(P-amino-hydroxyphenyl)-acrylamide derivatives and dyes containing said compounds

1. Field of the Invention

The invention relates to new (p-aminohydroxyphenyl)acrylamide derivatives and dyeing agents containing these compounds for dyeing keratin fibers, particularly human hair.

2. Description of the Related Art

In the area of keratin fiber dyeing, particularly hair dyeing, oxidation dyes have attained substantial importance. In this case, the coloration is produced by reaction of certain developers with certain couplers in the presence of an appropriate oxidant. Suitable developers are, in particular, 2,5-diaminotroluene, 2,5-diaminophenylethyl alcohol, p-aminophenol, 1,4-diaminobenzene and 4,5-diaminopyrazole-1-(2′-hydroxyethyl)-pyrazole, and suitable couplers are, for example, resorcinol, 2-methylresorcinol, 1-naphthol, 3-aminophenol, m-phenylenediamine, 2-amino-4-(2′-hydroxyethyl)aminoanisole, 1,3-diamino-4-(2′-hydroxyethoxy)benzene and 2,4-diamino-5-fluorotoluene.

The oxidation dyes used for dyeing human hair must meet numerous requirements in addition to that of being able to produce colorations of the desired intensity. For example, these dyes must be harmless from a toxicological and dermatological standpoint, and the hair colorations obtained must have good light fastness, resistance to permanent waving, acid fastness and rubbing fastness. In any case, however, in the absence of exposure to light, rubbing and chemicals, such colorations must remain stable over a period of at least 4 to 6 weeks. Moreover, by combining appropriate developers and couplers, it must be possible to create a wide range of different color shades.

To attain natural and, in particular, fashionable color shades in the red region, p-aminophenol, alone or in admixture with other developers, in combination with suitable couplers, is primarily used. Attempts have already been made to improve the properties of p-aminophenols by the introduction of substituents. In this regards, the reader is referred to German Unexamined Patent Application DE 196 07 751 which describes colorants containing as developers special substituted p-aminophenol derivatives, for example 5-amino-2-hydroxycinnamic acid.

With the currently known colorants, it is not possible, however, to meet the requirements placed on colorants in all respects. Hence, the need continued to exist for new developers capable of meeting the aforesaid requirements to a particularly high degree.

Surprisingly, in this respect we have now found that new (p-aminohydroxyphenyl)acrylamide derivatives of general formula (I) meet said requirements placed on developers to a particularly high degree. In fact, when these developers are used with most known couplers, they give intense color shades that are unusually light-fast and wash-fast.

The object of the present invention therefore are (p-aminohydroxyphenyl)acrylamide derivatives of general formula (I) or physiologically tolerated, water-soluble salts thereof

wherein

R1 denotes hydrogen, a halogen atom (F, Cl, Br, I), a C 1 -C 4 -alkyl group, a C 1 -C 4 -hydroxyalkyl group or a C 1 -C 4 -alkoxy group; R2 and R3 independently of each other denote hydrogen or a C 1 -C 6 -alkyl group; R4 and R5 independently of each other denote hydrogen, a C 1 -C 2 -alkoxy group, a C 1 -C 6 -alkyl group, an unsaturated C 3 -C 6 -alkyl group, a C 2 -C 4 -hydroxyalkyl group, a C 3 -C 4 -dihydroxyalkyl group, a C 2 -C 4 -aminoalkyl group, a C 2 -C 4 -dimethylaminoalkyl group, a C 2 -C 4 -acetylaminoalkyl group, a C 2 -C 4 -methoxyalkyl group, C 2 -C 4 -ethoxyalkyl group, a C 1 -C 4 -cyanoalkyl group, a C 1 -C 4 -carboxyalkyl group, a C 1 -C 4 -aminocarbonylalkyl group, a pyridylmethyl group, a furfuryl group, a thienylmethyl group, a hydrogenated furfuryl group a substituted pyridyl group, a group of formula (II)

a group of formula (III)

or a group of formula (IV)

or R4 and R5 together with the nitrogen atom form a ring of the following formula

R6 denotes hydrogen, a carboxy group or an aminocarbonyl group; R7 and R8 independently of each other denote hydrogen, a hydroxyl group, an aminocarbonyl group, a methylthiomethyl group, a phenyl-substituted or hydroxyl-substituted phenyl group or a group of formula

