Triaromatic azomethine direct dyes, dye composition comprising at least one such dye, method of implementation and use

Abstract

The present invention relates to azomethine-type direct dyes having a triaromatic unit of formula (I) below: and also the use thereof for dyeing keratin fibers, in particular human keratin fibers such as the hair. The invention also relates to a composition for dyeing keratin fibers, comprising, in a medium suitable for dyeing, such direct dyes. Another subject of the present invention is a method for dyeing keratin fibers using said dye composition. Finally, the present invention also relates to precursors of these direct dyes. ##STR00001##

Claims

1. Azomethine-type compound having a triaromatic unit of formula (I) below, the organic or inorganic acid or base salts thereof, the tautomeric, optical isomer or geometric isomer forms thereof and/or the solvates thereof: ##STR00048## wherein: n.sub.1 and n.sub.2 represent, independently of one another, an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; R.sub.1 represents: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; an aminocarbonyl radical; a radical of formula (II): ##STR00049## in which formula (II): m represents an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; a hydroxyl radical; an NR.sub.3R.sub.4 radical in which R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.5 alkyl radical, optionally substituted with one or more hydroxyl or C.sub.1-C.sub.4 alkoxy radicals; it being understood that, in formula (II), when m is greater than or equal to 2, the R radicals may be identical or different; R.sub.2 represents: a hydrogen atom; a C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; R.sub.1 and R.sub.2 may form, together with the nitrogen atom to which they are attached, a pyrrolidine, piperidine or morpholine ring; R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; a C.sub.1-C.sub.4 alkoxy radical; X.sub.1 and X.sub.2 represent, independently of one another: a hydroxyl radical; an NR.sub.3R.sub.4 radical in which: R.sub.3 represents: a hydrogen atom; a linear C.sub.1-C.sub.6 alkyl radical; R.sub.4 represents: a hydrogen atom; a linear or branched C.sub.3-C.sub.6 alkyl radical; a linear or branched C.sub.2-C.sub.6 alkyl radical substituted with one or more hydroxyl radicals; R.sub.3 and R.sub.4 may form, together with the nitrogen atom to which they are attached, a piperidino or morpholino ring; it being understood that the compounds of formula (I) may not represent the compounds A to F below: ##STR00050## ##STR00051##

2. Azomethine-type compound having a triaromatic unit of formula (I) according to claim 1, wherein, taken together or separately: n.sub.1 and n.sub.2 represent, independently of one another, an integer equal to 0, 1 or 2; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; R.sub.1 represents: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; an aminocarbonyl radical; a radical of formula (II): ##STR00052## in which formula (II): m represents an integer equal to 0, 1, 2 or 3; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; a hydroxyl radical; an NR.sub.3R.sub.4 radical in which R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.5 alkyl radical, optionally substituted with one or more hydroxyl radicals; it being understood that, in formula (II), when m is greater than or equal to 2, the R radicals may be identical or different; R.sub.2 represents: a hydrogen atom; a linear or branched C.sub.1-C.sub.6 alkyl radical, a butyl, methyl or ethyl radical; R.sub.1 and R.sub.2 may form, together with the nitrogen atom to which they are attached, a pyrrolidine, piperidine or morpholine ring; R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical; a C.sub.1-C.sub.4 alkoxy radical; and/or X.sub.1 and X.sub.2 represent, independently of one another: a hydroxyl radical; an NR.sub.3R.sub.4 radical in which: R.sub.3 represents: a hydrogen atom; a linear C.sub.1-C.sub.6 alkyl radical; R.sub.4 represents: a hydrogen atom; a linear or branched C.sub.3-C.sub.6 alkyl radical; a linear or branched C.sub.2-C.sub.6 alkyl radical substituted with one or more hydroxyl radicals.

3. Azomethine-type compound having a triaromatic unit of formula (I) according to claim 1, wherein n.sub.1 and n.sub.2 represent an integer equal to 0 or 1, R.sub.1 is other than a hydrogen atom, R.sub.2 represents a hydrogen atom and R.sub.4 represents a hydrogen atom.

