sulfosuccinic acid mono-and di-alkyl esters having from 8 to 18 carbon atoms in the alkyl group and sulfosuccinic acid monoalkylpolyoxyethyl esters having from 8 to 18 carbon atoms in the alkyl group and from 1 to 6 oxyethyl groups, - linear alkanesulfonates having from 12 to 18 carbon atoms, - linear a-olefin sulfonates having from 12 to 18 carbon atoms, - a-sulfo fatty acid methyl esters of fatty acids having from 12 to 18 carbon atoms, - alkyl sulfates and alkyl polyglycol ether sulfates of formula R'-O (CH2-CH2-O),-SO3H, in which R'is a preferably linear alkyl group having from 10 to 18 carbon atoms and e = 0 or from 1 to 12, - mixtures of surface-active hydroxysulfonates according to DE-A-3 725 030, - sulfated hydroxyalkylpolyethylene and/or hydroxyalkylenepropylene glycol ethers according to DE-A-3 723 354, - sulfonates of unsaturated fatty acids having from 12 to 24 carbon atoms and from 1 to 6 double bonds according to DE-A-3 926 344, - esters of tartaric acid and citric acid with alcohols that are addition products of approximately from 2 to 15 molecules of ethylene oxide and/or propylene oxide with fatty alcohols having from 8 to 22 carbon atoms.

Preferred anionic surfactants are alkyl sulfates, alkyl polyglycol ether sulfates and ether carboxylic acids having from 10 to 18 carbon atoms in the alkyl group and up to 12 glycol ether groups in the molecule, and also especially salts of saturated and especially unsaturated C8-C22carboxylic acids, such as oleic acid, stearic acid, isostearic acid and palmitic acid.

The term"zwitterionic surfactants"denotes surface-active compounds that carry at least one quaternary ammonium group and at least one-COO (-) or-SO3 (-3 group in the molecule.

Zwitterionic surfactants that are especially suitable are the so-called betaines, such as the N-alkyl-N, N-dimethylammonium glycinates, for example cocoalkyldimethylammonium glycinate, N-acylaminopropyl-N, N-dimethylammonium glycinates, for example cocoacylaminopropyidimethylammonium glycinate, and 2-alkyl-3-carboxymethyl-3- hydroxyethylimidazolines each having from 8 to 18 carbon atoms in the alkyl or acyl group and also cocoacylaminoethylhydroxyethylcarboxymethyl glycinate. A preferred zwitterionic surfactant is the fatty acid amide derivative known by the CTFA name cocamidopropyl betaine.

Ampholytic surfactants are to be understood as meaning surface-active compounds that, in addition to a Cs-C, e-alkyl or-acyl group, contain at least one free amino group and at least one-COOH or-SO3H group in the molecule and are capable of forming internal salts.

Examples of suitable ampholytic surfactants include N-alkylglycines, N-alkylpropionic acids, N-alkylaminobutyric acids, N-alkyliminodipropionic acids, N-hydroxyethyl-N-alkylamido- propylglycines, N-alkyltaurines, N-alkylsarcosines, 2-alkylaminopropionic acids and alkylaminoacetic acids, each having approximately from 8 to 18 carbon atoms in the alkyl group. Ampholytic surfactants to which special preference is given are N-cocoalkylamino- propionate, cocoacylaminoethylaminopropionate and C12-Cisacylsarcosine.

Non-ionic surfactants contain as the hydrophilic group, for example, a polyol group, a polyalkylene glycol ether group or a combination of polyol and polyglycol ether groups.

Such compounds are, for example : - addition products of from 2 to 30 mol of ethylene oxide and/or from 0 to 5 mol of propylene oxide with linear fatty alcohols having from 8 to 22 carbon atoms, with fatty acids having from 12 to 22 carbon atoms and with alkylphenols having from 8 to 15 carbon atoms in the alkyl group, -C12-C22 fatty acid mono-and di-esters of addition products of from 1 to 30 mol of ethylene oxide with glycerol, -C8-Cz2alkyl-mono-and-oligo-glycosides and ethoxylated analogues thereof, - addition products of from 5 to 60 mol of ethylene oxide with castor oil and hydrogenated castor oil, - addition products of ethylene oxide with sorbitan fatty acid esters, - addition products of ethylene oxide with fatty acid alkanolamides.

