FR2920781A1 - New cationic azo thiol/disulfide compounds useful as dye for coloring keratin fibers, preferably human keratin fibers such as hair - Google Patents

Abstract

Cationic azo thiol/disulfide compounds (A) and their organic acid addition salts, mineral salts, solvates, tautomers or optical and geometrical isomers as dye are new, where the electroneutrality of (A) is assured by one or more anionic counter-ions. Cationic azo thiol/disulfide compounds (A) of formula ([W 1-N=N-W 2-NR-W 3-NR2a-L-CH 2-S] x-[Y 1] yAn ->) (I) or ([W 5-NR-W 2-N=N-W 4-L-CH 2-S] x-[Y 1] yAn ->) (II) and their organic acid addition salts, mineral salts, solvates, tautomers or optical and geometrical isomers as dye are new, where the electroneutrality of (A) is assured by one or more anionic counter-ions. W 1pyridinium radical of formula (IIb) or imidazole group of formula (IIa); W 2substituted phenyl group of formula (III); W 3substituted phenyl group of formula (IV); W 4imidazole group of formula (Va) or pyridinium radical of formula (Vb); W 5substituted phenyl group of formula (VI); R, R2a : H, 1-4C alkyl (optionally substituted) or OH; R 11-6C alkyl, aryl-1-6C-alkyl, (hetero)aryl or heteroaryl(1-6C)alkyl (all optionally substituted), cycloalkyl(1-6C)alkyl or heterocycloalkyl(1-6C)alkyl; either R 2-R 51-6C alkyl, 2-4C (poly)hydroxyalkyl, OH, 1-4C alkoxy, 2-4C (poly)hydroxyalkoxy, alkoxycarbonyl (R 11O-CO-), alkoxycarbonyloxy (R 11CO-O-), amino (optionally substituted by one or more 1-4C alkyl and containing OH) (where two radical alkyl radical together with N form 5 or 6 membered heterocycle containing O or N), alkylcarbonylamino (R 11CO-NR 12-), dialkylaminocarbonyl (R 12R 12CO-NR 12-), guanidium group (R 12R 12N-C(=NH 2 +>)-NR 12) or halo; or CR 2R 2, CR 3R 3, CR 4R 4condensed aromatic 6 membered cycle (optionally substituted with OH, 1-4C alkyl, hydroxycarbonyl or alkoxy carbonyl (R 11OOC)), (alkyl)sulfonylamino (R 11SO 2NR 13) or methylcarbonylamino, where the two alkyl groups together optionally with N form 5 or 6 membered heterocycle containing heteroatoms of N; R 13H, 1-4C alkyl, 1-4C alkoxy, amino (optionally substituted by 1-4C alkyl and containing OH); R 111-4C alkyl; R 12H or 1-4C alkyl; m, n : 0-4, when m or n is less than 4, then the carbon atoms of the aromatic cycle is optionally substituted and carries H; o : 0-5, when o is less than 5, then the carbon atoms of the aromatic cycle is unsubstituted and carries H; e : 0-2, when e is less than 2, then the carbon atoms of the aromatic cycle is unsubstituted and carries H; G : O, S or -N(Alk)-; Alk : 1-4C alkyl; L : covalent bond (sigma bond), divalent group -CG-, 1-20C bivalent hydrocarbon chain (optionally substituted and optionally interrupted by one or more divalent groups or their combinations, two divalent groups or their combinations are separated by divalent hydrocarbon chain comprising -N(R)-, N +>(R)R 0-, An ->, -O-, -S-, -C(O)-, cationic heterocycle or cationic heteroaryl (Het +>An ->), cationic heterocycle comprising 5-10 chains such that piperazinyl) or (hetero)aryl (optionally substituted), where L does not comprises diazo, hydrazino, aminooxy, nitro, nitroso or peroxide; R : 1-4C alkyl, 2-6C (poly)hydroxyalkyl, alkoxy(1-6C)alkyl, aryl, aryl(1-6C)alkyl, (1-4C)alkylcarbonylamino(1-6C)alkyl or amino(1-4C)alkyl (in which the amino is substituted by one or more 1-4C alkyl, alkyl(1-6C)carbonyl or (1-4C)alkylcarbonylamino); R 0H or R; Het +>cationic heterocycle containing 5-10 chains (optionally saturated) or cationic heteroaryl containing 5-10 chains; x : 1 or 2; y : 0 or 1; Y 1H, alkali metal, alkaline earth metal, ammonium group of formula (N +>Ralpha Rbeta Rgamma Rdelta ), phosphonium group of formula (P +>Ralpha Rbeta Rgamma Rdelta ), or protecting group of functional thiol; Ralpha , Rbeta , Rgamma , Rdelta : 1-4C alkyl; and An ->anionic counter-ion, where the electroneutrality of (A) being assured by one or more An ->anions. Provided that: when x is 1 then y is 1; when x is 2 then y is 0; the bond (a) in (IIa), (IIb), (III), (IV), (Va), (Vb), or (VI) connects the groups W 1, W 2and W 4to N, in the case of formulas (IIa), (IIb), (Va), (Vb), when two R 2radical carried by two adjacent carbon atoms form an aromatic cycle such as benzyl; the bond (a) can connect W 1, W 2or W 4to N by aromatic cycle intermediate; the bond (a 1) in (III), (IV) and (VI) connects the groups W 2, W 3and W 5to -NR-; and the bond (b) in (Va) or (Vb) connects the groups W 4to the bond L; and the bond (a 2) in (IV) connects the groups W 3to -NR2a. Independent claims are included for: (1) dye composition comprising a dye compound (I) or (II) in a cosmetic medium; (2) a method of coloring of keratin fibers, comprising applying the composition comprising (A) on keratin fibers; and (3) multi-compartment device comprising: a first compartment containing a dye composition; and a second compartment containing a reducing agent. [Image] [Image].

Description

The present invention relates to cationic azo thiol / disulfide compounds for dyeing keratinous fibers. BACKGROUND OF THE INVENTION

It is known to dye keratinous fibers and in particular human keratin fibers, such as the hair, with dye compositions containing direct dyes. These compounds are colored molecules and dyes having an affinity for the fibers. It is known, for example, to use direct dyes of the nitrobenzene type, anthraquinone dyes, nitropyridines, dyes of the azo, xanthene, acridine, azine or triarylmethane type. Usually, these dyes are applied to the fibers, optionally in the presence of an oxidizing agent, if it is desired to obtain a simultaneous effect of lightening the fibers. Once the exposure time has elapsed, the fibers are rinsed, optionally washed and dried. The colorings which result from the use of direct dyes are temporary or semi-permanent dyes because the nature of the interactions which bind the direct dyes to the keratin fiber, and their desorption from the surface and / or the core of the fiber are responsible for their low dyeing power and their relative poor resistance to washes and perspiration. In order to increase the tenacity of the direct dyes, it is known to use disulfide dyes, in particular dyes with chromophore aza-imidazoliums, in the patent applications WO 2005/097051 or EP 1647580 and WO 2006/136617. The latter application describes mixtures of several disulfide dyes for the purpose of accessing brown / brown shades. However, certain disulfide dyes may have insufficient performance, particularly in terms of color increase in the keratin fiber, selectivity, stability. In addition, dyes of the state of the art do not have a satisfactory resistance to external aggressions such as bad weather, successive shampoos or the sun, which causes a color shift over time. One of the aims of the present invention is to provide direct dyes which do not have the disadvantages of existing disulfide dyes. This object is achieved with the present invention which relates to a process for dyeing keratinous substances, in particular human materials such as the hair, consisting in applying to keratin materials a dyeing composition comprising, in a suitable cosmetic medium, at least one cationic azo dye thiol / disulfide. In particular, one of the aims of the present invention is to provide dyes which make it possible to obtain natural shades, resistant to external aggressions (bad weather, shampoo, sun) over time.

These objects are achieved by the present invention which therefore relates to cationic azide disulfide or thiol compounds of formulas (I) and (I '):

[W1-N = N-W2-NR-W3-NR'-L-CH2-S] X - [Y] y An-formula (I) [W5-NR-W2-N = N-W4-L-CH2 -S] X [Y] y An-formula (I ') and their addition salts with an organic or inorganic acid, solvates, tautomers, optical and geometric isomers;

formulas (I) and (I ') in which: W1, represents a cationic heteroaromatic radical chosen from the following formulas: 4a (IV) W4 represents a heteroaromatic radical chosen from the following formulas: W2, identical, represent an aromatic group carbon dioxide compound of the following formula: (R3) m, a (III) W3, represents a carbon aromatic group of the following formula: ## STR2 ## W5 represents a carbon aromatic group of following formula : 2 3 (R5) mä (VI)

the bond resulting from formulas (IIa), (IIb), (III), (Va) and (Vb) connects the groups W 1, W 2 and W 4 to the azo group; in the case of the formulas (IIa), (IIb), (Va) and (Vb) when two radicals R2 carried by two adjacent carbon atoms form an aromatic ring such as benzyl, the link a may connect the group W ,, W2 or W4 to the azo moiety through said aromatic ring; the bond resulting from formulas (III), (IV) and (VI) connects the groups W2, W3 and W5 to -NR-,

the bond b resulting from the formulas (Va) and (Vb) connects the group W4 to the linkage arm L,

the bond from formula (IV) linking the group W3 to -NR'-; R and R 'independently of one another represents: • a hydrogen atom or • a C1-C4 alkyl group linear, optionally substituted by a hydroxyl group; R1, is directly attached to the nitrogen atom, quaternized or not via a carbon atom and, independently of each other, represent a group selected from • a optionally substituted C1-C6 alkyl group such as methyl, an optionally substituted aryl group such as phenyl, an optionally substituted heteroaryl group such as pyridyl, an optionally substituted aryl (C1-C6) alkyl group such as benzyl; An optionally substituted heteroaryl (C 1 -C 6) alkyl group such as pyridinylmethyl, a (C 1 -C 6) cycloalkyl alkyl group such as cyclohexylmethyl, and a heterocycloalkyl (C 1 -C 6) alkyl group such as piperidinylmethyl; R2, R3, R4, and R5 independently of each other represent: • a C1-C4 alkyl group; • a hydroxyl group; • a C1-C4 alkoxy group; A C2-C4 (poly) hydroxyalkoxy group; An alkoxycarbonyl group (RaO-C (O) -) in which Ra represents a C1-C4 alkyl radical; An alkylcarbonyloxy group (RaC (O) -O-) in which Ra represents an alkyl radical is C1-C4; An amino group optionally substituted with one or more identical or different C1-C4 alkyl radicals optionally bearing at least one hydroxyl group, the two alkyl radicals possibly being able to form, with the nitrogen atom to which they are attached, a substituted or unsubstituted 5- or 6-membered heterocycle and optionally carrying another heteroatom identical to or different from nitrogen, for example oxygen; An alkylcarbonylamino group (RaC (O) -NR'a-) in which Ra represents a C1-C4 alkyl radical and R'a represents a hydrogen atom or a C1-C4 alkyl radical; A (di-) (alkyl) aminocarbonyl ((Ra) 2 N-C (O)) group in which the Ra radicals independently of each other, which may be identical or different, represent a hydrogen atom or a C1-C4 alkyl radical; C4; A ureido group ((Ra) 2N-CO-NRb-) in which the radicals Ra and Rb, independently of one another, represent a hydrogen atom or a C1-C4 alkyl radical; A guanidinium group ((Ra) 2 N-C (= NH 2 +) - NRb-) in which the radicals Ra and Rb, independently of each other, represent a hydrogen atom, a C 1 -C 4 alkyl radical; A halogen atom, preferably chlorine, fluorine or bromine; Or two adjacent R 2 radicals, two adjacent R 3 radicals, two adjacent R 4 radicals or two adjacent R 5 radicals may form, with the carbon atoms to which they are attached, a fused, aromatic 6-membered ring, optionally substituted by one or more identical or different groups selected from hydroxyl, C1-C4 alkyl, hydroxycarbonyl (HO (O) C-), alkoxy carbonyl (RaO (O) C-) in which Ra represents a C1-C4 alkyl, (alkyl) sulphonylamino group (RaS (O) 2NRb) in which Ra, represent a C1-C4 alkyl and Rb represents a hydrogen atom; a C1-C4 alkyl group; C1-C4 alkoxy; amino optionally substituted with one or two identical or different C1-C4 alkyl groups and optionally bearing at least one hydroxyl or methylcarbonylamino group, the two alkyl groups possibly being able to form, with the nitrogen atom to which they are attached, a heterocycle 5- or 6-membered ring optionally carrying another heteroatom identical to or different from nitrogen, for example oxygen;

m represents an integer inclusive between 0 and 4; when m is less than 4, then the carbon atom (s) of the unsubstituted aromatic ring (s) carry a hydrogen atom;

m 'represents an integer inclusive between 0 and 4; when m 'is less than 4, then the carbon atom (s) of the unsubstituted aromatic ring (s) carry a hydrogen atom;

M is an integer from 0 to 5 inclusive; when m "is less than 5, then the carbon atom (s) of the unsubstituted aromatic ring (s) carry a hydrogen atom;

e is an integer from 0 to 2; when e is less than 2, then the carbon atom (s) of the unsubstituted aromatic heterocycle (s) carry a hydrogen atom;

