DYE COMPOSITION COMPRISING AT LEAST ONE COLORLESS
DISULFIDE/THIOL PRECURSOR, AND DYEING PROCESS USING THE
COMPOSITION
The present invention relates to the dyeing of keratin
materials using two colorless dye precursors, at least
one of which contains a disulfide/thiol unit, said
precursors reacting together chemically to form the
color in situ
Essentially two types of dyeing are used for coloring
human keratin fibers
The first is semi-permanent dyeing or direct dyeing,
which uses dyes that are capable of giving to the
natural color of the hair a more or less pronounced
change The process conventionally used in direct
dyeing consists in applying to the keratin fibers
direct dyes, which are colored and coloring molecules
that have affinity for the fibers, leaving them to
diffuse and then rinsing the fibers
The dyes used are colored and coloring substances that
have a certain affinity for keratin fibers The direct
dyes that are conventionally used are, for example,
dyes of the nitrobenzene type, anthraqumone dyes,
nitropyridines and dyes of the azo, xanthene, acridine,
azine or triarylmethane type
The dyeing of keratin fibers using these standard
direct dyes does not make it possible to appreciably
lighten the keratin fibers and does not have
satisfactory fastness especially with respect to
shampoos
When lightening of keratin fibers is desired, a
chemical bleaching process is conventionally performed
This process consists in treating the keratin fibers with a strong. oxidizing system, generally constituted

by hydrogen peroxide optionally combined with persalts,
usually in an alkaline medium If a lighter coloration
than the original color of the fibers is desired to be
obtained, while at the same time coloring the fibers,
this technique being known as lightening dyeing, it is
necessary to combine the direct dyes with at least one
oxidizing agent in alkaline medium
The drawback of lightening dyeing is, specifically, due
to the fastness of the dyes, which remains limited and
which leads to fading of the color, or even to a color
change over time, via loss of the dye(s)
Furthermore, the chemical bleaching system has the
drawback of degrading keratin fibers and of impairing
their cosmetic properties Specifically, the fibers
have a tendency to become coarse, more difficult to
disentangle and more brittle Finally, the lightening
or bleaching of keratin fibers with oxidizing agents is
incompatible with treatments for changing the shape of
said fibers, particularly relaxing treatments
Another lightening technique consists in applying to
dark hair fluorescent direct dyes This technique,
described especially in documents WO 03/028 685 and
WO 2004/091 473, makes it possible to respect the
quality of the keratin fiber during the treatment
However, these fluorescent direct dyes do not have
sufficient fastness with respect to external agents To
increase the fastness of direct dyes, it is known
practise to use disulfide dyes, especially dyes
containing an azo-imidazolium chromophore, in patent
applications WO 2005/097 051 or EP 1 647 580, and dyes
containing pyridinium/indolmium-styryl chromophores in
patent applications WO 2006/134 043 and
WO 2006/136 617
The second type of dyeing is permanent dyeing or oxidation dyeing. It is performed in the presence of

oxidation dye precursors, more particularly one or more
oxidation bases optionally combined with one or more
couplers These precursors are uncolored or sparingly
colored compounds, which, once mixed at the time of use
with oxidizing agents under alkaline conditions, lead
to colored and coloring compounds via a mechanism of
oxidative condensation
This type of dyeing gives access to colorations that
are longerlasting than those obtained with direct dyes.
However, the use requires an oxidizing agent under
alkaline conditions, which may, in the long term,
result in degradation of the keratin fiber
The two types of process using direct dyes or oxidation
dyeing of the hair have the drawback of being soiling
Specifically, with direct dyeing, for which the
composition applied to the fibers is already colored,
and with oxidation dyeing, which rapidly becomes highly
colored during the process, the risks of staining
clothing, dyeing tools, rinsing basins or towels are
great, during the application and the leave-on time of
the dye composition
Furthermore, the initial color of the composition
applied to the fibers, or the color that appears during
the process, masks the final coloration of the fibers,
and may cause certain difficulties. The first being
that the color of the composition, although often
highly chromatic, or even aggressive to the eye, may
worry the person on whom the dye composition is
applied, and all the more so if this person is not in
the habit of undertaking such hair treatments
Another drawback is that there is not at the present
time any way for the person on whom the treatment is
performed to exert any control of the coloration, in
the sense that she might request that the process be stopped at a point at which she finds the color

