阅读说明：本技术 用于染色角蛋白材料的带有脂族链和二硫化物/硫醇/受保护硫醇官能团的荧光直接染料 (Fluorescent direct dyes with aliphatic chains and disulfide/thiol/protected thiol functional groups for dyeing keratin materials ) 是由 C.布莱斯 V.伯克布克勒 于 2018-05-09 设计创作，主要内容包括：本发明涉及一种用于使用至少一种下式(I)的荧光直接染料染色和/或增亮角蛋白材料、特别是角蛋白纤维、优选人角蛋白纤维如头发的方法,所述荧光直接染料带有二硫化物、硫醇或受保护硫醇官能团并且包含至少一个脂族链：A-(X)p-C<Sub>sat</Sub>-S-U。本发明还涉及i)至少一种带有二硫化物、硫醇或受保护硫醇官能团的荧光直接染料(I)与ii)用于拉直角蛋白纤维的蒸汽和/或加热夹板组合用于染色和增亮角蛋白材料的用途,并且涉及下式(I)的带有二硫化物、硫醇或受保护硫醇官能团的新颖的荧光直接染料：A-(X)p-C<Sub>sat</Sub>-S-U,以及还有一种包含所述荧光直接染料的化妆品组合物。所使用的方法和式(I)的硫醇、受保护硫醇或二硫化物荧光直接染料与蒸汽组合使用使得尤其能够在角蛋白材料上获得具有护理效价的持久着色。(The present invention relates to a process for dyeing and/or lightening keratin materials, in particular keratin fibres, preferably human keratin fibres such as the hair, using at least one fluorescent direct dye of formula (I) below, bearing a disulfide, thiol or protected thiol function and comprising at least one aliphatic chain: a- (X) p-C sat -S-U. The invention also relates to the use of I) at least one fluorescent direct dye (I) having a disulfide, thiol or protected thiol function in combination with ii) steam and/or heated splints for straightening keratin fibres for dyeing and lightening keratin materials, and to the use of such a dyeNovel fluorescent direct dyes bearing a disulfide, thiol or protected thiol function of formula (I): a- (X) p-C sat -S-U, and also a cosmetic composition comprising said fluorescent direct dye. The method used and the use of the thiol, protected thiol or disulfide fluorescent direct dyes of formula (I) in combination with steam enable durable colourations with care titres to be obtained, in particular on keratin materials.)

1. A process for dyeing keratin materials, in particular keratin fibres, preferably human keratin fibres such as the hair, comprising the application to the said materials of one or more cationic, anionic, neutral or zwitterionic, preferably cationic, fluorescent direct dyes bearing a disulfide function or a thiol or protected thiol function, of formula (I):

A-(X)_p-C_sat-S-U (I)

a salt thereof with an organic or inorganic acid or base, an optical or geometric isomer thereof, a tautomer thereof, and a solvate thereof such as a hydrate;

in formula (I):

u represents a group selected from: a) -S-C'_sat-(X′)_p′-a'; and b) -Y;

a and A', which may be identical or different, represent cationic, anionic, nonionic or zwitterionic, preferably cationic, fluorescent chromophores, it being understood that at least one of the two chromophores carries at least one linear or branched, saturated or unsaturated C₁₀-C₃₀An aliphatic chain, preferably at least one of the two chromophores A and/or A', carries at least one ammonium group with a linear or branched, saturated or unsaturated C₁₀-C₃₀An aliphatic chain;

y represents i) a hydrogen atom; or ii) a thiol functional group protecting group;

x and X', which may be identical or different, represent a divalent C which may be linear or branched, saturated or unsaturated₁-C₃₀A hydrocarbon-based chain, optionally interrupted by one or more divalent groups selected from the following or combinations thereof and/or optionally terminated at one or both ends of the chain by one or more divalent groups selected from the following or combinations thereof:

-N(R)-、-N⁺(R)(R^o) -, -O-, -C (O) -, -S (O) -, and-S (O)₂-, wherein R and R^oWhich may be identical or different, are selected from hydrogen and C₁-C₄Alkyl, hydroxyalkyl or aminoalkyl groups;

an aromatic or non-aromatic, saturated or unsaturated, fused or non-fused (hetero) cyclic group optionally comprising one or more identical or different, optionally substituted, heteroatoms;

p and p', which may be identical or different, are equal to 0 or 1, preferably equal to 0;

·C_satand C'_satWhich may be identical or different, represent an optionally cyclic, optionally substituted, linear or branched C₁-C₁₈An alkylene chain;

it will be appreciated that the electroneutrality of the compounds of formula (I) can be ensured by one or more anionic or respectively cationic counterions, depending on whether the dye is cationic or respectively anionic.

