DE20110357U1 - p-aminophenol derivatives and colorants containing these compounds - Google Patents

Description

Description

p-Aminophenol derivatives and colorants containing these compounds

The present invention relates to novel p-aminophenol derivatives and to agents containing these compounds for the oxidative coloration of keratin fibers, for example wool, fur, silk or hair, in particular human hair.

Oxidation dyes have become very important in the field of coloring keratin fibers, especially hair coloring. The coloring is created by the reaction of certain developer substances with certain coupler substances in the presence of a suitable oxidizing agent. The developer substances used in particular are 2,5-diaminotoluene, 2,5-diaminophenylethyl alcohol, p-aminophenol, 1,4-diaminobenzene and 1-(2-hydroxyethyl)-4,5-diaminopyrazole, while the coupler substances used are, for example, resorcinol, 2-methyl-resorcinol, 1-naphthol, 3-aminophenol, m-phenylenediamine, 2-amino-4-(2'-hydroxyethyl)amino-anisole, 1,3-diamino-4-(2'-hydroxyethoxy)benzene and 2,4-diamino-5-fluoro-toluene.

In addition to the desired intensity, oxidation dyes used to dye human hair must meet numerous additional requirements. The dyes must be safe from a toxicological and dermatological point of view and the hair dyes produced must have good lightfastness, perm fastness, acid fastness and rubbing fastness. In any case, however,

such dyes must remain stable for a period of at least 4 to 6 weeks without the influence of light, friction and chemical agents. It is also necessary that a wide range of different color nuances can be produced by combining suitable developer substances and coupler substances.

The use of certain symmetrical diaminodihydroxydiphenyls in oxidation hair dyes is known from DE-OS 25 18 393. However, these dyes do not meet all the requirements placed on hair dyes and, moreover, only allow olive-brown to green-gray colorings. There was therefore still a need for new developer substances that meet the requirements placed on such dyes and enable a wide range of different color nuances.

It has now been found that 2-hydroxy-5-amino-biphenyl derivatives according to the general formula (I) meet the requirements shared by dyes for oxidation dyes in an excellent manner and, in combination with conventional coupler compounds, enable blonde to red color nuances.

The present invention therefore relates to novel p-aminophenol derivatives of the general formula (I) or their physiologically acceptable, water-soluble salts,

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X ₁ , X ₂ , X ₃ , X ₄ and X ₅ are independently nitrogen or a C-R1 group, C-R2 group, C-R3 group, C-R4 group or C-R5 group, with the proviso that at least one and at most three of the radicals X1 to X5 are nitrogen; and R1, R2, R3, R4 and R5 independently represent hydrogen, a halogen atom, a cyano group, a C _{1 -C 6} alkyl group, a C 1 -C 6 alkylthioether group, a mercapto group, a nitro group, an amino group, an alkylamino group, a dialkylamino group, a trifluoromethane group, a -C(O)H group, a -C(O)CH ₃ group, a -C(O)CF ₃ group, a -Si(CH ₃ ) ₃ group, a -C(O)-NH ₂ group, a C 1 -C 6 hydroxyalkyl group or a C ₃ -C ₄ dihydroxyalkyl group.

The following compounds may be mentioned as suitable compounds of the formula (I), for example: 4-amino-2-pyridin-2-yl-phenol, 4-amino-2-pyridin-3-yl-phenol, 4-amino-2-pyridin-4-yl-phenol, 4-amino-3-pyridin-2-yl-phenol. 4-amino-3-pyridin-3-yl-phenol, 4-amino-3-pyridin-4-ylphenol, 4-amino-2-pyrimidin-2-yl-phenol, 4-amino-2-pyrimidin-4-yl-phenol, 4-amino-2-pyrimidin-5-yl-phenol, 4-amino-3-pyrimidin-2-yl-phenol, 4-amino-3-pyrimidin-4-yl-phenol, 4-amino-3-pyrimidin-5-yl-phenol,

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4-Amino-2-(3-chloro-pyridin-2-yl)-phenol,4-amino-2-(3-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(3-methyl -pyridin-2-yl)-phenol, 4-amino-2-(3-nitropyridin-2-yl)-phenol, 4-amino-2-(3-trifluoromethyl-pyridin-2-yl)-phenol _F 4- Amino-2-(4-chloro-pyridin-2-yl)-phenol, 4-amino-2-(4-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(4-methyl-pyridine -2-yl)-phenol, 4-amino-2-(4-nitropyridin-2-yl)-phenol, 4-amino-2-(4-trifluoromethyl-pyridin-2-yl)-phenol, 4-Amino-2-(5-chloro-pyridin-2-yl)-phenol, 4-amino-2-(5-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(5-methyl -pyridin-2-yl)-phenol, 4-amino-2-(5-nitropyridin-2-yl)-phenol, 4-amino-2-(5-trifluoromethyl-pyridin-2-yl)-phenol, 4- Amino-2-(6-chloro-pyridin-2-yl)-phenol, 4-amino-2-(6-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(6-methyl-pyridine -2-yl)-phenol, 4-amino-2-(6-nitropyridin-2-yl)-phenol, 4-amino-2-(6-trifluoromethyl-pyridin-2-yl)-phenol, 4-Amino-3-(3-chloro-pyridin-2-yl)-phenol, 4-amino-3-(3-fluoro-pyridin-2-yl)-phenol, 4-amino-3-(3-methyl ·pyridin-2-yl)-pheno^ 4-amino-3-(3-nitropyridin-2-yl)-phenol, 4-amino-3-(3-trifluoromethyl-pyridin-2-yl)-phenol _> 4- Amino-3-(4-chloro-pyridin-2-yl)-phenol, 4-amino-3-(4-fluoro-pyridin-2-yl)-phenol, 4-amino-3-(4-methyl-pyridine -2-yl)-phenol, 4-amino-3-(4-nitropyridin-2-yl)-phenol, 4-amino-3-(4-trifluoromethyl-pyridin-2-yl)-phenol, 4-Amino-3-(5-chloro-pyridin-2-yl)-phenol, 4-amino-3-(5-fluoro-pyridin-2-yl)-phenol, 4-amino-3-(5-methyl -pyridin-2-yl)-phenol, 4-amino-3-(5-nitropyridin-2-yl)-phenol, 4-amino-3-(5-trifluoromethyl-pyridin-2-yl)-phenol, 4- Amino-3-(6-chloro-pyridin-2-yl)-phenol, 4-amino-3-(6-fluoro-pyridin-2-yl)-phenol, 4-amino-3-(6-methyl-pyridine -2-yl)-phenol, 4-amino-3-(6-nitropyridin-2-yl)-phenol, 4-amino-3-(6-trifluoromethyl-pyridin-2-yl)-phenol, 4-Amino-2-(2-chloro-pyridin-3-yl)-phenol,4-amino-2-(2-methyl-pyridin-3-yl)-phenol, 4-amino-2-(2-nitro -pyridin-3-yl)-phenol, 4-amino-2-(4-chloropyridin-3-yl)-phenol, 4-amino-2-(4-methyl-pyridin-3-yl)-phenol, 4- Amino-2-(4-nitro-pyridin-3-yl)-phenol, 4-amino-2-(5-chloro-pyridin-3-yl)-phenol,