4. Azomethine-type compound having a triaromatic unit of formula (I) according to claim 1, wherein n.sub.1 and n.sub.2 represent an integer equal to 0 or 1, R.sub.1 is other than a hydrogen atom, R.sub.2 represents a hydrogen atom, R.sub.4 represents a hydrogen atom and X.sub.1 and X.sub.2 represent an NR.sub.3R.sub.4 radical in which R.sub.3 represents a hydrogen atom or a linear C.sub.1-C.sub.3 alkyl radical and R.sub.4 represents a hydrogen atom or a linear or branched C.sub.3-C.sub.4 alkyl radical or a C.sub.2-C.sub.4 alkyl radical substituted with one or more hydroxyl radicals.

5. Azomethine-type compound having a triaromatic unit of formula (I) according to claim 1, wherein n.sub.1 and n.sub.2 represent an integer equal to 0 or 1, R.sub.1 is other than a hydrogen atom, R.sub.2 represents a hydrogen atom, R.sub.4 represents a hydrogen atom and X.sub.1 and X.sub.2 represent a hydroxyl radical.

6. Azomthenine-type compound a triaromatic unit of formula (I) according to claim 1, wherein X.sub.1 and X.sub.2 represent a NR.sub.3R.sub.4 radical wherein R.sub.3 and R.sub.4 represent hydrogen atom.

7. Azomethine-type compound a triaromatic unit of formula (I) according to claim 1, wherein X.sub.1 and X.sub.2 represent a NR.sub.3R.sub.4 radical wherein R.sub.3 and R.sub.4 are different from hydrogen atom.

8. Azomethine-type compound having a triaromatic unit of formula (I) according to claim 1, wherein the compound is selected from the following compounds and also the geometric or optical isomer forms thereof, the organic or inorganic acid or base salts thereof, or the solvates thereof, such as the hydrates: ##STR00053## ##STR00054## ##STR00055## ##STR00056## ##STR00057## ##STR00058## ##STR00059## ##STR00060## ##STR00061## ##STR00062## ##STR00063## ##STR00064## ##STR00065## ##STR00066## ##STR00067## ##STR00068## ##STR00069## ##STR00070## ##STR00071## ##STR00072## ##STR00073##

9. Composition for dyeing keratin fibers, wherein the composition comprises, in a medium suitable for dyeing, one or more compounds of azomethine type having a triaromatic unit of formula (I) below and also the organic or inorganic acid or base salts thereof, the tautomeric, optical isomer or geometric isomer forms thereof and/or the solvates thereof: ##STR00074## wherein: n.sub.1 and n.sub.2 represent, independently of one another, an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; R.sub.1 represents: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; an aminocarbonyl radical; a radical of formula (II): ##STR00075## in which formula (II): m represents an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; a hydroxyl radical; an NR.sub.3R.sub.4 radical in which R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.5 alkyl radical, optionally substituted with one or more hydroxyl or C.sub.1-C.sub.4 alkoxy radicals; it being understood that, in formula (II), when m is greater than or equal to 2, the R radicals may be identical or different; R.sub.2 represents: a hydrogen atom; a C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; R.sub.1 and R.sub.2 may form, together with the nitrogen atom to which they are attached, a pyrrolidine, piperidine or morpholine ring; R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; a C.sub.1-C.sub.4 alkoxy radical; X.sub.1 and X.sub.2 represent, independently of one another: a hydroxyl radical; an NR.sub.3R.sub.4 radical in which: R.sub.3 represents: a hydrogen atom; a linear C.sub.1-C.sub.6 alkyl radical; R.sub.4 represents: a hydrogen atom; a linear or branched C.sub.3-C.sub.6 alkyl radical; a linear or branched C.sub.2-C.sub.6 alkyl radical substituted with one or more hydroxyl radicals; R.sub.3 and R.sub.4 may form, together with the nitrogen atom to which they are attached, a piperidino or morpholino ring; it being understood that the compounds of formula (I) may not represent the compounds A to D below: ##STR00076##