2. Process according to the preceding claim, wherein the dye of formula (I) is a disulphide dye, wherein U represents a group a) -S-C'_sat-(X′)_p′-a'; in particular, the dyes of formula (I) are disulfides and are symmetrical, i.e. formula (I) has the following formula:

A-(X)_p-C_sat-S-S-C′_sat-(X′)_p′-a ', wherein a ═ a', X ═ X ', p ═ p', C_sat＝C′_sat。

3. Process according to claim 1, in which the dye of formula (I) is a dye bearing a thiol or protected thiol function, i.e. U represents a group b) Y as defined in the preceding claim, in particular Y represents a hydrogen atom.

4. The method according to any one of the preceding claims, wherein the dye of formula (I) is of C_satAnd C'_satThe dye of (1), the dye C_satAnd C'_satMay be the same or different and represents a chain- (CH)₂)_k-, where k is an integer from 1 to 8 inclusive.

5. Process according to any one of the preceding claims, in which the dye of formula (I) is a dye in which, when p and p 'are equal to 1, X and X', which may be identical or different, represent the following sequence:

-(T)_t-(Z)_z-(T′)_t′-

the sequences are symmetrically connected in formula (I) as follows:

-C_sat-(T)_t-(Z)_z-(T’)_t’-A or-C'_sat-(T)_t-(Z)_z-(T’)_t’-A’；

Wherein:

t and T', which may be the same or different, represent one or more groups selected from: -O-; -S-; -n (r) -; -N⁺(R)(R^o)-；-S(O)-；-S(O)₂-；

-c (o) -; r, R therein^oWhich may be the same or different, represent a hydrogen atom, C₁-C₄Alkyl radical, C₁-C₄Hydroxyalkyl or aryl (C)₁-C₄) An alkyl group; and a cationic or non-cationic, preferably monocyclic, heterocycloalkyl or heteroaryl group, preferably containing two heteroatoms (more preferably two nitrogen atoms) and preferably 5-to 7-membered, more preferably imidazolium;

t and t', which may be identical or different, equal to 0 or 1;

z represents:

-(CH₂)_m-, where m is an integer of 1 to 8;

-(CH₂CH₂O)_q-or- (OCH)₂CH₂)_q-, wherein q is an integer of 1 to 5 inclusive;

aryl, alkaryl or aralkyl, wherein the alkyl is C₁-C₄And the aryl group is preferably C₆Said aryl, alkaryl or aralkyl being optionally substituted by at least one group SO₃M, wherein M represents a hydrogen atom, an alkali metal or is substituted by one or more identical or different linear or branched C groups optionally bearing at least one hydroxyl group₁-C₈Alkyl-substituted ammonium groups;

z is 0 or 1;

preferably, when p andwhen p 'is equal to 1, X and X' are identical and represent the following sequence: -N (R) -C (O) - (CH)₂)_m-, said sequences being symmetrically linked in formula (I) as follows: -C_sat-N(R)-C(O)-(CH₂)_m-A or-C'_sat-N(R)-C(O)-(CH₂)_m-A’。