The alkyl-group-containing compounds used as surfactants may be single substances, but the use as starting materials of natural raw materials of vegetable or animal origin is generally preferred in the preparation of such substances, with the result that the substance mixtures obtained have different alkyl chain lengths according to the particular starting material used.

The surfactants that are addition products of ethylene and/or propylene oxide with fatty alcohols or derivatives of such addition products may either be products having a"normal" homologue distribution or products having a restricted homologue distribution. "Normal" homologue distribution is to be understood as meaning mixtures of homologues obtained in the reaction of fatty alcohol and alkylen oxide using alkali metals, alkali metal hydroxides or alkali metal alcoholates as catalysts. Restricted homologue distributions, on the other hand, are obtained when, for example, hydrotalcites, alkali metal salts of ether carboxylic acids, alkali metal oxides, hydroxides or alcoholates are used as catalysts. The use of products having restricted homologue distribution may be preferred.

Examples of further active ingredients, adjuvants and additives are: - non-ionic polymers, for example vinylpyrrolidonelvinyl acrylate copolymers, polyvinyl- pyrrolidone and vinylpyrrolidone/vinyl acetate copolymers and polysiloxanes, -zwitterionic and amphoteric polymers, for example acryiamidopropyl-trimethylammonium chloride/acrylate copolymers and octyiacrylamide/methyl methacrylate/tert-butylaminoethyl methacrylate/2-hydroxypropyl methacrylate copolymers, - anionic polymers, for example polyacrylic acids, crosslinked polyacrylic acids, vinyl acetate/crotonic acid copolymers, vinylpyrrolidone/vinyl acrylate copolymers, vinyl acetate/butyl maleate/isobornyl acrylate copolymers, methyl vinyl ether/maleic anhydride copolymers and acrylic acid/ethyl acrylate/N-tert-butyl acrylamide terpolymers, - thickeners, such as agar, guar gum, alginates, xanthan gum, gum arabic, karaya gum, locust bean flour, linseed gums, dextrans, cellulose derivatives, e. g. methyl cellulose, hydroxyalkyl cellulose and carboxymethyl cellulose, starch fractions and derivatives, such as amylose, amylopectin and dextrins, clays, e. g. bentonite or fully synthetic hydrocolloids such as, for example, polyvinyl alcohol, - structuring agents, such as glucose and maleic acid, - hair-conditioning compounds, such as phospholipids, for example soya lecithin, egg lecithin and cephalin, silicone oils, and also conditioning compounds, for example such as those described in DE-A-197 29 080, EP-A-834 303 or EP-A-312 343, -protein hydrolysates, especially elastin, collagen, keratin, milk protein, soya protein and wheat protein hydrolysates, condensation products thereof with fatty acids and also quaternised protein hydrolysates, -perfume oils, dimethyl isosorbitol and cyclodextrins, - solubilisers, such as ethanol, isopropanol, ethylene glycol, propylene glycol, glycerol and diethylene glycol, - anti-dandruff active ingredients, such as piroctone, lamines and Zinc Omadine, - further substances for adjusting the pH, -active ingredients such as panthenol, pantothenic acid, allantoin, pyrrolidonecarboxylic acids and salts thereof, plant extracts and vitamins, -cholesterol, - light stabilisers and UV absorbers, as described, for example, in EP-A-819 422, - consistency regulators, such as sugar esters, polyol esters or polyol alkyl ethers, - fats and waxes, such as spermaceti, beeswax, montan wax, paraffins, fatty alcohols and fatty acid esters, -fatty acid alkanolamides, - polyethylene glycols and polypropylene glycols having a molecular weight of from 150 to 50 000, for example such as those described in EP-A-801 942, - complexing agents, such as EDTA, NTA and phosphonic acids, - swelling and penetration substances, such as polyols and polyol ethers, as listed extensively, for example, in EP-A-962 219, for example glycerol, propylene glycol, propylene glycol monoethyl ether, butyl glycol, benzyl alcohol, carbonates, hydrogen carbonates, guanidines, ureas and also primary, secondary and tertiary phosphates, imidazoles, tannins, pyrrole, - opacifiers, such as latex, - pearlising agents, such as ethylene glycol mono-and di-stearate, - propellants, such as propane-butane mixtures, N2O, dimethyl ether, C02 and air, and also - antioxidants, for example isoascorbic acid, ascorbic acid, sodium sulfite, thioglycolic acid and thiolactic acid.