L represents a covalent bond 6; a divalent group C (G) - with G representing an oxygen atom, sulfur atom, or a group ûN (Alk) - where Alk represents a C 1 -C 4 alkyl group; or bivalent C 1 -C 20, especially C 1 -C 8, bivalent hydrocarbon chain, optionally substituted, optionally interrupted by one or more divalent groups or combinations thereof, it being understood that two divalent groups or their combinations are separated by a divalent hydrocarbon chain in C1 -C6, especially alkylene, said divalent groups being selected from: i) N (R) -; -N + (R) (R o) -, An-; -O-, -S-, -C (O) -, with R, represents a group chosen from C1-C4 alkyl, (poly) C2-C6 hydroxyalkyl, (C1-C6) alkoxyalkyl, aryl such as phenyl, aryl (C 1 -C 6) alkyl such as benzyl, (C 1 -C 4) alkylcarbonylamino (C 1 -C 6) alkyl, amino (C 1 -C 4) alkyl whose amine is substituted by one or more identical alkyl radicals or different C 1 -C 4, C 1 -C 6 alkylcarbonyl and C 1 -C 4 alkylcarbonylamino; and R ° represents a hydrogen atom or R; ii) a cationic heterocycle or cationic heteroaryl Het +, An-, with As defined above and Het + representing a cationic heterocycle comprising 5 to 10 members, saturated or unsaturated, or a cationic heteroaryl comprising 5 to 10 members such as imidazolium, piperazinium, benzimidazolium, pyrazolium; Iii) a non-cationic heterocycle comprising 5 to 10 members such as piperazinyl, and iv) an optionally substituted (hetero) aryl such as optionally substituted 1,3,5 triazine; with L not containing a diazo, hydrazino, aminooxy, nitro, nitroso, peroxide group;

x represents 1 or 2; y represents 0 or 1; with the proviso that: • when x = 1, then y = 1 and the compounds of the invention of formula (I) or (I ') have a group SY whose bond SY may be covalent: -SY or ionic -S Y + according to the nature of Y and the pH of the medium; When x = 2 then y = 0 and the compounds of the invention of formula (I) and (I ') are disulfide dyes;

Y represents: either a hydrogen atom or a protecting group of thiol function in which case the SY bond is covalent; - an alkali metal, an alkaline earth metal, an ammonium group (N + RaRRR7Rs) or a phosphonium group (P + RaRRR7Rs), with Ra, RR, R7 and R5, identical or different, representing a group (C, - C4) alkyl in which case the SY bond is ionic; it being understood that the electroneutrality of the compounds of formula (I) or (I ') is ensured by one or more anionic counterions An-, identical or different. Another subject of the invention is a dyeing composition for dyeing keratinous fibers such as hair comprising, in a cosmetic medium, at least one cationic azo thiol / disulphide dye of formula (I) or (I ') as defined previously. and optionally a reducing agent. The subject of the invention is also a method for dyeing keratinous fibers, such as the hair, which comprises applying to a keratinous material a dyeing composition comprising, in a suitable cosmetic medium, at least one cationic azo thiol / disulphide dye of formula (I) or (I ') as defined above. Another object of the invention is a multi-compartment keratinous fiber dyeing device comprising a compartment which contains the composition according to the invention, a second compartment comprising a reducing agent and optionally a third compartment containing an oxidizing agent.

The dyeing process according to the invention makes it possible to color the keratinous fibers without degrading them, in a permanent manner with respect to shampoos, against common aggressions such as sun, perspiration, and hair treatments. This process also makes it possible to color keratin fibers in a powerful, low-selectivity, homogeneous and chromatic manner. Mixed with yellow, orange and red dyes this process also allows to color keratin fibers in natural shades such as browns and blacks without observing a significant bend over time. Moreover, the new dyes according to the invention have a better chemical stability. These dyes are more soluble and stable than the dyes of the state of the art in conventional cosmetic formulations containing in particular acidified water and organic solvents. It is possible, for example, to mention lower C1-C4 alkanols, such as ethanol and isopropanol, polyols and polyol ethers such as 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and monomethyl ether. as well as aromatic alcohols such as benzyl alcohol or phenoxyethanol, and mixtures thereof.

For the purposes of the present invention, and unless a different indication is given: • An alkyl radical is a saturated C 1 -C 16 hydrocarbon radical and is linear or branched, particularly the alkyl radical is a C 1 -C 6 group such as methyl or ethyl. An alkyl radical or the alkyl part of a radical is said to be substituted when it comprises at least one substituent chosen from the groups: hydroxyl and C 1 -C 4 alkoxy; poly) C 2 -C 4 hydroxyalkoxy, amino, amino substituted with one or more identical or different C 1 -C 4 alkyl groups optionally bearing at least one hydroxyl group, said alkyl radicals being able to form with the nitrogen atom to which they are attached, a 5- or 6-membered heterocycle, optionally comprising at least one other heteroatom different or different from nitrogen. An aryl or heteroaryl radical or the aryl or heteroaryl part of a radical is said to be substituted when it comprises at least one substituent carried by a carbon atom chosen from: a radical C1-C16 alkyl, preferably C1-C8, optionally substituted by one or more radicals selected from hydroxy, C1-C2 alkoxy, (poly) -hydroxyalkoxy C2-C4, acylamino, amino substituted by two alkyl radicals; , identical or different, C1-C4, optionally bearing at least one hydroxyl group or, the two radicals may form with the nitrogen atom to which they are attached, a 5- or 7-membered heterocycle, preferably 5 or 6-membered, optionally comprising another heteroatom identical to or different from nitrogen; a halogen atom such as chlorine, fluorine or bromine; a hydroxyl group; a C1-C2 alkoxy radical; a C2-C4 (poly) -hydroxyalkoxy radical; an optionally amino radical substituted with one or two identical or different C 1 -C 4 alkyl radicals optionally bearing at least one hydroxyl or amino group with two optionally substituted C 1 -C 2 alkyl radicals; an (alkyl) carbonylamino radical (-NRa-CORb) in which the radical Ra is a hydrogen atom, a C1-C4 alkyl radical optionally bearing at least one hydroxyl group and the radical Rb is a C1-alkyl radical; C2. The cyclic or heterocyclic part of a nonaromatic radical is said to be substituted when it comprises at least one substituent borne by a carbon atom chosen from the groups: a hydroxyl group; C1-C4 alkoxy radical; - (C2-C4) poly (hydroxy) alkoxy radical; - (alkyl) carbonylamino radical ((RaC (O) -NRb-) in which the Rb radical is a hydrogen atom, a radical; C1-C4 alkyl optionally bearing at least one hydroxyl group and the radical Ra is a C1-C2 alkyl radical; an amino radical optionally substituted by two identical or different C1-C4 alkyl groups optionally carrying at least one hydroxyl group, said alkyl radicals being able to form, with the nitrogen atom to which they are attached, a 5- or 6-membered heterocycle optionally comprising at least one other heteroatom which may or may not be different from nitrogen • An aryl radical represents a group carbon mono or pol ycyclic, condensed or not, comprising from 6 to 22 carbon atoms, and at least one ring of which is aromatic; preferably the aryl radical is phenyl, biphenyl, naphthyl, indenyl, anthracenyl, or tetrahydronaphthyl. A heteroaryl radical represents a mono or polycyclic group, condensed or not, optionally cationic, comprising from 5 to 22 members, from 1 to 6 heteroatoms chosen from nitrogen, oxygen, sulfur and selenium, and at least one cycle is aromatic; preferably a heteroaryl radical is chosen from acridinyl, imidazolyl, benzothiazolyl, pyrazolyl, indazolyl, thiazolyl, benzothiazolyl, oxazolyl, benzoxazolyl, pyridinyl, quinolyl, isoquinolyl, benzoquinolyl, pyrazinyl, benzopyrazinyl, pyrrolyl, indolyl, pyridazinyl, benzopyridazinyl, triazolyl, benzotriazolyl; , benzobistriazolyl, tetrazolyl, hydrothiazolyl, imidazopyridinyl, naphthoimidazolyl, naphthooxazolyl, naphthopyrazolyl, oxadiazolyl, oxazolopyridyl, phenazinyl, phenooxazolyl, pyrazoyltriazyl, thiadiazolyl, thiazolopyridinyl, thiazoylimidazolyl, thiopyryl, xanthylyl and its ammonium salt. A cyclic or cycloalkyl radical is a non-aromatic, mono or polycyclic cycloalkyl radical, condensed or not, containing from 5 to 22 carbon atoms, which can comprise from one to several unsaturations; particularly the cyclic radical is cyclohexyl. A heterocyclic radical or heterocycle is a mono- or polycyclic non-condensed radical, condensed or not, containing from 5 to 22 members, comprising from 1 to 6 heteroatoms chosen from nitrogen, oxygen and sulfur. A sterically hindered cyclic radical is a cyclic radical, aromatic or not, substituted or unsubstituted, sterically hindered or hindered, comprising from 6 to 14 members, which can be bridged, as sterically hindered radicals, mention may be made of bicyclo [1.1. .0] butane, mesylates such as 1,3,5-trimethylphenyl, 1,3,5-triterbutylphenyl, 1,3,5-isobutylphenyl, 1,3,5-trimethylsillylphenyl and adamantyl

An alkylene radical is a linear or branched, C1-C30, divalent, especially C1-C20, hydrocarbon-based chain optionally substituted with the same substituents as those of an optionally substituted alkyl group or with a carboxy group; particularly the alkylene chain is not substituted such as methylene, ethylene or propylene. An organic or inorganic acid salt is more particularly chosen from a salt derived from i) hydrochloric acid HCl, ii) hydrobromic acid HBr, iii) sulfuric acid H 2 SO 4, iv) alkylsulphonic acids: Alk- S (O) 20H such as methylsulfonic acid or ethylsulfonic acid; v) arylsulfonic acids: Ar-S (O) 20H such as benzene sulfonic acid or toluene sulfonic acid; (vi) citric acid; vii) succinic acid; viii) tartaric acid; ix) lactic acid, X) oxalic acid and xi) alkoxysulfinic acids: Alk-O-S (O) OH such as methoxysulfinic acid or ethoxysulfinic acid; xi) aryloxysulfinic acids such as tolueneoxysulfinic acid or phenoxysulfinic acid; xii) phosphoric acid H3PO4; xiii) acetic acid CH3C (O) OH.

An anionic counterion is an anion or an anionic group associated with the cationic charge of the cosmetically acceptable dye; more particularly the anionic counterion is selected from i) halides such as chloride, bromide; ii) nitrates; iii) sulphonates, including C1-C6 alkylsulphonates: Alk-S (O) 20- such as methylsulphonate or mesylate or ethylsulphonate; iv) arylsulfonates: Ar-S (O) 20- such as benzenesulphonate or toluenesulphonate or tosylate; v) citrate; vi) succinate; (vii) tartrate; viii) lactate; ix) (alkyl) sulfates: (Alk-) O-S (O) O- such as hydrogen sulfate, methysulfate or ethylsulfate; x) arylsulfates: Ar-O-S (O) O- such as benzenesulphate or toluenesulphate; xi) alkoxysulfates: Alk-O-S (O) 20- such as methoxy sulfate or ethoxysulfate; xii) aryloxysulfates: Ar-O-S (O) 20-, xiii) phosphate; (xiv) acetate; xv) oxalate; (xvi) a hydroxide; xvii) carbonates and hydrogen carbonates.

The solvates represent the hydrates as well as the association with linear or branched C1-C4 linear or branched alcohols such as ethanol, isopropanol and n-propanol.

When a cycle does not carry the maximum number of substituents, then the unsubstituted position (s) carry a hydrogen atom.

As indicated above, a first subject of the invention consists of compounds corresponding to the above formulas (I) and (I ').

A particular embodiment of the invention relates to dyes of formula (I) or (I ') as defined previously for which the radicals R and R' taken separately preferably represent a hydrogen atom or a linear C 1 -C 2 alkyl radical. optionally substituted by a hydroxyl group; even more particularly, R and R ', which may be identical or different, represent a hydrogen atom, a methyl, ethyl or 2-hydroxyethyl radical.

In particular, the radicals R 1 represent, independently of one another, a C 1 -C 6 alkyl radical; a C2-C6 monohydroxyalkyl radical; a C2-C6 polyhydroxyalkyl radical; a C1-C6 alkoxy (C1-C6) alkyl radical; an optionally substituted aryl radical, such as phenyl; an optionally substituted arylalkyl radical, such as benzyl; a C2-C6 amidoalkyl radical; a C2-C6 aminoalkyl radical, the amine of which is substituted with two identical or different C1-C4 alkyl radicals which are optionally substituted. In addition, the radical R1 is such that the atom directly connected to the nitrogen atom is a carbon atom. Preferably, R 1 represents a C 1 -C 4 alkyl radical or a C 2 -C 4 monohydroxyalkyl radical; a C2-C4 polyhydroxyalkyl radical; a C1-C4 alkoxy (C1-C4) alkyl radical; a benzyl radical; a C1-C4 aminoalkyl radical; a C 1 -C 4 aminoalkyl radical, the amine of which is substituted by 4 two identical C 1 -C 2 alkyl radicals. Preferably, R 1 represents a methyl or ethyl radical or a 2-hydroxyethyl radical.

According to another particular embodiment of the invention, the dye of formulas (I) or (I ') have radicals R2, R3, R4, and R5 independently of each other, which represent: a C1-C16 alkyl radical; preferably C1-C8, optionally substituted; a halogen atom such as chlorine or fluorine; a hydroxyl group; a C1-C2 alkoxy radical; a C2-C4 (poly) -hydroxyalkoxy radical; an amino radical optionally substituted with one or two identical or different C 1 -C 4 alkyl radicals optionally bearing at least one hydroxyl group, the two alkyl radicals possibly being able to form, with the nitrogen atom to which they are attached, an optionally substituted saturated or unsaturated 5- or 6-membered heterocycle, optionally carrying another heteroatom identical to or different from the nitrogen. an alkylcarbonylamino radical (RaC (O) -NRb-) in which the radical Ra represents a C1-C4 alkyl radical and the radical Rb represents a hydrogen atom or a C1-C4 alkyl radical; a (di-) (alkyl) aminocarbonyl radical ((Ra) 2 N-C (O) -) in which the Ra radicals, which may be identical or different, represent a hydrogen atom or a C1-C4 alkyl radical; a ureido radical (N (Ra) 2 -C (O) -NRb-) in which the radicals Ra and Rb, which may be identical or different, and independently of one another, represent a hydrogen atom, an alkyl radical or C1-C4.

