THIOL/DISULFIDE INDOLE-DERIVED, STYRYL DYE, DYE

COMPOSITION COMPRISING SAID DYE, PROCESS FOR LIGHTENING

KERATIN MATERIALS USING THIS DYE

The invention relates to the dyeing of keratin materials using thiol and disulfide, indole-derived, styryl fluorescent dyes.

It is known practice to dye keratin fibers, in particular human keratin fibers, by direct dyeing. The process conventionally used in direct dyeing comprises applying to the keratin fibers direct dyes which are colored or coloring molecules having an affinity for the fibers, allowing them to diffuse and then rinsing the fibers.

The direct dyes which are conventionally used are, for example, dyes of the nitrobenzene type, anthraquinone dyes, nitropyridine dyes, or dyes of the azo, xanthene, acridine, azine or triarlymethane type.

It is also known practice to use hemicyanin styryl direct dyes to powerfully dye keratin fibers. These benzothiazolium or benzoimidazolium heteroaryl-group dyes are, for example, those described in patent applications EP 1166753 and EP 1166757.

The coloring of keratin fibers using these conventional direct dyes does not make it possible to significantly lighten keratin fibers.

The lightening of the color of dark keratin fibers to lighter shades, by optionally modifying the shade thereof, constitutes an important demand.

Conventionally, in order to obtain a lighter coloring, a chemical bleaching process is used. This process comprises treating the keratin fibers, such as the hair, with a strong oxidizing system, generally

composed of hydrogen peroxide, possibly in combination with persalts, generally in an alkaline medium.

This bleaching system has the drawback of damaging the keratin fibers, in particular the hair, and of detrimentally affecting their cosmetic properties. The fibers in fact have a tendency to become rough, more difficult to disentangle and more brittle. Finally, the lightening or the bleaching of keratin fibers with oxidizing agents is incompatible with the treatments for modifying the shape of said fibers, particularly in hair straightening treatments.

Another lightening technique comprises applying fluorescent direct dyes to dark hair. This technique, described in particular in documents WO 03/028685 and

WO 2004/091473, makes it possible to retain the quality of the keratin fiber during the treatment. However, these fluorescent direct dyes do not exhibit satisfactory fastness with respect to outside agents.

In order to increase the fastness of direct colorings on light keratin fibers, it is known practice to use disulfide dyes, in particular azo-imidazolium chromophore dyes in patent applications WO 2005/097051 or EP 1647580, and pyridinium/indolizinium styryl chromophore dyes in patent applications WO 2006/134043 and WO 2006/136617. Patent application WO 2007/039527 discloses particular styrylthiol dyes for dyeing hair bearing an indole moiety substituted on the 1,2- position of the indole group. None of those documents mentions the problem of lightening keratin fibers without the use of chemical oxidation agents.

The aim of the present invention is to provide new systems for dyeing keratin materials, in particular human keratin fibers, especially the hair, which do not have the drawbacks of the existing bleaching processes.

In particular, one of the aims of the present invention is to provide direct dyeing systems for obtaining lightening effects, especially on naturally or artificially dark keratin fibers, which are resistant to successive shampooing operations, which do not damage the keratin fibers and which do not detrimentally affect their cosmetic properties.

Another aim of the invention is to dye keratin materials chromatically and in a manner which is persistent with respect to outside attacks.

This aim is achieved with the present invention, a subject of which is a process for dyeing keratin materials, in particular keratin fibers, especially human keratin fibers such as the hair, more particularly dark hair, comprising applying, to the keratin materials, a dye composition comprising, in a suitable cosmetic medium, at least one disulfide or thiol, indole derived sytryl fluorescent dye, chosen from the dyes of formulae (I) and (II) below:

the organic or mineral acid salts, optical isomers and geometric isomers thereof, and the solvates such as hydrates :

in which formulae (I) and (II)

> n represents 1 or 2 ;

> m represents 0 or 1;

- A -

> p represents an integer between 1 and 4 inclusive; ^ R ¹ and R ³ , which may be identical or different, represent a hydrogen atom or an optionally substituted (Ci-C ₆ ) alkyl group; in particular, R ¹ and R ³ represent a hydrogen atom or a methyl group;

> R ² , which may be identical or different, represents a hydrogen or halogen atom, a (di) (Ci-C ₆ ) (alkyl) amino, cyano, hydroxyl, (poly) halo (Ci-C ₆ ) alkyl such as trifluoromethyl, acyl (Ci-C ₄ ) (alkyl) amino, (Ci-C ₆ ) alkoxy, (Ci-C ₆ )- alkylthio, (poly) hydroxy (C ₂ -C ₆ ) alkoxy, (Ci-C ₆ )- alkylcarbonyloxy, (Ci-C ₆ ) alkoxycarbonyl, (Ci-C ₆ )- alkylcarbonylamino, carbamoyl, (Ci-C ₆ ) alkyl- sulfonyl (Ci-C ₄ ) (alkyl) amino, (Ci-C ₄ ) (di) (alkyl) - aminosulfonyl or carboxyl group, or a (Ci-Ci ₆ ) alkyl group optionally substituted with a group chosen from (Ci-C ₆ ) alkoxy and hydroxyl; or else, when p is an integer greater than or equal to 2, two contiguous radicalsR , with the carbon atoms which bear them, at position C ⁴ -C ⁵ or C ⁵ -C ⁶ or C ⁶ -C ⁷ , together form a benzo ring; in particular, R ² represents a hydrogen atom;

> Het ⁺ represents a cationic heteroaryl radical chosen from those of formulae (A) , (B) , (C) and (D) below:

in which formulae (A) , (B) , (C) and (D) :

- either the nitrogen atom N ¹ contained in the 5-membered ring of formula (A) is linked to the radical L of formula (I) , or the nitrogen atom N ¹ is linked to the radical R ¹ of formula (II) and then the bond a of the same

5-membered ring is linked to the styryl group in the cis or trans position with respect to the styryl double bond;

- either the nitrogen atom Ni of the 6-membered ring of formula (B) , (C) or (D) is linked to the radical L of formula (I) , or the nitrogen atom N ₁ is linked to the radical R ¹ of formula (II) and then the bond Jb of the same 6-membered ring is linked to the styryl in the cis or trans position with respect to the styryl double bond;

- Zi represents an oxygen, sulfur or selenium atom or a radical NR ⁷ ;

- Z ₂ represents a nitrogen atom or a radical CR ⁸ ;

- Z ₃ represents a nitrogen atom or a radical CR ⁹ ;

- Z ₄ represents a nitrogen atom or a radical CR ¹⁰ ; - it being understood that the two radicals Z ₃ and Z ₄ cannot simultaneously represent a nitrogen atom; and when Z ₁ represents an oxygen, sulfur or selenium atom, then Z ₂ represents a radical CR ⁸ ;

- R ⁵ , R ⁶ , R ⁸ , R ⁹ and R ¹⁰ , which may be identical or different, represent a hydrogen atom or a group chosen from: (Ci-Cβ) alkyl, (Ci-Cβ) alkoxy,

(Ci-Cβ) alkylthio, carboxyl, cyano, (di) (Ci-Cβ) (alkyl) amino, hydroxyl, polyhydroxy (Ci-Cβ) alkyl, polyhydroxy (Ci-Cβ) alkoxy, polyhalo (Ci-Cβ) alkyl such as trifluoromethyl, acyl (Ci-C ₄ ) (alkyl) amino, (Ci-Cβ) alkylcarbonyloxy, (Ci-Cβ) alkoxycarbonyl,

(Ci-Cβ) alkylcarbonylamino, carbamoyl,

(Ci-Cβ) alkylsulfonyl (C1-C4) (alkyl) amino and (di) (C1-C4) (alkyl) aminosulfonyl; or else two contiguous radicals R ⁴ with R ⁸ or R ⁵ with R ⁶

and/or R ⁶ with R ¹⁰ and/or R ⁹ with R ¹⁰ form, together with the carbon atoms which bear them, a benzo ring, a fused heterocycle which is optionally substituted or a fused heteroaryl which is optionally substituted; in particular, a benzo group; - R ⁷ represents a hydrogen atom or an optionally substituted (Ci-Cβ) alkyl group; in particular, Het ⁺ represents one of the three formulae (A), (B) and (D);

> Q ^" represents an anionic counterion;