10. Method for dyeing keratin fibers, comprising: applying to said fibers a dye composition comprising, in a medium suitable for dyeing, one or more direct dyes of formula (I) below, the organic or inorganic acid or base salts thereof, the tautomeric, optical isomer or geometric isomer forms thereof and/or the solvates thereof for a time sufficient to obtain a desired coloration: ##STR00077## wherein: n.sub.1 and n.sub.2 represent, independently of one another, an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; R.sub.1 represents: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; an aminocarbonyl radical; a radical of formula (II): ##STR00078## in which formula (II): m represents an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; a hydroxyl radical; an NR.sub.3R.sub.4 radical in which R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.5 alkyl radical, optionally substituted with one or more hydroxyl or C.sub.1-C.sub.4 alkoxy radicals; it being understood that, in formula (II), when m is greater than or equal to 2, the R radicals may be identical or different; R.sub.2 represents: a hydrogen atom; a C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; R.sub.1 and R.sub.2 may form, together with the nitrogen atom to which they are attached, a pyrrolidine, piperidine or morpholine ring; R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; a C.sub.1-C.sub.4 alkoxy radical; X.sub.1 and X.sub.2 represent, independently of one another: a hydroxyl radical; an NR.sub.3R.sub.4 radical in which: R.sub.3 represents: a hydrogen atom; a linear C.sub.1-C.sub.6 alkyl radical; R.sub.4 represents: a hydrogen atom; a linear or branched C.sub.3-C.sub.6 alkyl radical; a linear or branched C.sub.2-C.sub.6 alkyl radical substituted with one or more hydroxyl radicals; R.sub.3 and R.sub.4 may form, together with the nitrogen atom to which they are attached, a piperidino or morpholino ring; it being understood that the compounds of formula (I) may not represent the compounds A to D below: ##STR00079## rinsing the fibers; optionally washing the fibers with shampoo; optionally rinsing the fibers again; and drying the resulting fibers or leaving the resulting fibers to dry.

11. Method for lightening keratin fibers, wherein (i) the dye composition as defined according to claim 9 free of oxidizing agent and (ii) a cosmetic composition comprising one or more oxidizing agents are applied to the keratin fibers; compositions (i) and (ii) being applied to said keratin fibers sequentially or simultaneously for a time sufficient to obtain a desired lightening, after which the fibers are rinsed, optionally washed with shampoo, rinsed again and the resulting fibers are dried or left to dry.

12. Leuco-type compound of formula (III) below, the organic or inorganic acid or base salts thereof, the tautomeric, optical isomer or geometric isomer forms thereof and/or the solvates thereof: ##STR00080## wherein: n.sub.1 and n.sub.2 represent, independently of one another, an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; R.sub.1 represents: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; an aminocarbonyl radical; a radical of formula (II): ##STR00081## in which formula (II): m represents an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; a hydroxyl radical; an NR.sub.3R.sub.4 radical in which R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.5 alkyl radical, optionally substituted with one or more hydroxyl or C.sub.1-C.sub.4 alkoxy radicals; it being understood that, in formula (II), when m is greater than or equal to 2, the R radicals may be identical or different; R.sub.2 represents: a hydrogen atom; a C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; R.sub.1 and R.sub.2 may form, together with the nitrogen atom to which they are attached, a pyrrolidine, piperidine or morpholine ring; R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; a C.sub.1-C.sub.4 alkoxy radical; X.sub.1 and X.sub.2 represent, independently of one another: a hydroxyl radical; an NR.sub.3R.sub.4 radical in which: R.sub.3 represents: a hydrogen atom; a linear C.sub.1-C.sub.6 alkyl radical; R.sub.4 represents: a hydrogen atom; a linear or branched C.sub.3-C.sub.6 alkyl radical; a linear or branched C.sub.2-C.sub.6 alkyl radical substituted with one or more hydroxyl radicals; R.sub.3 and R.sub.4 may form, together with the nitrogen atom to which they are attached, a piperidino or morpholino ring.

13. Composition for dyeing keratin fibers, comprising one or more compounds of formula (III) as defined according to claim 12 and optionally comprising one or more oxidizing agents.

14. Method for dyeing keratin fibers, wherein a dye composition comprising one or more compounds of formula (III) as defined according to claim 12 and an oxidizing composition comprising one or more oxidizing agents are applied simultaneously or sequentially to said keratin fibers, which may be wet or dry.