More preferably, the radicals R 2, R 3, R 4, and R 5 independently of each other represent: a C 1 -C 4 alkyl radical optionally substituted with one or more radicals chosen from hydroxyl, C 1 -C 2 alkoxy and methylcarbonylamino radicals, amino optionally substituted by two alkyl radicals, identical or different, C1-C4, optionally carrying at least one hydroxyl group; an amino radical optionally substituted with one or two identical or different C 1 -C 3 alkyl radicals optionally carrying at least one hydroxyl group, the two alkyl radicals possibly being able to form with the nitrogen atom to which they are attached; an optionally substituted saturated or unsaturated 5- or 6-membered heterocycle optionally containing another heteroatom identical to or different from nitrogen; a radical (di) (C 1 -C 4) alkylcarbonylamino such as (di) methylcarbonylamino; a hydroxyl radical; a C1-C2 alkoxy radical; a C2-C4 (poly) -hydroxyalkoxy radical; a halogen atom such as chlorine.

Advantageously, the radicals R 2, R 3, R 4 and R 5 represent, independently of each other: a C 1 -C 4 alkyl radical; a C1-C2 alkoxy radical; an amino radical optionally substituted with one or two identical or different C 1 -C 3 alkyl radicals, optionally bearing at least one hydroxyl radical.

More preferably, the radicals R2, R3, R4, and R5 independently of each other represent: a methyl, ethyl, propyl, 2-hydroxyethyl, methoxy or ethoxy radical; an amino, methylamino, dimethylamino, 2-hydroxyethylamino, 2-N, N-dihydroxyethylamino, 3-hydroxypropylamino radical; a methylcarbonylamino radical; a hydroxyl radical; a pyrrolidine radical; - a chlorine atom.

According to another particular variant of the invention, the dyes of formula (I) or (I ') have two radicals R2 derived from formulas (IIa), (IIb), (Va) and (Vb) borne by adjacent carbon atoms forming together with the carbon atom to which each is attached, a condensed ring, particularly benzo, optionally substituted preferably with a radical selected from methyl; hydroxy; methoxy; amino; methylamino; dimethylamino; pyrrolidine; methylsulfonylamino, 2-hydroxyethylamino, 2-N, N-dihydroxyethylamino, 3-hydroxypropylamino, hydroxycarbonyl (HO (O) C-), and ethoxycarbonyl (EtO (O) C-).

According to another particular embodiment of the invention, the dyes of formula (I) or (I ') have two radicals R3 derived from formula (III) carried by adjacent carbon atoms together with the carbon atom to which each is attached, a condensed ring optionally substituted by a radical selected from methyl; hydroxy; methoxy; amino; methylamino; dimethylamino; pyrrolidine; methylsulfonylamino, 2-hydroxyethylamino, 2-N, N-dihydroxyethylamino, and 3-hydroxypropylamino.

According to another particular variant of the invention, the dyes of formula (I) or (I ') have two radicals R4 resulting from formula (IV) carried by adjacent carbon atoms together with the carbon atom to which each is attached, a condensed ring particularly benzo, optionally substituted preferably with a radical selected from methyl; hydroxy; methoxy; amino; methylamino; dimethylamino; pyrrolidine; methylsulfonylamino, 2-hydroxyethylamino, 2-N, N-dihydroxyethylamino, and 3-hydroxypropylamino.

According to another particular variant of the invention, the dyes of formula (I) or (I ') have two radicals R5 derived from formula (VI) carried by adjacent carbon atoms which together with the carbon atom form to which each is attached, a fused ring optionally substituted preferably with hydrogen; a methyl radical; a hydroxy radical; a methoxy radical; an amino radical; a methylamino radical; a dimethylamino radical; a pyrrolidine radical; a methylsulfonylamino radical, a 2-hydroxyethylamino radical, a 2-N, N-dihydroxyethylamino radical or a 3-hydroxypropylamino radical.

According to one particular embodiment of the invention, the dyes of formula (I) or (I ') have values of m, m', m ", and e such that m = m '= e = 0 and m" is an integer equal to 0 or 1.

Another particular aspect of the invention relates to the dyes of formula (I) or (I ') having a non-cationic L bonding arm. According to this variant, the non-cationic divalent linking arm represents: an optionally substituted C1-C20, preferably C1-C10, alkyl radical, optionally interrupted by a saturated or unsaturated (hetero) ring, aromatic or otherwise, comprising 3- to 7-membered, optionally substituted, optionally fused; said alkyl radical being optionally interrupted by one or more heteroatoms or groups comprising at least one heteroatom preferably oxygen, nitrogen, such as ùC (0) -, or combinations thereof; a carbonyl radical -C (O) -.

L represents more particularly: an alkylene group -C nH 2n- in which n is an integer of 1 to 20, preferably 1 to 10 and even more preferably 1 to 6 - a radical -CpH2p C (O) -NR-CsH2s in which p and s, which are identical or different, represent an integer between 1 and 6 and R represents a hydrogen atom or a C 1 -C 4 alkyl group, preferably p = 1 to 4, s = 1 to 4 and R = H; a radical -CpH2p-NRC (O) with p and R are as defined for the preceding radical, or a carbonyl radical -C (O) - Another particular aspect of the invention relates to the dyes of formula (I) ) or (I ') having a cationic L bonding arm. According to this variant, the cationic bivalent linking arm L represents: a C2-C20 alkyl radical carrying at least one cationic charge, optionally substituted and / or optionally interrupted by one or more saturated or unsaturated (hetero) ring, aromatic or no, identical or different, comprising from 3 to 7 members and / or optionally interrupted by one or more heteroatoms or groups comprising at least one heteroatom or combinations thereof, such as, for example, oxygen, nitrogen, a group C (0) -, ùS (0) 2- or their combinations; the linking arm L not including azo bond, nitro, nitroso, peroxo; it being understood that the connecting arm L carries at least one cationic charge. According to this variant, the cationic L bonding arm, advantageously represents a C2-C20 alkyl radical: 1-interrupted by at least one group corresponding to the following formulas (a) and (b): In which: R independently independently on the other, represent: a linear or branched C1-C8 alkyl radical; a C2-C6 (poly) hydroxyalkyl radical; a (C 1 -C 6) -alkoxy (C 2 -C 6) alkyl radical; N + An-R 11 (a) (b) an aryl radical such as optionally substituted phenyl; an arylalkyl radical such as optionally substituted benzyl; a C2-C6 aminocarbonylalkyl radical; a C2-C6 aminoalkyl radical, the amine of which is optionally substituted with one or two identical or different C1-C4 alkyl radicals; Two radicals R a may together form, with the nitrogen atom to which they are attached, a saturated or unsaturated, optionally substituted, 5-, 6- or 7-membered ring; R12, which may be identical or different, represent: a halogen atom chosen from bromine, chlorine or fluorine; a C1-C6 alkyl radical; a C2-C6 (poly) hydroxyalkyl radical; a C1-C6 alkoxy radical; a C1-C4 (di-) alkylamino radical; a hydroxycarbonyl radical; a C1-C6 alkylcarbonyl radical; an optionally substituted benzyl radical; a phenyl radical optionally substituted with one or more radicals chosen from methyl, hydroxyl, amino and methoxy radicals; • An-represents anionic counterion or anionic counterion mixture; Z is an integer from 1 to 3; if z <3, then the unsubstituted carbon atoms carry a hydrogen atom; 2-optionally interrupted by one or more heteroatoms or groups comprising at least one heteroatom or combinations thereof, selected from oxygen, nitrogen, and the group C (O) -; And optionally substituted by one or more radicals chosen from hydroxyl, C 1 -C 2 alkoxy and C 2 -C 4 (poly) hydroxyalkoxy radicals, amino substituted by one or more linear or branched C 1 -C 2 alkyl groups optionally bearing carbon atoms. at least one hydroxyl group. According to a particular embodiment of the formula (a), R 11, separately, are preferably chosen from a C 1 -C 6 alkyl radical, a (C 2 -C 4) (poly) hydroxyalkyl radical and a (C 1 -C 6) alkyloxy radical. C2-C4, a C2-C6 dimethylaminoalkyl radical. Even more particularly, the radicals R11 separately represent a methyl, ethyl or 2-hydroxyethyl radical. According to one particular embodiment of formula (b), R12 represents a halogen atom chosen from chlorine and fluorine, a C1-C6 alkyl radical, a C1-C4 monohydroxylalkyl radical or a C1-C4 alkoxy radical. C4, a hydroxycarbonyl radical, a (C1-C6) alkyl radical thio, an amino radical disubstituted by a (C1-C4) alkyl radical. According to an even more particular embodiment of the formula (b), R12 represents a chlorine atom, a methyl, an ethyl, a 2-hydroxyethyl, a methoxy, a hydroxycarbonyl, a dimethylamino. According to another even more particular embodiment of the formula (b), z is equal to 0.

When the linker L is cationic, L advantageously represents a C2-C10 alkyl radical interrupted by at least one group of formula (a) or (b) in which the radicals R11 and / or R12 independently of one of the other, represent a linear or branched C1-C4 alkyl radical and An- is an anionic counterion or a mixture. Even more preferably, L is a C 2 -C 10 alkylene radical interrupted by a group of formula (a) in which the two R 11 radicals are identical and represent a C 1 -C 4 alkyl radical such as methyl. One particular embodiment relates to the thiol dyes of formula (I) or (I ') with x and y which are equal to 1, and Y represents a hydrogen atom, or an alkali metal. Advantageously, Y represents a hydrogen atom.

According to another particular embodiment of the invention, in the formulas (I) or (I ') mentioned above, Y is a protective group known to those skilled in the art, for example those described in the Protective Groups in Organic literature. Synthesis, TW Greene PGM Wuts, John Willey & Sons 3rd ed., NY, 1999, chap. 6, pp. 454-494; Protecting Groups, P. Kocienski, Thieme, 3rd ed., 2005, chap. 5. Particularly when Y is a protecting group for the thiol function, Y is selected from the following radicals: (C 1 -C 4) alkylcarbonyl; (C1-C4) alkylthiocarbonyl; (C1-C4) alkoxycarbonyl; (C1-C4) alkoxythiocarbonyl (C1-C4) alkylthiothiocarbonyl (di) (C1-C4) (alkyl) aminocarbonyl; ^ (di) (C1-C4) (alkyl) aminothiocarbonyl; arylcarbonyl as phenylcarbonyl; aryloxycarbonyl; aryl (C1-C4) alkoxycarbonyl such as benzoxycarbonyl; (di) (C1-C4) (alkyl) aminocarbonyl as dimethylaminocarbonyl; (C1-C4) (alkyl) arylaminocarbonyl; carboxy; S + M + with M + representing an alkali metal such as sodium or potassium, or else An "of the formula (I) or (I ') and M + are absent; optionally substituted aryl such as phenyl, 5'- dibenzosuberyl, 9-fluorenylmethyl, or 1,3,5-cycloheptatrienyl; cationic or non-optionally substituted heteroaryls, comprising from 1 to 4 following heteroatoms: i) monocyclic 5, 6 or 7-membered such as 2-furanyl or 2-furyl , 2-pyrrolyl, 2-thienyl, 3-pyrazolyl, 2-oxazolyl, 2-oxazolium, 3- or 4-isoxazolyl, 3- or 4-isoxazolium, 2-thiazolyl, 2-thiazolium, 3-or 4-isothiazolyl, 3- or 4-isothiazolium, 3- (1,2,4-triazolyl), 3- (1,2,4-triazolium), 4- (1,2,3-triazolyl), 4- (1,2, 3-triazolium), 3- (1,2,4-oxazolyl), 3- (1,2,4-oxazolium), 3- (1,2,4-thiadiazolyl), 3- (1,2,4-oxazolyl), thiadiazolium), 3-thiopyridyl, 2- or 3- or 4-pyridinium, 2-pyrimidinyl, 2-pyrimidinium, 2-pyrazinyl, 2-pyrazinium, 3-pyridazinyl, 3-pyridazinium, 2-triazinyl, 2-imidazolyl, 2-imidazolium; ii) 8 to 11-membered bicyclic compounds such as 2-indolyl, 2-indolinium, 2-benzoimidazolyl, 2-benzimidazolium, 2-benzoxazolyl, 2-benzoxazolium, 2-benzothiazolyl, 2-benzothiazolium, these mono or bicyclic groups being optionally substituted by one or more groups such as (C 1 -C 4) alkyl such as methyl, or polyhalogeno (C 1 -C 4) alkyl such as trifluoromethyl; optionally substituted heterocycloalkyl, optionally cationic, the heterocycloalkyl group represents in particular a saturated or partially saturated monocyclic group with 5, 6 or 7 members comprising 1 to 4 heteroatoms chosen from oxygen, sulfur and nitrogen, such as di / tetrahydrofuranyl; , di / tetrahydropyranyl, dihydropyridyl, piperazinyl, piperidinyl, tetramethylpiperidinyl, morpholinyl, di / tetrahydropyrimidinyl these groups being optionally substituted by one or more groups such as (C1-C4) alkyl, oxo or thioxo; or the heterocycle represents the following group: R'9 NR, n R, d An-in which R ', R'd, R'e, R'f, R'g and R'h, which are identical or different, represent a hydrogen atom or a (C1-C4) alkyl group, or two R'g groups with R'h, and / or R'e with R'f form an oxo or thioxo group, or R'g with R'e together form a cycloalkyl; and v represents an integer inclusive of between 1 and 3; preferably R ', at R'h represent a hydrogen atom; and An represents a counterion; a group (N, N, N '- (tri -) (C 1 -C 4 alkyl)) imidocarbamate - C (= N'R'h) NR'; R 'wherein R'h, R'; R '; the same or different represent a hydrogen atom or a group (C1-C4) alkyl; an aminium group -C (= N '+ R'hR'h') NR '; R' An- in which R'h, R'h R '; R'; identical or different represent a (C1-C4) alkyl group; and An- represents a counterion. optionally substituted (C 1 -C 4) alkyl (poly) aryl such as 9-anthracenylmethyl, phenylmethyl, diphenylmethyl or triphenylmethyl optionally substituted with one or more groups chosen in particular from (C 1 -C 4) alkyl, (C 1 -C 4) alkoxy, such as methoxy, hydroxyl, (C 1 -C 4) alkylcarbonyl, (di) (C 1 -C 4) (alkyl) amino such as dimethylamino; optionally substituted heteroaryl (C 1 -C 4) alkyl, the heteroaryl group is in particular, cationic or non-monocyclic, comprising 5 or 6 members and 1 to 4 heteroatoms chosen from nitrogen, oxygen and sulfur; , such as pyrrolyl, furanyl, thiophenyl, pyridyl, pyridyl N-oxide such as 4-pyridyl or 2-pyridyl-N-oxide, pyrylium, pyridinium, triazinyl, optionally substituted with one or more group such as alkyl particularly methyl preferably (di) heteroaryl (C 1 -C 4) alkyl is (di) heteroarylmethyl or (di) heteroarylethyl; R 1, R 2 R 3 with R 1, R 2 and R 3, which may be identical or different, representing a halogen atom or a group chosen from: a hydrogen atom. - (C 1 -C 4) alkyl optionally substituted with a C 1 -C 4 alkoxy; - (C 1 -C 4) alkoxy; optionally substituted aryl such as phenyl optionally substituted by one or more groups such as (C 1 -C 4) alkyl, (C 1 -C 4) alkoxy, hydroxyl; - optionally substituted heteroaryl such as thiophenyl, furanyl, pyrrolyl, pyranyl, pyridyl, optionally substituted with a (C 1 -C 4) alkyl group; I --P (= Z,) R'1R'2R'3 with R ',, and R'2 identical or different represent a hydroxyl group, (C, -C4) alkoxy or alkyl, R'3 represents a grouping hydroxyl or (C 1 -C 4) alkoxy, and Z 1 represents an oxygen or sulfur atom; sterically hindered cyclic; optionally substituted alkoxyalkyl such as methoxymethyl (MOM), ethoxyethyl (EOM) and isobutoxymethyl. In particular, the dyes of the invention for which x and y are 1, have a group Y chosen from a hydrogen atom, an imidocarbamate group (-C (= NH) NH 2), a 2- (N-alkyl) group. (C1-C4) pyridinium) such as 2- (N-methyl) pyridinium, a (C1-C4) alkoxycarbonyl such as ethoxycarbonyl and the (C1-C6) alkylcarbonyl group such as methylcarbonyl.