4-Amino-2-(5-methyl-pyridin-3-yl)-phenol, 4-amino-2-(5-nitropyridin-3-yl)-phenol, 4-amino-2-(6-chloro -pyridin-3-yl)-phenol, 4-amino-2-(6-methylpyridin-3-yl)-phenol, 4-amino-2-(6-nitro-pyridin-3-yl)-phenol, 4- Amino-3-(2-chloro-pyridin-3-yl)-phenol, 4-amino-3-(2-methyl-pyridin-3-yl)-phenol, 4-amino-3-(2-nitropyridine -3-yl)-phenol, 4-amino-3-(4-chloro-pyridin-3-yl)-phenol, 4-amino-3-(4-methyl-pyridin-3-yl)-phenol, 4-Amino-3-(4-nitropyridin-3-yl)-phenol, 4-amino-3-(5-chloro-pyridin-3-yl)-phenol, 4-amino-3-(5-methyl-pyridine -3-yl)-phenol, 4-amino-3-(5-nitropyridin-3-yl)-phenol, 4-amino-3-(6-chloro-pyridin-3-yl)-phenol,4- Amino-3-(6-methyl-pyridin-3-yl)-phenol, 4-amino-3-(6-nitropyridin-3-yl)-phenol, 4-amino-2-(2-chloropyridin-4 -yl)-phenol, 4-amino-2-(2-methyl-pyridin-4-yl)-phenol, 4-amino-2-(2-nitropyridin-4-yl)-phenol, 4-Amino-2-(3-chloro-pyridin-4-yl)-phenol, 4-Amino-2-(3-methyl-pyridin-4-yl)-phenol, 4-Amino-2-(3-nitro -pyridin-4-yl)-phenol,4-Amino-3-(2-chloro-pyridin-4-yl)-phenol, 4-Amino-3-(2-methylpyridin-4-yl)-phenol, 4- Amino-3-(2-nitro-pyridin-4-yl)-phenol, 4-Amino-3-(3-chloro-pyridin-4-yl)-phenol, 4-Amino-3-(3-methyl-pyridine -4-yl)-phenol and 4-amino-3-(3-nitro-pyridin-4-yl)-phenol, as well as their physiologically acceptable salts.

Preferred compounds of formula (I) are those in which (i) one of the radicals X ₁ to X ₆ is nitrogen or (ii) one of the radicals X ₁ to X ₆ is nitrogen and R1 to R6 are hydrogen.

Particularly preferred are the following compounds of formula (I): 4-amino-2-pyridin-2-yl-phenol, 4-amino-2-pyridin-3-yl-phenol and 4-amino-2-pyridin-4-yl-phenol and their physiologically acceptable salts.

•» ·

The preparation of the aminophenol derivatives of the formula (I) according to the invention can be carried out using synthesis methods known from the literature, for example by a palladium(O)-catalyzed coupling of a substituted benzene of the formula (II) with a heteroaryl compound of the formula (III) and subsequent cleavage of the protective group, optionally followed by a reduction of the nitro group;

I Ii

(III).

where the residual groups in formulas (II) and (III) have the following meaning:

Ra represents a protecting group - as described, for example, in the chapter "Protective Groups" in Organic Synthesis, Chapter 7, Wiley lnterscience, 1991 -; Rb represents an NHRa group or a nitro group; one of the two radicals Rc and Rd represents a halogen group while the other radical represents a B(OH) ₂ group, and X ₁ to X ₆ have the meaning given in formula (I).

The compounds of formula (I) according to the invention are readily soluble in water and enable dyeings with excellent color intensity and color fastness, particularly with regard to light fastness, wash fastness and rubbing fastness. They are particularly suitable as developer substances in oxidation dyes for keratin fibers and enable a wide range of different color nuances, which extend from blonde to brown, purple and even violet shades.

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A further subject matter of the present application are therefore agents for the oxidative coloration of keratin fibers, such as wool, silk or hair, in particular human hair, based on a developer substance-coupler substance combination, which contain at least one p-aminophenol derivative of the general formula (I) or its physiologically acceptable, water-soluble salts in a suitable cosmetic carrier.

The compounds of formula (I) can be used both as free bases and in the form of their physiologically acceptable salts with inorganic or organic acids, such as hydrochloric acid, sulphuric acid, phosphoric acid, acetic acid, propionic acid, lactic acid or citric acid.

The aminophenol derivative of formula (I) is contained in the colorant according to the invention in an amount of about 0.005 to 20 percent by weight, with an amount of about 0.01 to 5.0 percent by weight and in particular 0.1 to 2.5 percent by weight being preferred.

The preferred coupler substances are N-(3-dimethylaminophenyl)-urea, 2,6-diaminopyridine, 2-amino-4-[(2-hydroxyethyl)-amino]-anisole, 2,4-diamino-1-fluoro- 5-methyl-benzene, 2,4-diamino-1-methoxy-5-methyl-benzene, 2,4-diamino-1-ethoxy-5-methyl-benzene, 2,4-diamino-1-(2-hydroxyethoxy )-5-methyl-benzene, 2,4-Di[(2-hydroxyethyl)amino]-1,5-dimethoxy-benzene, 2,3-diamino-6-methoxy-pyridine, 3-amino-6-methoxy- 2-(methylamino)pyridine, 2,6-diamino-3,5-dimethoxypyridine, 3,5-diamino-2,6-dimethoxypyridine, 1,3-diaminobenzene,