15. Multicompartment device or kit comprising a first compartment containing a cosmetic composition comprising one or more dyes of formula (I) or containing one or more leuco-type compounds of formula (III), and a second compartment comprising one or more oxidizing agents: ##STR00082## wherein: n.sub.1 and n.sub.2 represent, independently of one another, an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; R.sub.1 represents: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; an aminocarbonyl radical; a radical of formula (II): ##STR00083## in which formula (II): m represents an integer equal to 0, 1, 2, 3 or 4; R represents: a linear or branched C.sub.1-C.sub.4 alkyl radical, optionally substituted with one or more identical or different radicals selected from hydroxyl or imidazolium, An.sup. radicals; An.sup. denoting a cosmetically acceptable anion or mixture of anions; a C.sub.1-C.sub.4 alkoxy radical; a halogen atom; a hydroxyl radical; an NR.sub.3R.sub.4 radical in which R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.5 alkyl radical, optionally substituted with one or more hydroxyl or C.sub.1-C.sub.4 alkoxy radicals; it being understood that, in formula (II), when m is greater than or equal to 2, the R radicals may be identical or different; R.sub.2 represents: a hydrogen atom; a C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; R.sub.1 and R.sub.2 may form, together with the nitrogen atom to which they are attached, a pyrrolidine, piperidine or morpholine ring; R.sub.3 and R.sub.4 represent, independently of one another: a hydrogen atom; a linear or branched C.sub.1-C.sub.8 alkyl radical, optionally substituted with one or more hydroxyl radicals; a C.sub.1-C.sub.4 alkoxy radical; X.sub.1 and X.sub.2 represent, independently of one another: a hydroxyl radical; an NR.sub.3R.sub.4 radical in which: R.sub.3 represents: a hydrogen atom; a linear C.sub.1-C.sub.6 alkyl radical; R.sub.4 represents: a hydrogen atom; a linear or branched C.sub.3-C.sub.6 alkyl radical; a linear or branched C.sub.2-C.sub.6 alkyl radical substituted with one or more hydroxyl radicals; R.sub.3 and R.sub.4 may form, together with the nitrogen atom to which they are attached, a piperidino or morpholino ring; it being understood that the compounds of formula (I) may not represent the compounds A to D below: ##STR00084##

Description

EXAMPLES

I. Synthesis Examples

Example 1

Synthesis of 2-[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-5-methylamino-cyclohexa-2,5-dienone (compound 1)

(1) ##STR00040##

(2) Added to a solution of 0.85 g (0.004 mol) of N-(4-aminophenyl)-N-ethyl-N-isopropylamine hydrochloride in 2 ml of water and 2 ml of ethanol, is a solution of 0.40 g (0.002 mol) of 3-(methylamino)phenol hydrobromide in 1 ml of water and 2 ml of ethanol. The pH is adjusted to 9.5 with 2 ml of 20% aqueous ammonia. 7 ml of 6% aqueous hydrogen peroxide solution are added and the mixture is stirred for 24 hours. A solid is formed; after filtration, it is washed with water and then with a water/methanol mixture. The product is purified on a silica column (eluent: dichloromethane/methanol 95/5).

(3) 0.24 g of black powder of 2-[4-(ethylisopropylamino)-phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-5-methylamino-cyclohexa-2,5-dienone (compound 1) is obtained.

(4) The molecular ion 474 (ES+) is detected by mass spectrometry.

Example 2

Synthesis of 2-[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-5-(2-hydroxyethylamino)cyclohexa-2,5-dienone (compound 4)

(5) ##STR00041##

(6) Added to a solution of 0.42 g (0.002 mol) of N-(4-aminophenyl)-N-ethyl-N-isopropylamine hydrochloride in 2 ml of water and 2 ml of ethanol, is a solution of 0.15 g (0.001 mol) of 3-[(2-hydroxyethyl)amino]phenol. The pH is adjusted to 9.5 with 2 ml of 20% aqueous ammonia. 7 ml of 6% aqueous hydrogen peroxide solution are added and the mixture is stirred for 5 hours at ambient temperature.