6. Process according to any one of the preceding claims, in which the dye of formula (I) comprises cationic, anionic, neutral or zwitterionic fluorescent chromophores a and/or a', which may be identical or different, derived from dyes of the following types: acridines; acridones; anthra associated anthrones; anthrapyrimidines; anthraquinones; azines; (poly) azo, hydrazono or hydrazone compounds, in particular arylhydrazone compounds; azomethines; benzanthracene ketones; benzimidazoles; benzimidazolones; benzazoles; benzoxazoles; benzopyrans; benzothiazoles; benzoquinones; bisazines; bis-isoindolines; carboxanilides; coumarins; (ii) cyanine groups such as diazacyclocyanine groups, tetraazacarbonylcyanine groups or (poly) methine groups such as stilbene or styryl/hemicyanine type methine groups; diazines; diketopyrrolopyrroles; dioxazines; diphenylamines; diphenylmethanes; dithiazines; flavonoids such as flavanthrones and flavones; fluoropyridines; formazans; indamines; indanthrones; indigoids and pseudoindigoids; indophenols; indoaniline compounds; isoindolines; isoindolinones; isoviolanthrones; naphthalimides; naphthanilides; naphthalimides; naphthoquinones; nitro dyes, especially nitro (hetero) aromatics; an oxadiazole; oxazines; perilla ketones; a cyanocyclic ketone; perylene; phenothiazines; phenoxazines; phenothiazines; phthalocyanines; polyenes/carotenoids; porphyrins; pyranthrones; pyrazolylanthrones; pyrazolones; pyrimidoanthracene ketones; pyronine compounds; quinacridones; quinolines; quinophthalones; squalane species; tetrazolium compounds; thiazines, thioindigoids; thiopyronines; triarylmethanes or xanthenes, in particular the chromophore is selected from (poly) methine chromophores such as styreneSecondary methides and naphthalimides of the mesityl/hemicyanine type, more particularly the chromophores being cationic; preferably, a and/or a' are derived from the following dyes: acridines, acridones, benzanthrones, benzimidazoles, benzimidazolones, benzimidazoles, benzoxazoles, benzopyrans, benzothiazoles, coumarins, difluoro {2- [ (2H-pyrrol-2-ylidene-kN) methyl]-1H-pyrrole-kN } boron, diketopyrrolopyrroles, fluoropyridines, (poly) methines such as methines (especially cyanines and styryls/hemicyanines), naphthalimides, naphthanilides, naphthylamines (such as dansyl), oxadiazoles, oxazines, perillanes, perinone, thionyls, benzophenanthrolines, benzophenones,(ii) a polyene, carotenoid, squalane, stilbene, xanthene; more preferably, said chromophores A and A' are selected from (poly) methine chromophores such as methines and naphthalimides of the styryl/hemicyanine type.

7. Process for dyeing and lightening dark keratin fibres having a depth of shade less than or equal to 6, in particular less than or equal to 4, according to any one of the preceding claims.

8. Process according to any one of the preceding claims, in which the dye of formula (I) comprises cationic fluorescent chromophores a and/or a' containing at least one quaternary ammonium group bearing an aliphatic chain, said group being chosen from:

a) polymethine radicals of the formulae (II) and (II'):

in formula (II) or (II'):

·W⁺denotes a cationic heterocycle or heteroaryl radical, in particular comprising a quaternary ammonium bearing an aliphatic chain, said heterocycle or heteroaryl radical being optionally substituted by one or more (C)₁-C₈) Alkyl substitution, said one or more (C)₁-C₈) Alkyl is optionally substituted, inter alia, by one or more hydroxy groups;

·W′⁺denotes a cationic heterocyclic or heteroaryl divalent radical, in particular comprising a quaternary ammonium, said heterocyclic or heteroaryl radical optionally being substituted by one or more (C)₁-C₈) Alkyl substitution, said one or more (C)₁-C₈) Alkyl is optionally substituted, inter alia, by one or more hydroxy groups; ar represents an aryl group with an aliphatic chain with an exocyclic ammonium charge, such as phenyl or naphthyl, optionally substituted preferably with: i) one or more halogen atoms such as chlorine or fluorine; ii) one or more (C)₁-C₈) Alkyl, preferably C₁-C₄Alkyl groups such as methyl; iii) one or more hydroxyl groups; iv) one or more (C)₁-C₈) Alkoxy groups such as methoxy groups; v) one or more hydroxyl groups (C)₁-C₈) Alkyl radicals such as hydroxyethyl, vi) one or more amino radicals or (di) (C)₁-C₈) Alkylamino, preferably having C optionally substituted by one or more hydroxy groups₁-C₄Alkyl moieties such as (di) hydroxyethylamino, vii) one or more amido groups; viii) one or more heterocycloalkyl groups such as piperazinyl, piperidinyl or 5-or 6-membered heteroaryl groups such as pyrrolidinyl, pyridinyl and imidazolinyl;

ar' is a divalent aromatic group such as phenyl or naphthyl, optionally substituted with: i) one or more halogen atoms such as chlorine or fluorine; ii) one or more (C)₁-C₈) Alkyl and preferably C₁-C₄Alkyl groups such as methyl; iii) one or more hydroxyl groups; iv) one or more (C)₁-C₈) Alkoxy groups such as methoxy groups; v) one or more hydroxyl groups (C)₁-C₈) Alkyl radicals such as hydroxyethyl, vi) one or more amino radicals or (di) (C)₁-C₈) Alkylamino, preferably having C optionally substituted by one or more hydroxy groups₁-C₄Alkyl moieties such as (di) hydroxyethylamino, vii) one or more amido groups; viii) one or more heterocycloalkyl groups such as piperazinyl, piperidinyl or 5-or 6-membered heteroaryl groups such as pyrrolidinyl, pyridinyl and imidazolineA group;

m' represents an integer from 1 to 4 inclusive; in particular, m is 1 or 2; more preferably 1;