2,4-diamino-1-(2-hydroxyethoxy)-benzene, 1,3-diamino-4-(2,3-dihydroxypropoxy)-benzene, 1,3-diamino-4-(3-hydroxypropoxy)-benzene, 1,3-diamino-4-(2-methoxyethoxy)-benzene, 2,4-diamino-1,5-di(2-hydroxyethoxy)-benzene, 1-(2-aminoethoxy)-2,4-diamino-benzene , 2-amino-1-(2-hydroxyethoxy)-4-methylamino-benzene, 2,4-diaminophenoxy-acetic acid, 3-[di(2-hydroxyethyl)amino]-aniline, 4-amino-2-di[( 2-hydroxyethyl)amino]-1-ethoxy-benzene, 5-methyl-2-(1-methylethyl)-phenol, 3-[(2-hydroxyethyl)amino]-aniline, 3-[(2-Aminoethyl)-amino]-aniline, 1,3-Di(2,4-diaminophenoxy)-propane, Di(2,4-diaminophenoxy)-methane, I.S-Diamino^^-dimethoxy- benzene, 2,6-bis(2-hydroxy-ethyl)amino-toluene,4-hydroxyindole, 3-dimethylaminophenol, 3-diethyl-amino-phenol, S-amino^-methyl-phenol, 5-amino-4-fluoro -2-methyl-phenol, S-amino^^-methoxy^-methyl-phenol, 5-amino-4-ethoxy-2-methyl-phenol, S-amino^^-dichloro-phenol, 5-amino-2,4 -dichlorophenol, S-amino^-methyl-phenol, S-amino^-chloro-B-methyl-phenol, 3-amino-phenol, 2-[(3-hydroxyphenyl)amino]-acetamide, 5-[(2-Hydroxyethyl)amino]-4-methoxy-2-methyl-phenol, 5-[(2-Hydroxyethyl)amino]-2-methyl-phenol, 3-[(2-Hydroxyethyl)amino]-phenol , 3-[(2-methoxyethyl)-amino]-phenol, 5-amino-2-ethyl-phenol, 5-amino-2-methoxy-phenol, 2-(4-amino-2-hydroxy-phenoxy)-ethanol , 5-[(3-Hydroxypropyl)amino]-2-methyl-phenol, 3-[(2,3-Dihydroxypropyl)amino]-2-methyl-phenol, 3-[(2-Hydroxyethyl)-amino]-2 -methyl-phenol, 2-amino-3-hydroxy-pyridine, 2,6-dihydroxy-3,4-dimethylpyridine, S-amino^-chloro^-methyl-phenol, 1-naphthol, 2-methyl-1-naphthol , 1,5-dihydroxy-naphthalene, 1,7-dihydroxy-naphthalene, 2,3-dihydroxy-naphthalene, 2,7-dihydroxynaphthalene, 2-methyl-1-naphthol acetate, (m-dihydroxy-phenyl)-acrylamide, i-chloro^^-dihydroxy-benzene, 2-chloro-(m-dihydroxy-phenyl)-acrylamide, 1^-dichloro-S^-dihydroxy^-methyl-benzene, 1,5-dichloro-2,4-dihydroxybenzene , 1,S-Dihydroxy^-methyl-benzene, 3,4-methylenedioxy-phenol,

3,4-methylenedioxy-aniline, 5-[(2-hydroxyethyl)amino]-1,3-benzodioxole, 6-bromo-1-hydroxy-3,4-methylenedioxy-benzene, 3,4-diamino-benzoic acid, 3 ,4-Dihydro-6-hydroxy-1,4(2H)-benzoxazine, 6-amino-3,4-dihydro-1,4(2H)-benzoxazine, S-methyl-i-phenyl-δ-pyrazolone, 5 ,6-Dihydroxy-indole, 5,6-Dihydroxy-indoline, 5-Hydroxy-indole, 6-Hydroxy-indole, 7-Hydroxy-indole and 2,3-Indolindione into consideration.

Although the advantageous properties of the aminophenol derivatives of formula (I) described here suggest that they should be used as the sole developer substance, it is of course also possible to use the p-aminophenol derivatives of formula (I) together with known developer substances, such as 1,4-diaminobenzene, 2,5-diaminotoluene, 2-(2,5-diaminophenyl)ethyl alcohol, 1-(2,5-diaminophenyl)ethyl alcohol, N,N-bis-(2'-hydroxyethyl)-1,4-diaminobenzene, 4-aminophenol and its derivatives, such as 4-amino-3-methylphenol, pyrazole derivatives, such as 4,5-diamino-1-(2-hydroxyethyl)pyrazole, 4,5-diamino-1-benzylpyrazole, 4,5-diamino-1-isopropylpyrazole, 4,5-diamino-1-methylpyrazole and 4,5-diamino-1-(4-methyl-benzyl)-pyrazole, or tetraaminopyrimidines.

The coupler substances and developer substances can be contained in the colorant according to the invention individually or in a mixture with one another, the total amount of coupler substances and developer substances in the colorant according to the invention (based on the total amount of the colorant) being in each case about 0.005 to 20 percent by weight, preferably about 0.01 to 5 percent by weight and in particular 0.1 to 2.5 percent by weight.

The total amount of the developer substance-coupler substance combination contained in the colorant described here is preferably about 0.01 to 20 percent by weight, with an amount of about 0.02 to 10 percent by weight and in particular 0.2 to 6.0 percent by weight being particularly preferred. The developer substances and coupler substances are generally used in approximately equimolar amounts; however, it is not disadvantageous if the developer substances are present in a certain excess or deficiency in this regard.

Furthermore, the colorant according to the invention can additionally contain other color components, for example 6-amino-2-methylphenol and 2-amino-5-methylphenol, as well as conventional direct dyes from the group of acidic or basic dyes, triphenylmethane dyes, aromatic nitro dyes, azo dyes and disperse dyes. The colorants according to the invention can contain these color components in an amount of about 0.1 to 4 percent by weight.

Of course, the coupler substances and developer substances as well as the other color components, if they are bases, can also be used in the form of physiologically acceptable salts with organic or inorganic acids, such as hydrochloric acid or sulfuric acid, or - if they have aromatic OH groups - in the form of salts with bases, for example as alkali phenolates.

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In addition, if the dyes are to be used to color hair, they may also contain other common cosmetic additives, for example antioxidants such as ascorbic acid, thioglycolic acid or sodium sulfite, as well as perfume oils, complexing agents, wetting agents, emulsifiers, thickeners and care substances.

The preparation form of the colorant according to the invention can be, for example, a solution, in particular an aqueous or aqueous-alcoholic solution. The particularly preferred preparation forms, however, are a cream, a gel or an emulsion. Their composition represents a mixture of the dye components with the additives customary for such preparations.