R9, R10, R11, R12 and R13 independently of each other denote hydrogen, a halogen atom (F, Cl, Br, I), a cyano group, a hydroxyl group, a C 1 -C 4 -alkoxy group, a C 1 -C 4 -hydroxyalkoxy group, a C 1 -C 6 -alkyl group, a C 1 -C 4 -alkyl thioether group, a mercapto group, a nitro group, an amino group, an alkylamino group, a C 1 -C 4 -hydroxyalkylamino group, a dialkylamino group, a di(C 1 -C 4 -hydroxyalkyl)amino group, a (C 3 -C 4 -dihydroxyalkyl)amino group, a (C 1 -C 4 -hydroxyalkyl)-C 1 -C 4 -alkylamino group, a trifluoromethyl group, a —C(O)H group, a —C(O)CH 3 — group, a —C(O)CF 3 group, an —Si(CH 3 ) 3 group, a C 1 -C 4 -hydroxyalkyl group or a C 3 -C 4 dihydroxyalkyl group, or two adjacent R9 to R13 groups form an —O—CH 2 —O— bridge; R14 denotes a C 1 -C 4 -alkyl group, a benzyl group or a C 2 -C 4 -hydroxyalkyl group; R15 denotes hydrogen or a C 1 -C 6 -alkyl group; R16 denotes hydrogen, a hydroxyl group, a carboxy group, an aminocarbonyl group or a hydroxymethyl group; and R17 denotes hydrogen or a C 1 -C 6 -alkyl group.