·R^cand R^dWhich may be identical or different, represent a hydrogen atom or an optionally substituted (C)₁-C₈) Alkyl, preferably C₁-C₄Alkyl, or alternatively R^cAnd W⁺Or W'⁺Adjacent and/or R^dAdjacent to Ar or Ar', forming with the atom carrying them a (hetero) cycloalkyl group; in particular, R^cAnd W⁺Or W'⁺Adjacent to and forming a (hetero) cycloalkyl group such as cyclohexyl; preferably, R^cAnd R^dRepresents a hydrogen atom;

·Q^-which may or may not be present, is an anionic counterion to ensure electroneutrality of the molecule;

h represents the part of the chromophore attached to the remainder of formula (I);

it being understood that the radical W⁺、W′⁺At least one of Ar and Ar' carries at least one ammonium group with a linear or branched, saturated or unsaturated C₁₀-C₃₀An aliphatic chain; preferably, the ammonium group is R¹R²R³N⁺-，An^-Wherein R is¹Represents a straight chain or branched chain (C)₁₀-C₃₀) Alkyl or straight or branched chain (C)₁₀-C₃₀) Alkenyl, especially C₁₄H₂₉、C₁₆H₃₃Or C₁₈H₃₇Preferably n-C₁₄H₂₉、n-C₁₆H₃₃Or n-C₁₈H₃₇(ii) a And R is²And R³Which may be the same or different, represent a hydrogen atom or a linear or branched chain (C)₁-C₃₀) Alkyl or straight or branched chain (C)₂-C₃₀) Alkenyl, preferably (C)₁-C₆) Alkyl radical, and An^-Which may or may not be present, is an anionic counterion to ensure electroneutrality of the molecule, such as a halide or alkylsulfate;

b) a naphthalimide group of the following formula (III) or (III'):

whereinIs represented by the formula with X or X', C_satOr C'_satBond of radicals

In the formulae (III) and (III'), R^e、R^f、R^gAnd R^hWhich may be the same or different, represent a hydrogen atom or C₁-C₆Alkyl, in which the radical R of the naphthalimide group (III)^eOr R^fOr alternatively R of naphthalimide group (IV)^gOr R^hAt least one of which is substituted by a trialkylammonium group R_aR_bR_cN⁺-，An^-Is substituted in which R_aAnd R_bWhich may be the same or different, represents (C)₁-C₃₀) Alkyl radicals such as methyl, and R_cIs represented by C₁₀-C₃₀In particular C₁₄H₂₉、C₁₆H₃₃Or C₁₈H₃₇Preferably n-C₁₄H₂₉、n-C₁₆H₃₃Or n-C₁₈H₃₇An aliphatic chain, and An^-Which may or may not be present, denotes an anionic counterion ensuring the electroneutrality of the molecule, such as a halide or alkylsulfate.

9. The method according to any one of the preceding claims, wherein the dye of formula (I) is a disulfide dye selected from those of formulae (IV) to (VIII) and a thiol or protected thiol dye selected from those of formulae (IV ') to (VIII') below:

organic or inorganic acid salts thereof, optical and geometric isomers thereof, and solvates such as hydrates; in formulae (IV) to (VIII) and (IV ') to (VIII'):

g and G', which may be identical or different, represent i) a group-NR_cR_d、-NR′_cR′_dIi) optionally substituted, preferably unsubstituted, C₁-C₆An alkoxy group; or iii) a group R¹R²R³N⁺-，An^-Wherein R is¹Represents a straight chain or branched chain (C)₁₀-C₃₀) Alkyl, especially C₁₄H₂₉、C₁₆H₃₃Or C₁₈H₃₇Preferably n-C₁₄H₂₉、n-C₁₆H₃₃Or n-C₁₈H₃₇A group; and R is²And R³Which may be the same or different, represent a linear or branched chain (C)₁-C₃₀) Alkyl, preferably (C)₁-C₆) Alkyl radicals such as methyl, and An^-Which may or may not be present, represents an organic or inorganic anionic counterion such as a halide or alkylsulfate;

·R_aand R'_aWhich may be the same or different, represent aryl (C)₁-C₄) Alkyl or C optionally substituted by hydroxy or amino₁-C₆Alkyl radical, C₁-C₄Alkylamino or C₁-C₄Dialkylamino, the alkyl groups possibly forming with the nitrogen atom bearing them a 5-to 7-membered heterocyclic ring, the heterocyclic ring optionally containing another nitrogen or non-nitrogen heteroatom; preferably, R_aAnd R'_aRepresents C optionally substituted by hydroxy₁-C₃Alkyl or benzyl; preferably, R_aAnd R'_aThe same;