(7) The precipitate formed is filtered off, rinsed with water and dried. Thus, 80 mg of a black powder corresponding to 2-[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-5-(2-hydroxyethylamino)cyclohexa-2,5-dienone (compound 4) are obtained.

(8) The molecular ion 504 (ES+) is detected by mass spectrometry.

Example 3

Synthesis of 5-dimethylamino-2-[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-cyclohexa-2,5-dienone (compound 6)

(9) ##STR00042##

(10) Added to a solution of 0.53 g (0.003 mol) of N-(4-aminophenyl)-N-ethyl-N-isopropylamine hydrochloride in 2 ml of water and 2 ml of ethanol, is 0.41 g (0.003 mol) of 3-(dimethylamino)phenol. The pH is adjusted to 9.5 with 1.5 ml of 20% aqueous ammonia. 1 ml of 6% aqueous hydrogen peroxide solution is added and the mixture is stirred for 48 hours. The solid formed is filtered off and then purified by chromatography (eluent: dichloromethane/methanol 99/1).

(11) 250 mg of brown powder corresponding to 5-dimethylamino-2-[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]cyclohexa-2,5-dienone (compound 6) are obtained.

(12) The molecular ion 489 (ES+) is detected by mass spectrometry.

Example 4

Synthesis of 3,6-bis[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-2-methoxycyclohexa-2,5-dienone (compound 28)

(13) ##STR00043##

(14) Added to a solution of 0.64 g (0.003 mol) of N-(4-aminophenyl)-N-ethyl-N-isopropylamine hydrochloride in 2 ml of water and 3 ml of ethanol, is a solution of 0.47 g (0.003 mol) of 2,3-dimethoxyphenol in 1 ml of water and 3 ml of ethanol. The pH is adjusted to 9.5 with 1.5 ml of 20% aqueous ammonia. 10.5 ml of 6% aqueous hydrogen peroxide solution are added and the mixture is stirred for 5 hours 30 minutes. The product is extracted with dichloromethane. The organic phase is dried with disodium sulfate, filtered and then concentrated until the solvents are eliminated. The product obtained is purified by chromatography (eluent: dichloromethane/methanol 95/5).

(15) 0.12 g of black product corresponding to 3,6-bis[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-2-methoxycyclohexa-2,5-dienone (compound 28) is obtained.

(16) The molecular ion 651 (ES+) is detected by mass spectrometry. The .sup.1H NMR spectrum is in agreement.

Example 5

Synthesis of 2-[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-5-phenylaminocyclohexa-2,5-dienone (compound 29)

(17) ##STR00044##

(18) Added to a solution of 1.1 g (0.005 mol) of N-(4-aminophenyl)-N-ethyl-N-isopropylamine hydrochloride in 5 ml of water and 5 ml of ethanol, is 0.93 g (0.005 mol) of 3-hydroxydiphenylamine. The pH is adjusted to 9.5 with 20% aqueous ammonia. 17 ml of 6% aqueous hydrogen peroxide solution is added and the mixture is stirred for 48 hours. The gum formed is washed with water and then purified by chromatography (eluent: dichloromethane).

(19) 211 mg of brown powder corresponding to 2-[4-(ethylisopropylamino)phenylamino]-4-[4-(ethylisopropylamino)phenylimino]-5-phenylaminocyclohexa-2,5-dienone (compound 29) are obtained.

(20) The molecular ion 535 (ES+) is detected by mass spectrometry.

Example 6

Synthesis of 2-{4-[ethyl-(2-hydroxyethyl)amino]-2-methylphenylamino}-4-{4-[ethyl-(2-hydroxyethyl)amino]-2-methyl-phenylimino}-5-phenylaminocyclohexa-2,5-dienone (compound 30)

(21) ##STR00045##

(22) Added to a solution of 4.39 g (0.015 mol) of 2-[(4-amino-3-methylphenyl)(ethyl)amino]ethanol sulfate in 10 ml of water and 30 ml of ethanol, are 2.78 g (0.015 mol) of 3-hydroxydiphenylamine. The pH is adjusted to 9.5 with 20% aqueous ammonia. 25.5 ml of 6% aqueous hydrogen peroxide solution are added and the mixture is stirred for 24 hours. The gum formed is washed with water and then purified by chromatography (eluent: dichloromethane/methanol 9/1). 802 mg of brown powder corresponding to 2-{4-[ethyl-(2-hydroxyethyl)amino]-2-methylphenylamino}-4-{4-[ethyl-(2-hydroxyethyl)amino]-2-methyl-phenylimino}-5-phenylaminocyclohexa-2,5-dienone (compound 30) are obtained.