Common additives in solutions, creams, emulsions or gels are, for example, solvents such as water, lower aliphatic alcohols, for example ethanol, propanol or isopropanol, glycerin or glycols such as 1,2-propylene glycol, as well as wetting agents or emulsifiers from the classes of anionic, cationic, amphoteric or non-ionic surface-active substances such as fatty alcohol sulfates, oxyethylated fatty alcohol sulfates, alkyl sulfonates, alkylbenzenesulfonates, alkyltrimethylammonium salts, alkyl betaines, oxyethylated fatty alcohols, oxyethylated nonylphenols, fatty acid alkanolamides and oxyethylated fatty acid esters, as well as thickeners such as higher fatty alcohols, starch, cellulose derivatives, petrolatum, paraffin oil and fatty acids, as well as care substances such as cationic resins, lanolin derivatives, cholesterol, pantothenic acid and betaine. The ingredients mentioned are used in the amounts customary for such purposes, for example the wetting agents and emulsifiers in concentrations of about 0.5 to 30 weight percent.

percent, the thickeners in an amount of about 0.1 to 30 percent by weight and the care ingredients in a concentration of about 0.1 to percent by weight.

Depending on the composition, the colorant according to the invention can react in a slightly acidic, neutral or alkaline manner. In particular, it has a pH value of 6.5 to 11.5. The basic setting is preferably carried out with ammonia, although organic amines, for example monoethanolamine or triethanolamine, or inorganic bases, for example sodium hydroxide or potassium hydroxide, can also be used. Inorganic or organic acids, for example phosphoric acid, acetic acid, citric acid or tartaric acid, can be used for pH adjustment in the acidic range.

For use in the oxidative coloring of hair, the dye described above is mixed with an oxidizing agent immediately before use and a sufficient amount of this mixture for the hair coloring treatment, depending on the thickness of the hair, generally about 60 to 100 grams, is applied to the hair.

The oxidizing agents used to develop hair coloring are mainly hydrogen peroxide or its addition compounds with urea, melamine, sodium borate or sodium carbonate in the form of a 3 to 12 percent, preferably 6 percent, aqueous solution, but also atmospheric oxygen. If a 6 percent hydrogen peroxide solution is used as the oxidizing agent, the weight ratio between hair dye and oxidizing agent is 5:1 to

1:2, but preferably 1:1. Larger amounts of oxidizing agent are used especially when the dye concentration in the hair dye is higher or when a stronger bleaching of the hair is desired.

In principle, however, it is also possible to use atmospheric oxygen instead of an oxidizing agent for oxidation, with the addition of suitable enzyme systems, for example an oxygen oxidoreductase/substrate system, if necessary.

The mixture is left to act on the hair at 15 to 50 degrees Celsius for about 10 to 45 minutes, preferably 30 minutes, then the hair is rinsed with water and dried. If necessary, the hair is washed with a shampoo after this rinse and possibly rinsed with a weak organic acid, such as citric acid or tartaric acid. The hair is then dried.

The hair dyes according to the invention containing p-aminophenol derivatives of formula (I) as a developer substance enable hair dyes with excellent color fastness, particularly with regard to light fastness, wash fastness and rubbing fastness. In terms of coloring properties, the hair dyes according to the invention offer a wide range of different color nuances, depending on the type and composition of the color components, which range from blonde to brown, purple, violet to blue and black shades. The shades are characterized by their particular color intensity and a good color balance between damaged and undamaged hair. The very good coloring properties of the

Hair dyes according to the present application are further shown in that these agents enable greying hair that has not been chemically damaged to be dyed easily and with good coverage.

The following examples are intended to illustrate the subject matter of the invention in more detail without limiting it thereto.

Examples

Examples 1 : Synthesis of substituted p-aminophenol derivatives of the general formula (I) (General synthesis procedure)

A. Synthesis of N-(3-bromo-4-hydroxy-phenyl)-carbamic acid

tert.butyl ester

A solution of 9.4 g (52.8 mmol) of N-bromosuccinimide in 450 ml of chloroform is added dropwise to a suspension of 10 g (47.8 mmol) of N-(4-hydroxyphenyl)-carbamic acid tert-butyl ester in 100 ml of chloroform at 0 ⁰ C over the course of 2 hours. The reaction mixture is stirred for a further 15 minutes, washed twice with water (first 400 ml, then 200 ml), dried over magnesium sulfate, filtered and partially concentrated. The residue is mixed with hexane while stirring, whereupon a precipitate forms. The precipitate is filtered off and washed with hexane.

9.7 g (70% of theory) of N-(3-bromo-4-hydroxy-phenyl)-carbamic acid tert-butyl ester are obtained.
¹ H-NMR (300 MHz, CDCI ₃ ): S= 7.68 (brs, 1H), 7.05 (dd, 1H), 6.93 (d, 1H), 6.37 (brs; 2H), 5.39 (s, 1H), 1.51 (s, 9H)

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B. Synthesis of N-(3-bromo-4-ethoxymethoxy-phenyl)-carbamic acid tert.butyl ester

0.76 g (17.4 mmol) of a sodium hydride dispersion (55% in oil) is added portionwise at 0 ⁰ C to a solution of 5.0 g (17.4 mmol) of N-(3-bromo-4-hydroxy-phenyl)-carbamic acid tert-butyl ester from step A in 60 ml of THF. The mixture is then stirred at 0 ⁰ C for 50 minutes. 1.83 g (19.4 mmol) of chloromethyl ethyl ether is then added and the mixture is stirred at 0 ⁰ C for 1 hour. The reaction mixture is then poured onto ice, extracted with ethyl acetate and the organic phase is washed with a saturated aqueous sodium chloride solution, dried over Na ₂ SO ₄ and, after filtration, concentrated. The residue is purified on silica gel with petroleum ether/ethyl acetate (9:1).

4.8 g (80% of theory) of N-(3-bromo-4-hydroxy-phenyl)-carbamic acid tert-butyl ester are obtained.