·R_band R'_bWhich may be the same or different, represents a hydrogen atom, an aryl group (C)₁-C₄) Alkyl or optionally substituted C₁-C₆An alkyl group; preferably, R_bAnd R'_bRepresents a hydrogen atom or C₁-C₃Alkyl or benzyl; preferably, R_bAnd R'_bAre the same and represent a hydrogen atom;

·R_c、R′_c、R_dand R'_dWhich may be the same or different, represents a hydrogen atom, an aryl group (C)₁-C₄) Alkyl, or C₁-C₆Alkoxy, or optionally substituted C₁-C₆An alkyl group; r_c、R′_c、R_dAnd R'_dPreferably represents a hydrogen atom, a hydroxyl group, C₁-C₃Alkoxy, amino or C₁-C₃(di) alkylamino, or optionally substituted by i) hydroxy, ii) amino, iii) C₁-C₃(di) alkylamino, or iv) quaternary ammonium R as defined above¹R²R³N⁺-，An^-Substituted C₁-C₃An alkyl group;

or alternatively two adjacent radicals R carried by the same nitrogen atom_cAnd R_d，R′_cAnd R'_dTogether form a heterocycle or heteroaryl; preferably, the heterocycle or heteroaryl is monocyclic and 5-to 7-membered; more preferably, the group is selected from imidazolyl and pyrrolidinyl;

·R_eand R'_eWhich may be identical or different, represent a divalent C which is linear or branched, optionally unsaturated₁-C₆Alkylene hydrocarbon-based chain, preferably R_eAnd R'_eWhich are identical, represent a linear divalent C₁-C₆Alkylene hydrocarbon-based chains such as- (CH)₂)₃-a chain;

·R_fand R'_fWhich may be identical or different, represent a quaternary ammonium group R as defined above¹R²R³N⁺-，An^-；

·R_g、R′_g、R″_g、R″′_g、R_h、R′_h、R″_hAnd R'_hWhich may be the same or different, represents a hydrogen atom, a halogen atom, an amino group, C₁-C₄Alkylamino radical, C₁-C₄Dialkylamino, cyano, carboxyl, hydroxyl or trifluoromethyl, amido, C₁-C₄Alkoxy, (poly) hydroxy (C)₂-C₄) Alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkylcarbonylamino, acylamino, carbamoyl or alkylsulfonylamino, aminosulfonyl or optionally substituted by C₁-C₁₂Alkoxy, hydroxy, cyano, carboxy, amino, C₁-C₄Alkylamino and C₁-C₄Radical-substituted C of dialkylamino₁-C₁₆Alkyl, or alternatively two alkyl groups carried by the nitrogen atom of the amino group, form a 5-to 7-membered heterocyclic ring, optionally containing another heteroatom, identical or different from said nitrogen atom; preferably, R_g、R’_g、R”_g、R”’_g、R_h、R’_h、R”_hAnd R'_hRepresents a hydrogen or halogen atom or C₁-C₃An alkyl group; more preferably, R_g、R′_g、R_hAnd R'_hRepresents a hydrogen atom;

or alternatively two radicals R carried by two adjacent carbon atoms_gAnd R'_g；R″_gAnd R'_g；R_hAnd R'_h；R″_hAnd R'_hTogether form a benzo or indeno ring, a fused heterocycloalkyl, or a fused heteroaryl; the benzo, indeno, heterocycloalkyl, or heteroaryl ring is optionally substituted with: halogen atom, amino group, (C)₁-C₄) Alkylamino radical, C₁-C₄Dialkylamino, nitro, cyano, carboxyl, hydroxyl or trifluoromethyl, amido, C₁-C₄Alkoxy, (poly) hydroxy (C)₂-C₄) Alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkylcarbonylamino, acylamino, carbamoyl or alkylsulfonylamino, aminosulfonyl or C optionally substituted by₁-C₁₆Alkyl groups: is selected from C₁-C₁₂Alkoxy, hydroxy, cyano, carboxy, amino, C₁-C₄Alkylamino radical, C₁-C₄A dialkylamino group or, alternatively, two alkyl groups carried by the nitrogen atom of the amino group forming a 5-to 7-membered heterocyclic ring optionally containing another heteroatom which is the same or different from the nitrogen atom; preferably, R_gAnd R'_g；R”_gAnd R'_gTogether form a benzo group;

or alternatively, when G represents-NR_cR_dAnd G 'represents-NR'_cR′_dWhen two radicals R are present_cAnd R'_g；R’_cAnd R "_g；R_dAnd R_g；R’_dAnd R'_gTogether form a radical C optionally substituted by one or more groups₁-C₆Alkyl-substituted saturated heteroaryl or heterocycle, preferably a 5-to 7-membered heterocycle containing one or two heteroatoms selected from nitrogen and oxygen; more preferably the heterocycle is selected from morpholinyl, piperazinyl, piperidinyl and pyrrolidinyl;