obtained satisfactory-
Using standard dyeing processes, it is also not
possible to perform "progressive dyeing" or "dyeing
with a progressive lightening effect" by applying a
reagent contained, for example, in a shampoo that would
generate gradually as it is used, after several days or
even weeks, color on the hair, without denaturing the
keratin fibers.
Moreover, it is known practise to apply to keratin
fibers, instead of direct dyes, dye precursors that
form the color in situ via a chemical reaction For
example, aromatic aldehyde/ketone precursors and a
precursor with an activated CH, which form the direct
dye in situ, have been described in patents
US 6 790 239 and US 6 770 102 These precursors do not
bear any disulfide or thiol functions
(Hetero)aryl disulfide compounds have been widely used
in fields other than that of dyeing of the hair, for
example, in the study of the reactivity of isochroman
and isothiochroman [Justus Liebigs Annalen der Chemie
(1978), (7), 1123-8, ibid (1974), (5), 734-40]; in
models of molecular recognition by interaction of
hydrogen bonds [Chemical Communications (1996), (10) ,
1193-1194], in the formation of golC1-affmity
multilayer materials [Organic Letters (2000), 2(26),
4141-4144, Chemistry Letters (2006), 35(8), 870-871],
in controlling the electron transfer between cytochrome
C and gold electrons [Langmuir (2003), 19(6), 2378-
2387, Journal of the American Chemical Society (2003),
125(25), 7704-7714], in liquid crystals [Molecular
Crystals and Liquid Crystals Science and Technology,
Section A (2002), 377, 137-140], or in the synthesis
of modified nanoparticles [Journal of the American
Chemical Society (2004), 126(10), 3026-3027] However,
the prior art does not mention the use of disulfide or thiol precursors for dyeing keratin fibers

The object of the present invention is to propose a
process for dyeing keratin fibers, especially with a
lightening effect, particularly on dark hair, which
does not have the drawbacks mentioned above, and which
makes it possible in the case of certain variants to
solve the problems due to the color generated during
the process, while at the same time not degrading the
efficacy of the coloration, and especially of the
lightening effect.
The colorations obtained are moreover powerful,
chromatic, sparingly selective, and fast with respect
to external agents such as sunlight, perspiration and
especially shampoo
Thus, one subject of the present invention is a process
for dyeing keratin fibers, especially the hair, more
particularly dark hair, which consists in applying to
said fibers, which have optionally been pretreated with
a reducing agent
I) a cosmetically acceptable composition comprising at
least one colorless thiol/disulfide dye precursor
of formula (I)
formula (I): [Z-A-L-S]x- (Y) y
II) and a cosmetically acceptable composition
comprising at least one colorless dye precursor of
formula (II)
formula (II) B-X
in which the portion B of the precursor of formula (II)
reacts chemically with portion A of the precursor of
formula (I) to form a colored or colored and
fluorescent chromophore B-X'-A-,
in which formulae (I) and (II)
> y represents 0 or 1,
> x represents 1 or 2,
> L represents an optionally substituted divalent C1-
C2o hydrocarbon-based chain, optionally interrupted
and/or optionally ending at one or other of its ends
i with one or more divalent groups or combinations.

thereof chosen from -N(Ra)-, -N+(Ra) (Rb) -, An", -O-,
-S-, -CO- and -SO2- with Ra and Rb, which may be
identical or different, chosen from a hydrogen and a
(C1-C6) alkyl, hydroxy (C1-C6) alky 1 or (d1) (C1-
C6) (alkyl) amino (C1-C6) alkyl radical and An"
representing an anionic counterion, or 11) with a
cationic heterocycle or cationic heteroaryl Het+,
An", with An" as defined above and Het+ representing
a saturated or unsaturated 5- to 10-membered
heterocycle, or a 5- to 10-membered heteroaryl such
as lmidazolium, pyndinium, piperazmium,
piperidmium, pyrrolidmium or benzimidazolium, L
especially represents a (C^Cs) alkylene chain
connected to A via a bond NR, -NRC(O)- or -C(0)NR-,
A and B, which may be identical or different,
represent a colorless chromophore;
A and B especially represent cationic or noncatiomc
aryl or heteroaryl groups,
the optionally substituted aryl radical especially
represents a phenyl, biphenyl, naphthyl, mdenyl,
anthracenyl or tetrahydronaphthyl, more particularly
an optionally substituted phenyl,
the optionally substituted heteroaryl radical
especially represents a group chosen from the
following cationic or noncatiomc heteroaryl
radicals comprising from 1 to 4 heteroatoms
I) 5-, 6- or 7-membered monocyclic radicals 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-
oxazoliam, 1,2,4-thiadiazolyl, 1,2,4-
thiadiazolium, pyrylium, thiopyridyl,
pyndinium, pyrimidmyl, pyrimidinium,
pyrazmyl, pyrazinium, pyridazmyl,
pyridazmium, triazmyl, triazmium,
^tetrp.zjLny|l^ fce£ra;zxnium, azepme, azepmium,