> L represents an optionally substituted Ci-C ₂ O divalent hydrocarbon-based chain, optionally interrupted i) with one or more divalent groups or combinations thereof chosen from: -NR-; -N ⁺ RR ⁰ -, An ^" ; -O-, -S-, -C(O)- and -S(O) ₂ - with R, R ⁰ , which may be identical or different, chosen from a hydrogen, and a C ₁ -C ₄ alkyl, hydroxyalkyl or aminoalkyl radical, and An ^" representing an anionic counterion, or ii) with a cationic heterocycle or cationic heteroaryl Heti ⁺ , An ^" , with An ^" being an anionic counterion and Heti ⁺ representing a saturated or unsaturated heterocycle comprising from 5 to 10 members, or a heteroaryl comprising from 5 to 10 members, such as imidazolium, piperazinium, piperidinium, pyrrolidinium or benzoimidazolium; in particular, L represents a (Ci-Cβ) alkylene chain such as methylene, ethylene, propylene or butylene or - (CH ₂ )m _' -T _a - (CH ₂ )n _' - with m' and n' being integers between 1 and 6 inclusive, with the sum m'+n' being an integer between 2 and 6, and with T _a representing a linkage -NR-C(O)- or -C(O)-NR-;

^ Y represents: i) a hydrogen atom, ii) an alkali metal; iii) an alkaline earth metal; iv) an ammonium group: N ⁺ R ^α R R ^γ R , An'' ^" or a phosphonium group: P ⁺ R ^α R ^β R ^γ R ^δ , An'' ^" with R ^α , R ^β , R ^γ and R ^δ , which may be identical or different, representing a hydrogen atom or a (Ci-C ₄ ) alkyl group and An'' ^" an

anionic counterion; or v) a thiol-function- protecting group; it being understood that, when n is 2, then m is zero, and when n is 1, then m is 1.

Another subject of the invention is a dye composition for dyeing keratin materials such as dark hair, comprising, in a suitable cosmetic medium, at least one disulfide or thiol, indole-derived, styryl fluorescent dye (I) or (II) as defined above, and optionally a reducing agent.

A subject of the invention is also novel disulfide or thiol, indole-derived, styryl fluorescent dyes of formula (I) or (II) as defined above.

The dyeing process according to the invention makes it possible to visibly color dark keratin materials, in particular dark human keratin fibers, especially dark hair. Furthermore, the process of the invention makes it possible to obtain a coloring of the hair, without damaging it, which is persistent with respect to shampooing operations, common attacks (sunlight, perspiration) and other hair treatments. The process of the invention also makes it possible to obtain lightening of keratin materials such as keratin fibers, in particular dark keratin fibers, and more particularly dark hair.

Moreover, the new dyes according to the invention are particularly photostable. This process also makes it possible to dye bleached keratin fibers in a powerful, relatively nonselective, homogenous and chromatic manner .

For the purpose of the present invention, the term "dark keratin material" is intended to mean that which exhibits a lightness L* measured in the C. I. E. L*a*b* system of less than or equal to 45, and preferably less

than or equal to 40, given that, moreover, L* = 0 is equivalent to black and L* = 100 is equivalent to white .

For the purpose of the invention, the expression

"naturally or artificially dark hair" is intended to mean whose tone height is less than or equal to 6 (dark blond) and preferably less than or equal to 4

(chestnut-brown) .

The lightening of the hair is evaluated by the variation in "tone height" before and after application of the compound of formula (I) or (II) . The notion of "tone" is based on the classification of the natural shades, one tone separating each shade from the shade immediately following or preceding it. This definition and the classification of the natural shades are well known to hair styling professionals and are published in the book "Science des traitements capillaires" [Hair Treatment Sciences], by Charles Zviak 1988, published by Masson, pp. 215 and 278.

The tone heights range from 1 (black) to 10 (very light blond), one unit corresponding to one tone; the higher the figure, the lighter the shade.

An artificially colored hair is a hair whose color has been modified by a dyeing treatment, for example dyeing with direct dyes or oxidation dyes.

For the purpose of the invention, the term "bleached hair" is intended to mean hair whose tone height is greater than 6 and preferably greater than 8.

One means for measuring the lightening effect given to the hair after application of the fluorescent dyes of the invention is to use the phenomenon of hair reflectance .

Preferably, the composition should, after application to dark hair, lead to the results below.

Interest is focused on the hair reflectance performance levels when said hair is irradiated with visible light in the wavelength range from 400 to 700 nanometers.

The curves of reflectance as a function of wavelength, of the hair treated with the composition of the invention and of untreated hair, are then compared.

The curve corresponding to the treated hair should show a reflectance in the wavelength range of from 500 to 700 nanometers which is higher than the curve corresponding to the untreated hair.

This means that, in the wavelength range of from 540 to 700 nanometers, there is at least one range where the reflectance curve corresponding to the treated hair is higher than the reflectance curve corresponding to the untreated hair. The term "higher" is intended to mean a difference of at least 0.05% in reflectance, and preferably of at least 0.1%. All the same, there may be, in the wavelength range of from 540 to 700 nanometers, at least one range where the reflectance curve corresponding to the treated hair is superimposable on or lower than the reflectance curve corresponding to the untreated hair.

Preferably, the wavelength where the difference is at a maximum between the reflectance curve of the treated hair and that of the untreated hair is within the wavelength range of from 500 to 650 nanometers, and preferably within the wavelength range of from 550 to 620 nanometers.

For the purpose of the present invention, and unless otherwise indicated:

the "aryl" or "heteroaryl" radicals or the aryl or heteroaryl part of a radical may be substituted with at least one substituent chosen from:

• a C1-C16, preferably Ci-Cs, alkyl radical optionally substituted with one or more radicals chosen from the radicals: hydroxyl, C1-C2 alkoxy, C2-C4 (poly) hydroxyalkoxy, acylamino and amino substituted with two Ci-C ₄ alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, or the two radicals possibly forming, with the nitrogen atom to which they are attached, a heterocycle comprising from 5 to 7 members, preferably 5 or 6 members, which is saturated or unsaturated, which is optionally substituted, and which optionally comprises another heteroatom which may be identical or different from the nitrogen;

• a halogen atom such as chlorine, fluorine or bromine; • a hydroxyl group;

• a C1-C2 alkoxy radical;

• C1-C2 alkylthio radical;

• a C2-C4 (poly) hydroxyalkoxy radical;

• an amino radical; • a 5- or 6-membered heterocycloalkyl radical;

• an optionally cationic 5- or 6-membered heteroaryl radical, preferably imidazolium, optionally substituted with a Ci-C ₄ alkyl radical, preferably methyl; • an amino radical substituted with one or two Ci-Cβ alkyl radicals, which may be identical or different, optionally bearing at least: i) one hydroxyl group, ii) one amino group optionally substituted with one or two optionally substituted C1-C3 alkyl radicals, said alkyl radicals possibly forming, with the nitrogen atom to which they are attached, a heterocycle comprising from 5 to 7 members, which is saturated or

unsaturated, which is optionally substituted, and which optionally comprises at least one other heteroatom which may or may not be different from nitrogen, • -NR-C(O)R' in which the R radical is a hydrogen atom or a C1-C4 alkyl radical optionally bearing at least one hydroxyl group, and the R' radical is a C1-C2 alkyl radical;

. R ₂ N-C(O)- in which the R radicals, which may or may not be identical, represent a hydrogen atom, or a C1-C4 alkyl radical optionally bearing at least one hydroxyl group;

• R' S (0) 2-NR- in which the R radical represents a hydrogen atom or a C1-C4 alkyl radical optionally bearing at least one hydroxyl group, and the R' radical represents a Ci-C ₄ alkyl radical or a phenyl radical;

• R ₂ N-S(O) ₂ - in which the R radicals, which may or may not be identical, represent a hydrogen atom or a Ci-C ₄ alkyl radical optionally bearing at least one hydroxyl group,

• a carboxylic radical in acid or salified form (preferably with an alkali metal or an ammonium, which is substituted or unsubstituted) ; • a cyano group;

• a polyhaloalkyl group containing from 1 to 6 carbon atoms and from 1 to 6 halogen atoms, which may be identical or different; the polyhaloalkyl group is, for example, trifluoromethyl; - the cyclic or heterocyclic part of a nonaromatic radical may be substituted with at least one substituent, chosen from the groups: . hydroxyl;

• Ci-C ₄ alkoxy; • C ₂ -C ₄ (poly) hydroxyalkoxy;

• a Ci-C ₂ alkylthio radical;

