Use, as a coupler, of 2,4-diamino-1,3-dimethoxybenzene or one of its salts, in combination with oxidation dye precursors, for dyeing human hair, hair dyeing composition containing the said coupler and process for preparing the said coupler

Claim 2

A hair dyeing composition, which contains, in a cosmetically acceptable aqueous vehicle, 2,4-diamino-1,3-dimethoxybenzene or acid addition salts, in combination with at least one oxidation dye precursor of the para type.

Claim 3

The dye composition according to claim 1, which contans 0.05 to 3.5% by weight of 2,4-diamino-1,3-dimethoxybenzene or acid addition salts, based on the total weight of the composition.

Claim 4

The dye composition according to claim 1, wherein the oxidation dye precursor of the para type is selected from the group consisting of para-phenylenediamines, para-aminophenols, heterocyclic para compounds and mixtures thereof.

Claim 5

The dye composition according to claim 3, wherein the para-phenylenediamines correspond to the formula: ##STR7## in which formula R 1 , R 2 and R 3 are identical or different and denote a hydrogen or halogen atom, an alkyl radical having 1 to 4 carbon atoms or an alkoxy radical having 1 to 4 carbon atoms, R 4 and R 5 are identical or different and denote a hydrogen atom, an alkyl, hydroxyalkyl, alkoxyalkyl, carbamylalkyl, mesylaminoalkyl, acetylaminoalkyl, ureidoalkyl, carbethoxyaminoalkyl, piperidinoalkyl or morpholinoalkyl radical, the alkyl or alkoxy groups denoted by R 4 , R 5 having from 1 to 4 carbon atoms, or alternatively R 4 and R 5 can form, together with the nitrogen atom to which they are attached, a piperidino or morpholino heterocycle, with the proviso that R 1 or R 3 denotes a hydrogen atom when R 4 and R 5 do not denote a hydrogen atom; or consist of the salts of the compounds of formula (III) above.

Claim 6

The dye composition according to claim 4 which contains at least one para-phenylenediamine selected from the group consisting of p-phenylenediamine, p-tolylenediamine, methoxy-para-phenylenediamine, chloro-para-phenylene-diamine, 2,6-dimethyl-p-phenylenediamine, 2,5-dimethyl-para-phenylenediamine, 2,3-dimethyl-p-phenylenediamine, isopropyl-p-phenylenediamine, 2-methyl-5-methoxy-para-phenylenediamine, 2,6-dimethyl-5-methoxy-para-phenylene-diamine, N,N-dimethyl-para-phenylenediamine, 3-methyl-4-amino-N,N-diethylaniline, N,N-bis(β-hydroxyethyl)-para-phenylenediamine, 3-methyl-4-amino-N,N-bis(β-hydroxy-ethyl)aniline, 3-chloro-4-amino-N,N-bis(β-hydroxyethyl)-aniline, 4-amino-N-ethyl-N-(carbamylmethyl)aniline, 3-methyl-4-amino-N-ethyl-N-(carbamylmethyl)aniline, 4-amino-N-ethyl-N-(β-piperidinoethyl)aniline, 3-methyl-4-amino-N-ethyl-N-(β-piperidinoethyl)aniline, 4-amino-N-ethyl-N-(β-morpholinoethyl)aniline, 3-methyl-4-amino-N-ethyl-N-(β-morpholinoethyl)aniline, 4-amino-N-ethyl-N-(β-acetylaminoethyl)aniline, 4-amino-N-(β-methoxyethyl)-aniline, 3-methyl-4-amino-N-ethyl-N-(β-acetylaminoethyl)-aniline, 4-amino-N-ethyl-N-(β-mesylaminoethyl)aniline, 3-methyl-4-amino-N-ethyl-N-(β-mesylaminoethyl)aniline, 4-amino-N-ethyl-N-(β-sulphoethyl)aniline, 3-methyl-4-amino-N-ethyl-N-(β-sulphoethyl)aniline, N-(4-aminophenyl)morpholine and N-(4-aminophenyl)piperidine, in the form of the free base or in the form of a cosmetically acceptable salt.

Claim 7

The dye composition according to claim 3, which contains at least one para-aminophenol selected from the group consisting of p-aminophenol, 2-methyl-4-aminophenol, 3-methyl-4-aminophenol, 2-chloro-4-aminophenol, 3-chloro-4-aminophenol, 2,6-dimethyl-4-aminophenol, 3,5-dimethyl-4-aminophenol, 2,3-dimethyl-4-aminophenol, 2,5-dimethyl-4-aminophenol, 2-hydroxymethyl-4-aminophenol, 2-(β-hydroxyethyl)-4-aminophenol, 2-methoxy-4-aminophenol and 3-methoxy-4-aminophenol.