oxazepinyl, oxazepinium, thiepinyl, thiepimum,
lmidazolyl, lmidazolium,
11) 8- to 11-membered bicyclic radicals such as
indolyl, indolinium, benzimidazolyl,
benzimidazolium, benzoxazolyl, benzoxazolium,
dihydrobenzoxazolmyl, benzothiazolyl,
benzothiazolium, pyridoimidazolyl,
pyridoimidazolium, thienocycloheptadienyl, said
radicals possibly being substituted with a (C1-
C3)alkenyl group bearing a function -C=(G)-R° in which the double bond(s) of the (C1-C3) alkenyl
group is (are) conjugated with the double bond
-C=G, with R° representing a hydrogen atom or a
(C1-C4) alkyl group and G representing an oxygen
or sulfur atom or a group NR', and R and R1 may
be identical or different,
in particular, said radicals may be substituted
with a group =CR-C(G)R° with the double bond
directly connected to the nonaromatic part of
the bicycle,
more particularly, A or B represents a group as
defined below

with
- R1, which may be identical or different, represents
a halogen atom or a (C1-C6) alkyl, (C1-C6) alkoxy,
(C1-CeJalkylthio, (d1) (C1-C6) (alkyl) amino, (C1-
C6)polyhaloalkyl, hydroxyl, (C1-C6) polyhydroxy-
alkyl, polyhydroxy(C1-C6)alkoxy, cyano, R-G-C(G')-,
R-C(G')-G-, R'S(0)2-N(R) -, RR'N-S(0)2- group with G
or G1, which may be identical or different,
representing an oxygen or sulfur atom or a group
NR', and R and R', which may be identical or
different, representing a hydrogen atom or a (C1-
C6) alkyl group,

R1 is particularly in position 5 and more
particularly R1 represents a halogen such as
chlorine or a (C1-C6) alkoxy group such as methoxy,
RR'N-S(0)2- such as Me-S(0)2, or RR'N-C(O)- such as
H2N-C(0)-,
- or two contiguous groups R1 form with the two
carbon atoms that bear them an optionally
substituted benzo group,
- t represents an integer between 0 and 4 inclusive,
- G and R° are as defined previously,
- R representing a hydrogen atom or a (C1-C4) alkyl
group,
- R" represents a hydrogen atom or a
(polyhydroxy) (C!-C4)alkyl group,
- Z1 represents an oxygen or sulfur atom or a
methylene group -C(R2) (R3) - with R2 and R3, which
may be identical or different, representing a
hydrogen atom or a (C1-C6) alkyl group,
preferably, the heteroaryl radical represents a
pyridyl, pyridmium, triazmium, lmidazolyl,
lmidazolium, pyrazolyl, thiazolium, oxazolium,
benzothiazolium, benzoxazolium, quinolmium,
mdolyl, mdolmium or a group

> X and Z represent a chemical function capable of
reacting together to form a group X',
X1 representing a chain allowing the electron
transfer between chromophore A and chromophore B; X'
is particularly a divalent C2-C8 alkenylene group
comprising from 1 to 4 conjugated double bonds such
as =CH-CH=CH-, a C1-C7 (poly)methine chain, a
divalent (C1-C7) alkenyleneimmo group, comprising
from 1 to 3 conjugated double bonds such as -CR=N-,
-N=CR-, . -CR=CRFN=CR-r , -, -JST=CR-CR=CR- , =CR-N=CH-, an