¹ H-NMR (300 MHz, CDCI ₃ ): S = 7.66 (d, 1H), 7.16 (dd, 1H), 7.08 (d, 1H), 5.23 (s; 2H), 3.77 (q, 2H), 1.51 (s, 9H), 1.22 (t, 3H)

C. Synthesis of N-[4-ethoxymethoxy-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-carbamic acid tert.butyl ester

A mixture of 7 g (20.2 mmol) of N-(3-bromo-4-ethoxymethoxy-phenyl)-carbamic acid tert-butyl ester from step B, 12.8 g (50.6 mmol) of diboron pinacol ester, 2.0 g (2.9 mmol) of dichloro(1,1'-bis(diphenyl-phosphino)-ferrocene)palladium (PdCl ₂ (dppf)) and 6.2 g (63.2 mmol) of potassium acetate are treated under argon with 210 ml of degassed dioxane. The mixture is stirred at 80 ⁰ C for 26 hours and then treated with a mixture of 4.2 g (16.9 mmol) of diboron pinacol ester and 700 mg (0.95 mmol) of PdCl ₂ (dppf). The reaction mixture is stirred for a further 14

The mixture is stirred for 12 hours at 80 ^° C, then poured into water and extracted with ethyl acetate. The organic phase is then washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate and concentrated after filtration. The crude product obtained is purified on deactivated silica gel with hexane/ethyl acetate (1:1).

5.30 g (61% of theory) of N-[4-ethoxymethoxy-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-carbamic acid tert-butyl ester are obtained.

D. Synthesis of substituted p-aminophenol derivatives of the formula (I) 0.036 g (0.1 mmol) of N-[4-ethoxymethoxy-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-arbamic acid tert-butyl ester from step C and 0.013 mol of the corresponding bromine derivative are dissolved under argon in 70 ml of 1,2-dimethoxyethane. Then 0.5 g (0.5 mmol) of tetrakis-(triphenylphosphine)-palladium and 13 ml of a 2 normal potassium carbonate solution are added and the reaction mixture is heated to 80 ^° C. After the reaction has ended, the reaction mixture is poured into 100 ml of ethyl acetate, the organic phase is extracted with dilute sodium hydroxide solution and then dried over magnesium sulfate. The solvent is distilled off in a rotary evaporator under vacuum and the residue is purified on silica gel with petroleum ether/ethyl acetate (9:1). The product thus obtained is heated to 50 ^° C in 40 ml of ethanol. 15 ml of a 2.9 molar ethanolic hydrochloric acid solution are then added dropwise to produce the hydrochloride. The precipitate is filtered off, washed twice with 10 ml of ethanol and then dried.

a. 4-Amino-2-pyridin-2-yl-phenol hydrochloride Bromine derivative used: 2-bromo-pyridine Mass spectrum: MH+ 187 (100)

b. ^Amino^-pyrimidin^-yl-phenol hydrochloride Bromine derivative used: 2-bromo-pyrimidine Mass spectrum: MH+ 188 (100)

c. 4-Amino-2-(3-methyl-pyridin-2-yl)-phenol hydrochloride Bromine derivative used: 2-bromo-3-methyl-pyridine Mass spectrum: MH+ 201 (100)

d. 4-Amino-2-(5-methyl-pyridin-2-yl)-phenol hydrochloride Bromine derivative used: 2-bromo-5-methyl-pyridine Mass spectrum: MH+ 201 (100)

e. 4-Amino-2-(6-methyl-pyridin-2-yl)-phenol hydrochloride Bromine derivative used: 2-bromo-6-methyl-pyridine Mass spectrum: MH+ 201 (100)

f. 4-Amino-2-(4-methyl-pyridin-2-yl)-phenol hydrochloride Bromine derivative used: 2-bromo-4-methyl-pyridine Mass spectrum: MH+ 201 (100)

g. S^S-Amino^-hydroxy-phenyQ-nicotinonitrile hydrochloride Bromine derivative used: 5-bromo-nicotinonitrile Mass spectrum: MH+ 212 (100)

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18
Examples 2 to 8: Hair dye

Hair dye solutions of the following composition are produced:

1.25 mmol developer substance of formula (I) according to Table 1

1.25 mmol coupler substance according to Table 1

1.0 g potassium oleate (8% aqueous solution)

1.0 g ammonia (22% aqueous solution)

1.0 g ethanol

0.3 g ascorbic acid

ad 100.0 g water

Immediately before use, 30 g of the above dye solution are mixed with 30 g of a 6% aqueous hydrogen peroxide solution. The mixture is then applied to bleached hair. After an exposure time of 30 minutes at 40 ⁰ C, the hair is rinsed with water, washed with a commercially available shampoo and dried. The resulting dyes are summarized in Table 1.

19

Table 1:

Example
No. developer
substance
the formula
(I) Coupler substance III.
5-Amino-2-
methylphenol IV.
1-Naphthol 2. According to
Example 1a II.
1,3-Diamino-4-
(2-hydroxy-
ethoxy)-benzene-
sulfate Red orange violet 3. according to
Example 1b reddish brown Red orange violet 4. according to
Example 1c reddish brown Red orange violet 5. according to
Example 1d reddish brown Red orange light purple 6. according to
Example 1e reddish brown Red orange light purple 7. according to
Example 1f reddish brown Red orange light purple 8th. according to
Example 1g reddish brown Red orange light purple reddish brown

•♦ · ·

20 Example 9 to 24: Hair dye

Hair dye solutions of the following composition are produced:

X g 4-amino-2-pyridin-2-yl-phenol hydrochloride

U g developer substance E3 to E10 according to Table 2

Y g coupler substance K1 1 to K36 according to Table 4

Z g direct dye D1 to D3 according to table

10.0 g potassium oleate (8% aqueous solution)

10.0 g ammonia (22% aqueous solution)

10.0 g ethanol

0.3 g ascorbic acid

ad 100.0 g water

Immediately before use, 30 g of the above dye solution are mixed with 30 g of a 6% aqueous hydrogen peroxide solution. The mixture is then applied to bleached hair. After an exposure time of 30 minutes at 40 ⁰ C, the hair is rinsed with water, washed with a commercially available shampoo and dried. The dyeing results are summarized in Table 5.

21 Example 25 to 30: Hair dye

Cream-like color carrier masses of the following composition are produced:

X g 4-amino-2-pyridin-2-yl-phenol hydrochloride (E1)

U g developer substance E3 to E10 according to Table 2

Y g coupler substance K11 to K36 according to Table 4

Z g direct dye D2 according to Table 3

15.0 g cetyl alcohol

0.3 g ascorbic acid

3.5 g sodium lauryl alcohol diglycol ether sulfate, 28% aqueous

Solution

3.0 g ammonia, 22% aqueous solution

0.3 g sodium sulphite, anhydrous

ad 100 g water

Immediately before use, 30 g of the above coloring cream are mixed with 30 g of a 6% hydrogen peroxide solution. The mixture is then applied to the hair. After 30 minutes, the hair is rinsed with water, washed with a commercially available shampoo and dried. The coloring results are summarized in Table 6 below.