(23) The molecular ion 568 (ES+) is detected by mass spectrometry.

Example 7

Synthesis of 5-amino-2-[(4-amino-2,3-dimethylphenyl)amino]-4-[(4-amino-2,3-dimethylphenyl)imino]cyclohexa-2,5-dien-1-one (compound 20)

(24) ##STR00046##

(25) Added to a solution of 3.14 g (0.015 mol) of 2,3-dimethylbenzene-1,4-diamine and 0.817 g (0.075 mol) of 3-aminophenol in 10 mL of water and 20 mL of ethanol whose the pH were adjusted to 9.5 with 20% aqueous ammonia, are 4.25 mL of 30% (0.0375 mol) aqueous hydrogen peroxide. The mixture is stirred for 24 hours. The precipitate formed is filtered off.

(26) The solid is then dissolved in 10 mL of dimethylsulfoxyde, the obtained solution is filtered and 15 mL of water is added to the filtrate.

(27) The precipitate formed once again is filtrated and is washed with 8 mL of a mixture of dimethylsulfoxyde/water (50/50) and 100 mL of water. The product is purified by silica chromatography (eluent dichloromethane/methanol 98/2).

(28) 804 mg of black powder corresponding to 5-amino-2-[(4-amino-2,3-dimethylphenyl)amino]-4-[(4-amino-2,3-dimethylphenyl)imino]cyclohexa-2,5-dien-1-one (compound 20) are obtained.

(29) The molecular ion 376 (ES+) is detected by mass spectrometry.

Example 8

Synthesis of 5-amino-2-({4-[ethyl(propan-2-yl)amino]phenyl}amino)-4-({4-[ethyl(propan-2-yl)amino]phenyl}imino)cyclohexa-2,5-dien-1-one (compound 16)

(30) ##STR00047##

(31) Added to a solution of 6.44 g (0.03 mol) of N-(4-aminophenyl)-N-ethyl-N-isopropylamine and 1.65 g (0.015 mol) of 3-aminophenol in 20 mL of water and 40 mL of ethanol brought to pH 9.5 with 20% aqueous ammonia, are 15 mL of 30% aqueous hydrogen peroxide. The mixture is stirred for 10 hours. A gum is formed.

(32) After decantation of the supernatant, the gum is washed with 20 mL of water/ethanol 50/50 mixture and the gum is added to methanol. The product crystallized for two days.

(33) The product obtained is purified by silica chromatography (eluent dichloromethane/methanol 98/2). 1.8 g of black powder corresponding 5-amino-2-({4-[ethyl(propan-2-yl)amino]phenyl}amino)-4-({4-[ethyl(propan-2-yl)amino]phenyl}imino)cyclohexa-2,5-dien-1-one (compound 16) are obtained.

(34) The molecular ion 460 (ES+) is detected by mass spectrometry

II. Dyeing Evaluations of the Compounds Synthesized

(35) The following dye compositions were prepared: 500 mg of exemplified compound, 79 grams of water, 15 grams of ethanol, 5 grams of benzyl alcohol, 0.5 gram of benzoic acid.

(36) 1 gram of the mixture is applied to a 0.25 gram lock of grey hair containing 90% white hairs. After a leave-on time of 30 minutes, the lock is rinsed, washed with a standard shampoo, then rinsed again and then dried.

(37) The results are collated in the following table:

(38) TABLE-US-00001 Compound 1 Medium orange-grey Compound 4 Light orange-grey Compound 6 Medium orange-grey Compound 28 Medium orange-grey Compound 29 Medium orange-grey Compound 30 Medium orange-grey