aza group -N=N-, a triaza group -N=N-N-, a hydrazono
group -CH=N-NR-, NR-N=CH-, =CR-, =CR-CR=CR-, with R,
which may be identical or different, representing a
hydrogen atom or a (C1-C4)alkyl group,
> Y represents 1) a hydrogen atom, 11) an alkali
metal, m) an alkaline-earth metal, IV) an aminonium
group N+RaRpRYR , An1'" or a phosphonium group:
P+RaRpRYR5, An1'" with Ra, Rp, Ry and R8, which may be
identical or different, representing a hydrogen atom
or a (C1-C4) alkyl group, and An'1" being an anionic
counterion, or v) a protecting group for a thiol
function,
it being understood that when x is 2, then y is zero,
and when x is 1, then y is 1
A subject of the invention is furthermore a cosmetic
composition comprising at least one colorless disulfide
dye precursor of formula (Ix) , (I2) , or a colorless
thiol or thiol-protected dye precursor of formula (I3),
(I4) or (I5)



the organic or mineral acid salts, optical isomers,
geometrical isomers, and solvates such as hydrates
thereof,
m which formulae (Ix) , (I2) , (I3) , (I4) or (I5)
a Ar represents an optionally substituted arylene or
heteroarylene group such as phenylene, naphthylene,
pyridmylene or pyrazolene and more particularly
phenylene,
H R represents a hydrogen atom or a (C1-C6) alkyl group,
■ Y represents- 1) a hydrogen atom, 11) an alkali
metal; 111) an alkaline-earth metal, IV) an aminonium
grcup N+RaRpRYR5, An" or a phosphonium group P+RaRpRYR5,
An" with Ra, Rp, RY and R , which may be identical or
different, representing a hydrogen atom or a (C1-
C4)alkyl group and An" representing an anionic
counterion, or v) a protecting group for a thiol
function,
■ L is as defined previously,
■ n is 0 or 1, advantageously, n is 0,
B represents a 5- to 13-membered cationic
heteroaryl group which may comprise, besides the
cationic nitrogen atom, from 1 to 3 heteroatoms
chosen from nitrogen, oxygen and sulfur, and which
bears on a carbon atom a methyl group, in particular,
the heteroaryl group represents a pyridmium group
substituted in the ortho or para position with a
methyl group,
■ Het+ represents a cationic heteroarylene group bearing
at least one methyl group, chosen from


in which radicals (A) to (E)
- the methyl group of the Het+ groups (C) and (D) is
in position 2 or 4,
- R1 represents a halogen atom or a (C1-C6) alkyl, (C1-
C6)alkoxy, (C1-C6) alkylthio, (d1) (C1-C6) (alkyl) amino,
(C1-C6)polyhaloalkyl, hydroxyl, (C1-
C6) polyhydroxyalkyl, polyhydroxy (C1-C6) alkoxy,
cyano, R-G-C(G')-, R-C(G')-G-, R'S(0)2-N (R)-, RR'N-
S(0)2- group with G or G', which may be identical or
different, representing an oxygen or sulfur atom or
a group NR1, and R and R', which may be identical
or different, representing a hydrogen atom or a (C1-
C6)alkyl group, in particular, R1 is in position 5
and R1 more particularly represents a halogen such
as chlorine or a (C;L-C6) alkoxy group such as
methoxy, RR'N-S(0)2- such as Me-S(0)2 or RR'N-C(O)-
such as H2N-C(0) - ,
- R represents a hydrogen atom or a (polyhydroxy)(C1-
C4) alkyl group,
- or alternatively two contiguous groups R1 form with
the two carbon atoms that bear them an optionally
substituted benzo group,
- t represents an integer between 0 and 4 inclusive,
- t' represents an integer between 0 and 2 inclusive,
- Z' represents an oxygen or sulfur atom or a
methylene group -C(R2) (R3) - with R2 and R3, which may
be identical or different, representing a hydrogen

atom or a (C1-C6) alkyl group,
a An" represents an anionic counterion,
it being understood that the compounds of formula (Ii),
(I2) , (I3) , (I4) or (I5) cannot represent the following
compounds (1) to (xxvm)



with Ac representing an acetyl group (xxn) ,


it bexng understood that the aldehyde functions of
formulae (Ii) , (I3) and (I4) may be protected, for
example with acetals
Another subject of the invention concerns a disulfide
compound of formula (Ii) or (I2) , or a thiol or thiol-
protected compound of formula (I3) , (I4) or (I5) as
defined previously, said compound being different from
the compounds
A subject of the invention is also a multi-compartinent
device comprising, in a first compartinent, a cosmetic
composition containing at least one colorless
thiol/disulfide precursor of formula (I) as defined
previously, a second compartinent comprising a cosmetic
composition containing at least one colorless precursor
of formula (II) as defined previously, optionally,
another compartinent comprising a reducing agent capable
of reducing keratin fibers and the disulfide precursor
of fcrmula (I) , and/or optionally another compartinent
containing an oxidizing agent capable of fixing the
, precursor, of- formula ^ I-). to -the keratin fibers