All percentages contained in this application are by weight unless otherwise stated.

Table 2: Developer substances E3 2-{4,5-Diamino-3-[(4-amino-phenylamino)-methyl]-pyrazol-1-yl}-
ethanol hydrochloride E4 5-[(4-Amino-phenylamino)-methyl]-2-isopropyl-2H-pyrazole-3,4-
diamine hydrochloride E5 2-isopropyl-5^henylaminomethyl-2H-pyrazole-3,4-diamine-
Hydrochlorid E6 2-(4,5-Diamino-3-phenylaminomethyl-pyrazol-1-yl)-ethanol-
Hydrochlorid E12 4-Aminophenol E13 N,N-Bis(2'-hydroxyethyl)-p-phenylenediamine sulfate E14 4,5-Diamino-1-(2'-hydroxyethyl)-pyrazole sulfate E15 2,5-Diaminotoluene sulfate

Table 3:

Direct dyes D1 2,6-Diamino-3-((pyridin-3-yl)azo)pyridine D2 6-Chloro-2-ethylamino-4-nitro-phenol D3 2-Amino-6-chloro-4-nitro-phenol

·

·

·

Table 4:

Couplers K11 1,3-Diaminobenzene K12 2-Amino-4-(2'-hydroxyethyl)aminoanisole sulfate K13 1,3-Diamino-4-(2'-hydroxyethoxy)benzene sulfate K14 2,4-Diamino-5-fluoro-toluene sulfate K16 S.S-Diamino^e-dimethoxy-pyridine dihydrochloride K17 2,4-diamino-5-ethoxy-toluene sulfate K18 N-(3-Dimethylamino)phenyl urea K19 1,3-Bis(2,4-diaminophenoxy)propane tetrahydrochloride K21 3-Aminophenol K22 5-Amino-2-methylphenol K23 S-Amino^-chloro-ß-methyl-phenol K24 5-Amino-4-fluoro-2-methylphenol sulfate K25 1-Naphthol K26 1 -Acetoxy-2-methyl-naphthalene K31 1,3-Dihydroxybenzene K32 2-methyl-1,3-dihydroxybenzene K33 1-Chloro-2,4-dihydroxybenzene K34 4-(2'-Hydroxyethyl)amino-1,2-methylenedioxybenzene
Hydrochlorid K35 3,4-methylenedioxyphenol K36 2-Amino-5-methyl-phenol

24

Table 5: Hair dyes

Example 9 10 11 12 13 14 (Amount of dye in grams) 0.096 0.24 0.30 0.04 0.01 0.70 Color
fabrics E1 0.096 1.80 0.90 E9 E10 0.01 0.03 K12 0.02 0.06 K18 0.08 0.20 0.25 0.056 0.58 K21 0.03 K22 0.20 0.80 K25 0.03 0.05 0.316 K31 0.018 K32 0.03 0.05 0.01 K35 K36 0.01 0.04 0.06 0.025 D2 light blonde
until
copper-
gold copper-
gold light copper
-colors purple
brown silver
blond dark-
mahogany D3 hue

·

·

·

25

Table 5 (continued )

Example 15 16 17 18 19 20 (Amount of dye in grams) 0.01 0.60 1.00 0.20 0.80 0.60 Dyes E1 0.05 1.00 E3 1.00 0.70 E8 2.00 1.90 E9 E10 1.10 0.07 0.80 K12 1.00 K13 1.10 K16 1.25 K17 0.40 0.28 K18 0.08 0.50 K21 0.80 K22 0.80 K25 0.03 K31 0.75 K32 0.03 K33 K36 0.25 0.15 D1 black
-brown orange blue
violet blue red pink-
colors burgundy
-colors D3 hue

• · ft ft «

26

Table 5 (continued )

Example 21 22 23 m 0.01 0.01 0.05 0.60 Dyes (Amount of dye in grams) E1 1.40 4.50 0.25 E3 0.10 E5 0.80 0.50 0.01 E6 2.50 E8 E9 0.60 0.20 0.80 K12 0.25 K13 0.01 K14 1.25 K16 0.80 K18 0.30 0.28 K19 5.00 K21 0.60 K22 0.40 K23 1.10 K25 0.33 K31 0.19 K32 K36 0.50 black red-violet Red orange warm yellow D2 hue

Table 6: Hair dyes

Example 25 26 27 28 29 30 (Amount of dye in grams) 0.10 0.20 0.01 2.00 0.50 0.70 Dyes E1 1.60 0.25 0.80 0.20 E4 3.20 1.71 0.02 1.80 E8 E9 0.23 0.10 1.30 0.20 K13 0.015 K14 1.70 K16 0.40 0.80 0.02 K19 0.08 0.25 1.80 4.50 K21 0.20 0.03 K22 0.55 K23 0.03 K25 1.05 0.135 0.02 0.25 0.80 K26 0.27 K31 K36 0.01 dark
brown chocolate
brown silver
blond orange
colors blue
violet red-violet D2 hue

Claims (14)

1. p-aminophenol derivative of the general formula (I) or its physiologically acceptable, water-soluble salts,