Claim 8

The dye composition according to claim 3, wherein the oxidation dye precursor of the para type is a heterocyclic para compound selected from the group consisting of 2,5-diaminopyridine, 2-hydroxy-5-aminopyridine and tetra-aminopyrimidine.

Claim 9

The dye composition according to claim 1, which contains other couplers selected from the group consisting of meta-diphenols, meta-aminophenols, meta-phenylenediamines, meta-acylaminophenols, meta-ureidophenols, meta-carbalkoxyaminophenols, α-naphthol, β-keto compounds and pyrazolones.

Claim 10

The dye composition according to claim 1 wherein the total concentration of couplers and of oxidation dye precursors of the para type is between 0.1 and 7% by weight.

Claim 11

The dye composition according to claim 1 which contains, in addition, dye precursors of the ortho type, selected from ortho-aminophenols, ortho-phenylenediamines and orthodiphenols.

Claim 12

The dye composition according to claim 1, which contains, in addition, direct dyes chosen from the group consisting of azo and anthraquinone dyes and nitro derivatives of the benzene series.

Claim 13

The dye composition according to claim 1 which has a pH of between 8 and 11, and preferably between 9 and 11.

Claim 14

The dye composition according to claim 1 which contains 1 to 40% by weight of an organic solvent chosen from the group consisting of lower alkanols, glycerol, glycols, glycol ethers, and mixtures thereof.

Claim 15

The dye composition according to claim 1 which it contains, in addition, 0.5 to 40% by weight of at least one anionic, cationic, nonionic or amphoteric surfactant or mixtures thereof.

Claim 16

The dye composition according to claim 1 which contains, in addition, cosmetic adjuvants chosen from the group consisting of thickeners, antioxidation agents, penetrating agents, sequestering agents, buffers, perfumes, alkalinizing agents and propellants.

Claim 17

A process for preparing 2,4-diamino-1,3-dimethoxybenzene or one of its addition salts with an acid, which consists in performing the consecutive or simultaneous reduction and dehalogenation of 2,4-dimethoxy, 3,5-dinitrochlorobenzene.

Claim 18

A process for preparing 2,4-diamino-1,3-dimethoxybenzene or one of its addition salts with an acid, which consists in performing the consecutive or simultaneous reduction and dehalogenation of 2,4-dimethoxy, 3,5-dinitrochlorobenzene.

Claim 19

A process for preparing 2,4-diamino-1,3-dimethoxybenzene or its addition salts with an acid according to claim 16, which consists, in the first stage, in reducing 2,4-dimethoxy-3,5-dinitrochlorobenzene with iron in the presence of acetic acid at a temperature of between 50° and 100° C., and then, in a second stage, in dehalogenating the compound thereby obtained, the second stage being performed in water, in a lower alcohol, in an aqueous-alcoholic mixture, in the presence of palladium on charcoal, ammonium acetate and triethylamine formate, at a temperature between 50° C. and the refluxing temperature of the solvent.

Claim 20

A process for preparing 2,4-diamino-1,3-dimethoxybenzene or one of its addition salts with an acid according to claim 16, which consists in simultaneously reducing and dehalogenating 2,4-dimethoxy-3,5-dinitrochlorobenzene under hydrogen pressure in the presence of palladium on charcoal, in a solvent chosen from the group consisting of water, lower alcohols, and aqueous alcoholic mixtures at a temperature of between 50° C. and 200° C. and preferably in the presence of ammonium acetate or triethylamine.

Claim 21

A process for dyeing keratinous fibers comprising contacting the keratinous fibers with an effective amount of the hair dye composition of claim 1.

Claim 22

A process for dyeing hair comprising the steps of (a) mixing a dyeing composition according to claim 1 with an effective amount of an oxidizing solution; (b) applying to the hair the mixture of step (a); (c) permitting said mixture to remain in contact with the hair for a period of about 10 to 40 minutes; then (d) rinsing; (e) shampooing; and (f) drying the dyed hair.

Claim 23

The process for dyeing hair comprising in sequence the steps of (a) applying to the hair a dyeing composition containing at least one oxidation dye precursor of claim 4; (b) applying to the hair a dyeing composition containing 2,4-diamino-1,3-dimethoxybenzene or acid salts thereof in admixture with an oxidizing agent; (c) permitting said compositions from steps (a) and (b) to remain in contact with the hair for a period of about 10 to 40 minutes; (d) rinsing; (f) shampooing; and (g) drying the dyed hair.