The constituents of the aqueous carrier are used in the preparation of the colouring compositions according to the invention in the amounts customary for that purpose; for example emulsifiers are used in concentrations of from 0.5 to 30 % by weight and thickeners in concentrations of from 0.1 to 25 % by weight of the total colouring composition.

To colour keratin-containing fibres, especially to colour human hair, the colouring compositions are usually applied to the hair in an amount of from 50 to 100 g in the form of the aqueous cosmetic carrier, left on the hair for approximately 30 minutes and then rinsed off or washed off with a commercially available hair shampoo.

The colouring compositions used in accordance with the invention and the optionally used oxidation dye precursors may be applied to the keratin-containing fibres either simultaneously or successively, the order in which they are applied being unimportant.

The colouring compositions used in accordance with the invention and the optionally used oxidation dye precursors may be stored either separately or together, either in a liquid to paste-like preparation (aqueous or non-aqueous) or in the form of a dry powder. When the components are stored together in a liquid preparation, the preparation should be substantially anhydrous in order to reduce reaction of the components. When they are stored separately, the reactive components are intimately mixed with one another only immediately before use. In the case of dry storage, before use a defined amount of hot (from 50 to 80°C) water is usually added and a homogeneous mixture prepared.

The following Examples serve to illustrate the invention without limiting the invention thereto.

Unless specified otherwise, parts and percentages relate to weight. The amounts of dye specified are relative to the material being coloured.

Example 1: 26 g of 86% by weight of a compound of the following formula (10) is added with stirring under nitrogen at 293 K to a solution of 26 g of N, N-2, 2-tetramethyl-1, 3- propanediamine in 45g dimethylformamide, whereby a viscose mixture is obtained. Then, the temperature is raised to 355 K, and stirred 3 hour at this temperature. Then, 25 g of a compound of formula (10) is added to the reaction mixture, and the reaction mixture is stirred 25 hour at this temperature under nitrogen atmosphere. Afterwards, 170 g dimethyl- formamide is added in 1.5 hours by a constant rate, while the temperature adjusted to 333 K.

During further stirring for 4 hours, the temperature is decreased to 295 K. Then the reaction mass is filtered. The filter residue is washed with 45 mi of dimethylformamide and then mixed with 300 ml water. The mixture is stirred for 3 hours at 343 K. Then, the temperature is decreased to 295 K and the mixture filtered. Then, the filter residue is washed with 100 ml of 3% sodium salt solution, filtered and dried in vacuum to obtain 68 g of product with the following formula (11) Example 2: 24 g of 2, 2-dimethyl-1, 3-propanediamine is added at 293 K, under nitrogen atmosphere, with stirring to 100g isopropanol and 62 g of 85% by weight of a compound of the following formula (10), as given in example 1. Then the temperature is raised then to 333 K, and viscosity of the reaction mixture decreases. The reaction mixture is stirred 28 hour at this temperature. Then, the reaction mass is stirred for 4 hours, while the temperature is decreased to 295 K. The reaction mass is filtered, and the filter residue is washed with 45 mi of isopropanol and again filtered. Then, 300 mi water is added to the humid filter residue and the mixture stirred for 3 hours at 353 K. Then, the temperature is decreased to 295 K and the mixture filtered. Then, the filter residue is washed with 100 ml water, filtered and dried in vacuum to obtain 57. 6 g of product with the following formula (12) Example 3 : 21.4 g of 2, 2-dimethyl-1, 3-propanolamine is added at 293 K, under nitrogen atmosphere, with stirring to 100g isopropanol, 4 g 1, 4-diazabicyclo [2.2. 2] octan and 52 g of 85% by weight of a compound of the following formula (18) Then the temperature is raised then to 333 K, and viscosity of the reaction mixture decreases. The reaction mixture is stirred at this temperature during 5 hours. Then, the reaction mass is stirred for 4 hours, while the temperature is decreased to 295 K. The reaction mass is filtered and the filter residue is washed with 45 mi of isopropanol and again filtered. Then, 300 mi water is added to the humid filter residue and the mixture stirred for 3 hours at 353 K. Then, the temperature is decreased to 295 K and the mixture filtered. Then, the filter residue is washed with 100 ml water, filtered and dried in vacuum to obtain 46 g of product with the following formula (13) Example 4: 1g sodium methoxide is added under nitrogen atmosphere, at 293 K, to a stirred mixture of 10.2 g of 2, 2-dimethyl-1, 3-propanediamine, 100g isopropanol, and 62 g of 85% by weight of a compound of formula (10) as given in example 1. Then, the temperature is raised then to 333 K. The reaction mixture is stirred 28 hour at this temperature under nitrogen atmosphere.