According to another variant of the invention, Y is especially a hydrogen atom, or alkylcarbonyl group, in particular acetyl, a radical C (= NH) NH 2, an alkoxycarbonyl radical such as CO2Et, an alkylpyridinium radical such as 2- (N -methyl) pyridinium. One particular mode relates to disulfide dyes of formula (I) or (I ') wherein x = 2 and y = 0.

According to a particular embodiment of the invention, the compounds correspond to the following formulas, as well as their salts and solvates: ## STR1 ## NR (R 2) m (R 3) m, (16) N + H 2 (R 2) n NR 'H 2, S ~ LC S NR' H 2 (R 4) m - NR (2 An- (13) NR ', SY LC H 2 (R 3) m '(R 4) NR An- (14) H NR' S, NR

LC ~ S \ NR H2 e) m "2 An- (15) N * N NR NR H2 (R 2 An- (R5 (R5) m- (R3) m, 2 An- (R3) m, (R5) (2) (R3 2 AN-NIIN + -h (R2) m H2 NNN (R2) m CLlN ~ / s ~ If LC (R NR H2 AN- (IN1)) R2 INA / SY H2 R1 N ( R 2) n = R (R 3) m '(R 5) m L L H2 \ ss / H2 H2 L I + C) _- N = N (R2) e • NR R ~ 2 An- N (R3) m An ## STR2 ## R ', Y, An-, m, m' and m "are as defined above, the electroneutrality of the molecule being respected by the presence of one or more anionic counterions As defined above. for example, the compounds of formulas (I) and (I ') correspond to one of the following compounds 1 to 54: ## STR1 ## ## STR2 ## , HH oo 2 3 4 6 N \ N SùH HO 8 7 Me / + An- MeO NN

NN Me 9 24 SH Me N + An- "--NN N Me 14 n ~ ^ -SùS ~~ iN N ~ Me-N YN Yr-yr NNN ~ 'NN NH SS Me 2 YEAR 15 16 ùsN. Embedded image NH 2 N (CH 2 CH 2 OH) 2 Me / N Me Me, NIN Me / An An An NH 18 e NH e N (CH 2 CH 2 OH) 2 OMe S 1 H 19 OMe NH SH 20 N (CH 2 CH 2 OH) 2 OMe 22 OMe N (CH 2 CH 2 OH) 2 Me 23 NH An 24 OMe 25 26 N ~ N SS HO 27 28 29 30 31 / N SiH H 33 ~ MeùN ùN N \ Me Me Me 34 SùH 32 Me 35 An 36 37 38 39 NH OMe NH OMe An IL NO, NN 40 MeO NIINH SùS OMe 41 30 OH An H ~ ùS-NN He NNIIN 42 OMe MeO H 43 44 SH NHNH 31 OH NII Nui \ + O ~ An H SùS NIIN OH 47 S 1 H

## STR2 ## ## STR0000 ## ## STR0000 ## ## STR0000 ## ## STR2 ## (CH2CH2OH) 2 51 OH OH e N

## STR5 ## wherein Y is an identical or different, representing a counterstain. These compounds can in particular be obtained from the similar preparation processes described for example in the documents Khimiya Geterotsiklicheskikh Soedinenii, 1991, 9, 1209-1214, and 1982, 6. According to a first embodiment, the method for synthesizing the compounds of formula (I ') used in the invention may consist in carrying out the following steps: (R 3) m' NR 1 -diazotation 2-coupling with 1 eq of W "1 (W", represents a nucleus (benz) imidazole NR 3-monoalkylation 4-quaternization with H2 C (R5) m. ~ Gp GpùL "- '' S ~ C, L 4 N In this process, a first diazotization step of a diphenylamine is carried out in a manner known to those skilled in the art. ## STR2 ##

Thus, said amine is contacted in the presence of sodium nitrite or nitrosylsulfuric acid. Usually this reaction takes place at a temperature between -15 ° C and 30 ° C, preferably between -10 ° C and 20 ° C at a pH between 0 and 12.

In a conventional manner, the reaction takes place in the presence of a suitable solvent among which mention may be made of water, aliphatic alcohols comprising in particular up to 4 carbon atoms, organic acids for example carboxylic acid or sulphonic acid comprising up to 10 carbon atoms and / or minerals of the type of hydrochloric acid, sulfuric.

Once the reaction has been carried out, the product obtained is coupled with a compound of the type W "4.15 Usually this reaction is carried out in the presence of a solvent which may be that of the preceding step. -15 ° C and 30 ° C, preferably between -10 ° C and 20 ° C at a pH preferably between 0 and 8.

The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.). The synthesis of the substituted diphenylamineamine is known to those skilled in the art (see, for example, Eur J. Org Chem 2007, (9), 1423-1428, Advanced Synth Catalysis 2006, 348 (15), 2197-2202). Synlett, 2004, 6, 955-958; Synthesis, 2003, 16, 2511-2517; J. Org Chem 2003, 68 (22), 8416-8423; Org. Lett. 2003, 5 (8), 1265; Chem., Materials, 2006, 18 (18), 4513-4518).

The resulting product is then monoalkylated in the usual manner (see, for example, Synth.Com 2005, 35 (23), 3021-3026, EP1386916, Synthesis, 1986, 5, 382-383, Liebigs Annalen der Chemie, 1987, 1, 77 -79); Bull. Chem. Soc. Jap. 1977, 50 (6), 1510-1512; J. Org. Chem. 1979, 44 (4), 638-639. For example, the product obtained can be brought into contact with an alkyl sulphate such as dimethyl sulphate, diethyl sulphate, dipropyl sulphate or an alkyl halide or an aryl alkyl halide such as iodomethane or iodoethane. 2-bromoethanol, benzyl bromide in the presence of a polar or apolar protic or aprotic solvent such as dichloromethane, toluene, ethyl acetate, water at spontaneous or alkaline pH. The resulting product can also be contacted with dialkyl carbonate such as dimethylcarbonate, diethylcarbonate in the presence of base. Usually, the temperature is between 10 ° C and 180 ° C, preferably between 20 ° C and 100 ° C.

The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.).

In a final step, the resulting product is then dimerized in a manner known to those skilled in the art. Thus, said resultant product is brought into contact in the presence of a double alkylation agent having a disulfide unit in the presence of an aprotic polar or apolar solvent such as acetonitrile, dimethylformamide, toluene, dimethyl-2-oxohexahydropyrimidine (DMPU), N-methylpyrrolidone. Usually, the temperature is between 10 ° C and 180 ° C, preferably between 20 ° C and 140 ° C.

The double alkylating agent having a disulfide unit can be prepared according to the methods described in the literature and which are known to those skilled in the art: Synthesis of the Disulfide Diol: see, for example, J. Org. Chem. 1985, 50 (26), 5716-5719; J. Am. Chem. Soc. 1970, 92 (24), 7224-7225; Tetrahedron 2004, 60 (51), 11911-11922; J. Org. Chem. 1990, 55 (9), 2580-2586; J. Org. Chem. 1985, 50 (26), 5716-5719; J. Chem. Soc., Chem. Comm. 1981, 15, 741-742; Tet. Lett. 2005, 46 (36), 6097-6099; J. Org. Chem. 1990, 55 (9), 2580-2586; J. Org. Chem. 1985, 50 (26), 5716-5719). Synthesis of the double disulfide-type alkylation agent: See, for example, Bioorganic Medicinal Chemistry Letters, 2004, 14 (21), 5347-5350; W004039771; Chem. Berichte, 1983, 116 (1), 323-347, Tetrahedron 1985, 41 (15), 3063-3069; J. Am. Chem. Soc. 1987, 109 (25), 7648-7653; J. Org. Chem. 1995, 60 (8), 2638-2639; Sulfur Lett. 2000, 24 (3), 137-145.

The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.).

With: - W'4 which represents the following group (VII): a (R2) e 4 (VII) - W "4 which represents the following group (VIII): a (R) e 4 (VIII) - Gp which represents a leaving group such as a halide such as bromide or chloride, a mesylate, a tosylate, etc. After the quaternization, the anionic counterion of the groups (Va) of W4 will become Gp-, W4, L, a, R, R1, R2 , R3, R5, m ', m "and e are as defined above.

According to a second embodiment, the process for synthesizing the compounds of formula (I) used in the invention may consist in carrying out the following steps: 1- Formation Wä4 of a N-oxide NI-1Z NR 2- Diazotation 3- Coupling W "4`NHZ + W" 4 .. 4- 0-Alkylation (R5) m. 5-Deaternization W "4N.4-quaternization with H 2, Gp GpuL'C, SC G p -NR 5) m NR According to this method, a first step of N-oxidation of the heteroaromatic unit is carried out (formation of an N- oxide) in a manner known to those skilled in the art.

This can be carried out starting from the protected heteroaromatic amine or not.

Thus, said amine is brought into contact in the presence of an oxidizing agent such as hydrogen peroxide, optionally in the presence of a molybdenum or tunsgene catalyst, m-chloroperoxybenzoic acid (Synth.Comm.177, 7 ( 8), 509-514, Gazzetta Chimica Italiana, 1964, 94 (5), 458-466), peroxyacetic acid (J. Am Chem Soc 1954, 76, 2785-2786). As an example of a catalyst, the derivatives of phosphomolybdic acid or of phosphotungstic acid described in J. Molecular Cat. A: Chemical, 2006, 252 (1-2) 219-225. Usually this reaction takes place at a temperature between 0 ° C and 180 ° C, preferably between 10 ° C and 150 ° C. In a conventional manner, the reaction takes place in the presence of a suitable solvent among which mention may be made of water, acetone, toluene, benzene, and aliphatic alcohols comprising up to 4 carbon atoms.

The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.).

The resulting product is then diazotized and the diazonium salt thus formed is then coupled to a diphenylamine (Indian J. Chem, Section B: Organic Chemistry Including Medicinal Chemistry, 1995, 34B (2), 161-163; Chem. Pharmaceutical Bull. 1979, 27 (8), 1824-1829). The conditions for carrying out such a synthesis have been summarized previously.

The synthesis of substituted diphenylamineamine is known to those skilled in the art (see, for example, J. Org Chem 2006, 71 (14), 5117-5125, Russ J. General Chem., 2005, 75 (2), 207-211, Tet Lett., 2003, 44 (40), 7549-7552, Org., Lett., 2003, 5 (8), 1265-1267, Synlett, 2003, 6, 885-887, US2006258887, J. Catalysis, 2005, 236 (2), 387-391, J. Organometallic Chem 2005, 690 (24-25), 6169-6177, Eur J. Org Chem 2007, 9, 1423-1428, Pure and Applied Chemistry, 2006, 78 (10), 1867-1876.