.RC(O)-N(R')- in which the R' radical is a hydrogen atom or a Ci-C ₄ alkyl radical optionally bearing at least one hydroxyl group, and the R

radical is a C1-C2 alkyl radical or an amino radical substituted with two Ci-C ₄ alkyl groups, which may be identical or different, optionally bearing at least one hydroxyl group; .RC(O)-O- in which the R radical is a Ci-C ₄ alkyl radical or an amino radical substituted with one or two Ci-C ₄ alkyl groups, which may be identical or different, optionally bearing at least one hydroxyl group, said alkyl radicals possibly forming, with the nitrogen atom to which they are attached, a heterocycle comprising from 5 to 7 members, which is saturated or unsaturated, which is optionally substituted, and which optionally comprises at least one other heteroatom which may or may not be different from nitrogen;

.RO-C(O)- in which the R radical is a Ci-C ₄ alkyl radical optionally bearing at least one hydroxyl group; a cyclic or heterocyclic radical or a nonaromatic part of an aryl or heteroaryl radical may also be substituted with one or more oxo or thioxo groups; an "aryl" radical represents a condensed or noncondensed, monocyclic or polycyclic group containing from 6 to 22 carbon atoms, and at least one ring of which is aromatic; preferably, the aryl radical is a phenyl, biphenyl, naphthyl, indenyl, anthracenyl or tetrahydronaphthyl; a "diarylalkyl" radical represents a group comprising, on the same carbon atom of an alkyl group, two aryl groups, which may be identical or different, such as diphenylmethyl or 1,1- diphenylethyl ; a "heteroaryl radical" represents an optionally cationic, condensed or noncondensed, monocyclic or polycyclic group comprising from 5 to 22 members and from 1 to 6 heteroatoms chosen from a nitrogen, oxygen, sulfur and selenium atom, and at least one ring of which is aromatic; preferably, a heteroaryl radical is chosen from acridinyl,

benzimidazolyl, benzobistriazolyl, benzopyrazolyl, benzopyridazinyl, benzoquinolyl, benzothiazolyl, benzotriazolyl, benzoxazolyl, pyridinyl, tetrazolyl, dihydrothiazolyl, imidazopyridinyl, imidazolyl, indolyl, isoquinolyl, naphthoimidazolyl, naphthooxazolyl, naphthopyrazolyl, oxadiazolyl, oxazolyl, oxazolopyridyl, phenazinyl, phenooxazolyl, pyrazinyl, pyrazolyl, pyrilyl, pyrazoyltriazyl, pyridyl, pyridinoimidazolyl, pyrrolyl, quinolyl, tetrazolyl, thiadiazolyl, thiazolyl, thiazolopyridinyl, thiazoylimidazolyl, thiopyrylyl, triazolyl, xanthylyl and its ammonium salt; a "diheteroarylalkyl" radical represents a group comprising, on the same carbon atom of an alkyl group, two heteroaryl groups, which may be identical or different, such as difurylmethyl, 1, 1-difurylethyl, dipyrrolylmethyl or dithienylmethyl ; a "cyclic radical" is a condensed or noncondensed, monocyclic or polycyclic, nonaromatic cycloalkyl radical containing from 5 to 22 carbon atoms, possibly comprising one or more unsaturations; in particular, the cyclic radical is a cyclohexyl; a "sterically hindered cyclic" radical is a substituted or unsubstituted, aromatic or nonaromatic, cyclic radical hindered by steric effect or constraint, comprising from 6 to 14 members, which may be bridged; by way of sterically hindered radicals, mention may be made of bicyclo [ 1.1.0 ] butane, mesityls such as 1,3,5- trimethylphenyl, 1, 3, 5-tri-tert-butylphenyl, 1, 3, 5-isobutylphenyl, 1, 3, 5-trimethylsilylphenyl and adamantyl; a "heterocyclic radical or heterocycle" is a condensed or noncondensed, monocyclic or polycyclic, nonaromatic radical containing from 5 to 22 members, comprising from 1 to 6 heteroatoms

chosen from nitrogen, oxygen, sulfur and selenium; an "alkyl radical" is a linear or branched, C1-C16, preferably Ci-Cs, hydrocarbon-based radical; the expression "optionally substituted" assigned to the alkyl radical implies that said alkyl radical may be substituted with one or more radicals chosen from the radicals: i) hydroxyl; ii) C1-C4 alkoxy; iii) acylamino; iv) amino optionally substituted with one or two Ci-C ₄ alkyl radicals, which may be identical or different, said alkyl radicals possibly forming, with the nitrogen atom which bears them, a heterocycle comprising from 5 to 7 members, optionally comprising another heteroatom which may or may not be different from nitrogen; v) or a quaternary ammonium group -N ⁺ R' R' ' R' ' ' , M ^" for which R', R'', R' ' ' , which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl group, or else -N ⁺ R' R' 'R''' forms a heteroaryl such as imidazolium optionally substituted with a Ci-C ₄ alkyl group, and M ^~ represents the counterion of the corresponding organic acid, mineral acid or halide; an "alkoxy radical" is an alkyloxy or alkyl-O- radical for which the alkyl radical is a linear or branched, C1-C16, preferably Ci-Cs, hydrocarbon- based radical; an "alkylthio radical" is an alkyl-S- radical for which the alkyl radical is a linear or branched, C1-C16, preferably Ci-Cs, hydrocarbon-based radical; when the alkylthio group is optionally substituted, this implies that the alkyl group is optionally substituted as defined above; the limits delimiting the extent of the range of values are included in this range of values; an "organic or mineral acid salt" is more particularly chosen from a salt derived: i) from hydrochloric acid HCl; ii) from hydrobromic acid HBr; iii) from sulfuric acid H ₂ SO ₄ ; iv) from

alkylsulfonic acids: AIk-S (O) 2OH such as methylsulfonic acid and ethylsulfonic acid; v) from arylsulfonic acids: Ar-S(O) ₂ θH such as from benzenesulfonic acid and from toluenesulfonic acid; vi) from citric acid; vii) from succinic acid; viii) from tartaric acid; ix) from lactic acid; x) from alkoxysulfinic acids: AIk-O-S(O)OH such as from methoxysulfinic acid and from ethoxysulfinic acid; xi) from aryloxysulfinic acids such as from tolueneoxysulfinic acid and from phenoxysulfinic acid; xii) from phosphoric acid H ₃ PO ₄ ; xiii) from acetic acid CH ₃ C(O)OH; xiv) from triflic acid CF ₃ SO ₃ H and xv) from tetrafluoroboric acid HBF ₄ ; - an "anionic counterion" is an anion or an anionic group associated with the cationic charge of the dye; more particularly, the anionic counterion is chosen from: i) halides such as chloride or bromide; ii) nitrates; iii) sulfonates, among which are Ci-C ₆ alkyl sulfonates: AIk-S(O) ₂ O ^" such as methyl sulfonate or mesylate and ethyl sulfonate; iv) aryl sulfonates: Ar-S(O) ₂ O- such as benzene sulfonate and toluenesulfonate or tosylate; v) citrate; vi) succinate; vii) tartrate; viii) lactate; ix) alkyl sulfates: AIk- 0-S(0)0 ^~ such as methyl sulfate and ethyl sulfate; x) arylsulfates : Ar-O-S (0)0 ^~ such as benzenesulfate and toluenesulfate; xi) alkoxysulfates : AIk-O- S(O) ₂ O- such as methoxy sulfate and ethoxy sulfate; xii) aryloxysulfates : Ar-O-S(O) ₂ O-; xiii) phosphate; xiv) acetate; xv) triflate; and xvi) borates such as tetrafluoroborate; the "solvates" represent the hydrates and also the association with linear or branched Ci-C ₄ alcohols such as ethanol, isopropanol or n-propanol.

The disulfide or thiol, indole-derived, styryl fluorescent dyes of formula (I) or (II) as defined above are fluoresent dyes, i.e. capable of absorbing in

the UV radiation or visible range at a wavelength γ _abs of between 250 and 800 nm and capable of re-emitting in the visible range at an emission wavelength γ _em of between 400 and 800 nm.

Preferably, the fluorescent compounds of formula (I) or (II) of the invention are dyes capable of absorbing in the visible range γ _abs of between 400 and 800 nm and of re-emitting in the visible range γ _em of between 400 and 800 nm. More preferably, the dyes of formula (I) or (II) are dyes capable of absorbing at a γ _abs of between 420 and 550 nm and of re-emitting in the visible range at a γ _em of between 470 and 600 nm.