Then, he reaction mass is stirred for 4 hours, while the temperature is decreased to 295 K.

The reaction mass is filtered and the filter residue is washed with 45 ml of isopropanol and again filtered. Then, 300 ml water is added to the humid filter residue and the mixture stirred for 3 hours at 353 K. Then, the temperature is decreased to 295 K and the mixture filtered.

Then, the filter residue is washed with 100 ml water, filtered and dried in vacuum to obtain 37.6 g of product with the following formula (14) Example 5: 16 g triethylamineis added under nitrogen atmosphere, during stirring at 293 K, to a mixture of 10.2 g of 2, 2-dimethyl-1, 3-propanediamine, 100g methanol, and 55 g of a compound of the following formula (13) as given in example 3, whereby a viscose mixture is obtained.

Then the temperature is raised then to 335 K, and viscosity of the reaction mixture decreases. The reaction mixture is stirred 10 hour at this temperature under nitrogen atmosphere. Then, the reaction mass is stirred for 4 hours, while the temperature is decreased to 295 K. The reaction mass is filtered, and the filter residue is washed with 45 mi of methanol and again filtered. Then, 300 ml water is added to the humid filter residue and the mixture stirred for 3 hours at 353 K. Then, the temperature is decreased to 295 K and the mixture filtered. Then, the filter residue is washed with 100 mi water, filtered and dried in vacuum to obtain 47.6 g of product with the following formula (15) Example 7: 37.6 g of compound of formula (14) of example 4 is added, under nitrogen atmosphere, at 293 K, to a stirred mixture of 16 g potassium acetate (water free) and 400 g isopropanol.