In a fourth step, the resulting product is engaged in an O-alkylation reaction in a manner known to those skilled in the art (J. Am Chem Soc., 2004, 126 (43), 14071-14078; Soc., Perk Trans 2: Phys Org Chem, 1992, 7, 1011-1017, Pol J Chem 1981, 55 (9), 1957-1958). For example, the product obtained can be brought into contact with an alkyl sulphate such as dimethyl sulphate, diethyl sulphate, dipropyl sulphate or an alkyl halide or an aryl alkyl halide such as iodomethane or iodoethane. 2-bromoethanol, benzyl bromide in the presence of a protic or aprotic polar or apolar solvent such as dichloromethane, toluene, ethyl acetate, dimethylformamide, N-methylpyrrolidone, spontaneous pH water or alkaline. Usually, the temperature is between 10 ° C and 180 ° C, preferably between 20 ° C and 100 ° C. The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.).

In a fifth step, the resulting product is dealkoxylated in a manner known to those skilled in the art. For example, the product obtained can be brought into contact with an alkaline agent, such as ammonia, in the presence or absence of an aprotic polar protic solvent, such as aliphatic alcohols comprising up to 4 carbon atoms, and water with a spontaneous pH. Usually, the temperature is between 10 ° C and 180 ° C, preferably between 20 ° C and 100 ° C. The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.). The double alkylating agent having a disulfide unit can be prepared according to the methods described in the literature and which are known to those skilled in the art. The conditions for carrying out such a synthesis have been summarized previously.

The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.).

With: - W "4 which represents the following group (IX): t (R2) ma N - W" '4 which represents the following groups (X) and (XI): t (R2) m; a; a NN I_ It OO

(x) (xi) - Gp which represents a leaving group such as the halide such as bromide or chloride, a mesylate, a tosylate. Gp- will become after quaternization the anionic counterion of the groups (Vb) of W4. -W4, L, a, R, R2, R3, R5, m ', m ", m and An- are as defined above.

According to a third embodiment, the process for synthesizing the compounds used in the invention may consist in carrying out the following steps: (R 2) m 1 diazotization 2 coupling R 1 W '4 NH 2 + (R 3) m' N (R4) m, R 1 N quaternization with: H2, Gp GpuL-S, -S, C, L H2 G p -NR SS H2C 1 (R3) m. W4N \ Gp- ~ N 2Gp- (equivalent to 2An) NR The conditions for carrying out such a synthesis have been summarized previously. The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, etc.).

With: - W'4 which represents the following group (VII): a (R2) e 4 (VII) - Gp which represents a leaving group such as halide such as bromide or chloride, a mesylate, a tosylate. Gp- will become after quaternization the anionic counter-ion of the groups (Va) of W4. - W4, L, a, R, R1, R2, R3, R5, m ', m "and e are as defined above.

According to a fourth embodiment, the process for synthesizing the compounds of formula (I) used in the invention may consist in carrying out the following 5 steps: (R 4) m .sub.2 H.sub.2 H.sub.2 NR'L, C ' S_S ~ c ~ The 3 quaternization (R4) m .. NR 1 diazotation 2 coupling with 2 eq. of a cationic heterocycle W '1H 2 H 2 NR'LS_S "LIN N R 1 ((R 4) m (R 3) m, NR NH 2 -NuW'i N ~ N 1 W NR NR, N An- (R 4) m .. (R 4 ) H.sub.2 H.sub.2 H.sub.2 H.sub.2 H.sub.2 L.sub.1 H.sub.2 H.sub.2 H.

(R2) e 4 (VIII) -W1, L, a, R, R ', R2, R3, R4, m', m ", e and An- are as defined above. Such a synthesis has been summarized previously According to a fifth embodiment, the method for synthesizing the compounds of formula (I) of the invention may consist in carrying out the following steps: ## EQU1 ## (R.sub.4) m.sup.H.sub.2 H.sub.2 H.sub.2 H.sub.2 H.sub.2 H.sub.2 R.sub.2 NR.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.1 R.sub.1 R.sub.1 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 R.sub.3 H. a hydrazone derivative whose synthesis is known to those skilled in the art and a dimerized aromatic amine The compounds mentioned above are reacted in the presence of an oxidizing agent in a polar solvent, at a temperature of between 0 ° C. and 120 ° C. The pH of the solution is between 3 and 11.5 The oxidizing agent is chosen from an oxidase, among which mention may be made of peroxidases, 2-electron oxidoreductases such as uricase and 4-electron oxygenases such as laccases, O 2, Na 2 O, KMnO 4, K 3 Fe (CN) 6, MnO 2, H 2 O 2, Ag 2 O, AgO, NiO 2, NaBO 3, Na 2 S 2 O 8, CH 3 CO 3 H, C 6 H 5 CO 3 H, CuX (X = Br, Cl), CuSO 4, (NH4) 2Ce (NO3) 6, PbO2, Pb (OCOCH3) 4, SeO2, CrO3.2C5H4N, NaOCI Preferred oxidants will be selected from KMnO4, K3Fe (CN) 6, MnO2, H2O2, CuX (X = Br, Cl) ), CuSO4, Pb (OCOCH3) 4, NaOCI. Preferably, the preferred oxidizing agents will be selected from K3Fe (CN) 6, MnO2, H2O2, CuBr, NaOCI. The reaction is preferably carried out at a temperature of between 0 ° C. and 80 ° C. in a preferably polar solvent chosen from water, in particular aliphatic comprising up to 4 carbon atoms, dimethylformamide, dimethylsulfoxide and acetonitrile. N-Methylpyrrolidone, 1,3-dimethyl-2-oxohexahydropyrimidine (DMPU) at a pH of between 5 and 9.5.

The product can be isolated for the techniques known to those skilled in the art (precipitation, evaporation, chromatography, etc.).

With: - W "1 which represents the following group (XI) and (XII): (R4), HH 2 2 NR NF2'S-S ~ C \ NR '- W1, L, R, R1, R2, R3, R4, m ', m ", m and An-are as defined above.

Hydrazones of formula (XI) and (XII) are known to those skilled in the art. They can be obtained from the operating protocols described for example in patents FR1599968, DE1922400, FR2822062, FR2822063 and associated references. According to a sixth embodiment, the process for synthesizing the compounds of formula (I) of the invention may consist in carrying out the following steps: Dimerization with H 2, Gp G ù L ~ C ~ S ~ S ~ C ~ L H2 NHR 'NR H2 NR' C. SC, LL H2 An- An- with R3, R4, R ', m', m ", L and An- are as previously defined; Such a synthesis has been summarized previously.

Protected thiol dyes of formula (I-Y) or (I-Y ') for which x and y are 1 can be synthesized in two stages. The first step of preparing unprotected thiol dye (IH) or (I-H ') according to methods known to those skilled in the art such as Thiols and organic Sulfides, Thiocyanates 44 and Isothiocyanates, organic, Ullmann's Encyclopedia, Wiley-VCH, Weinheim, 2005. And the second step of protecting the thiol function according to conventional methods known to those skilled in the art to lead to protected thiol dyes of formula (IY) or (I-Y '). By way of example, to protect the thiol function of the thiol dye, the methods of Protective Groups in Organic Synthesis, T.W. Greene, John Willey & Sons, Ed., NY, 1981, pp.193-217; Protecting Groups, P. Kocienski, Thieme, 3rd ed., 2005, chap. 5. We can illustrate this method by the method consisting of i) generating thiol dyes of formula (IH) or (I-H ') by reduction of a dye with two azo chromophores, carrying a disulfide function -SS- such that (IS) or (I-S ') and ii) to protect according to conventional methods said thiol function of (IH) or (I-H') with the reagent YX to access protected thiol dyes of formula (IY) or ( I-Y '). The thiol compound (I-H) or (I-H ') may also be metallized with an alkali metal or alkaline earth metal Met * to yield the thiolate dye of formula (I-Met) or (I-Met').

R3) m (R4) m 'H H2 2 WRN \ NR' ~ C ~ ~ C ~ CNR '~ NùW reducer N NR L SùS L NR An- (R,) ,,. H2 z NR'LSH NR (1H) An- H2 NR '(IY)' L SY NR YX -HX An-H 2 (1-Met) NR'LSMet (IH) to NO reducing agent LN C H 2 SH An-L W a N, N NR (R 5) m, An-NR NR (I-S ') (I-H') (I-H ') 4 N YX LN -HX CH 2 SY An-NR (I-Y') (R) metallization 74-NL \ N "NR H2 An-Met with Y representing a protecting group of thiol function and X a leaving group nucleofuge, such as, for example, mesylate, tosylate, triflate or halide and Met * representing an alkali metal or an alkaline metal It is understood that when the metal is an alkaline-earth metal, 2 chromophores with a thiolate-S-function may be associated with 1 Metal2 + and with W ,, W4, R3, R4, R5, R R ', m', m ", L and An- are as previously defined;

According to another possibility, a thiol compound protected by a protective group Y as defined above, prepared according to one of the procedures described in the works cited above, can be reacted, said protected thiol compound comprising at least one nucleophilic function with a sufficient quantity. , preferably equimolar, of a chromophore j or j, and which comprises an electrophilic function to form a covalent bond E; see below the preparation of dyes of formula (I'-Y) or (I'-Y ') (I-Met') sy ~~ (CH2) n '/ (CH2) fl NR' SY Wu \ ((H2 ## STR1 ## ## EQU1 ## where: ## STR2 ## ## STR2 ## ## STR1 ## where: ## STR1 ## ## STR1 ## ## STR1 ## where: ## STR5 ## represents the nucleophilic group, wherein E represents an electrophilic group, and the bond generated after the nucleophile is attacked on the electrophile, wherein n 'and n "represent an integer between 1 and 6 with n '+ n "from 2 to 10 and with W 1, W 4, R 3, R 4, R 5, m', m", R, R ', L and An- are as previously defined.

By way of example, the covalent bonds E that can be generated are listed in the table below from the condensation of electrophiles with nucleophiles: Electrophiles E Activated esters * Acyl azides ** Acyl halide halides acyl cyanides acyl cyanides alkyl halides alkyl halides alkyl halides alkyl halides sulphonic acids and their salts sulphonic acids and their salts nucleophiles Wu Amines Amines Amines Alcohols Alcohols Amines Amines Carboxylic acids Thiols Alcohols Thiols Liaisons covalents Carboxamides Carboxamides Carboxamides Esters Esters Carboxamides Alkylamines Esters Thioethers Ethers Thioesters Carboxylic acids Esters 5 47 Sulfonic acids and their alcohols Salt esters Anhydrides Alcohols Esters Anhydrides Amines Carboxamides Halides of aryls Thiols Thioethers Halides of aryl Amines Arylamines Aziridines Thiols 13-aminothioethers Carboxylic acids s Amines Carboxamides Carboxylic Acids Alcohols Esters Carbodiimides N-Acylurea Carboxylic Acids Diazoalkanes Carboxylic Acids Esters Epoxides Thiols 13-hydroxy thioethers Haloacetamides Thiols a-acetamidothioethers Amide Esters Amines Amidines Isocyanates Amines Urea Isocyanates Alcohols Urethanes Isothiocyanates Amines Thioureas Maleimides Thiols Thioethers Sulphonic esters Amines Alkylamines Sulphonic esters Thiols Thioethers Sulphonic esters Carboxylic acids Esters Sulphonic esters Alcohols Ethers Sulphonyl halides Amines Sulfonamides * Activated esters of the general formula ùCO-Part with Part representing a leaving group such as oxysuccinimidyl, oxybenzotriazolyl, optionally substituted aryloxy ** acyl azides may rearrange to give the isocyanates. An alternative to this method is to use a chromophore having an electrophilic acrylate function (-OCO-C = C-) on which an addition reaction is carried out which will generate an L bond. It will also be possible to use a thiol reagent (a): Y -SH comprising a group Y Y as defined above, the SH nucleophile function can react on the carbon atom bearing the halogen atom (nucleophilic substitution reaction) of the radical L carried by a chromophore to lead to thiol dye protected compound of formula (IY) or (I-Y '): ## STR2 ## (HS-Y-HHaI (R4 HS-Y NR -HHaI (I-Y')) CueHal An-H2 with Hal representing a nucleofugal halogen atom such as bromine, iodine or chlorine and W ,, W4, R3, R4, R5, m ', m ", R, R', R ', , R'd, L Hal and An- are as defined above, more particularly one may substitute a leaving group nucleofuge by a thiouré group (S = C (NRR) NRR) to generate the isothiouron For example, if the thiourea group is an N, N-disubstituted thioimidazole (13), it will be possible to obtain an S-protected dye with a thioimidazolium (I "-Y) or (I" -Y ') group: R'cN W, N \ N AN- N ~ NR 'SAN + Hal R'd LùC

H2 NR RC, N H2 WrN NR ~ C (R) ~ tl Wr N L Hal (R4) m "NR An- (Ia_Y) NR NR Hal C H2

An- H2C, s ~ N ~ RC R'd ~ NI Hal Anfia ,,,) (I "-Y. With W ,, W4, R3, R4, R5, m ', m", R, R' , L Hal and An- are as defined above.

Hal- having the same meaning as An- R ', and R'd have the same meaning as R ,.

Another variant may provide access to the compound (I "'- Y) or (I"' - Y ') from the cyclic thiourea of imidazoline type (b'), followed by the alkylation of said imidazoline at 1 using R'd-Gp with Gp leaving group such as chloride, bromide, tosylate, mesylate: R. SH NN W- NS ~ 'N - H Hal Alkylation NR' SN R'd-Gp

---- CH

R'cN N NR An- R'cN W -NN An- / NH Gp_ H2 NR NR 's L \ I R'd (I "- Y)> NR o N With W1, W4, R3, R4, R5 , m ', m ", R, R', R ', R'd, L Hal and An-are as defined above. Gp- having the same meaning as An-.

An alternative is to use in place of the halide comprising chromophore (a ") or (a") a chromophore comprising another type of nucleofuge such as tosylate, mesylate.