The compounds of the invention of formula (I) or (II) where n and m are 1 contain an SY function which may be in the covalent form -S-Y or ionic form -S ^~ Y ⁺ depending on the nature of Y and on the pH of the medium.

A specific embodiment relates to the disulfide or thiol, indole-derived, styryl fluorescent dyes of formula (I) or (II) with n and m equal to 1 and where Y represents a hydrogen atom or an alkali metal. Advantageously, Y represents a hydrogen atom.

In accordance with another specific embodiment of the invention, in the abovementioned formula (I) or (II) , Y is a protecting group known to those skilled in the art, for instance those described in the books "Protective Groups in Organic Synthesis", T. W. Greene, John Wiley & Sons Ed., NY, 1981, pp. 193-217; "Protecting Groups", P. Kocienski, Thieme, 3rd Ed., 2005, Chap. 5. It being understood that Y as protective group cannot constitute with the sulphur atom on which it is linked a disulfide dye i.e. cannot constitute a formula (I) or (II) in which n=m=l . Y as protective group cannot represent a group directly linked to the sulphur atom of formula (I) and (II) via another non oxidized sulphur atom.

Particularly when Y represents a thiol-function- protecting group, Y is chosen from the following radicals :

^■ (Ci-C ₄ ) alkylcarbonyl;

■ (Ci-C ₄ ) alkylthiocarbonyl;

^■ (Ci-C ₄ ) alkoxycarbonyl;

^■ (Ci-C ₄ ) alkoxythiocarbonyl;

■ (Ci-C ₄ ) alkylthiothiocarbonyl; ■ (di) (Ci-C ₄ ) (alkyl) aminocarbonyl;

^■ (di) (Ci-C ₄ ) (alkyl) aminothiocarbonyl;

■ arylcarbonyl such as phenylcarbonyl;

^■ aryloxycarbonyl;

■ aryl (Ci-C ₄ ) alkoxycarbonyl; ■ (di) (Ci-C ₄ ) (alkyl) aminocarbonyl such as dimethylaminocarbonyl ;

^■ (Ci-C ₄ ) (alkyl) arylaminocarbonyl;

^■ carboxyl

^■ SO ₃ , M ⁺ with M ⁺ representing an alkali metal such as sodium or potassium, or else Q ^~ or An ' ^~ of formula

(I) or (II) and M ⁺ are absent;

^■ optionally substituted aryl such as phenyl, dibenzosuberyl or 1, 3, 5-cycloheptatrienyl;

^■ optionally substituted heteroaryl; including in particular the cationic or noncationic heteroaryl comprising from 1 to 4 heteroatoms below: i) monocyclic comprising 5, 6 or 7 members, such as furanyl or furyl, pyrrolyl or pyrryl, thiophenyl or thienyl, pyrazolyl, oxazolyl, oxazolium, isoxazolyl, isoxazolium, thiazolyl, thiazolium, isothiazolyl, isothiazolium, 1, 2, 4-triazolyl, 1,2,4- triazolium, 1, 2, 3-triazolyl, 1,2,3- triazolium, 1, 2, 4-oxazolyl, 1, 2, 4-oxazolium, 1, 2, 4-thiadiazolyl, 1, 2, 4-thiadiazolium, pyrylium, thiopyridyl, pyridinium, pyrimidinyl, pyrimidinium, pyrazinyl, pyrazinium, pyridazinyl, pyridazinium, triazinyl, triazinium, tetrazinyl,

tetrazinium, azepine, azepinium, oxazepinyl, oxazepinium, thiepinyl, thiepinium, imidazolyl, imidazolium; ii) bicyclic comprising 8 to 11 members, such as indolyl, indolinium, benzoimidazolyl, benzoimidazolium, benzoxazolyl, benzoxazolium, dihydrobenzoxazolinyl, benzothiazolyl, benzothiazolium, pyridoimidazolyl, pyridoimidazolium, thienocycloheptadienyl, these monocyclic or bicyclic groups being optionally substituted with one or more groups such as (Ci-C ₄ ) alkyl, for instance methyl, or polyhalo (Ci-C ₄ ) alkyl, for instance trifluoromethyl; iϋ) or tricyclic ABC below:

in which the two rings A, C optionally comprise a heteroatom, and the ring B is a

5-, 6- or 7-membered, particularly 6-membered ring and contains at least one heteroatom, for instance piperidyl or pyranyl; optionally cationic, optionally substituted heterocycloalkyl, the heterocycloalkyl group represents in particular a saturated or partially saturated, 5-, 6- or 7-membered monocyclic group comprising from 1 to 4 heteroatoms chosen from oxygen, sulfur and nitrogen, such as di/tetrahydrofuranyl, di/tetrahydrothiophenyl, di/tetrahydropyrrolyl, di/tetrahydropyranyl, di/tetra/hexahydrothiopyranyl, dihydropyridyl, piperazinyl, piperidinyl, tetramethylpiperidinyl, morpholinyl, di/tetra/hexahydroazepinyl or di/tetrahydropyrimidinyl, these groups being optionally substituted with one or more groups such as (Ci-C ₄ ) alkyl, oxo or thioxo; or the heterocycle

represents the following group:

in which R' ^c , R' ^d , R' ^e , R' ^f , R' ^g and R' ^h , which may be identical or different, represent a hydrogen atom or a (Ci-C ₄ ) alkyl group, or else two groups R' ^g with R' ^h , and/or R' ^e with R' ^f , form an oxo or thioxo group, or else R' ^g with R' ^e together form a cycloalkyl; and v represents an integer between 1 and 3 inclusive; preferably, R' ^c to R' ^h represent a hydrogen atom; and An' ' ' represents a counterion;

^■ isothiouronium;

-C (NR' ^c R' ^d )=N ⁺ R' ^e R' ^f ; An ^" with R' ^c , R' ^d , R' ^e and R' ^f , which may be identical or different, represent a hydrogen atom or a (Ci-C ₄ ) alkyl group; preferably, R' ^c to R' ^f represent a hydrogen atom; and An''' ^" represents a counterion;

^■ isothiourea; ■ -C (NR' ^c R' ^d )=NR' ^e ; with R' ^c , R' ^d and R' ^e as defined above;

^■ optionally substituted (di) aryl (Ci-C ₄ ) alkyl, such as 9-anthracenylmethyl, phenylmethyl or diphenylmethyl optionally substituted with one or more groups in particular chosen from (Ci-C ₄ ) alkyl, (Ci-C ₄ ) alkoxy such as methoxy, hydroxyl, alkylcarbonyl and (di) (Ci-C ₄ ) (alkyl) amino such as dimethylamino;

^■ optionally substituted (di) heteroaryl (Ci-C ₄ ) alkyl, the heteroaryl group is in particular cationic or noncationic, and monocyclic, comprising 5 or 6 members and from 1 to 4 heteroatoms chosen from nitrogen, oxygen and sulfur, such as the groups pyrrolyl, furanyl, thiophenyl, pyridyl, pyridyl N-oxide such as 4-pyridyl or 2-pyridyl N-oxide,

pyrylium, pyridinium or triazinyl, optionally substituted with one or more groups such as alkyl, particularly methyl, advantageously the

(di) heteroaryl (Ci-C ₄ ) alkyl is (di) heteroarylmethyl or (di) heteroarylethyl;

^■ CR 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:

(Ci-C ₄ ) alkyl; - (Ci-C ₄ ) alkoxy; optionally substituted aryl, such as phenyl optionally substituted with one or more groups such as (Ci-C ₄ ) alkyl, (Ci- C ₄ ) alkoxy or hydroxyl; - optionally substituted heteroaryl, such as thiophenyl, furanyl, pyrrolyl, pyranyl or pyridyl, optionally substituted with a (Ci-C ₄ ) alkyl group; P (Z ¹ ) R' ¹ R' ² R' ³ with R' ¹ and R' ² , which may be identical or different, representing a hydroxyl, (Ci-C ₄ ) alkoxy or alkyl group, R' ³ representing a hydroxyl or (Ci- C ₄ ) alkoxy group and Z ¹ representing an oxygen or sulfur atom; ■ a sterically hindered cyclic; and

^■ optionally substituted alkoxyalkyl, such as methoxymethyl (MOM) , ethoxyethyl (EOM) or isobutoxymethyl .