Suitable compounds of formula (I) are, for example, the following: 3-(5-amino-2-hydroxyphenyl)-N-cyclopropylacrylamide, 3-(5-amino-2-hydroxyphenyl)-N-propylacrylamide, 3-(5-amino-2-hydroxyphenyl)-1-pyrrolidin-1-ylpropenone, 3-(5-amino-2-hydroxyphenyl)-N-(2-methoxyethyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-1-morpholin-4-ylpropenone, 3-(5-amino-2-hydroxyphenyl)-N-(1-hydroxymethylpropyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-furan-2-ylmethylacrylamide, 3-(5-amino-2-hydroxyphenyl)-N-methoxy-N-methylacrylamide, 3-(5-amino-2-hydroxyphenyl)-1-(4-methylpiperazin-1-yl)propenone, 3-(5-amino-2-hydroxyphenyl)-1-(4-hydroxypiperidin-1-yl)-propenone, N-(2-acetylaminoethyl)-3-(5-amino-2-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(2-morpholin-4-ylethyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-[3-(2-ketopyrrolidin-1-yl)propyl]acrylamide, N-allyl-3-(5-amino-2-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(2-hydroxy-1-methylethyl)acryl-amide, 3-(5-amino-2-hydroxyphenyl)-N-[2-(5-nitropyridin-2-yl-amino)ethyl]acrylamide, N-(2-aminoethyl)-3-(5-amino-2-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(3-imidazol-1-ylpropyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(tetrahydrofuran-2-ylmethyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(4-aminophenyl)acrylamide, N-[4-amino-2(3)-(2-hydroxyethyl)phenyl]-3-(5-amino-2-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-{4-[bis-(2-hydroxyethyl)amino]phenyl}acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(3-aminophenyl)acrylamide, N-[5-amino-2(4)-(2-hydroxyethoxy)phenyl]-3-(5-amino-2-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-[2-chloro-4-(2-hydroxyethylamino)-5-nitrophenyl]acrylamide, N-[4-amino-2-(2-hydroxyethyl)-2H-pyrazol-3-yl]-3-(5-amino-2-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-benzo[1,3]dioxol-5-ylacrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(2-hydroxyethyl)-N-methylacrylamide, 3-(5-amino-2-hydroxyphenyl)-N-ethyl-N-(2-hydroxyethyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-1-(2-hydroxymethylpyrrolidin-1-yl)propenone, 1-[3-(5-amino-2-hydroxyphenyl)acryloyl]pyrrolidin-2-carboxamide, 3-(5-amino-2-hydroxyphenyl)-1-(3-hydroxypiperidin-1-yl)propenone, 3-(5-amino-2-hydroxyphenyl)-N-(2-hydroxy-1-hydroxymethylethyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-ethylacrylamide, 2-[3-(5-amino-2-hydroxyphenyl)acryloylamino]-3-methylbutyric acid, 3-(5-amino-2-hydroxyphenyl)-N-(4-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(1-carbamoyl-2-hydroxyethyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(4-amino-2(3)-methylphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(3-hydroxy-4-methylphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(2-hydroxy-5-nitrophenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)acrylic acid, 3-(2-amino-5-hydroxyphenyl)-N-cyclopropylacrylamide, 3-(2-amino-5-hydroxyphenyl)-N-propylacrylamide, 3-(2-amino-5-hydroxyphenyl)-1-pyrrolidin-1-ylpropenone, 3-(2-amino-5-hydroxyphenyl)-N-(2-methoxyethyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-1-morpholin-4-ylpropenone, 3-(2-amino-5-hydroxyphenyl)-N-(1-hydroxymethylpropyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-furan-2-ylmethylacrylamide, 3-(2-amino-5-hydroxyphenyl)-N-methoxy-N-methylacrylamide, 3-(2-amino-5-hydroxyphenyl)-1-(4-methylpiperazin-1-yl)-propenone, 3-(2-amino-5-hydroxyphenyl)-1-(4-hydroxypiperidin-1-yl)propenone, N-(2-acetylaminoethyl)-3-(2-amino-5-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(2-morpholin-4-ylethyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-[3-(2-ketopyrrolidin-1-yl)propyl]acrylamide, N-allyl-3-(2-amino-5-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(2-hydroxy-1-methylethyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-[2-(5-nitropyridin-2-ylamino)ethyl]acrylamide, N-(2-aminoethyl)-3-(2-amino-5-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(3-imidazol-1-ylpropl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(tetrahydrofuran-2-ylmethyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-aminophenyl)acrylamide, N-[4-amino-2(3)-(2-hydroxyethyl)phenyl]-3-(2-amino-5-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-{4-[bis-(2-hydroxyethyl)amino]phenyl}acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(3-aminophenyl)acrylamide, N-[5-amino-2-(4)-(2-hydroxyethoxy)phenyl]-3-(2-amino-5-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-[2-chloro-4-(2-hydroxyethylamino)-5-nitrophenyl]-acrylamide, N-[4-amino-2-(2-hydroxyethyl)-2H-pyrazol-3-yl]-3-(2-amino-5-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-benzo[1,3]dioxol-5-ylacrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(2-hydroxyethyl)-N-methylacrylamide, 3-(2-amino-5-hydroxyphenyl)-N-ethyl-N-(2-hydroxyethyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-1-(2-hydroxymethylpyrrolidin-1-yl)propenone, 1-[3-(2-amino-5-hydroxyphenyl)acryloyl]pyrrolidin-2-carboxamide, 3-(2-amino-5-hydroxyphenyl)-1-(3-hydroxypiperidin-1-yl)propenone, 3-(2-amino-5-hydroxyphenyl)-N-(2-hydroxy-1-hydroxymethylethyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-ethylacrylamide, 2-[3-(2-amino-5-hydroxyphenyl)acryloylamino]-3-methylbutyric acid, 3-(2-amino-5-hydroxyphenyl)-N-(4-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(1-carbamoyl-2-hydroxyethyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(4-amino-2(3)-methylphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(3-hydroxy-4-methylphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(2-hydroxy-5-nitrophenyl)acrylamide and 3-(2-amino-5-hydroxyphenyl)acrylic acid and the physiologically tolerated salts thereof.

Preferred compounds of formula (I) are those wherein (i) one, several or all R1, R2 and R3 groups denote hydrogen and/or (ii) R4 denotes a C 1 -C 2 -alkyl group, a methoxy group or a C 2 -C 4 -hydroxyalkyl group and R5 denotes a C 2 -C 4 -hydroxyalkyl group and/or (iii) R4 and R5 independently of each other denote hydrogen, a C 1 -C 4 -alkyl group, an unsaturated C 1 -C 6 -alkyl group, a C 2 -C 4 -hydroxyalkyl group, a C 3 -C 4 -dihydroxyalkyl group, a furfuryl group a substituted phenyl group of formula (III) or a substituted pyrazolyl group of formula (IV) and/or (iv) R4 denotes hydrogen and R5 denotes a C 1 -C 4 -alkyl group, an unsaturated C 3 -C 6 -alkyl group, a C 2 -C 4 -hydroxyalkyl group, a C 3 -C 4 -dihydroxyalkyl group, a furfuryl group, a substituted phenyl group of formula (III) or a substituted pyrazolyl group of formula (IV).