According to another possibility, certain protected thiol dyes (I'-Y) or (I'-Y ') can be obtained by reacting a protected thiol compound having an electrophilic group E (d) prepared according to conventional methods and a chromophore j or j, carrying a nucleophilic function .Ivu, for example a primary or secondary amine group, or aliphatic alcohol type: H2C, s (R5) R ;. Alkylation R'd-Gp NR L H2C, s An- (I '"- Y') NR Hal + Eii (CH2) SY (Y-Y) NR / (CHZ) ~, INu j W- N \ N An - (R4) NR1, NR + E1 (CH2) SY (I'Y ') (R5 m., NR With W1, W4, R3, R4, R5, m', m ", R, R ', L , Y, Nu, E and An- are as defined above.

Another alternative is to react a thiolactone derivative in the presence of compound c "or cc as shown by the scheme below: ## STR2 ## (R4) m '/ (CH2) n' NR 'N (1-12) n' NR R '(B) SH G' (CH2) n, NR '1N / (1-12) n' (I "'- Y) (B) R "S --- YR" SMet NR 'N (Ir-Met) / (H2) No metallation W-NN An- Compounds of formula (I) NR YX W-N-HX An-N NR 51 oxidation and (R (CH 2) n '1 NHR "(CH 2) n' 1 NR" "WN N An- (c") NR oxidation (I "" - Y Compounds of formula (I ') W4 - NR N YX - HX (CH 2) ## STR2 ## The thiol derivative LB 1 or LU may be: - oxidized according to the techniques known to those skilled in the art to obtain For this purpose, it is possible to use an oxidizing agent listed above, for example manganese or cobalt complexes (see, for example, Phosphorus, Sulfur, and Silicon and the Related Elements, 1998, 143, 125-131, Synth.Commun., 1999, 29 (14), 2527-2531, 2003, 33 (6), 1057-1065, 2004, 34 (18), 3303-3315, 2005, ( 4), 571-580); - Be protected to form the protected thiol dye (I "" - Y) or (I'-Y ') or be metallized with an alkali metal to give the metallized dye (II'-Met) or (II'- Met ') according to the methods described previously; With G 'representing an oxygen atom, sulfur atom or a group NR "' with R" 'representing a hydrogen atom or a C1-C4 alkyl radical, and R "representing a hydrogen atom, an alkyl radical C1-C4, hydroxy-C1-C4 alkyl or aryl (C1-C4) alkyl.The thiolactone derivative is preferably selected with n "= 3 and G 'represents an oxygen atom. And with W1, W4, R3, R4, R5, m ', m ", n', R, R ', L, Y, Nu, E and An- are as defined above.

Reference may be made to Advanced Organic Chemistry, Reactions, Mechanisms and Structures, J. March, 4th Ed, John Willey & Sons, 1992 or TW Greene Protective Groups in Organic Synthesis, for further details on operating conditions. for the processes mentioned above.

The thiol dyes formed can be converted to Y-protected thiol dyes by thiol protection using standard protecting groups. The thiol dyes are metallated using also conventional methods known to those skilled in the art such as those described in Advanced Organic Chemistry, Reactions, Mechanisms and Structures, J. March, 4th Ed, John Willey & Sons, NY, 1992. The protected thiol dyes may be deprotected by conventional routes such as those described in Protective Groups in Organic Synthesis, TW Greene, John Willey & Sons ed., NY, 1981; Protecting Groups, P. Kocienski, Thieme, 3rd ed., 2005.

The starting reagents are commercial or accessible by conventional methods known to those skilled in the art. By way of example, mention may be made of US 4579949.

Another subject of the invention is a composition for the dyeing of human keratinous fibers such as the hair comprising in a cosmetic medium at least one disulfide, thiol or protected thiol dye of formula (I) or (I '). In addition to the presence of at least one dye of formula (I) or (I '), the composition of the invention may also contain a reducing agent. This reducing agent may be chosen from thiols, for example cysteine, homocysteine, thiolactic acid, the salts of these thiols, phosphines, bisulfite, sulphites, thioglycolic acid and its esters, especially the glycerol monothioglycolate, and thioglycerol. This reducing agent may also be chosen from borohydrides and their derivatives, such as, for example, borohydride, cyanoborohydride, triacetoxyborohydride or trimethoxyborohydride salts: sodium, lithium, potassium, calcium, quaternary ammonium salts (tetramethylammonium, tetraethylammonium, tetra butylammonium, benzyltriethylammonium); catechol borane. The dye composition useful in the invention generally contains an amount of dye of formula (I) or (I ') of between 0.001 and 50% relative to the total weight of the composition. Preferably, this amount is between 0.005 and 20% by weight and even more preferably between 0.01 and 5% by weight relative to the total weight of the composition. The composition according to the invention may optionally comprise at least one additional direct dye different from the compounds of formula (I) or (I '). This can be selected from neutral, acidic or cationic species.

By way of non-limiting examples, mention may be made of nitrobenzene dyes, azo, azomethine, methine, tetraazapenthamethine, anthraquinone, naphthoquinone, benzoquinone, phenotiazine indigo, xanthene, phenanthridine, phthalocyanine dyes, those derived from triarylmethane and natural dyes. alone or in mixtures.

It may for example be chosen from the following red or orange nitro benzene dyes: 1-hydroxy-3-nitro-4-N- (γ-hydroxypropyl) amino benzene, N-O-hydroxyethyl-amino-3- nitro-4-amino benzene, 1-amino-3-methyl-4-N- (13-hydroxyethyl) amino-6-nitro benzene, 1-hydroxy-3-nitro-4-N- hydroxyethyl) amino benzene, 1,4-diamino-2-nitrobenzene, 1-amino-2-nitro-4-methylamino benzene, N-O-hydroxyethyl-2-nitro-para-phenylenediamine, amino-2-nitro-4-yl-hydroxyethyl) amino-5-chloro-benzene, 2-nitro-4-amino-diphenylamine, -1-amino-3-nitro-6-hydroxybenzene. 1 - ((3-aminoethyl) amino-2-nitro-4 - ((3-hydroxyethyloxy) benzene, 1 - ((3, y-dihydroxypropyl) oxy-3-nitro-4 - ((3- hydroxyethyl) amino benzene, 1-hydroxy-3-nitro-4-aminobenzene, 1-hydroxy-2-amino-4,6-dinitrobenzene, 1-methoxy-3-nitro-4-β-hydroxyethyl ) amino benzene, 2-nitro-4'-hydroxydiphenylamine, 1-amino-2-nitro-4-hydroxy-5-methylbenzene.

The additional direct dye may also be chosen from yellow and green-yellow nitro-benzene direct dyes, for example compounds selected from: 1-13-hydroxyethyloxy-3-methylamino-4-nitrobenzene; methylamino-2-nitro-5 - ((3, y-dihydroxypropyl) oxybenzene, - 1-03-hydroxyethyl) amino-2-methoxy-4-nitrobenzene, - 1-03-aminoethyl) amino-2 Nitro-5-methoxy-benzene, 1,3-di (13-hydroxyethyl) amino-4-nitro-6-chlorobenzene, 1-amino-2-nitro-6-methyl-benzene, -03-hydroxyethyl) amino-2-hydroxy-4-nitrobenzene, N-03-hydroxyethyl-2-nitro-4-trifluoromethylaniline, 4-hydroxy-hydroxyethyl) amino-3-nitro-benzenesulfonic acid, 4-ethylamino-3-nitro-benzoic acid, 4-03-hydroxyethyl) amino-3-nitro-chlorobenzene, 4-03-hydroxyethyl-amino-3-nitro-methylbenzene, 4- 03, γ-dihydroxypropyl) amino-3-nitro-trifluoromethylbenzene, 1-ery-ureidoethyl-amino-4-nitrobenzene, 1,3-diamino-4-nitrobenzene enzene, 1-hydroxy-2-amino-5-nitrobenzene, 1-amino-2- [tris (hydroxymethyl) methyl] amino-5-nitro-benzene, 1-03-hydroxyethyl) amino-2 nitrobenzene; 4-03-hydroxyethyl) amino-3-nitrobenzamide. Mention may also be made of blue or violet nitrobenzene direct dyes, such as, for example: 1 - ((3-hydroxyethyl) amino-4-N, N-bis-((3-hydroxyethyl) amino-2-nitrobenzene, 1- (γ-Hydroxypropyl) amino 4-N, N-bis-3-hydroxyethyl) amino-2-nitrobenzene, 1- (3-hydroxyethyl) amino-4- (N-methyl, N-13-hydroxyethyl) amino 2- nitrobenzene, 1-03-hydroxyethyl) amino 4- (N-ethyl, N-13-hydroxyethyl) amino 2-nitrobenzene, 1--03- (y-dihydroxypropyl) amino 4- (N-ethyl, N-13) -hydroxyethyl) amino 2-nitrobenzene, 2-nitroparaphenylenediamines of the following formula: NHRa NO2 NRbRc wherein: - Rb represents a C1-C4 alkyl radical, a 13-hydroxyethyl or 13-hydroxypropyl or γ-hydroxypropyl radical; Ra and Rc, which may be identical or different, represent an R-hydroxyethyl, -13-hydroxypropyl, γ-hydroxypropyl or 13, γ-dihydroxypropyl radical, at least one of Rb, Rc or Ra radicals representing a γ-hydroxypropyl radical; and Rb and Rc can not simultaneously designate an R-hydroxyethyl radical when Rb is a hydroxypropyl radical, such as those described in French Patent FR 2,692,572.

Among the azo direct dyes that may be used according to the invention, mention may be made of the cationic azo dyes described in patent applications WO 95/15144, WO 95/01772, EP 714954, FR 2 822 696, FR 2 825 702 and FR 2 825 625. , FR 2 822 698, FR 2 822 693, FR 2 822 694, FR 2 829 926, FR 2 807 650, WO 02/078660, WO 02/100834, WO 02/100369, FR 2 844 269. Among these compounds, mention may be made, in particular, of the following dyes: 1,3-dimethyl-2 - [[4- (dimethylamino) phenyl] azo] -1H-imidazolium chloride, - 1,3-dimethyl-2 - [(4) chloride 1-methyl-4 - [(methylphenylhydrozono) methyl] pyridinium 1-methylphenyl) azo] -1H-imidazolium methylsulphate. Mention may also be made, among the azo direct dyes, of the following dyes, described in the COLOR INDEX INTERNATIONAL 3rd edition: - Disperse Red 17 - Acid Yellow 9 - Acid Black 1 - Basic Red 22 - Basic Red 76 - Basic Yellow 57 - Basic Brown 16 Acid Yellow 36 Acid Orange 7 Acid Red 33 Acid Red 35 Basic Brown 17 Acid Yellow 23 Acid Orange 24 Disperse Black 9 1- (4'-Aminodiphenylazo) -2-methyl -4bis- (13-hydroxyethyl) aminobenzene and 4-hydroxy-3- (2-methoxyphenylazo) -1-naphthalenesulfonic acid.

Among the quinone direct dyes that may be mentioned are the following dyes: - Disperse Red 15 - Solvent Purple 13 - Acid Violet 43 - Disperse Violet 1 - Disperse Violet 4 - Disperse Blue 1 - Disperse Violet 8 - Disperse Blue 3 - Disperse Red 11 - Acid Blue 62 - Disperse Blue 7-Basic Blue 22 - Disperse Violet 15 - Basic Blue 99 and the following compounds: - 1-N-methylmorpholiniumpropylamino-4-hydroxyanthraquinone -1-Aminopropylamino-4-methylaminoanthraquinone -1-Aminopropylaminoanthraquinone -5-13 1-hydroxyethyl-1,4-diaminoanthraquinone -2-aminoethylaminoanthraquinone-1,4-bis-3-yl-dihydroxypropylamino) anthraquinone. Among the azine dyes there may be mentioned the following compounds: - Basic Blue 17 - Basic Red 2.

Among the triarylmethane dyes that can be used according to the invention, mention may be made of the following compounds: - Basic Green 1 - Acid Blue 9 - Basic Violet 3 -Basic Violet 14 - Basic Blue 7 - Acid Violet 49 - Basic Blue 26 - Acid Blue 7 the indoamine dyes that can be used according to the invention include the following compounds: -2-13-hydroxyethylamino-5- [bis- (13-4'-hydroxyethyl) amino] anilino-1,4-benzoquinone -2-13 hydroxyethylamino-5- (2'-methoxy-4'-amino) anilino-1,4-benzoquinone-3-N (2'-chloro-4'-hydroxy) phenyl-acetylamino-6-methoxy-1,4- benzoquinone imine-3-N (3'-chloro-4'-methylamino) phenyl-ureido-6-methyl-1,4-benzoquinone imine -3- [4'-N- (ethyl, carbamylmethyl) amino] phenyl -ureido-6-methyl-1,4-benzoquinone imine. Among the natural direct dyes that may be used according to the invention, lawsone, juglone, alizarin, purpurine, carminic acid, kermesic acid, purpurogalline, protocatechaldehyde, indigo, isatin , curcumin, spinulosin, apigenidine. It is also possible to use the extracts or decoctions containing these natural dyes, and in particular poultices or extracts made from henna.

If present, the content of additional direct dye (s) in the composition generally varies from 0.001 to 20% by weight relative to the weight of the composition, and preferably from 0.01 to 10% by weight. weight relative to the weight of the composition.

The composition according to the invention may optionally comprise at least one additional disulfide or thiol dye as described in documents WO2006 / 136617 and FR2876576.

By way of nonlimiting examples, a dye of formula (I) or (I ') according to the invention which has a maximum absorption of between 540 and 630 nm is advantageously associated with a dye of general formula (III) (azo dyes red disulfides) and / or a dye of general formula (IV) (yellow disulfide hydrazone dyes) in proportions such that the color obtained after the application of the composition to hair, rinsing and drying, makes it possible to obtain an aesthetic cover (natural, brown, with, if necessary, copper, iridescent, mahogany, matte, red, purple hues) sufficiently intense and stable.