According to a specific embodiment, the protected thiol dyes of formula (I) or (II) for which m and n are 1, comprising a group Y i) which is a cationic, aromatic 5- or 6-membered monocyclic heteroaryl group comprising from 1 to 4 heteroatoms chosen from oxygen, sulfur and nitrogen, such as oxazolium, isoxazolium, thiazolium, isothiazolium, 1, 2, 4-triazolium, 1, 2, 3-triazolium, 1, 2, 4-oxazolium, 1, 2, 4-thiadiazolium, pyrylium, pyridinium, pyrimidinium, pyrazinyl, pyrazinium, pyridazinium, triazinium, tetrazinium, oxazepinium,

thiepinyl, thiepinium or imidazolium; ii) cationic 8- to 11-membered bicyclic heteroaryl group, such as indolinium, benzoimidazolium, benzoxazolium or benzothiazolium, these monocyclic or bicyclic heteroaryl groups being optionally substituted with one or more groups such as alkyl, for instance methyl, or polyhalo (Ci-C ₄ ) alkyl, for instance trifluoromethyl; iii) or heterocyclic group below:

in which R' ^c and R' ^d , which may be identical or different, represent a hydrogen atom or a (Ci-C ₄ ) alkyl group; preferably, R' ^c to R' ^d represent a (Ci-C ₄ ) alkyl group such as methyl; and An''' represents an anionic counterion .

In particular, Y represents a group chosen from oxazolium, isoxazolium, thiazolium, isothiazolium, 1, 2, 4-triazolium, 1, 2, 3-triazolium, 1, 2, 4-oxazolium, 1 , 2 , 4-thiadiazolium, pyrylium, pyridinium, pyrimidinium, pyrazinium, pyridazinium, triazinium and imidazolium, benzoimidazolium, benzoxazolium, benzothiazolium, these groups being optionally substituted with one or more (Ci-C ₄ ) alkyl groups, in particular methyl.

In particular, Y represents an alkali metal or a protecting group such as: > (Ci-C ₄ ) alkylcarbonyl, such as methylcarbonyl or ethylcarbonyl ;

> arylcarbonyl such as phenylcarbonyl;

> (Ci-C ₄ ) alkoxycarbonyl;

> aryloxycarbonyl; > aryl (Ci-C ₄ ) alkoxycarbonyl;

> (di) (Ci-C ₄ ) (alkyl) aminocarbonyl such as dimethylaminocarbonyl ;

> (Ci-C ₄ ) (alkyl) arylaminocarbonyl;

> optionally substituted aryl, such as phenyl; > 5- or 6-membered monocyclic heteroaryl, such as imidazolyl or pyridyl;

> 5- or 6-membered cationic monocyclic heteroaryl, such as pyrylium, pyridinium, pyrimidinium, pyrazinium, pyridazinium, triazinium or imidazolium; these groups being optionally substituted with one or more identical or different (Ci-C ₄ ) alkyl groups, such as methyl;

> 8- to 11-membered cationic bicyclic heteroaryl, such as benzoimidazolium or benzoxazolium; these groups being optionally substituted with one or more identical or different (Ci-C ₄ ) alkyl groups, such as methyl; ^ cationic heterocycle of the following formula:

> isothiouronium;

> C (NH ₂ ) =N+H ₂ ; An' ' ' ^" ;

> isothiourea; > -C (NH ₂ ) =NH;

> SO ₃ , M ⁺ with M ⁺ representing an alkali metal such as sodium or potassium, or else Q ^~ or An' ^~ of formula (I) or (II) and M ⁺ are absent.

According to a specific embodiment of the invention, the dyes of formula (I) or (II) are disulfide dyes with n = 2 and m = 0.

By way of example, mention may be made of the following dyes of formula (I) or (II)

with An , which may be identical or different, representing an anionic counterion.

For all the exemplary embodiments, which follow, of preparation of the new indole-derived thiol and disulfide styryl fluorescent dyes of formulae (I) and (II) , those skilled in the art know how to pre-protect the reactive functions such as ketone functions, and then deprotect them for the needs of the synthesis reaction, by the known conventional methods of

protection/deprotection such as those described in the books mentioned above by T. W Greene John Willey & Sons ed., NY, 1981, or P. Kocienski "Protecting Groups", P. Kocienski, Thieme, 3rd ed., 2005.

The protected thiol dyes of formula (I—Y) or (II—Y) for which m and n are 1 can be synthesized in two stages. The first stage consists in preparing the nonprotected thiol dye (I-H) or (II-H) according to the methods known to those skilled in the art, for instance "Thiols and organic sulfides", "Thiocyanates and isothiocyanates, organic", Ullmann' s Encyclopedia, Wiley-VCH, Weinheim, 2005. In addition, the second step consists in protecting the thiol function according to the conventional methods known to those skilled in the art in order to produce the protected thiol dyes of formula (I-Y) or (II-Y) . By way of example, for protecting the thiol function -SH of the thiol dye, use may be made of the methods in the books "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. This method can be illustrated by means of the method consisting i) in generating thiol, indole-derived, styryl fluorescent dyes of formula (I-H) or (II-H) by reduction of an indole-derived, styryl, two-chromophore fluorescent dye bearing a disulfide function -S-S- such as (I-S) or (II-S) and ii) in protecting said thiol function of (I-H) or (II-Y) , according to the conventional methods, with the reactant 7 Y' R in order to obtain the protected thiol, indole-derived, styryl fluorescent dyes of formula (I—Y) or (II—Y) . The thiol compound (I-H) or (II-H) may also be metallated with an alkali metal or alkaline earth metal Met* so as to produce the thiolate dye of formula (I-Met) or (II- Met) .

with Y' representing a thiol-function-protecting group; Met* representing an alkali metal or an alkaline earth metal, particularly sodium or potassium, it being understood that, when the metal is an alkaline earth metal, 2 chromophores comprising a thiolate -S ^~ function can be associated with 1 Metal ²⁺ ; and with R ¹ to R ³ , Het ⁺ , L and Q ^~ being as defined above; Y' represents a thiol-function-protecting group; and R represents a nucelofuge leaving group, for instance mesylate, tosylate, triflate or halide.

According to another possibility, a protected thiol compound (b) protected with a protecting group Y' as defined above, prepared according to one of the procedures described in the books described above, said protected thiol compound comprising at least one nucleophilic function, can be reacted with a sufficient, preferably equimolar, amount of an indole- derived, styryl fluorescent chromophore (a) or (ai) , and which comprises an electrophilic function, so as to form a ∑ covalent bond; see below, the preparation of dyes of formula (l ^' -Y) and (Il ^' -Y) :

with R ¹ to R ³ , Het ⁺ and Q as defined above; m' and n' being integers between 1 and 6 inclusive, with the sum m' + n' being an integer between 2 and 6; Nu

representing a nucleophilic group; E representing an electrophilic group; and σ representing the link generated after attack by the nucleophile on the electrophile .

By way of example, the σ covalent bonds that can be generated are listed in the table below based on condensation of electrophiles with nucleophiles :

*the activated esters of general formula -CO-Part with Part representing a leaving group such as oxysuccinimidyl, oxybenzotriazolyl, aryloxy which is optionally substituted;

**the acyl nitrides may rearrange to give isocyanates .

A variant to this process is to use an indole-derived, styryl fluorescent chromophore having an electrophilic acrylate function (-OCO-C=C-) on which is carried out an addition reaction that will generate a σ bond.

It is also possible to use a thiol reactant (α) : Y' -SH comprising a Y' group as defined above, the nucleophilic SH function of which can react with the carbon atom of the radical L in the α-position with respect to the halogen atom borne by an indole-derived, styryl fluorescent chromophore (a' ) or (a' i) , so as to give the protected thiol dye of formula (I-Y) or (II-Y) as defined above:

with R ₁ to R ₃ , Het\ L, p and Q ^" (I-Y) and (H-Y) as defined above, and Hal representing a nucleofuge halogen atom such as bromine, iodine or chlorine.

More particularly, a nucleofuge leaving group may be replaced with a derivative of a thiourea (S=C (NRR) NRR) so as to generate isothiouroniums; for example, based on chromophores (a' ) or (a' 1) as defined above if the thiourea group is a thioimidazolium (β) , to give the dye which is S-protected with an imidazolium group (I' '-Y) or (H' '-Y) :

with (a ¹ ) , (a'l) , R' _c , R' _d , R ¹ to R ^J , Het ⁺ , L, p, Q ^" , Hal and An ^" as defined above.