Particularly preferred are the following compounds of formula (I): 3-(5-amino-2-hydroxyphenyl)-N-ethylacrylamide, 3-(2-amino-5-hydroxyphenyl)-N-ethylacrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(4-hydroxyphenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(4-hydroxyphenyl)acrylamide, 3-(5-amino-2-hydroxyphenyl)-N-(4-aminophenyl)acrylamide, 3-(2-amino-5-hydroxyphenyl)-N-(4-aminophenyl)acrylamide, N-[4-amino-2-(2-hydroxyethyl)-2H-pyrazol-3-yl]-3-(5-amino-2-hydroxyphenyl)acrylamide and N-[4-amino-2-(2-hydroxyethyl)-2H-pyrazol-3-yl]-3-(2-amino-5-hydroxyphenyl)acrylamide and the physiologically tolerated salts thereof.

The compounds of formula (I) can be used as the free bases as well as in the form of their physiologically tolerated salts with inorganic or organic acids, for example hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, propionic acid, lactic acid or citric acid.

The aminophenol derivatives of formula (I) of the invention can be prepared by methods of synthesis known from the literature. For example, the synthesis of the compounds of the invention can be carried out as follows:

by aminolysis of a substituted benzene of formula (V)

with an amine of formula NHR4R5 followed by elimination of the protective group and/or reduction of the nitro group,

wherein Ra stands for an appropriate protective group as described, for example, in Organic Synthesis, Chapter 3, “Protection for Phenols”, p, 143 ff, Wiley Interscience, 1991; Rb stands for NHRa or NO 2 , R18 denotes a carboxylic acid group, a carboxylic acid chloride group, a carboxylate ester group or a carboxylic anhydride group, and the R1, R2, R3, R4 and R5 group have the same meaning as in formula (I).

The compounds of formula (I) of the invention can be used, in particular, as developers in oxidative colorants for keratin fibers. They make it possible to produce a wide range of different color shades going from blond to brown to purple and all the way to violet shades.

Another object of the invention are therefore agents for oxidative dyeing of keratin fibers, for example hair, furs, feathers or wool, particularly human hair, based on a developer-coupler combination, which as developer contain at least one (p-aminohydroxyphenyl)acrylamide derivative of formula (I).

The colorant of the invention contains the aminophenol derivative of formula (I) in an amount from about 0.005 to 20 weight percent, an amount of about 0.01 to 5.0 weight percent and particularly 0.1 to 2.5 weight percent being preferred.