The azo disulfide red dyes are particularly of the following general formula (III): ## STR1 ## as well as their addition salts with an organic or mineral acid, solvate, hydrates, tautomers, geometric isomers; formula (III) in which: R "independently of each other, represent a hydrogen atom or a group NR" "C (O) R" "

R ', R "', R" "and R" "independently of one another represent a hydrogen atom or a group optionally selected from C1-C14alkyl optionally substituted, C5-C10cycloalkyl optionally substituted; C2-C14alkyenyl optionally substituted; Optionally substituted C5-Cloaryl (C1-C10alkyl); C1-C10alkyl (C5-Cloaryl) optionally substituted; C5-C10aryl optionally substituted.

Lx independently of each other, represents a bivalent C1-C20, especially C1-C10, optionally substituted hydrocarbon-based chain, optionally interrupted by one or more divalent groups or combinations thereof, it being understood that two divalent groups or their combinations are interrupted by one or more divalent hydrocarbon chain at 02-06, especially alkylene, said divalent groups being chosen from ùN (R) -; -O-, -S-, -C (O) -, with R, represents a group selected from a hydrogen atom, a C1-C4 alkyl group, (poly) hydroxyalkyl at 02-06, alkoxy (C1- C6) alkyl, aryl such as phenyl, aryl (C1-C6) alkyl such as benzyl, (C1-C4) alkylcarbonylamino (C1-C6) alkyl, amino (C1-C4) alkyl whose amine is substituted by one or more identical or different C 1 -C 4 alkyl, C 1 -C 6 alkylcarbonyl and C 1 -C 4 alkylcarbonylamino radicals; The yellow hydrazone disulfide dyes are particularly of general formula (IV): ## STR1 ## as well as their addition salts with an organic or inorganic acid, solvate, hydrates, tautomers, geometric isomers; formula (IV) in which:

Rx and Ry independently of each other, represent a hydrogen atom, a halogen or a group selected from C1-C16alkyl optionally substituted, optionally interrupted by one or more heteroatoms, optionally substituted phenyl, Rz independently of each other, represent a hydrogen atom or a group NR "" C (O) R "", with R "" and R "" 'are as previously defined; Lx are as defined previously. If present, the content of additional disulfide dye (s) / thiol (s) in the composition generally ranges from 0.001 to 20% by weight relative to the weight of the composition, and preferably from 0.01 to 5% by weight. % by weight relative to the weight of the composition. The dye composition may contain one or more oxidation bases and / or one or more couplers conventionally used for dyeing keratinous fibers.

Among the oxidation bases that may be mentioned are para-phenylenediamines, bisphenylalkylenediamines, para-aminophenols, bis-para-aminophenols, ortho-aminophenols, heterocyclic bases and their addition salts. Among these couplers, mention may notably be made of meta-phenylenediamines, meta-aminophenols, meta-diphenols, naphthalenic couplers, heterocyclic couplers and their addition salts. The coupler or couplers are each generally present in an amount of between 0.001 and 10% by weight of the total weight of the dye composition, preferably between 0.005 and 6%. The oxidation base (s) present in the dyeing composition are in general each present in an amount of between 0.001% and 10% by weight relative to the total weight of the dyeing composition, preferably between 0.005% and 6% by weight.

In general, the addition salts of the oxidation bases and couplers that can be used in the context of the invention are chosen especially from the addition salts with an acid such as hydrochlorides, hydrobromides, sulphates, citrates, succinates, tartrates, lactates, tosylates, benzenesulfonates, phosphates and acetates and addition salts with a base such as alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, ammonia, amines or alkanolamines.

The medium suitable for dyeing, also called dyeing medium, is a cosmetic medium generally consisting of water or a mixture of water and at least one organic solvent. As organic solvent, there may be mentioned for example lower alkanols C1-C4, such as ethanol and isopropanol; polyols and polyol ethers such as 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and monomethyl ether, as well as aromatic alcohols such as benzyl alcohol or phenoxyethanol, and mixtures thereof.

The solvents when present are preferably present in proportions preferably of between 1 and 40% by weight approximately relative to the total weight of the dye composition, and even more preferably between 5 and 30% by weight approximately. The dye composition may also contain various adjuvants conventionally used in compositions for dyeing hair, such as anionic, cationic, nonionic, amphoteric, zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric and zwitterionic polymers. or mixtures thereof, inorganic or organic thickeners, and in particular anionic, cationic, nonionic and amphoteric polymeric associative thickeners, antioxidants, penetrating agents, sequestering agents, perfumes, buffers, dispersing agents, conditioning agents such as, for example, volatile or non-volatile silicones, modified or otherwise, such as aminosilicones, film-forming agents, ceramides, preserving agents, opacifying agents, conductive polymers.

The adjuvants above are generally present in an amount for each of them between 0.01 and 20% by weight relative to the weight of the composition. Of course, one skilled in the art will take care to choose this or these optional additional compounds in such a way that the advantageous properties intrinsically attached to the dyeing composition according to the invention are not, or not substantially, impaired by the or the additions envisaged. The pH of the dyeing composition is generally between 3 and 14 approximately, and preferably between 5 and 11 approximately. It can be adjusted to the desired value by means of acidifying or alkalizing agents usually used for dyeing keratin fibers or else using conventional buffer systems.

Among the acidifying agents, mention may be made, by way of example, of mineral or organic acids such as hydrochloric acid, orthophosphoric acid, sulfuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid, lactic acid, sulphonic acids. Among the alkalinizing agents that may be mentioned, by way of example, are ammonia, alkaline carbonates, alkanolamines such as mono-, di- and triethanolamines and their derivatives, sodium or potassium hydroxides and following formula (y): R ~ 1 R / at N-Wa-N

Ra4 Rai (Y) in which Wa is a propylene residue optionally substituted by a hydroxyl group or a C1-C4 alkyl radical; Ra1, Ra2, Ra3 and Ra4, which may be identical or different, represent a hydrogen atom, a C1-C4 alkyl radical or a C1-C4 hydroxyalkyl radical. The dye composition may be in various forms, such as in the form of liquid, cream, gel, or in any other form suitable for dyeing keratinous fibers, and in particular hair.

Another subject of the invention is a method for dyeing keratin fibers, such as the hair, comprising applying to said fibers a composition comprising at least one dye of formula (I) or (I '). According to a particular embodiment in the process of the invention, a reducing agent may be applied pre-treatment before the application of the composition containing at least one dye of formula (I) or (I '). This pretreatment may be of short duration, in particular from 0.1 second to 30 minutes, preferably from 1 minute to 15 minutes with a reducing agent as mentioned above. According to another method, the composition comprising at least one dye of formula (I) or (I ') and also contains at least one reducing agent as defined above. This composition is then applied to the hair. According to one variant, the reducing agent is added to the dyeing composition containing at least one dye of formula (I) or (I ') at the time of use. According to another method, the composition comprising at least one dye of formula (I) or (I ') also contains at least one reducing agent as defined above. This composition is then applied to the hair. According to another variant, the reducing agent is applied in post-treatment, after the application of the composition containing at least one dye of formula (I) or (I '). The duration of the post-treatment with the reducing agent may be short, for example from 0.1 second to 30 minutes, preferably from 1 minute to 15 minutes, with a reducing agent as described above. According to a particular embodiment, the reducing agent is a thiol or borohydride type agent as described above. A particular embodiment of the invention relates to a process in which the dye of formula (I) or (I ') can be applied directly to hair without reducing agents, free from pre or post-treatment reducers. A treatment with an oxidizing agent may optionally be associated. Any type of conventional oxidizing agent may be used in the art. Thus, it may be chosen from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulphates, as well as the enzymes among which may be mentioned peroxidases, oxides, 2-electron reductases such as uricases and 4-electron oxygenases such as laccases. The use of hydrogen peroxide is particularly preferred. The oxidative pause time can be between 0.01 and 40 minutes.

When the thiol dye of formula (I) or (I ') for which x and y are equal to 1 comprises a protecting group Y of the thiol function, the process of the invention consists of a deprotection step intended to restore the SH function.

By way of example, it is possible to deprotect the SY function of the dyes of the invention with the protective group by adjusting the pH as follows: Y: alkylcarbonyl deprotecting protecting group, pH> 9 arylcarbonyl pH> 9 alkoxycarbonyl pH> 9 aryloxycarbonyl pH > 9 Arylalkoxycarbonyl pH> 9 (di) (alkyl) aminocarbonyl pH> 9 (alkyl) arylaminocarbonyl pH> 9 optionally substituted aryl such as phenyl pH> 9 monocyclic 5-, 6- or 7-membered heteroaryl such as oxazolium pH> 9 8 to 11-membered fused heteroaryl such as pH> 9 benzoimidazolium or benzoxazolium The deprotection step can be carried out during a pretreatment stage of the hair, such as, for example, the hair reduction pretreatment. According to one variant, the deprotection step may be carried out post-treatment or at the same time as the coloration.

The application of the dye composition according to the invention is generally carried out at room temperature. It can however be carried out at temperatures ranging from 20 to 180 ° C. The invention also relates to a multi-compartment device or "kit" of dyeing in which a first compartment contains a dye composition comprising at least one dye of formula (I) or (I ') and a second compartment contains a reducing agent capable of reducing the disulfide functions of the keratin materials and / or of the disulfide dye of formula (I) or (I '). One of these compartments may further contain one or more other dyes of direct dye type or oxidation dye.

It also relates to a multi-compartment device in which a first compartment contains a dye composition comprising at least one dye of formula (I) or (I '); a second compartment contains a reducing agent capable of reducing the disulphide bond of the keratin materials and / or of the disulphide dye of formula (I) or (I '); a third compartment contains an oxidizing agent.

Alternatively, the dyeing device contains a first compartment containing a dyeing composition which comprises at least one protected thiol dye of formula (I) or (I ') with x and y being 1, a second compartment containing an agent capable of deprotecting the thiol protected to release the thiol, and optionally a third compartment comprising an oxidizing agent.

Each of the above-mentioned devices may be equipped with means for delivering the desired mixture onto the hair, for example such as the devices described in patent FR 2 586 913. The following examples serve to illustrate the invention without however to be limiting in nature. Synthesis Example Compound [1] Synthesis of 2,2 '- {disulfanediylbis [(1-oxobutane-4,1-diyl) imino-4,1-phenyleneimino-4,1-phenylenediazene-2,1-diyl] dichloride } bis (1,3-dimethyl-1H-imidazol-3-ium) ## STR2 ## [1] Synthesis scheme NH, O 2 N o N v ~ ~ S ~ SHH o N VN. Cl CI [1]

0.5 g of 2 - (- {4 - [(4-aminophenyl) amino] phenyl} diazenyl) -1,3-dimethyl-1H-imidazol-3-ium chloride are dispersed in 5 mL of water, 1.26 mL dihydrothiophen-2 (3H) -one (4-butyrothiolactone) are added to the mixture. Stirring is maintained at 80 ° C for 8h, with addition of 20 mg of potassium carbonate after 1 h. A precipitate is formed, it is filtered, taken up in 10 ml of methanol and 10 ml of ethanol, poured into 150 ml of ethyl acetate, refiltered and dried under vacuum. A dark blue glossy powder is collected. Analyzes show that the product conforms to the expected structure Coloring process - compound [1] Preparation of composition A Compound [1] 0.3 g Benzyl alcohol 4 g Polyethylene glycol 60E 6 g Hydroxyethylcellulose 0.7 g Alkylpolyglucoside in aqueous solution 4.5 g 65% MA Demineralized water qs 100g20 Preparation of a composition B Thioglycolic acid 1M Sodium hydroxide qsp pH 8, 5 Demineralized water qs 100g First dyeing process: One-time application At the time of use, the compositions are mixed A (9 mL) and B (1 mL), then apply the formulas on locks of natural white hair with 90% white (BN), permed white hair (BP). The exposure time is 20 minutes at room temperature. The locks are then rinsed, shampooed and dried.

Second coloring process: Two-step application Composition A is applied to strands of natural white hair (BN), of permed white hair (BP). The exposure time is 10 minutes at room temperature. The locks thus treated are rinsed with water.

Composition B is then applied to these same locks. The exposure time is 15 minutes at room temperature. The locks are then rinsed, shampooed and dried.

In both cases a blue color is obtained on white hair.

Light fastness and shampoo study: A light toughness study was carried out by exposure to Xenotest on the strands of natural white hair (BN) and white permed (BP) having been stained according to the two processes above for 3 hours. The exposure conditions are 90W / m2, 60% relative humidity and with a chamber temperature of 35 ° C of exposure.

The wicks once treated with the compositions according to the two above processes are shampooed according to 5 cycles of shampooing consisting of a shampoo, followed by rinsing with running water and finally drying in the air afterwards. This cycle is repeated 5 times. 65 In shampoos, there is no visible bleeding, shampoo foam and rinsing water are not colored.

It appears visually that the stains obtained by both methods together withstand exposure to light and shampoos.