wherein
X ₁ , X ₂ , X ₃ , X ₄ and X ₅ are independently nitrogen or a C-R1 group, C-R2 group, C-R3 group, C-R4 group or C-R5 group, with the proviso that at least one and at most three of the radicals X1 to X5 are nitrogen; and
R1, R2, R3, R4 and R5 independently represent hydrogen, a halogen atom, a cyano group, a C ₁ -C ₆ alkyl group, a C ₁ -C ₄ alkylthioether group, a mercapto group, a nitro group, an amino group, an alkylamino group, a dialkylamino group, a trifluoromethane group, a -C(O)H group, a -C(O)CH ₃ group, a -C(O)CF ₃ group, a -Si(CH ₃ ) ₃ group, a -C(O)-NH ₂ group, a C ₁ -C ₄ hydroxyalkyl group or a C ₃ -C ₄ dihydroxyalkyl group. 2. p-aminophenol derivative according to claim 1, characterized in that it is selected from 4-amino-2-pyridin-2-yl-phenol, 4-amino-2-pyridin-3-yl-phenol, 4-amino-2-pyridin-4-yl-phenol, 4-amino-3-pyridin-2-yl-phenol, 4-amino-3-pyridin-3-yl-phenol, 4-amino-3-pyridin-4-yl-phenol, 4-amino-2-pyrimidin-2-yl-phenol, 4-amino-2-pyrimidin-4-yl-phenol, 4-amino-2-pyrimidin-5-yl-phenol, 4-amino-3-pyrimidin-2-yl-phenol, 4-amino-3-pyrimidin-4-yl-phenol, 4-amino-3-pyrimidin-5-yl-phenol, 4-Amino-2-(3-chloro-pyridin-2-yl)-phenol, 4-amino-2-(3-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(3-methyl-pyridin-2-yl)-phenol, 4-amino-2-(3-nitropyridin-2-yl)-phenol, 4-amino-2-(3-trifluoromethyl-pyridin-2-yl)-phenol, phenol, 4-amino-2-(4-chloro-pyridin-2-yl)-phenol, 4-amino-2-(4-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(4-methyl-pyridin-2-yl)-phenol, 4-amino-2-(4-nitropyridin-2-yl)-phenol, 4-amino-2-(4-trifluoromethyl-pyridin-2-yl)-phenol, -phenol, 4-Amino-2-(5-chloro-pyridin-2-yl)-phenol, 4-amino-2-(5-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(5-methyl-pyridin-2-yl)-phenol, 4-amino-2-(5-nitropyridin-2-yl)-phenol, 4-amino-2-(5-trifluoromethyl-pyridin-2-yl)-phenol, phenol, 4-amino-2-(6-chloro-pyridin-2-yl)-phenol, 4-amino-2-(6-fluoro-pyridin-2-yl)-phenol, 4-amino-2-(6-methyl-pyridin-2-yl)-phenol, 4-amino-2-(6-nitropyridin-2-yl)-phenol, 4-amino-2-(6-trifluoromethyl-pyridin-2-yl)-phenol, -phenol, 4-Amino-3-(3-chlor-pyridin-2-yl)-phenol, 4-Amino-3-(3-fluor-pyridin-2-yl)- phenol, 4-Amino-3-(3-methyl-pyridin-2-yl)-phenol, 4-Amino-3-(3-nitro- pyridin-2-yl)-phenol, 4-Amino-3-(3-trifluormethyl-pyridin-2-yl)-phenol, 4-Amino-3-(4-chlor-pyridin-2-yl)-phenol, 4-Amino-3-(4-fluor-pyridin-2-yl)- phenol, 4-Amino-3-(4-methyl-pyridin-2-yl)-phenol, 4-Amino-3-(4-nitropyridin-2-yl)-phenol, 4-Amino-3-(4-trifluormethyl-pyridin-2-yl)-phenol, 4-Amino-3-(5-chloro-pyridin-2-yl)-phenol, 4-amino-3-(5-fluoro-pyridin-2-yl)-phenol, 4-amino-3-(5-methyl-pyridin-2-yl)-phenol, 4-amino-3-(5-nitropyridin-2-yl)-phenol, 4-amino-3-(5-trifluoromethyl-pyridin-2-yl)-phenol, phenol, 4-amino-3-(6-chloro-pyridin-2-yl)-phenol, 4-amino-3-(6-fluoro-pyridin-2-yl)-phenol, 4-amino-3-(6-methyl-pyridin-2-yl)-phenol, 4-amino-3-(6-nitropyridin-2-yl)-phenol, 4-amino-3-(6-trifluoromethyl-pyridin-2-yl)-phenol, -phenol, 4-Amino-2-(2-chloro-pyridin-3-yl)-phenol, 4-amino-2-(2-methyl-pyridin-3-yl)-phenol, 4-amino-2-(2-nitropyridin-3-yl)-phenol, 4-amino-2-(4-chloro-pyridin-3-yl)-phenol, 4-amino-2-(4-methyl-pyridin-3-yl)-phenol, 4-Amino-2-(4-nitro-pyridin-3-yl)-phenol, 4-amino-2-(5-chloro-pyridin-3-yl)-phenol, 4-amino-2-(5-methyl-pyridin-3-yl)-phenol, 4-amino-2-(5-nitro-pyridin-3-yl)-phenol, 4-amino-2-(6-chloro-pyridin-3-yl)-phenol, 4-Amino-2-(6-methylpyridin-3-yl)-phenol, 4-amino-2-(6-nitro-pyridin-3-yl)-phenol, 4-amino-3-(2-chloro-pyridin-3-yl)-phenol, 4-amino-3-(2-methyl-pyridin-3-yl)-phenol, 4-amino-3-(2-nitro-pyridin-3-yl)-phenol, 4-Amino-3-(4-chloro-pyridin-3-yl)-phenol, 4-amino-3-(4-methyl-pyridin-3-yl)-phenol, 4-amino-3-(4-nitropyridin-3-yl)-phenol, 4-amino-3-(5-chloro-pyridin-3-yl)-phenol, 4-amino-3-(5-methyl-pyridin-3-yl)-phenol, 4-Amino-3-(5-nitro-pyridin-3-yl)-phenol, 4-Amino-3-(6-chlor-pyridin-3-yl)-phenol, 4-Amino-3-(6-methyl-pyridin-3-yl)- phenol, 4-Amino-3-(6-n itro-pyridin-3-yl)-phenol, 4-Amino-2-(2-chlor- pyridin-4-yl)-phenol, 4-Amino-2-(2-methyl-pyridin-4-yl)-phenol, 4-Amino-2- (2-nitro-pyridin-4-yl)-phenol, 4-Amino-2-(3-chlor-pyridin-4-yl)-phenol, 4-Amino-2-(3-methyl-pyridin-4-yl)-phenol, 4-Amino-2-(3-nitro-pyridin-4-yl)- phenol, 4-Amino-3-(2-chloro-pyridin-4-yl)-phenol, 4-Amino-3-(2-methyl-pyridin-4-yl)-phenol, 4-Amino-3-(2-nitro-pyridin-4-yl)-phenol, 4-Amino-3-(3-chloro-pyridin-4-yl)-phenol, 4-Amino-3-(3-methyl-pyridin-4-yl)-phenol and 4-Amino-3-(3-nitro-pyridin-4-yl)-phenol, as well as their physiologically acceptable salts. 3. p-Aminophenol derivative according to claim 1, characterized in that it is selected from compounds of formula (I) in which (i) one of the radicals X ₁ to X ₆ is nitrogen or (ii) one of the radicals X ₁ to X ₆ is nitrogen and R1 to R6 are hydrogen. 