·R_i、R′_i、R″_iand R'_iWhich may be the same or different, represent a hydrogen atom or C₁-C₄An alkyl group; preferably, R_iAnd R'_iRepresents a hydrogen atom;

·R₁、R₂、R₃、R₄、R′₁、R′₂、R′₃and R'₄Which may be the same or different, represent a hydrogen atom or C₁-C₄Alkyl radical, C₁-C₁₂Alkoxy, hydroxy, cyano, carboxy, amino, C₁-C₄Alkylamino or C₁-C₄Dialkylamino, the alkyl groups possibly forming with the nitrogen atom bearing them a 5-to 7-membered heterocyclic ring, the heterocyclic ring optionally containing another nitrogen or non-nitrogen heteroatom; preferably, R₁、R₂、R₃、R₄、R’₁、R'₂、R'₃And R'₄Is a hydrogen atom or an amino group; more preferably, R₁、R₂、R₃、R₄、R’₁、R'₂、R’₃And R'₄Represents a hydrogen atom;

·T_aand T_bWhich may be the same or different, represent i) a sigma covalent bond, ii) or one or more groups selected from: -SO₂-、-O-、-S-、

-N(R)-、-N⁺(R)(R^o) -and-CO-, wherein R and R^oWhich may be the same or different, represent a hydrogen atom, C₁-C₄Alkyl or C₁-C₄A hydroxyalkyl group; or aryl (C)₁-C₄) An alkyl group; preferably, T_aAnd T_bAnd which represent a covalent bond or are selected from the group consisting of-N (R) -, -C (O) -N (R) -, -N (R) -C (O) -, -O-C (O) -, -C (O) -O-and-N⁺(R)(R^o) A group of (A) wherein R and R^oWhich may be the same or different, represent a hydrogen atom or C₁-C₄An alkyl group; more preferably, T_aAnd T_bRepresents a sigma bond or-C (O) -N (R) -or-N (R) -C (O) -; iii) or a cationic or non-cationic, preferably monocyclic, heterocycloalkyl or heteroaryl group, which are preferably identical, preferably containing two heteroatoms (more preferably two nitrogen atoms) and preferably 5-to 7-membered, such as imidazolium; preferably, T_aRepresents a group-N (R) -C (O) -, wherein R represents a hydrogen atom or C₁-C₄Alkyl, and more preferably, wherein R represents a hydrogen atom or T_aRepresents a sigma covalent bond;

which may be identical or different, represent an optionally substituted heterocyclic radical, preferably substituted by a quaternary ammonium group R as defined above¹R²R³N⁺-，An^-Substitution; preferably, the heterocyclic rings are identical, monocyclic, saturated, and contain a total of two nitrogen atoms, and are 5-to 8-membered;

represents an aryl or heteroaryl group fused to an imidazolium or phenyl ring; or alternativelyNot present on imidazolium or benzene rings; preferably, when said ring is present, said ring is a benzo ring;

m, m ', n and n', which may be identical or different, represent integers from 0 to 6 inclusive, where m + n and m '+ n', which may be identical or different, represent integers from 1 to 10 inclusive; preferably, m + n' is an integer from 2 to 8 inclusive; more preferably, m + n is an integer from 1 to 8 inclusive, more preferably an integer from 1 to 6; even more preferably, m + n-5 or m + n-2;

y is as defined in claim 1 or 3; in particular, Y represents a hydrogen atom or a protecting group such as:

(C₁-C₄) Alkylcarbonyl such as methylcarbonyl or ethylcarbonyl;

arylcarbonyl, such as phenylcarbonyl;

(C₁-C₄) An alkoxycarbonyl group;

an aryloxycarbonyl group;

aryl radical (C)₁-C₄) An alkoxycarbonyl group;

(II) (C)₁-C₄) (alkyl) aminocarbonyl groups such as dimethylaminocarbonyl;

(C₁-C₄) (alkyl) arylaminocarbonyl;

optionally substituted aryl, such as phenyl;