Then, the temperature is raised then to 333 K, and viscosity of the reaction mixture decreases. The reaction mixture is stirred 2 hour at this temperature under nitrogen atmosphere. Then, the reaction mass is stirred for 4 hours, while the temperature is decreased to 293 K. The reaction mass is filtered and the filter residue is washed with 45 mi of isopropanol and again filtered. Then, the filter residue is washed with 10 mi isopropanol, filtered and dried in vacuum to obtain 30 g of product with the following formula (16) Example 8 : 16 g 1, 4-diazabicyclo [2. 2.2] octan is added, under nitrogen atmosphere, at 293 K, to a stirred mixture of 150g isopropanol, 23 g of 1-amino-2, 2-dimethyl-propane and 55 g of a compound of the following formula (13) as given in example 3. Then, the temperature is raised then to 335 K, and viscosity of the reaction mixture decreases. The reaction mixture is stirred 3 hour at this temperature under nitrogen atmosphere. Then, the reaction mass is stirred for 4 hours, while the temperature is decreased to 295 K. The reaction mass is filtered and the filter residue is washed with 45 ml of isopropanol and again filtered. Then, 300 ml water is added to the humid filter residue and the mixture stirred for 3 hours at 353 K. Then, the temperature is decreased to 295 K and the mixture filtered. Then, the filter residue is washed with 100 mi water, filtered and dried in vacuum to obtain 57 of product with the following formula (17) Example 9: 12.4 g 4-Fluoroanilin is added to a stirred solution of 25 ml water and 25 ml of 32% hydrochloric acid at 295 K. Then, the reaction mixture is cooled to 273 K and 19 ml 36% sodium nitrite solution is dropped at such a rate that the temperature of the mixture is maintained in the range of 273 to 276 K. After the addition of the sodium nitrite solution, the mixture is stirred for one hour. If no excess of nitrite is detected during one hour (detection by using a potassium iodide paper), further amounts of sodium nitrite solution is added. After this one hour the remaining excess of nitrite is destroyed with sulfamic acid. Then, the obtained diazo solution is dropped to a 273 K cold solution of 7.4 g imidazole in 30 ml water, whereby the pH of the solution is maintained in the range of pH 10 to 11 by adding 36% sodium hydroxide solution. After completing the diazo addition, the obtained suspension is warmed up to 295 K, the pH is adjusted to 10.5 with 36% sodium hydroxide solution. After one hour stirring at this pH and temperature, the suspension is filtrated and then washed twice with 50 ml water to obtain 55 g of the humid product Introduce into a reaction vessel 500 ml water, add the filtercake from the previouse step and suspend by stirring. Start the addition of dimethylsulphate and parallel that of sodium Hydroxide, maintaining the pH at 10-10,3 and the temperature at 25-30°C. Add the amount of 0.3 mole of dimethylsulphate in ca. 5 hours. Hold for one more hour, to finish the hydrolysis of excess of dimethylsulphate and control the disappearance of DMS. Then add 100 g of sodium chloride and 50 g of potassium chloride, cool to 0°C. After 16 hours the product is separated by filtration and washed with a cold solution of sodium/potassium chloride. Ca. 20 g cake with 0.07 mole product is obtained with the following formula (18) Example 10: 12.4 g 4-Methoxyanilin is added to a stirred solution of 25 ml water and 25 mi of 32% hydrochloric acid at 295 K. Then, the reaction mixture is cooled to 273 K and 19 mi 36% sodium nitrite solution is dropped at such a rate that the temperature of the mixture is maintained in the range of 273 to 276 K. After the addition of the sodium nitrite solution, the mixture is stirred for one hour. If no excess of nitrite is detected during one hour (detection by using a potassium iodide paper), further amounts of sodium iodide solution is added. After this one hour the remaining excess of nitrite is destroyed with sulfamic acid. Then, the obtained diazo solution is dropped to a 273 K cold solution of 7.4 g imidazole in 30 mi water, whereby the pH of the solution is maintained in the range of pH 10 to 11 by adding 36% sodium hydroxide solution. After completing the diazo addition, the obtained suspension is warmed up to 295 K, the pH is adjusted to 10.5 with 36% sodium hydroxide solution. After one hour stirring at this pH and temperature, the suspension is filtrated and then washed twice with 50 mi water to obtain 55 g of the humid product. This humid product is added to 500 mi water, and suspend by stirring. Then, 0.3 mole dimethylsulphate and sodium hydroxide is added in such a rate that a pH of pH 10-10,3 and a temperature in the range of 298 to 303 K are maintained. After the addition, the mixture is stirred for one more hour to finish the hydrolysis of the excess of dimethylsulphate. Then, 100 g of sodium chloride and 50 g of potassium chloride, is added by 273 K. After 16 hours the product is separated by filtration and washed with a cold solution of sodium/potassium chloride. About. 20 g compound with 0.07 mole product is obtained with the following formula (19) Example 11: A strand of blond undamaged human hair is colored with 5 g of a composition according to the following table behentrimonium chloride 3. 8 g cetylalcohol 4 g phenoxyethanol and isobutylparaben 0.5 g perfume 0.1 g direct Dye, of formula (6), wherein X- is 0.5 g chloride monoethanolamine ad pH 6.5 water ad 100 The coloring mixture is allowed to act on the hair for 30 minutes at about 22°C. After contact the strand is rinsed and then dried.

A strong, intense, striking coloration having good fastness to washing and fastness to rubbing properties is obtained.

Example 12 : 2 g of a composition A according to the following table' COMPOSITION A sodium stearat 11. 0 g aluminium distearat 2. 7 g sodium laurylsulfat (Duponol C) 1.0 g disperse silicic acid (Aerosil 200) 9. 1 g hydroxypropylcellulose 2.7 g ammoniumpersulfat 19.0 g sodium metasilicat 12.0 g disodium salt of ethylentetraminacetic acid 1.0 g potassium persulfat 31. 5 g and 3.6 g of a composition B according to the following table COMPOSITION B water 188 9 hydrogenperoxide 12g are mixed to a nomogenous mixture. This homogenous mixture is allowed to act on a strana of blond undamaged human hair for 30 minutes at about 22°C. After contact the strand is rinsed, shampooed.

Then the hair is colored with 5 g of a composition according to the following table behentrimonium chloride 3. 8 g cetylalcohol 4 g phenoxyethanol and isobutylparaben 0.5 g perfume 0.1 g direct Dye, of formula (5), wherein C is 0.5 g chloride monoethanolamine ad pH 6.5 water ad100 The coloring mixture is allowed to act on the hair for 30 minutes at about 22°C. After contact the strand is rinsed and then dried.

A strong, intense, striking coloration having good fastness to washing and fastness to rubbing properties is obtained.