The dyeing process according to the invention allows
the dyeing of keratin fibers, especially of dark hair,
cleanly since the rinsing liquors are not colored The
compositions comprising the dye precursors according to
the invention have, in the context of certain variants
thereof, the advantage of being colorless and of
remaining so during the leave-on time of the
composition
Moreover, and this represents another particular
advantage of the process according to the invention,
during the process the fibers can be seen to be colored
or lightened under the effect of the composition
comprising the colorless precursor of formula (II) ,
this color being the real coloration, not masked by the
color of the composition applied to the fibers Thus,
the person on whom the treatinent is performed can ask
for the process to be stopped when the desired level of
coloration is reached
A contrario, the colorations obtained using the
composition also make it possible to achieve
progressive colorations Specifically, it is possible
to react a precursor of formula (I) with the keratin
fibers and then, after a few days or even a few weeks,
to "reveal" the color or "intensify it" Revealing the
color by adding a precursor of formula (II) capable of
reacting with the first of formula (I) to generate the
color Intensifying the color or modifying the color by
adding a precursor of formula (II) capable of reacting
with the precursor of formula (I) or by adding another
colorless precursor of formula (II), different from the
one which was added during the revelation
The dyeing process according to the invention makes it
possible to visibly dye dark human keratin fibers,
especially dark hair

The dyeing process according to the invention also has
the advantage of not requiring the use of a standard
lightening agent, while at the same time giving access
to powerful colorations, of the order of those achieved
by using an oxidation dye Specifically, it is possible
to dye with lightening using colorless precursors of
formula (I) or (II) taken separately, without having to
use oxidizing agents, which thus avoids degrading the
keratin fibers
The composition according to the invention also makes
it possible to dye keratin fibers in natural colors,
such as golden, coppery, brown, mahogany and black
colors, without, however, coloring the dye formulation
Moreover, the dyes and colors derived from the dye
precursors of formulae (Ix) to (I5) broaden the color
range from yellows to greens This also makes it
possible to achieve strong and chromatic dyeing of
bleached keratin fibers
The process of the invention makes it possible to
obtain a coloration on the hair, without degrading it,
which is remnant with respect to shampooing, common
attacking factors (sunlight and perspiration), and hair
treatinents
However, other characteristics and advantages of the
invention will emerge more clearly on reading the
description and the examples that follow
For the purposes of the invention, the term "dark
keratin material" means keratin material whose
lightness L* measured in the CIEL L*a*b* system is less
than or equal to 45 and preferably less than or equal
to 40, given that L* = 0 is equivalent to black and
L*=100 is equivalent to white
For the purposes of the invention, the expression
t"^a-t^ura^lly-j ptr> arttrf lqially ^dark hair" means hair whose

tone depth 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 "tone
depth" before and after application of the precursors
of formula (II) . The notion of "tone" is based on the
classification of natural shades, one tone separating
each shade from the shade immediately following or
preceding it This definition and the classification of
natural shades are well known to hairstylmg
professionals and are published in the book "Sciences
des traitements capillaires [Hair treatinent sciences]"
by Charles Zviak, 1988, published by Masson, pp 215
and 278
The tone depths range from 1 (black) to 10 (very light
blond), one unit corresponding to one tone, the higher
the figure, the lighter the shade
Artificially dyed hair is hair whose color has been
modified by a coloration treatinent, for example a
coloration with direct dyes or oxidation dyes.
For the purposes of the invention, the term "bleached
hair" means hair whose tone depth is greater than 6 and
preferably greater than 7
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 reflectance
of the hair
Preferably, the composition should, after application
to dark hair, lead to the results below
- What is concerned is the reflectance performance of
the hair when it is irradiated with visible light in
the wavelength range from 4 00 to 700 nanometers