Another variant may make it possible to obtain the compound (I''—Y) or (II''—Y) from the cyclic thiourea derivative of imidazoline type (b^_) , followed by alkylation of said imidazoline using R' _d -Lg, with Lg being a leaving group such as chloride, bromide, tosylate or mesylate:

with R' _c , R' _d , R ¹ to R ³ , Het ⁺ , p, L, (a'), (a'l), Q ^" , Hal and Lg as defined above.

A variant is to use, in place of the halide comprising the indole-derived, styryl fluorescent chromophore (a' ) or (a' 1) , a chromophore comprising another type of nucleofuge such as tosylate or mesylate.

In accordance with another possibility, certain protected thiol dyes (I' -Y) or (II' -Y) can be obtained by reacting a protected thiol compound with a compound bearing two carboxylic acid functions that are activated, according to the conventional methods (for example, reaction with a carbodiimide or with thionyl chloride) . The resulting product (d) or (dl) is subsequently reacted with an indole-derived, styryl fluorescent chromophore (c) or (cl) , bearing a nucleophilic function (c) , for example of primary or secondary amine type, or of aliphatic alcohol type.

with R ¹ to R ^J Het^ L, p, m' n' Q ^" , E, Nu, (l ^' -Y) and

( II ' -Y) as def ined above .

Another variant is to use a thiolactone derivative based on specific nucleophilic chromophores (c' ) and (c' i) so as to give the derivatives (I' -H) or (II' -H) comprising a linker L interrupted with an amide function as represented by the scheme below:

With R to R , Het ⁺ , Q , p, n' and m' as defined above, G' representing an oxygen or sulfur atom or an NR' group with R' representing a hydrogen atom or a alkyl radical, and R representing a hydrogen atom, a Ci-C ₄ alkyl radical, a C1-C4 hydroxyalkyl radical or an aryl (Ci-C ₄ ) alkyl . The thiolactone derivative is preferably chosen with n' = 3 and G' represents an oxygen atom.

The derivatives (I'—H) or (II'—H) comprising a free SH function can subsequently be protected or metallated as seen above.

In accordance with another possibility, the protected thiol dyes of formula (1'''-Y) and (11'''-Y) can be obtained by reaction of a compound (d' ) comprising a thiol group protected with a Y' group, and a nucleofuge leaving group Lg, for instance mesylate, tosylate, triflate or halide, with an indole-derived, styryl fluorescent chromophore (c' ) or (c' '

With R ¹ to R ³ , Het\ L, p and Q ^" as defined above, and Het of the reactant (c' ' ) representing a group chosen from (A'), (B'), (C) and (D'):

With ^1/ Z ₂ , Z ₃ and ώ4 as defined above, or representing the bond which links the groups (A' ) to

(D' to the styryl radical of and Z' representing a hydrogen atom or a group which activates the nucleophilicity of the nitrogen atom of the indole of (Ci' ' ) . The activating group Z' is conventionally used by those skilled in the art to activate a nitrogen atom contained in a heteroaryl such as indole. In a nonexhaustive manner, mention may be made of Z' representing an alkali metal such as sodium, lithium or potassium, or a magnesium compound MgX, with X representing a halogen atom such as bromine; it being understood that the use of reactants comprising Li, K, Na or MgX is carried out once the other functions capable of reacting with these same reactants have been pre-protected according to the methods as described in "Protective Groups in Organic Synthesis", T. W. Greene,

John Willey & Sons ed., NY, 1981, or "Protecting Groups", P. Kocienski, Thieme, 3rd ed., 2005.

By way of example, compounds containing a protected thiol group (1'''-Y) or (11'''-Y) contain a nucleofuge leaving group R, for instance mesylate, tosylate or triflate, which can undergo nucleophilic attack from the amine of the indole-derived styryl fluorescent chromophore (c' ) or (c' ' ) as follows:

In accordance with another possibility, the indole- derived, styryl thiol dyes of formula (I) or (II) according to the invention can be obtained by reaction of a compound comprising a thiol group possibly protected with Y' as defined above and an electophilic group (f) or (f' ) , with an indole-derived compound comprising a nucleophilic group. By way of example, it is possible to condense an aldehyde or a thioaldehyde when G' represents an oxygen or sulfur atom, with an "activated methylene" such as the cationic heteroaryl derivative (e) or (e' ) bearing an activated methyl group linked to Het ⁺ via the bond a or b of group (A) , (B) , (C) or (D) so as to generate an ethylene bond >C=C< . This reaction is commonly referred to as "Knoevenagel" condensation:

with R ¹ to R ³ , L, Q ^" , p, (I-Y) and (H-Y) as defined above and Het ⁺ being as defined above, except that, for (e) and (e' ) , the methyl group is borne by the bond a or b of group (A) , (B) , (C) or (D) .

The starting reactants are commercially available or accessible by the conventional methods known to those skilled in the art.

By way of example, it is possible to synthesize the reactant (II—S) using 2 equivalents of indole derivative 1. optionally activated on the nitrogen atom of the indole Z', and one equivalent of disulfide reactant comprising two leaving groups Lg, so as to give the derivative bearing two -C(G')- disulfide functions 3_ _j _ which can in turn be condensed with two equivalents of cationic heteroaryl compound Het ⁺ comprising an activated methyl group 4_, so as to give (H-S) .

with R ¹ , R ² , R ³ , p, L, Het ⁺ and Q as defined above, Z' representing a hydrogen atom or a group which activates the nucleophilicity of the nitrogen atom of the indole, and Lg representing a nucleofuge leaving group, for instance mesylate, tosylate, triflate, alkoxy or halide .

It is also possible to synthesize the reactant (I-S) using 2 equivalents of heteroaryl derivative Het comprising a methyl group, so as to give the disulfide derivative _5 which can in turn be condensed with two equivalents of indole derivative bearing two functions -C ( G' ) - 6 , so as to give ( I-S) .

With Het representing a group chosen from (A' ) , (B' ) , (C ) and (D ' ) :

where Z ₁ , Z ₂ , Z ₃ and Z ₄ are as defined above, a or b represents the bond which links the groups (A' ) to (D' ) to the methyl group of the reactant Het-CH ₃ ; R ¹ , R ² , R ³ , p, L and Het ⁺ are as defined above; and Lg ^" represents the counterion subsequent to the departure of Lg such as mesylate, tosylate, triflate alk-O ^~ , or halide. The counterions Lg ^" of the compounds of the invention, above, can be replaced with counterions Q ^~ of other types, using methods known to those skilled in the art, in particular by ion-exchange resin.

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

The thiol, indole-derived, styryl fluorescent dyes formed can be converted to -S Y' protected thiol fluorescent dyes by protection of the -SH thiol using the conventional protecting groups. The thiol, indole- derived, styryl dyes are metallated by also using the 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, indole-derived, styryl fluorescent dyes can be deprotected by conventional pathways such as those described in the books "Protective Groups in

Organic Synthesis", T. W. Greene, John Willey & Sons

Ed., NY, 1981; "Protecting Groups", P. Kocienski, Thieme, 3rd Ed. , 2005.

The composition of the invention contains at least one disulfide, thiol or protected thiol, indole-derived styryl fluorescent dye of formula (I) or (II) . In addition to the presence of at least one dye of formula (I) or (II) , the composition of the invention may also contain at least one reducing agent.

This reducing agent may be chosen from thiols, for example cysteine, homocysteine or thiolactic acid, the salts of these thiols, phosphines, bisulfite, sulfites, thioglycolic acid, and also its esters, in particular glyceryl monothioglycolate, and thioglycerol . This reducing agent may also be chosen from borohydrides and derivatives thereof, for instance the salts of borohydride, of cyanoborohydride, of triacetoxyborohydride or of trimethoxyborohydride : sodium salts, lithium salts, potassium salts, calcium salts, quaternary ammonium (tetramethylammonium, tetraethylammonium, tetra-n-butylammonium or benzyltriethylammonium) salts; and catechol borane.

The dye composition that can be used in the invention generally contains an amount of fluorescent dye of formula (I) or (II) 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 dye composition may also contain additional direct dyes. These direct dyes are, for example, chosen from neutral, acidic or cationic nitrobenzene direct dyes, neutral, acidic or cationic azo direct dyes, tetraazapentamethine dyes, neutral, acidic or cationic quinone, in particular anthraquinone dyes, azine direct

dyes, triarylmethane direct dyes, indoamine direct dyes and natural direct dyes.