Claims (21)

1. Dyestuff of formula (I) or (I '): [W1-N = N-W2-NR-W3-NR'-L-CH2-S] X - [Y] y An-formula (I) [W5 -NR-W2-N = N-W4-L-CH2-Six [Y] y An formula (I ') and their addition salts with an organic or inorganic acid, solvates, tautomers, optical and geometric isomers; formulas (I) and (I ') in which: W1 represents a cationic heteroaromatic radical chosen from the following formulas: 4 a (IV) W4 represents a heteroaromatic radical chosen from the following formulas: W2, identical, represent a carbon aromatic group of the following formula: (R3) m, (III) W3, represents a carbon aromatic group of the following formula: a ~ (R2) m 2 + W5 represents a carbon aromatic group of following formula: (VI) the bond from formulas (IIa), (IIb), (III), (Va) and (Vb) connects the groups W1, W2, and W4 to the azo group; in the case of the formulas (IIa), (IIb), (Va) and (Vb) when two radicals R2 carried by two adjacent carbon atoms form an aromatic ring such as benzyl, the link a may connect the group W1, W2 or W4 to the azo moiety through said aromatic ring; the bond resulting from the formulas (III), (IV) and (VI) connects the groups W2, W3 and W5 to -NR-, the bond b resulting from the formulas (Va) and (Vb) connects the group W4 to the arm of In the case of the L bond, the bond from formula (IV) linking the group W3 to -NR'- R and R 'independently of one another represents: a hydrogen atom or an alkyl group C1-C4 linear optionally substituted by a hydroxyl group; R1, is directly attached to the nitrogen atom, quaternized or not by means of a carbon atom and, independently of each other, represent a chosen grouping from: • an optionally substituted C1-C6 alkyl group • an optionally substituted aryl group • an optionally substituted heteroaryl group • an optionally substituted aryl (C1-C6) alkyl group • a heteroaryl (C1-C6) alkyl group optionally substituted • a cycloalkyl (C1-C6) alk group and a heterocycloalkyl (C1-C6) alkyl group; R2, R3, R4, and R5, independently of one another, represent: a C1-C4 alkyl group; • a hydroxyl group; • a C1-C4 alkoxy group; A (C 2 -C 4) poly (hydroxy) alkoxy group; An alkoxycarbonyl group (RaO-C (O) -) in which Ra represents a C1-C4 alkyl radical; An alkylcarbonyloxy group (RaC (O) -O-) in which Ra represents an alkyl radical is C1-C4; An amino group optionally substituted by one or more identical or different C1-C4 alkyl radicals optionally bearing at least one hydroxyl group, the two alkyl radicals possibly being able to form, with the nitrogen atom to which they are attached, a substituted or unsubstituted 5- or 6-membered heterocycle and optionally carrying another heteroatom identical to or different from nitrogen, for example oxygen; An alkylcarbonylamino group (RaC (O) -NR'a-) in which Ra represents a C1-C4 alkyl radical and R'a represents a hydrogen atom or a C1-C4 alkyl radical; A (di-) (alkyl) aminocarbonyl group ((Ra) 2 N-C (O)) in which the Ra radicals independently of each other, which may be identical or different, represent a hydrogen atom or a C 1 -C 4 alkyl radical; C4; A ureido group ((Ra) 2N-CO-NRb-) in which the radicals Ra and Rb, independently of one another, represent a hydrogen atom or a C1-C4 alkyl radical; A guanidinium group ((Ra) 2N-C (= NH 2 +) - NRb-) in which the radicals Ra and Rb, independently of each other, represent a hydrogen atom or a C 1 -C 4 alkyl radical; • a halogen atom; Or two adjacent R 2 radicals, two adjacent R 3 radicals, two adjacent R 4 radicals or two adjacent R 5 radicals may form, with the carbon atoms to which they are attached, a fused, aromatic 6-membered ring, optionally substituted by one or more the same or different groups selected from hydroxyl, C1-C4 alkyl, hydroxycarbonyl (HO (O) C-), alkoxy carbonyl (RaO (O) C-) wherein Ra represents a C1-C4 alkyl, (alkyl) sulfonylamino group (RaS (O) 2 NRb) in which Ra, represent a C1-C4 alkyl and Rb represents a hydrogen atom; a C1-C4 alkyl group; C1-C4 alkoxy; amino optionally substituted with one or two identical or different C1-C4 alkyl groups and optionally bearing at least one hydroxyl or methylcarbonylamino group, the two alkyl groups possibly being able to form, with the nitrogen atom to which they are attached, a heterocycle 5- or 6-membered ring optionally carrying another heteroatom identical to or different from nitrogen; m represents an integer inclusive between 0 and 4; when m is less than 4, then the carbon atom (s) of the unsubstituted aromatic ring (s) carry a hydrogen atom; M 'represents an integer inclusive between 0 and 4; when m 'is less than 4, then the carbon atom (s) of the unsubstituted aromatic ring (s) carry a hydrogen atom; m "is an integer from 0 to 5 inclusive; when m" is less than 15, then the carbon atom (s) of the unsubstituted aromatic ring (s) carry a hydrogen atom; e is an integer from 0 to 2; when e is less than 2, then the carbon atom (s) of the unsubstituted aromatic heterocycle (s) carry a hydrogen atom; L represents a covalent bond 6; a divalent group C (G) - with G representing an oxygen atom, sulfur atom, or a group - N (Alk) - where Alk represents a C 1 -C 4 alkyl group; or optionally substituted C1-C20 bivalent hydrocarbon chain, optionally interrupted by one or more divalent groups or combinations thereof, it being understood that two divalent groups or combinations thereof are separated by a divalent C1-C6 hydrocarbon chain, said divalent groups being selected from: i) ùN (R) -; -N + (R) (R o) -, An-; -O-, -S-, -C (O) -, with R, represents a group chosen from C1-C4 alkyl, (poly) hydroxyalkyl from 02-06, (C1-C6) alkoxyalkyl, aryl, aryl (C1-C6) alkyl, (C1-C4) alkylcarbonylamino (C1-C6) alkyl, amino (C1-C4) alkyl whose amine is substituted by one or more identical or different alkyl radicals C1-C4, alkyl ( C 1 -C 6) carbonyl and (C 1 -C 4) alkylcarbonylamino; and R ° represents a hydrogen atom or R; Ii) a cationic heterocycle or cationic heteroaryl Het +, An-, with As defined above and Het + representing a cationic heterocycle comprising from 5 to 10 members, saturated or unsaturated, or a cationic heteroaryl comprising from 5 to 10 members; iii) a non-cationic heterocyclic ring comprising from 5 to 10 ring members such as piperazinyl, and iv) an optionally substituted (hetero) aryl, with L not containing a diazo, hydrazino, aminooxy, nitro, nitroso or peroxide group; x represents 1 or 2; y represents 0 or 1; provided that when x = 1, then y = 1 and when x = 2 then y = 0; Y represents: either a hydrogen atom or a protecting group of thiol function; an alkali metal, an alkaline earth metal, an ammonium group (N + R 1 R R R TR ') or a phosphonium group (P + R R R R' R '), with R a, R', RT and R ', identical or different, representing a group (C 1 -C 4) alkyl; It being understood that the electroneutrality of the compounds of formula (I) or (I ') is ensured by one or more anionic counterions An, identical or different. 2. Dye of formula (I) according to the preceding claim wherein x and y are 1, and Y represents a hydrogen atom, or an alkali metal. 3. Dye of formula (1) according to claim 1 wherein x and y are 1, and Y represents a protective group. 4. Dye of formula (1) according to the preceding claim wherein Y 25 represents a protective group selected from the following radicals: ^ (C 1 -C 4) alkylcarbonyl; (C 1 -C 4) alkylthiocarbonyl; • (C 1 -C 4) alkoxycarbonyl; (C 1 -C 4) alkoxythiocarbonyl (C 1 -C 4) alkylthio thiocarbonyl • (di) (C 1 -C 4) (alkyl) aminocarbonyl; (Di) (C1-C4) (alkyl) aminothiocarbonyl; arylcarbonyl; Aryloxycarbonyl; • aryl (C 1 -C 4) alkoxycarbonyl; • (di) (C1-C4) (alkyl) aminocarbonyl; (C1-C4) (alkyl) aryiaminocarbonyl; Carboxy; --SO 3 M + with M + representing an alkali metal, or else An "of the formula (1) or (I ') and M + are absent, optionally substituted aryl, optionally substituted heteroaryls, optionally substituted heterocycloalkyl, optionally cationic; a group (N, N, N '- (tri -) (C1-C4 alkyl)) imidocarbamate: -C (= N'R'h) NR'; R 'wherein R'h, R'; R the same or different radicals represent a hydrogen atom or a (C 1 -C 4) alkyl group, an amidinium group: -C (= N '+ R'hRh), NR'; R 'An- in which R R 1, R ', R', R '1, which are identical or different, represent a (C 1 -C 4) alkyl group, and A 1 represents a counter-ion, • (di) aryl (C 1 -C 4) alkyl optionally substituted; optionally substituted C1- (di) heteroaryl (C1-C4) alkyl; CR1R2R3 with the same or different RI, R2 and R3, representing a halogen atom or a group selected from: - a hydrogen atom; -C4) alkyl optionally substituted with a C1-C4 alkoxy; - (C 1 -C 4) alkoxy; - optionally substituted aryl; optionally substituted heteroaryl; - -P (= Z1) R'1R'2R'3 with R'1, and R'2 identical or different represent a hydroxyl group, (C1-C4) alkoxy or alkyl, R'3 represents a hydroxyl group or ( C 1 -C 4) alkoxy, and Z 1 represents an oxygen or sulfur atom; Cyclic sterically hindered; and • optionally substituted alkoxyalkyl. 5. Colorant of formula (I) or (I ') according to any one of the preceding claims wherein Y is selected from hydrogen, a group - C (= NH) NH2, a group 2- (N- (C 3 -C 4) alkylpyridinium), (C 1 -C 4) alkoxycarbonyl and (C 1 -C 6) alkylcarbonyl. A disulfide dye of formula (I) or (I ') according to any one of the preceding claims wherein x = 2 and y = 0. 7. A dye of formula (I) or (I ') according to any one of the preceding claims wherein m = m' = e = 0 and m "is an integer equal to 0 or 1. 8. A dye of formula (I) or (I ') according to any one of the preceding claims belonging to any one of the following formulas: NR' H2 \ L_CSS H NR 2 2 An- (R4) mä (R3) m, ( R2) m R N (N) N N R1 (12) NR (13) NR ', SY L1C H2 (R3) m, (R4) m, NR An- (14) R (R 2) e CNIN NNR) ## STR2 ## wherein R (R) is NR (R), R (R), R (R), R (R), R (R), R (R), N (R) n An- NR NR (R 3) m '(R 5) m ((R 2) m 2 An-NR (1'2) (R NR 2 AN-NIN + ~ (R 2) m H2 NA / SS / C 1 L LC H2 AN- (R2) m I + LC H2 (R5) m, NR NR R-N (R2) e [> -N = N + (R3) m, 2 An- NAm 0'6) formulas in which R1, R2, R3, R4, R5, L, R, R ', Y, An-, m, m' and m "are as defined in any one of the preceding claims. 9. A dye of formula (I) or (I ') according to any preceding claim of the following chemical structure: OHN ~~~ S, SNHO 1 2An- O / ~ f Me HN ~ N SùS \ N- / NNHO Me 2 Me / + 3 Me 4 77 2 An- 5 SùH Me MeO 6 7 Me 9 SùH Me N + An-) - NN N Me 11 1213 14 Mes N, ùSnùMe Y Yr An NNN NH NH OMe OMe 15 16 NNHH NH NH N (CH 2 CH 2 OH) 2 N (CH 2 CH 2 OH) 2 17Me NN 3 / N + SiM N = Me, Me / Me AnN N N An An NH 18 e NH e OMe SiH 19 An NH OMe 20 N (CH 2 CH 2 OH ## STR2 ## SiH HO 32 33MeNNNN \ N Me An Me 34 SùH Me 35 An 36 NH 37 Me An 38 39 An ILN * NN * N NH OMe NH OMe 40N It N ~ i \ + O (H SùS MeO It N OMe 41 NN ## STR2 ## ## STR2 ## ## STR2 ## ## STR2 ## ## STR2 ## ## STR2 ## NH 2 NH (CH 2 CH 2 OH) 2 NH N (CH 2 CH 2 OH) 2 NH NH NH (CH 2 CH 2 OH) 2 N (CH 2 CH 2 OH) 2 N 86 N OH ## EQU1 ## With An-, representing an anionic counterion. 10. Dye composition comprising in a cosmetic medium, at least one dye of formula (I) or (I ') as defined in any one of claims 1 to 9. 11. Dyeing composition according to the preceding claim comprising in a cosmetic medium: at least one dye of formula (I) or (I ') as defined in any one of claims 1 to 9; o and at least one reducing agent. 12. Dyeing composition according to the preceding claim wherein the reducing agent is chosen from: cysteine, homocysteine, thiolactic acid, the salts of these thiols, phosphines, bisulfite, sulfites, thioglycolic acid, and its esters, borohydrides and their derivatives, sodium, lithium, potassium, calcium, quaternary ammonium salts and catecholborane. 13. Composition according to any one of claims 10 to 12, wherein the dye of formula (I) or (I ') is present in an amount of between 0.001 and 50% by weight relative to the total weight of the composition. 14. A process for dyeing keratinous fibers, wherein a suitable dye composition comprising at least one dye of formula (I) or (I ') according to any one of claims 10 to 13 is applied to the fibers. 15. The method of dyeing according to the preceding claim wherein when the dye of formula (I) or (I ') comprises a protective Y group, the application is preceded by a deprotection step. 16. A process according to any one of claims 14 or 15, wherein a reducing agent is applied before or after the application of the dye of formula (I) or (I ') as defined in claims 1 to 9. 17. The process according to any one of claims 14 to 16, wherein the composition comprises an oxidizing agent. 18. A method according to any one of claims 14 to 16 comprising a further step of applying to the keratin fibers an oxidizing agent. 15 19. A multi-compartment device in which a first compartment contains a dye composition comprising a dye of formula (I) or (I ') as defined in claims 1 to 9 and a second compartment contains a reducing agent. 20 20. Device according to the preceding claim comprising a third compartment which contains an oxidizing agent. 21. Use of dyes of formula (I) or (I ') as defined in claims 1 to 9 for dyeing keratinous fibers.