Example 13: 2 g of a composition A according to the following table COMPOSITION A sodium stearat 11. 0 g aluminium distearat 2. 7 g sodium laurylsulfat (Duponol C) 1.0 g disperse silicic acid (Aerosil 200) 9.1 g hydroxypropylcellulose 2.7 g ammoniumpersulfat 19.0 g sodium metasilicat 12.0 g disodium salt of ethylentetraminacetic acid 1.0 g potassium persulfat 31. 5 g direct Dye, of formula (3), wherein X- is 10 g chloride and 4 9 of a composition B according to the following table COMPOSITION B water 188 g hydrogenperoxide 12 g are mixed to a homogenous mixture. This homogenous mixture is allowed to act on a strand of blond undamaged human hair for 30 minutes at about 22°C. After contact the strand is rinsed, shampooed and dried.

Example 14: 2 g of a composition A according to the following table COMPOSITION A sodium stearat 11. 0 9 aluminium distearat 2. 7 g sodium laurylsulfat (Duponol C) 1.0 g disperse silicic acid (Aerosil 200) 9.1 g hydroxypropylcellulose 2.7 g ammoniumpersulfat 19.0 g sodium metasilicat 12.0 g disodium salt of ethylentetraminacetic acid 1.0 g potassium persulfat 31.5 g Dye, **D1-D5 10 g "*D1-D5 stands for a single direct dye with the following meaning: D1 is Basic Yellow 87; D2 is Basic Orange 31 ; D3 is Basic Red 51; D4 is the cationic dye of example 4 as described in WO 01/66646; D5 is the cationic dye of example 6, compound of formula 106, as described WO 01/11708, WO 02/31056 ; and 4 g of a composition B according to the following table COMPOSITIONS B water 188g hydrogenperoxide 12 g are mixed to a homogenous mixture. This homogenous mixture is allowed to act on a strand of blond undamaged human hair for 30 minutes at about 22°C. After contact the strand is rinsed, shampooed.

Then the hair is colored with 5 g of a composition according to the following table behentrimonium chloride 3.8 g cetylalcohol 4 g phenoxyethanol and isobutylparaben 0.5 g perfume 0. 1 g Direct Dye, of formula (4), wherein X- is 0.5 g chloride monoethanolamine ad pH 6.5 water ad100 The coloring mixture is allowed to act on the hair for 30 minutes at about 22°C. After contact the strand is rinsed and then dried.

A strong, intense, striking coloration having good fastness to washing and fastness to rubbing properties is obtained.

Example 15: 2 g of a composition A according to the following table COMPOSITION A sodium stearat, 11. 0 g aluminium distearat 2.7 g sodium laurylsulfat (Duponoi C) 1.0 g disperse silicic acid (Aerosil 200) 9.1 g hydroxypropylcellulose 2.7 g ammoniumpersulfat 19. 0 g sodium metasilicat 12.0 g disodium salt of ethylentetraminacetic acid 1.0 g potassium persulfat 31.5 g is mixed with 2 g of a composition C, and 4gofa composition B according to the following table | B water 188g hydrogenperoxide 12 g to a homogenous mixture. This homogenous mixture is allowed to act on a strand of blond undamaged human hair for 30 minutes at about 22°C. After contact the strand is rinsed and shampooed.

Then the hair is colored with 5 g of a composition according to the following table behentrimonium chloride 3.8 g cetylalcohol 4 g phenoxyethanol and isobutylparaben 0.5 g perfume 0. 1 g direct Dye, of formula (4), wherein X is 0.5 g chloride monoethanolamine ad pH 6.5 water ad 100 The coloring mixture is allowed to act on the hair for 30 minutes at about 22°C. After contact the strand is rinsed and then dried.

A strong, intense, striking coloration having good fastness to washing and fastness to rubbing properties is obtained.

Example 16: Composition (A') polyglycerol alcohol with 2 mols of glycerol 4. 09 polyglycerol alcohol wit h 4 mols of glycerol 5.69g of 78% (M.A.) oil acid 3. 0 g oil amine with 2 mols ethylenoxide available 7. Og from ETHOMEEN 012 from AKZO Laurylamine succinamate of 3.0 g diethylaminopropylene, salt of sodium with 55%. oil alcohol 5. Og diethynolamide of oil acid 12. Og propylenglycol 3. 5g ethylenalcohol 7.0g monobutylether of diethylenglycol 0.5g monomethylether of propylenglycol 0. 5g sodium metabisulfite as solution a 35% 0. 455g ammonium acetate 0. 8g paraphenylendiamine 0.35g 1,3-dihydroxybenzene 0. 4g 3-amino phenol 0. 03g 2, 4-diamino-1-('3-hydroxyethyloxy) benzene, 0. 012g 2HCI 1, 3-bis- [ (4-aminophenyl) 2-hydroxyethyl)- 0. 037g amino]-2-propanol, 4HCI 1, 3-dihydroxy-2-methyl-benzene 0. 2g antioxidant parfume qs ammonia 20% de NH3 10.0 g water 100g Composition (B') direct dye of formula (3), wherein X is 20g chloride, in powder form oil of parafine 3g cationic polymeric powder (Merquat 280 Dry lOg de Calgon) sawdust 100g Composition (C') : hydrogenperoxide 20% by volume Just before the coloration of human hair a mixture of 1 equivalent of weight of Composition (A'), 01 equivalent of weight of composition (B') and 1 equivalent of weight of composition (C') is mixed.