Among the natural direct dyes, mention may be made of lawsone, juglone, alizarin, purpurin, carminic acid, kermesic acid, purpurogallin, protocatechaldehyde, indigo, isatin, curcumin, spinulosin and apigenindin.

Extracts or decoctions containing these natural dyes, and in particular poultices or henna-based extracts, may also be used.

The dye composition may contain one or more oxidation bases and/or one or more couplers conventionally used for dyeing keratin fibers.

Among the oxidation bases, mention may be made of para- phenylenediamines, bisphenylalkylenediamines, para- aminophenols, bis-para-aminophenols, ortho- aminophenols, heterocyclic bases, and addition salts thereof.

Among these couplers, mention may in particular be made of meta-phenylenediamines, meta-aminophenols, meta- diphenols, naphthalene couplers, heterocyclic couplers, and addition salts thereof.

The coupler (s) is (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 dye composition is

(are) in general each 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% by weight .

In general, the addition salts of the oxidation bases and of the couplers that can be used in the context of

- A A - the invention are in particular chosen from addition salts with an acid, such as hydrochlorides, hydrobromides, sulfates, citrates, succinates, tartrates, lactates, tosylates, benzenesulfonates, phosphates and acetates, and addition salts with a base, such as hydroxides of an alkali metal such as sodium or potassium, aqueous ammonia, amines or alkanolamines .

The medium suitable for dyeing, also called dye support, is a cosmetic medium generally constituted of water or of a mixture of water and at least one organic solvent. By way of organic solvent, mention may, for example, be made of Ci-C ₄ lower 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 diethylene glycol monomethyl ether, and also aromatic alcohols such as benzyl alcohol or phenoxyethanol, and mixtures thereof.

The solvents, when they are present, are preferably present in proportions of preferably 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 hair-dyeing compositions, such as anionic, cationic, nonionic, amphoteric or zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic polymers, or blends thereof, mineral or organic thickeners, and in particular anionic, cationic, nonionic and amphoteric associative polymer thickeners, antioxidants, penetrating agents, sequestering agents, fragrances, buffers, dispersing agents, conditioning agents such as, for example, modified or unmodified, volatile or nonvolatile silicones, such as amino

silicones, film-forming agents, ceramides, preservatives, opacifiers or conductive polymers.

The above adjuvants are in general present in an amount, for each of them, of between 0.01% and 20% by weight relative to the weight of the composition.

Of course, those skilled in the art will take care to select this or these possible additional compounds in such a way that the advantageous properties intrinsically associated with the dye composition in accordance with the invention are not, or are not substantially, impaired by the addition (s) envisaged.

The pH of the dye composition is generally between 3 and 14 approximately, and preferably between 5 and 11 approximately. It may be adjusted to the desired value by means of acidifying or basifying agents normally used in the dyeing of keratin fibers or else by means of conventional buffer systems.

Among the acidifying agents, mention may, by way of example, be made of mineral or organic acids, such as hydrochloric acid, orthophosphoric acid, sulfuric acid, carboxylic acids, for instance acetic acid, tartaric acid, citric acid or lactic acid, or sulfonic acids.

Among the basifying agents, mention may, by way of example, be made of aqueous ammonia, alkali carbonates, alkanolamines such as mono-, di- and triethanolamines, and also derivatives thereof, sodium hydroxide or potassium hydroxide and the compounds of formula (γ) below:

in which W _a is a propylene residue optionally substituted with a hydroxyl group or a Ci-C ₄ alkyl radical; R _a i, R _a 2, Ra3 and R _a4 , which may be identical or different, represent a hydrogen atom, a Ci-C ₄ alkyl radical or a Ci-C ₄ hydroxyalkyl radical.

The dye composition may be in various forms, such as in the form of a liquid, a cream or a gel, or in any other form suitable for dyeing keratin fibers, and in particular the hair.

A subject of the invention is also a process for dyeing keratin materials, in particular keratin fibers, more particularly dark hair, consisting in applying thereto a dye composition comprising, in a cosmetic medium, at least one indole-derived, disulfide or thiol styryl fluorescent dye chosen from the fluorescent dyes of formulae (I) and (II) as defined above.

According to a specific embodiment, in the process of the invention, a reducing agent may also be applied as a pretreatment before the application of the composition containing at least one indole-derived, styryl fluorescent dye of formula (I) or (II) .

This pretreatment may be of short duration, in particular from 1 second to 30 minutes, preferably from 1 minute to 15 minutes, with a reducing agent as mentioned above.

According to another process, the composition comprising at least one indole-derived, styryl fluorescent dye of formula (I) or (II) also contains at least one reducing agent as defined above. This composition is then applied to the hair.

When the indole-derived, styryl thiol fluorescent dye of formula (II) for which m and n are 1 comprises a thiol-function-protecting group Y, the process of the

invention may be preceded by a deprotection step aimed at restoring the SH function in situ.

By way of example, it is possible to deprotect the S-Y function of the dyes of the invention with a Y protecting group by adjusting the pH as follows:

The deprotection step can also be carried out during a hair pretreatment step, for instance reducing pretreatment of the hair.

According to one variant, the reducing agent is added to the dye composition containing at least one indole- derived, styryl fluorescent dye of formula (I) or (II) at the time of use.

According to another process, the composition comprising at least one indole-derived, styryl fluorescent dye of formula (I) or (II) 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 as a post-treatment, after the application of the composition containing at least one indole-derived, styryl fluorescent dye of formula (I) or (II) . The duration of the post-treatment with the reducing agent may be short, for example from 1 second to 30 minutes, preferably from 1 minute to 15 minutes, with a reducing agent as described above. According to a specific embodiment, the reducing agent is an agent of thiol or borohydride type as described above.

A specific embodiment of the invention relates to a process in which the indole-derived, styryl fluorescent dye of formula (I) or (II) can be applied directly to the hair without reducing agents, free of reducing pretreatment or reducing post-treatment.

A treatment with an oxidizing agent may optionally be combined. In a specific embodiment the process of the invention comprises an additional step consisting in applying an oxidizing agent to the keratin fibers.

Any type of oxidizing agent conventional in the field may be used. Thus, it may be chosen from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulfates, and also enzymes, among which mention may be made of peroxidases, 2-electron oxidoreductases such as uricases and 4-electron oxygenases such as laccases. The use of hydrogen peroxide is particularly preferred.

The duration of the possible post-treatment with an oxidizing agent is between 1 second and 10 minutes.

The application of the dye composition according to the invention is generally carried out at ambient temperature. It may, however, be carried out at temperatures ranging from 20 to 180 ⁰ C.

A subject of the invention is also a multicompartment dyeing device or dyeing "kit" in which a first compartment contains a dye composition comprising at least one indole-derived, styryl fluorescent dye of formula (I) or (II) and a second compartment contains a reducing agent capable of reducing the disulfide functions of keratin materials and/or of the indole- derived, styryl disulfide fluorescent dye of formula (I) or (II) .

One of these compartments may also contain one or more other dyes of direct dye or oxidation dye type.

The invention also relates to a multicompartment device in which a first compartment contains a dye composition comprising at least one indole-derived, styryl fluorescent dye of formula (I) or (II); a second compartment contains a reducing agent capable of reducing the disulfide bond of keratin materials and/or of the indole-derived, styryl disulfide fluorescent dye of formula (I) or (II) ; and a third compartment contains an oxidizing agent.

Alternatively, the dyeing device contains a first compartment containing a dye composition which comprises at least one protected thiol, indole-derived, styryl fluorescent dye of formula (I) or (II) where m and n are 1 and a second compartment containing an agent capable of deprotecting the protected thiol so as to free the thiol, and optionally a third compartment comprising an oxidizing agent.

Each of the devices mentioned above may be equipped with a means for delivering the desired mixture to the

hair, for example such as the devices described in patent FR 2 586 913.

The examples which follow serve to illustrate the invention without, however, being limiting in nature. The thiol fluorescent dyes of the examples hereinafter have been entirely characterized by conventional spectroscopic and spectrometric methods.