Preferred couplers are N-(3-dimethylaminophenyl)urea, 2,6-diaminopyridine, 2-amino-4-[(2-hydroxyethyl)amino]anisole, 2,4-diamino-1-fluoro-5-methylbenzene, 2,4-diamino-1-methoxy-5-methylbenzene, 2,4-diamino-1-ethoxy-5-methylbenzene, 2,4-diamino-1-(2-hydroxyethoxy)-5-methylbenzene, 2,4-di[(2-hydroxyethyl)amino]-1,5-dimethoxybenzene, 2,3-diamino-6-methoxypyridine, 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-diaminobenzene, 2-amino-1-(2-hydroxyethoxy)-4-methylaminobenzene, 2,4-diaminophenoxyacetic acid, 3-[di(2-hydroxyethyl)amino]aniline, 4-amino-2-di[(2-hydroxyethyl)amino]-1-ethoxybenzene, 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, 1,3-diamino-2,4-dimethoxybenzene, 2,6-bis-(2-hydroxyethyl)aminotoluene, 4-hydroxyindole, 3-dimethylaminophenol, 3-diethylaminophenol, 5-amino-2-methylphenol, 5-amino-4-fluoro-2-methylphenol, 5-amino-4-methoxy-2-methylphenol, 5-amino-4-ethoxy-2-methylphenol, 3-amino-2,4-dichlorophenol, 5-amino-2,4-dichlorophenol, 3-amino-2-methylphenol, 3-amino-2-chloro-6-methylphenol, 3-aminophenol, 2-[(3-hydroxyphenyl)amino]acetamide, 5-[(2-hydroxyethyl)amino]-4-methoxy-2-methylphenol, 5-[(2-hydroxyethyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]phenol, 3-[(2-methoxyethyl)amino]phenol, 5-amino-2-ethylphenol, 5-amino-2-methoxyphenol, 2-(4-amino-2-hydroxyphenoxy)ethanol, 5-[(3-hydroxypropyl)amino]-2-methylphenol, 3-[(2,3-dihydroxypropyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]-2-methylphenol, 2-amino-3-hydroxypyridine, 2,6-dihydroxy-3,4-dimethylpyridine, 5-amino-4-chloro-2-methylphenol, 1-naphthol, 2-methyl-1-naphthol, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-methyl-1-naphthol acetate, 1,3-dihydroxybenzene, 1-chloro-2,4-dihydroxybenzene, 2-chloro-1,3-dihydroxybenzene, 1,2-dichloro-3,5-dihydroxy-4-methylbenzene, 1,5-dichloro-2,4-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 3,4-methylenedioxyphenol, 3,4-methylenedioxyaniline, 5-[(2-hydroxyethyl)amino]-1,3-benzodioxole, 6-bromo-1-hydroxy-3,4-methylenedioxybenzene, 3,4-diaminobenzoic acid, 3,4-dihydro-6-hydroxy-1,4(2H)benzoxazine, 6-amino-3,4-dihydro-1,4[2H]benzoxazine, 3-methyl-1-phenyl-5-pyrazolone, 5,6-dihydroxyindole, 5,6-dihydroxyindoline, 5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole and 2,3-indolinedione.

Although the advantageous properties of the aminophenol derivatives of formula (I) described herein suggest that they alone be used as developers, it is, of course, also possible to use the p-aminophenol derivatives of formula (I) together with other known developers, for example with 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 the derivatives thereof, for example 4-amino-3-methylphenol, pyrazole derivatives, for example 4,5-diamino-1-(2-hydroxyethyl)pyrazole, 4,5-diamino-1-benzylpyrazole and 4,5-diamino-1-(4-methylbenzyl)pyrazole, or tetraaminopyrimidines.

The couplers and developers can be present in the colorant of the invention either individually or in admixture with one another, the total amount of each of the couplers and developers in the colorant of the invention being about 0.005 to 20 wt. % preferably about 0.01 to 5 wt. % and particularly 0.1 to 2.5 wt. % (based on the total amount of colorant).

The total amount of the developer-coupler combination contained in the colorant described herein is preferably about 0.01 to 20 wt. %, an amount of about 0.02 to 10 wt. % and especially 0.2 to 6.0 wt. % being particularly preferred. In general, the developers and couplers are used in approximately equimolar amounts. In this respect, it is not disadvantageous, however, if the developers are present in a certain excess or deficiency.

Moreover, the colorant of the invention can also contain other dye components, for example 6-amino-2-methylphenol and 2-amino-5-methylphenol, as well as common direct dyes, for example triphenylmethane dyes such as 4-[(4′-aminophenyl)-(4′-imino-2″,5″-cyclohexadien-1″-ylidene)methyl]-2-methylaminobenzene monohydrochloride (Color Index [C.I.] 42 510) and 4-[(4′-amino-3′-methylphenyl)-(4″-imino-3″-methyl-2″,5″-cyclohexadien-1″-ylidene)methyl]-2-methylaminobenzene monohydrochloride (C.I. 42 520), aromatic nitro dyes such as 4-(2′-hydroxyethyl)aminonitrotoluene, 2-amino-4,6-dinitrophenol, 2-amino-5-(2′-hydroxyethyl)aminonitrobenzene, 2-chloro-6-(ethylamino)-4-nitrophenol, 4-chloro-N-(2-hydroxyethyl)-2-nitroaniline, 5-chloro-2-hydroxy-4-nitroaniline, 2-amino-4-chloro-6-nitrophenol and 1-(2′-ureidoethyl)amino-4-nitrobenzene, azo dyes such as sodium 6-[(4′-aminophenyl)azo]-5-hydroxynaphthalene-1-sulfonate (C.I. 14 805) and disperse dyes, for example 1,4-diaminoanthraquinone and 1,4,5,8-tetraaminoanthraquinone. The colorants of the invention can contain the aforesaid dye components in an amount from about 0.1 to 4 wt. %.