5-or 6-membered monocyclic heteroaryl, such as imidazolyl or pyridyl;

cationic 5-or 6-membered monocyclic heteroaryl groups, such as pyrylium, pyridinium, pyrimidinium, pyrazinium, pyridazinium, triazinium, imidazolium; said radicals optionally being substituted by one or more identical or different (C)₁-C₄) Alkyl such as methyl;

cationic 8-to 11-membered bicyclic heteroaryl groups such as benzimidazolium or benzoxazolium; said radicals optionally being substituted by one or more identical or different (C)₁-C₄) Alkyl such as methyl;

a cationic heterocycle having the formula:

-C(NH₂)＝N⁺H₂；An″′^-(ii) a Wherein An'^-Is an anionic counterion as defined previously;

-C(NH₂)＝NH；

SO₃ ^-，M⁺wherein M is⁺Represents an alkali metal such as sodium or potassium; and is

M' represents an anionic counterion ensuring the electroneutrality of the molecule, derived from a salt of an organic or inorganic acid, or from an organic or inorganic base;

it being understood that the radicals G, G', R_a、R′_a、R_c、R′_c、R_d、R′_d、R_fOr R'_fAt least one of which carries at least one radical R as defined above¹R²R³N⁺-，An^-。

10. The process according to any one of the preceding claims, wherein the dye of formula (I) is selected from those of formulae (IX) to (X'):

organic or inorganic acid salts thereof, optical and geometric isomers thereof, and solvates such as hydrates; in formulae (IX) to (X'):

g and G', which may be the same or different, represent i) (two) (C)₁-C₆) Alkylamino groups in which at least one alkyl group is an ammonium group R as defined above¹R²R³N⁺，An^-Substituted, or ii) ammonium as defined aboveRadical R¹R²R³N⁺，An^-(ii) a Preferably, G and G' are the same;

R_g、R′_g、R″_g、R″′_g、R_h、R′_h、R″_hand R'_hWhich may be the same or different, represents a hydrogen or halogen atom, an amino group, or a (di) (C)₁-C₄) Alkylamino, cyano, carboxyl, hydroxyl, trifluoromethyl, acylamino, C₁-C₄Alkoxy radical, C₂-C₄(poly) hydroxyalkoxy, (C)₁-C₄) Alkylcarbonyloxy, (C)₁-C₄) Alkoxycarbonyl, (C)₁-C₄) Alkylcarbonylamino, acylamino, carbamoyl or (C)₁-C₄) Alkylsulfonylamino, aminosulfonyl, or optionally substituted by (C)₁-C₁₂) Alkoxy, hydroxy, cyano, carboxy, amino, and (di) (C)₁-C₄) Substituted by radicals of alkylamino groups (C)₁-C₁₆) Alkyl, or alternatively two alkyl groups carried by the nitrogen atom of the amino group, forming a 5-to 7-membered heterocyclic ring, optionally containing another nitrogen or non-nitrogen heteroatom; in particular, R_g、R’_g、R”_g、R”’_g、R_h、R’_h、R”_hAnd R'_hRepresents a hydrogen atom or (C)₁-C₄) An alkyl group; preferably, R_g、R’_g、R”_g、R”’_g、R_h、R’_h、R”_hAnd R'_hRepresents a hydrogen atom;

R′_i、R″_i、R″′_iand R "")_iWhich may be the same or different, represent a hydrogen atom or (C)₁-C₄) An alkyl group; especially, R'_i、R”_i、R”’_iAnd R'_iRepresents a hydrogen atom;

T_aand T_bWhich may be identical or different, represent i) a sigma covalent bond, ii) or one or more radicals selected from-O-, -N (R) -and-C (O) -or a combination thereof, wherein R represents a hydrogen atom or C₁-C₄An alkyl group; preferably, T_aAnd T_bSame and represent a covalent bond or a group selected from-N (R) -, -C (O) -N (R) -and-N (R) -C (O) -wherein R represents a hydrogen atom or C₁-C₄An alkyl group; more preferably, T_aAnd T_bWhich are identical, represent-C (O) -N (R) -or