The pH of the mixture is adjusted to 9.8.

The coloring mixture is applied on human grey hair. This mixture is allowed to act on a strand of blond undamaged human hair for 30 minutes. After contact the strand is rinsed, shampooed and dried.

Example 17: Composition (B') direct dye of formula (4), wherein X- is 20g chloride, in powder form oil of parafine 3g cationic polymeric powder (Merquat 280 Dry lOg de Calgon) sawdust 100g Composition (C') : hydrogenperoxide20% byvolume | 1009 Just before the coloration of human hair a mixture of 1 equivalent of weight of Composition (B'), and 1 equivalent of weight of composition (C') is mixed.

The pH of the mixture is adjusted to 9.8.

The coloring mixture is applied on human grey hair. This mixture is allowed to act on a strand of blond undamaged human hair for 30 minutes. After contact the strand is rinsed, shampooed and dried.

Example 18: Composition (B') direct dye, direct dye of formula (5), wherein X'is chloride, 20g in powder form oil of parafine 3g cationic polymeric powder (Merquat 280 Dry de Calgon) log sawdust 1009 Composition (C') : hydrogenperoxide20% byvolume | 1009 Just before the coloration of human hair a mixture of 1 equivalent of weight of Composition (B'), and 1 equivalent of weight of composition (C') is mixed.

The pH of the mixture is adjusted to 9.8 with ammonia 20% by volume.

The coloring mixture is applied on human grey hair. This mixture is allowed to act on a strand of blond undamaged human hair for 30 minutes. After contact the strand is rinsed, shampooed and dried.

Example 19: A strongly alkaline 10 % solution of a non-ionic surfactant (Plantaren 2000, Henkei) is adjusted to pH 9.5 using citric acid. 0.1 % of the dye of formula (11), example 1, according to the present application, is dissolved therein and a strand of human hair, bleached white, is treated with that dye solution at 293 K. After only a short period of time, the strand has been dyed an orange shade, which is still very intensive even shampooing ten times. The dye also has a strong affinity to undamaged hair. In that case, too, the wash fastness is very good.

The light fastness on damaged and undamaged hair is excellent. The perm fastness is on un-and damaged hair very good as well.

Example 20: A 10 % solution of a non-ionic surfactant (Plantaren 2000, Henkel) is adjusted to pH 5.5 using citric acid. 0.1 % of the dye of formula (12), example 2, as given above, is dissolved therein and a strand of middle blonde undamaged human hair is treated with the dye solution at room temperature. After only a short period of time, the strand has been dyed a red shade, which has a good wash, perm and lightfastness.

Example 21: A dye emulsion, containing 0.1 % of the dye of formula (14) according to example 4 of the present application, 3. 5 % cetearyl alcohol, 1.0% ceteareth 80, 0.5 % glyceryl mono-di-stearate, 3.0 % stearamide DEA, 1.0 % stearamphopropyl sulfonate, 0.5 % polyquarternium-6 and water ad 100%, is applied for 30 minutes, at room temperature, to bleached human hair, and rinsed. The result is a very attractive vibrant red dyeing with good fastnesses.

Example 22 : A dye emulsion with pH= 9.8, containing: dye ot tormula (11) ot examp ! e 1 according to the present application 1 u cetylstearylalcohol 11. 0 oleth-5 5. 0 oleic acid 2. 5 stearic acid monoethanolamide 2.5 coco fatty acid monoethanolamide 2.5 sodium laurylsuphate 1.7 1, 2-propanediol 1.0 ammoniumchloride 0.5 EDTA, tetrasodiumsalt 0. 2 Perfume 0.4 cornproteinhydrolysate 0.2 Silica 0. 1 is mixed with the same weight of 6 % hydrogen peroxide solution and the mixture is immediately applied to a tress of brown hair. After 30 minutes the tress is rinsed, shampooed, rinsed and dried.