The couplers and developers as well as the other dye components, provided they are bases, can, of course, also be used in the form of their physiologically tolerated salts with organic or inorganic acids, for example hydrochloric acid or sulfuric acid, or—if they contain aromatic OH groups—in the form of their salts with bases, for example as alkali metal phenoxides.

Moreover, if the colorants are to be used for coloring hair, they can 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 hair-care agents.

The colorant of the invention can be in the form of, for example, a solution, particularly an aqueous or aqueous-alcoholic solution. A particularly preferred formulation form, however, is a cream, gel or emulsion. Such a composition consists of a mixture of the dye components and the usual additives employed for such compositions.

Common additives to solutions, creams, emulsions or gels are, for example solvents such as water, lower aliphatic alcohols, for example ethanol, propanol or isopropanol, glycerol or glycols such as 1,2-propylene glycol, moreover wetting agents or emulsifiers from the classes of anionic, cationic, amphoteric or nonionic surface-active agents, for example fatty alcohol sulfates, ethoxylated fatty alcohol sulfates, alkylsulfonates, alkylbenzenesulfonates, alkyltrimethylammonium salts, alkylbetaines, ethoxylated fatty alcohols, ethoxylated nonylphenols, fatty acid alkanolamides and ethoxylated fatty esters, furthermore thickeners such as the higher fatty alcohols, starch, cellulose derivatives, petrolatum, paraffin oil and fatty acids, also hair-care agents such as cationic resins, lanolin derivatives, cholesterol, pantothenic acid and betaine. The said constituents are used in amounts commonly employed for such purposes, for example the wetting agents and emulsifiers at a concentration of about 0.5 to 30 wt. %, the thickeners in an amount from about 0.1 to 30 wt. % and the hair-care agents at a concentration from about 0.1 to 5 wt. %.

Depending on the composition, the colorant of the invention can be weakly acidic, neutral or alkaline. In particular, it can have a pH of about 6.5 to 11.5. The adjustment to a basic pH is preferably made with ammonia, but it can also be made with an organic amine, for example with monoethanolamine and triethanolamine, or with an inorganic base such as sodium hydroxide and potassium hydroxide. The adjustment to an acidic pH can be made with an inorganic or organic acid, for example phosphoric, acetic, citric or tartaric acid.

For oxidative dyeing of hair, the afore-described colorant is mixed with an oxidant just before use, and an amount sufficient for hair treatment, generally about 60 to 200 grams, of this mixture, depending on the hair fullness, is applied to the hair.

Suitable oxidants for developing the hair coloration are primarily hydrogen peroxide or its products of addition to urea, melamine, sodium borate or sodium carbonate in the form of a 3 to 12% and preferably 6% aqueous solution, atmospheric oxygen also being suitable. When a 6% hydrogen peroxide solution is used as oxidant, the weight ratio of hair colorant to oxidant is from 5:1 to 1:2 and preferably 1:1. Higher amounts of oxidant are used especially with higher dye concentrations in the hair colorant or when stronger bleaching of the hair is wanted at the same time. The mixture is allowed to act on the hair at 15 to 50° C. for about 10 to 45 minutes, preferably 30 minutes. The hair is then rinsed with water and dried. Optionally, following this rinsing, the hair is washed with a shampoo and optionally post-rinsed with a weak organic acid such as citric acid or tartaric acid. The hair is then dried.

The colorants of the invention containing a p-aminophenol derivative of formula (I) as developer give hair colorations of excellent color stability, particularly in terms of light fastness, wash fastness and rubbing fastness. As far as the dyeing properties are concerned, the hair colorants of the invention provide a wide range of different color shades from blond to brown to purple, violet and even blue and black, depending on the kind and composition of the dye components used. The shades stand out by their unusual color intensity and good color balancing between damaged and un-damaged hair. The very good coloring properties of the hair colorants of the present patent application also manifest themselves in that these colorants make it possible to dye gray hair, previously not damaged chemically, without any problems and with good covering power.

The following examples illustrate the object of the invention in greater detail without limiting its scope.