4. p-Aminophenol derivative according to one of claims 1 to 3, characterized in that it is selected from 4-amino-2-pyridin-2-yl-phenol, 4-amino-2-pyridin-3-yl-phenol and 4-amino-2-pyridin-4-yl-phenol and their physiologically acceptable salts. 5. Agent for the oxidative dyeing of keratin fibers based on a developer substance-coupler substance combination, characterized in that it contains at least one p-aminophenol derivative of the formula (I) according to one of claims 1 to 4 in a suitable cosmetic carrier. 6. Agent according to claim 5, characterized in that the p-aminophenol derivative of the formula (I) is contained in an amount of 0.005 to 20 percent by weight. 7. Agent according to claim 5 or 6, characterized in that the coupler substance is selected from the group consisting of N-(3-dimethylamino-phenyl)-urea, 2,6-diamino-pyridine, 2-amino-4-[(2-hydroxyethyl)amino]-anisole, 2,4-diamino-1-fluoro-5-methyl-benzene, 2,4-diamino-1-methoxy-5-methyl-benzene, 2,4-diamino-1-ethoxy-5-methyl-benzene, 2,4-diamino-1-(2-hydroxyethoxy)-5-methyl-benzene, 2,4-di[(2-hydroxyethyl)amino]-1,5-dimethoxy-benzene, 2,3-diamino-6-methoxy-pyridine, 3-amino-6-methoxy-2-(methylamino)-pyridine, 2,6-diamino-3,5-dimethoxy-pyridine, 3,5-Diamino-2,6-dimethoxy-pyridine, 1,3-diaminobenzene, 2,4-diamino-1-(2-hydroxyethoxy)-benzene, 1,3-diamino-4-(2,3-dihydroxypropoxy)-benzene, 1,3-diamino-4-(3-hydroxypropoxy)-benzene, 1,3-diamino-4-(2-methoxyethoxyeth oxy)-benzene, 2,4-diamino-1,5-di(2-hydroxyethoxy)-benzene, 1-(2-aminoethoxy)-2,4-diaminobenzene, 2-amino-1-(2-hydroxyethoxy)-4-methylamino-benzene, 2,4-diaminophenoxy-acetic acid, 3-[di(2-hydroxyethyl)amino]-aniline, di[(2-hydroxyethyl)amino]-1-ethoxy-benzene, 5-Methyl-2-(1- methylethyl)-phenol, 3-[(2-Hydroxyethyl)amino]-anilin, 3-[(2-Aminoethyl)- amino]-anilin, 1,3-Di(2,4-diaminophenoxy)-propan, Di(2,4-diaminophenoxy)-methan, 1,3-Diamino-2,4-dimethoxy-benzol, 2,6-Bis(2-hydroxyethyl)amino-toluol, 4-Hydroxyindol, 3-Dimethylamino-phenol, 3-Diethylamino-phenol, 5-Amino-2-methyl-phenol, 5-Amino-4-fluor-2-methyl-phenol, 5-Amino-4-methoxy-2-methyl-phenol, 5-Amino-4-ethoxy-2-methyl-phenol, 3-Amino-2,4-dichlor-phenol, 5-Amino-2,4-dichlor-phenol, 3-Amino- 2-methyl-phenol, 3-Amino-2-chloro-6-methyl-phenol, 3-amino-phenol, 2-[(3-hydroxyphenyl)amino]-acetamide, 5-[(2-hydroxyethyl)amino]-4-methoxy-2-methyl-phenol, 5-[(2-hydroxyethyl)amino]-2-methyl-phenol, 3-[(2-hydroxyethyl)amino]-phenol, 3- [(2-Methoxyethyl)amino]-phenol, 5-amino-2-ethyl-phenol, 5-amino-2-methoxy-phenol, 2-(4-amino-2-hydroxy-phenoxy)-ethanol, 5-[(3-hydroxypropyl)amino]-2-methyl-phenol, 3-[(2,3-dihydroxypropyl)amino]-2-methyl-phenol, 3-[(2-hydroxyethyl)-amino ]-2-methyl-phenol, 2-amino-3-hydroxy-pyridine, 2,6-dihydroxy-3,4- dimethylpyridine, 5-amino-4-chloro-2-methyl-phenol, 1-naphthol, 2-methyl-1-naphthol, 1,5-dihydroxy-naphthalene, 1,7-dihydroxy-naphthalene, 2,3-dihydroxy-naphthalene, 2,7-dihydroxy-naphthalene, 2-methyl-1-naphthol acetate, (m-dihydroxy-phenyl)-acrylamide, 1-chlorine -2,4-dihydroxy-benzene, 2-chloro-(m-dihydroxy-phenyl)-acrylamide, 1,2-dichloro-3,5-dihydroxy-4-methyl-benzene, 1,5-dichloro-2,4-dihydroxy-benzene, 1,3-dihydroxy-2-methyl-benzene, 3,4-methylenedioxy-phenol, 3,4-methylenedioxy-aniline, 5-[(2-Hydroxyethyl)amino]-1,3-benzodioxole, 6-bromo-1-hydroxy-3,4-methylenedioxy-benzene, 3,4-diamino-benzoic acid, 3,4-dihydro-6-hydroxy-1,4(2H)-benzoxazine, 6-amino-3,4-dihydro-1,4(2H)-benzoxazine, Methyl-1-phenyl-5-pyrazolone, 5,6-dihydroxy-indole, 5,6-dihydroxy-indoline, 5-hydroxy-indole, 6-hydroxy-indole, 7-hydroxy-indole and 2,3-indolindione. 8. Agent according to one of claims 5 to 7, characterized in that it contains, in addition to the p-aminophenol derivative of the formula (I), at least one conventional developer substance which is selected from the group consisting of 1,4-diaminobenzene, 2,5-diaminotoluene, 2-(2,5-diaminophenyl)ethyl alcohol, 1-(2,5-diaminophenyl)ethyl alcohol, N,N-bis-(2'-hydroxyethyl)-1,4-diaminobenzene, 4-aminophenol and its derivatives, pyrazole derivatives and tetraaminopyrimidines. 9. Agent according to one of claims 5 to 8, characterized in that the developer substances and coupler substances are each contained in a total amount of 0.005 to 20 percent by weight, based on the total amount of the colorant. 10. Agent according to one of claims 5 to 9, characterized in that it additionally contains at least one direct dye. 11. Agent according to one of claims 5 to 10, characterized in that it has a pH value of 6.5 to 11.5. 12. Agent according to one of claims 5 to 11, characterized in that it is a hair dye. 13. Ready-to-use agent for the oxidative dyeing of hair, characterized in that it contains at least one 1,3-dihydroxybenzene derivative of the formula (I) according to one of claims 1 to 3 and an oxidizing agent.