EXAMPLES

SYNTHESIS EXAMPLES

Example 1 : Synthesis of 1, 1 ' - (disulfanediyldiethane- 2,l-diyl)bis{4-[2-(l-methyl-lH-indol-3-yl)vinyl]- pyridinium}dimethane sulfonate [1]

Synthesis scheme :

Procedure :

Stage 1: Synthesis of disulfanediyldiethane-2, 1-diyl dimethanesulfonate

10 g of 2,2' -dithiodiethanol and 14.44 g of triethylamine (TEA) are diluted in 100 ml of ethyl acetate (EtOAc). At 0 ⁰ C, 16.35 g of methanesulfonyl chloride diluted in 35 ml of ethyl acetate are added dropwise to the reaction medium with vigorous stirring. 7.22 g of triethylamine are introduced, and the stirring is continued at ambient temperature for 4 h 30. 8.2 g of methanesulfonyl chloride are added dropwise at 15°C, and then the stirring is maintained at ambient temperature for 17 h. The precipitate is filtered off and washed with 3 times 50 ml of ethyl acetate. The organic phases are extracted with 100 ml

of ice-cold water, 100 ml of water, 3 times 50 ml of a saturated solution of sodium hydrogen carbonate (NaHCOs) and with 2 times 20 ml of a saturated solution of sodium chloride (NaCl), and are then dried over anhydrous sodium sulfate (Na2SO ₄ ) .

The ethyl acetate is evaporated off, and 17.49 g of a translucent pale yellow oil are recovered. The analyses show that the product is in conformity and pure.

Stage 2: Synthesis of 1, 1 ' - (disulfanediyldiethane- 2, l-diyl)bis (4-methylpyridinium) dimethanesulfonate

3.51 g of 4-picoline and 5 g of disulfanediyldiethane- 2,1-diyl dimethanesulfonate are diluted in 5 ml of N-methylpyrrolidinone (NMP) and then heated at 80 ⁰ C for 2 h with stirring. The stirring is maintained at ambient temperature for 17 h. The reaction medium is made up with 50 ml of ethyl acetate, and the resulting mixture is then filtered, washed with 3 times 100 ml of ethyl acetate and dried under vacuum in the presence of P2O5. 7.29 g of brown powder are recovered. The analyses indicate that the product is in conformity and pure.

Stage 3: Synthesis of 1, 1 '- (disulfanediyldiethane- 2,l-diyl)bis{4-[2-(l-methyl-lH-indol-3-yl)vinyl]- pyridinium} dimethanesulfonate [1]

1.22 g of l-methyl-lH-indole-3-carbaldehyde, 8 ml of isopropanol and 630 μl of pyrrolidine are mixed with stirring for 10 minutes. 440 μl of acetic acid are added and the mixture is left at ambient temperature for 20 minutes with stirring. 1.91 g of 1,1'- (disulfanediyldiethane-2, 1-diyl) bis (4-methylpyridinium) dimethanesulfonate in 7 ml of isopropanol are added to the reaction mixture, which is kept stirring for 3 days at ambient temperature. The reaction mixture is poured into 55 ml of ethyl acetate, it is filtered and washed with 50 ml of ethyl acetate and then dried. 2.4 g of dark green powder are

recovered. The analyses indicate that the product is in conformity and pure.

¹ H NMR (400 MHz, MeOH-d ₄ ) 2.71 (s, 6 H), 3.31 (t, 4 H), 3.75 (s, 6 H), 4.64 (t, 4 H), 7.02 (d, 2 H), 7.28 (2 t, 4 H), 7.38 (d, 2 H), 7.67 (s, 2 H), 7.87 (d, 4 H), 7.96 (d, 2 H) 7.98 (d, 2 H), 8.45 (d, 4 H).

Exemple 2 : Synthesis of 4, 4 ' -{disulfanediyl- bis [ethane-2, 1-diylimino (2-oxoethane-2, 1-diyl) (2- methyl-lH-indole-l,3-diyl)ethene-2, 1-diyl] }bis(l- methylpyridinium) bis tosylate [2]

Synthesis scheme :

Stage 1 : Synthesis of N, N'- (disulfanediyldiethane-2, 1- diyl) bis [2- (3-formyl-2-methyl-lH-indol-l-yl) acetamide]

10.43 g of 2-methyl-lH-indole-3-carbaldehyde are solubilized in 80 mL DMSO at room temperature, 7.8 g potassium tertiobutylate are added to the solution and the resulting mixture is heated at 100 ⁰ C then cooled back to room temperature. A solution of 10 g of N, N'-

(disulfanediyldiethane-2, l-diyl)bis (2-chloroacetamide) in 80 mL DMSO is added. After stirring for 3h, the mixture is poured on 1.5L water, pH brought to 6.8 by addition of IN aqueous hydrochloric acid 150 mL of saturated aqueous sodium chloride solution are added. The resulting precipitate is washed three times with 100 mL water, twice with 100 mL diethyl ether. It is dried, washed with acetone at room temperature, stirred in 100 mL refluxing acetone for Ih, cooled and filtered after 1 day, washed again twice with 50 mL acetone. 9.47 g of solid are obtained. Analyses are in accordance with the expected structure. The product is used for following steps without further purification

Stage 2 : Synthesis of 4, 4 ' -{disulfanediylbis [ethane- 2, 1-diylimino (2-oxoethane-2, 1-diyl) (2-methyl-lH-indole- 1, 3-diyl)ethene-2, 1-diyl] }bis (1-methylpyridinium) bis tosylate

0.55g of N, N'- (disulfanediyldiethane-2, l-diyl)bis [2- (3- formyl-2-methyl-lH-indol-l-yl) -acetamide] and 0.56 g of 4-methylpicolinium tosylate were mixed inlO mL ethanol and 5 mL JV-methylpyrrolidinone (NMP) . After 10 min. lOOμL piperidine were added and the mixture was stirred at 80 ⁰ C for 24h. After cooling, it was poured on 100 mL acetone. The resulting solid was filtered, washed with acetone and dried (576 mg - brownish orange powder) . Analyses were in accordance with the expected structure LCMS m/z = 365.5 (dication) λ _max : 438 nm.

DYEING EXAMPLE

Dyeing process - compound [1]

Preparation of a composition A

Preparation of a composition B

At the time of use, compositions A (9 ml) and B (1 ml) are mixed, then the formulations are applied to locks of natural white hair containing 90% white hairs (NW) , permanent-waved white hair (PW) or chestnut-brown hair having a tone height of 4 (TH4) . The leave-in time is 20 minutes at ambient temperature (AT) .

After rinsing with running water, a fixer (Dulcia Vital II®) diluted 10-fold with water is applied for 5 minutes at AT. After rinsing with running water and shampooing, the locks are air-dried. During the shampooing operations, there is no visible bleeding of the color; the shampoo foam and the rinsing water are uncolored.

(i) Dyeing Optical lightening on dark locks:

Lightening of the hair thus treated with dye 1 is observed: the locks of tone height 4 have become visually lighter than untreated control locks.

The lightening effectiveness of the compositions in accordance with the invention and their fastness with respect to successive shampooing operations were also expressed as a function of the reflectance of the hair. These reflectances are compared with the reflectance of a lock of untreated hair of tone height TH4.

The reflectance is measured by means of a KONIKA- MINOLTA ^® , CM 360Od spectrophotocolorimeter apparatus and after irradiation of the hair with visible light in the wavelength range of from 400 to 700 nanometers.

It is noted that the reflectance of a lock of hair treated with compositions according to the invention comprising compound [1] and [2] is greater than that of untreated hair (reference / Dark hair TH4) . The treated locks therefore appear to be lighter.

Dyeing of NW and PW white locks

The natural white (NW) hair and permanent-waved (PW) white hair are colored bright orange.

ii) Fastness with respect to successive shampooing operations :

The locks treated are divided into two, half are subjected to 5 successive shampooing operations according to a cycle which comprises wetting the locks with water, washing with a conventional shampoo, rinsing with water, followed by drying.

Results: Visual observations

During the shampooing operations, there is no visible bleeding of the color; the shampoo foam and the rinsing water are not colored.

The color observed and the lightening effect remain visible on the hair of tone height 4 thus treated.

iii) Fastness with respect to light:

A study of light-fastness was carried out, by exposure to the Xenotest, on the locks of natural white (NW) and permanent-waved white (PW) hair dyed beforehand

according to the dyeing process, for 3 hours. The exposure conditions are 90 W/m ² , 60% relative humidity and with a chamber temperature of 35 ⁰ C.

Results: Visual observations

After 3 hours of exposure to the light, the natural white hair and the permanent-waved white hair dyed with the dye of the invention are virtually unchanged.

The results show that the colorings done with dye 1 of the invention have a very satisfactory light-fastness.