The color result is a very brilliant red shade.

Example 23: A dye emulsion with pH 9.8, containing: dye of formula (11) of example 1 according to the present application 0. 5 cetylstearylalcohol 11.0 oleth-5 5. 0 oleic acid 2.5 stearic acid monoethanolamide 2. 5 coco fatty acid monoethanolamide 2. 5 sodium laurylsuphate 1. 7 sodiumsulphite 1. 0 ascorbic acid 0. 5 1, 2-propanediol 1.0 ammoniumchloride 0.5 EDTA, tetrasodiumsalt 0. 2 perfume 0.4 cornproteinhydrolysate 0.2 silica 0.1 toluene-2, 5-diamine sulfate 0.07 resorcinol 0.02 2-amino-6-chloro-4-nitrophenol 0.01 4-amino-m-cresol 0.03 2-amino-3-hydroxypyridine 0.001 is mixed with the same weight of 6 % hydrogen peroxide solution and the mixture is immediately applied to a tress of brown hair. After 30 minutes the tress is rinsed, shampooed, rinsed and dried.

The color result is a very brilliant ruby shade.

Example 24: A strongly alkaline 10 % solution of a non-ionic surfactant (Plantaren 2000, Henkel) is adjusted to pH 9.5 using citric acid. 0.2 % of dye of formula (11) of example 1 according to the present application and 0.1 % of the dye formula (17) of example 8 according to the present application are dissolved therein and a strand of middle blonde undamaged human hair is treated with the dye solution at room temperature. After only 10 minutes, the strand has been dyed an intensive orange shade, which has a good wash, perm and light fastness.

Example 25: A strongly alkaline 10 % solution of a non-ionic surfactant (Plantaren 2000, Henkel) is adjusted to pH 9.5 using citric acid. 0.2 % of dye of formula (11) of example 1 according to the present application and 0.1 % of the dye formula are dissolved therein and a strand of dark blonde undamaged human hair is treated with the dye solution at room temperature. After 20 minutes, the strand has been dyed an intensive red-copper shade, which has a good wash, perm and light fastness.

Example 26: A strand of bleached human hair is treated with 10 g of a dye composition having a pH of 9.8, comprising 5 g of a 6 % hydrogen peroxide solution and 5 g of a composition A given below Composition A oleic acid 10.0 toluene-2, 5-diamine sulfate 0.07 resorcinol 0.02 2-amino-6-chloro-4-nitrophenol 0.01 4-amino-m-cresol 0.03 2-amino-3-hydroxypyridine 0.001 sodium sulfite 1.0 ascorbinic acid 0.5 water Ad 100 After 15 minutes, 10 g of a 12, 5% citric acid gel, comprising the dye of formula (11) of example 1 according to the present application is applied on the hair and combed, so that the hair has a pH of 7. After 15 minutes the hair is washed with water, rinsed and dried. The strand has been dyed in an intensive red shade, which has a good wash and light fastness.

Example 27: A strand of middle blonde human hair is dyed with 10 g of a composition having a pH of 9.8, which is obtained by mixing 5g of 6 % hydrogen peroxide solution and 5 g of a composition A as given above in example 26. After 15 minutes, the pH of the hair is adjusted to pH 5 by addition of citric acid. Then, 5gofa 12, 5% citric acid gel, comprising the dye of formula (13) of example 3 according to the present application, is applied on the hair and combed, so that the hair has a pH of 7. After 15 minutes the hair is washed with water, rinsed and dried. The strand has been dyed in an intensive red shade, which has a good wash and light fastness.

Example 28: A strand of bleached human hair is dyed with 10 g of a composition having a pH of 9.8, which is obtained by mixing 5g of 6 % hydrogen peroxide solution and 5 g of a composition A given in example 26. After 15 minutes, the pH of the hair is adjusted to pH 5 by addition of citric acid. Then, 5 g of a 12,5% citric acid gel, comprising the dye of formula (11) of example 1 according to the present application, is applied on the hair and combed, so that the hair has a pH of 7. After 15 minutes the hair is washed with water, rinsed and dried. The strand has been dyed in an intensive red shade, which has a good wash and light fastness.