-N (R) -C (O) -, wherein R represents a hydrogen atom or C₁-C₄Alkyl, and more preferably, wherein R represents a hydrogen atom;

m, m ', n and n', which may be the same or different, represent integers from 0 to 6 inclusive, wherein m + n and m '+ n', which may be the same or different, represent integers from 1 to 10 inclusive; preferably, m + n + m '+ n' and m + n is an integer from 1 to 8 inclusive; more preferably an integer of 1 to 6; even more preferably, m + n-5 or m-2;

y is as defined in any one of claims 1, 3 and 9;

in particular, the formula (IX) or (IX ') bears an ethylene group linking the pyridinium moiety to the phenyl group in ortho or para position relative to the pyridinium, i.e. in the 2-4 ', 4-2 ' or 4-4 ' position, preferably in the 4-4 ' para position; and/or in para position with respect to the phenyl radical carrying the group G or G ', i.e.with its ethylene radical in the 1 ' -4 ' position; preferably, the dyes of the present invention belong to the following formula (IXa) or (IX' a):

in formulae (IXa) and (IXb):

g represents R as defined above¹R²R³N⁺-，An^-；

·An^-Represents an anionic counterion as previously defined;

b represents a divalent amide group-C (O) -N (R) -or-N (R) -C (O) -wherein R represents a hydrogen atom or (C)₁-C₆) An alkyl group; preferably, R represents a hydrogen atom;

n and m, which may be the same or different, represent integers from 1 to 4 inclusive; preferably, n is equal to 3 and m is equal to 2;

y is as defined in any one of claims 1, 3 and 9;

it is understood that the bond between the pyridinium ring and the double bond of the ethylene or styryl group is in the 2 or 4, preferably 4, position of the pyridinium.

11. The process according to any one of the preceding claims, wherein the dye of formula (I) is selected from those of:

and also organic or inorganic acid salts and geometric isomers thereof, and solvates such as hydrates; wherein An^-M', which may be the same or different, preferably the same, represents an anionic counterion; more particularly, the anionic counterions are selected from halides such as chloride, alkylsulfates such as methylsulfate and methanesulfonate; y is as defined in any one of claims 1, 3 and 9, and G' represents R¹R²R³N⁺，An′^-Wherein R is¹Denotes straight-chain or branched, preferably straight-chain (C)₁₀-C₃₀) An alkyl group; and R is²And R³Which may be the same or different, represent a hydrogen atom or (C)₁-C₆) Alkyl radical, and An^-Represents an organic or inorganic anionic counterion, such as a halide or alkylsulfate; in particular, R¹R²R³N⁺-，An^-Represents n-C₁₅H₃₃-N⁺(CH₃)₂-，An′^-Wherein An'^-As previously for An^-As defined; especially, An'^-Represents a halogen ion such as Cl^-。

12. The process according to any one of the preceding claims, wherein the dye of formula (I) is selected from the following(A)And(B)：

and also organic or inorganic acid salts and geometric isomers thereof, and solvates such as hydrates;

in formulae (A) and (B):

r, which are identical, represent a linear chain (C)₁₀-C₃₀) Alkyl, preferably selected from n-C₁₄H₂₉-、n-C₁₆H₃₃-and n-C₁₈H₃₇-；

R', which are identical, represent a linear chain (C)₁₀-C₃₀) Alkyl, preferably selected from n-C₁₄H₂₉-、n-C₁₆H₃₃-and n-C₁₈H₃₇-; and is

·An^-Which may be identical or different, represent an anionic counterion, in particular a halide, such as Cl, as defined in the preceding claim^-Or Br^-。

13. The method according to any one of the preceding claims, the method comprising: i) applying to said fibres, in particular keratin fibres such as the hair, preferably dark hair, one or more fluorescent dyes bearing a disulfide, thiol or protected thiol function of formula (I) as defined in any one of the preceding claims and ii) a heat source for straightening said fibres, such as steam and/or a splint.

14. The process according to claim 13, wherein the step ii) of applying steam onto the keratin fibres is carried out after applying i) at least one fluorescent direct dye bearing a disulfide function or a thiol or protected thiol function as defined in any one of claims 1 to 12 to the keratin fibres.

15. The method of any one of the preceding claims, which does not use a reducing agent.

16. The method of any one of the preceding claims, which does not use a chemical oxidant.

17. Use of one or more fluorescent direct dyes of formula (I) as defined in any one of claims 1 to 12, carrying a disulfide function or a thiol or protected thiol function, for dyeing keratin materials, in particular keratin fibres, preferably human keratin fibres such as the hair.

18. Use according to the preceding claim for dyeing and lightening dark keratin fibre materials, in particular human keratin fibres such as the hair, having a depth of shade of less than or equal to 6, preferably less than or equal to 4.

19. A compound of formula (I) as defined in any one of claims 1 to 12.

20. A composition comprising one or more compounds of formula (I) as defined in any one of claims 1 to 12.