- The curves of reflectance as a function of the
wavelength, for hair treated with the composition of
the invention and for untreated hair, are then
compared
- The curve corresponding to the treated hair should
show a reflectance in the wavelength range from 500
to 7 00 nanometers higher than the curve corresponding
to the untreated hair
- This means tnat, in the wavelength range from 54 0 to
700 nanometers, there is at least one region in which
the reflectance curve corresponding to the treated
hair is higher than the reflectance curve
corresponding to the untreated hair The term
"higher" means a difference in reflectance of at
least 0.05% and preferably of at least 0 1% This
does not prevent there from being in the wavelength
range from 54 0 to 700 nanometers at least one region
in which the reflectance curve corresponding to the
treated hair is superposable, or lower than the
reflectance curve corresponding to the untreated
hair
Preferably, the wavelength at which the difference is
maximal between the reflectance curve for the treated
hair and that for the untreated hair is in the
wavelength range from 500 to 650 nanometers and
preferably in the wavelength range from 550 to
62 0 nanometers
For the purposes of the present invention, and unless
otherwise indicated
- the term "colorless compound or chromophore" means a
compound or chromophore that does not absorb light in
the visible spectrum, l e in the spectrum at a
wavelength of between 250 and 8 00 nm, particularly
between 400 and 700 nm (Ullmann's Encyclopedia, 2005,
^ ^lley^-VcH,^Verlag "Dye^,7 General Survey", § 2 1 Basic

Principle of Color),
- the term "colored compound or chromophore" means a
compound or chromophore that absorbs light in the
visible spectrum at an absorption wavelength of
between 250 and 800 nm as defined previously,
particularly between 400 and 800 nm,
- the term "fluorescent compound or chromophore" means
a compound or chromophore that absorbs light at a
maximum wavelength that is in the visible spectrum
and that re-emits the light in the visible spectrum
at a wavelength longer than the maximum absorption
wavelength, the difference between the maximum
absorption wavelength and the emission or
fluorescence wavelength being commonly referred to as
the Stoke's shift the Stoke's shift is particularly
between 1 and 10 0 nm,
- the "aryl" or "heteroaryl" radicals or the aryl or
heteroaryl portion of a radical may be substituted
with at least one substituent chosen from

• a C1-C16 and preferably C1-C8 alkyl radical,
optionally substituted with one or more radicals
chosen from the following radicals hydroxyl, C!-C2
alkoxy, C2-C4 (poly) hydroxyalkoxy, acylamino, amino
substituted with two identical or different C1-C4
alkyl radicals, optionally bearing at least one
hydroxyl group, or both radicals possibly forming
with the nitrogen atom to which they are attached
a saturated or unsaturated, optionally substituted
5- to 7-membered and preferably 5- or 6-membered
neterocycle, optionally comprising another
heteroatom identical to or different from
nitrogen,
• a halogen atom such as chlorine, fluorine or
bromine,
o a hydroxyl group,
9 a CrC2 alkoxy radical,
• a C!-C2 alkylthio radical,
• a C2-C4 (poly)hydroxyalkoxy radical,
. A"f &anlaF!:rt5>2^.acf:iL5:a-14 3-23

• a 5- or 6-membered heterocycloalkyl radical,
o an optionally cationic 5- or 6-membered heteroaryl
radical, preferentially lmidazolium, optionally
substituted with a (C;L-C4) alkyl radical,
preferentially methyl,
• an amino radical substituted with one or two
identical or different C!-C6 alkyl radicals,
optionally bearing at least
1) one hydroxy1 group,
n) 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 saturated or unsaturated,
optionally substituted 5- to 7-membered
heterocycle, optionally comprising at least
one other heteroatom identical to or different
from nitrogen,
» -N(R)-C(0)-R' in which the radical R is a hydrogen
atom or a C1-C4 alkyl radical optionally bearing at
least one hydroxyl group and the radical R1 is a
C1-C2 alkyl radical,
• (R)2N-C(0)- in which the radicals R, which may be
identical or different, represent a hydrogen atom
or a Cn-CU alkyl radical optionally bearing at
least one hydroxyl group;
• R'S(0)2-N(R) - in which the radical R represents a
hydrogen atom or a C1-C4 alkyl radical optionally
bearing at least one hydroxyl group and the
radical R' represents a C1-C4 alkyl radical, or a
phenyl radical,
• (R)2N-S(0)2- in which the radicals R, which may be
identical or different, represent a hydrogen atom
or a C].-C4 alkyl radical optionally bearing at
least one hydroxyl group,
• a carboxylic radical in acid or salified form
(preferably with an alkali metal or a substituted
or unsubstituted aminonium),

c a polyhaloalkyl group containing from 1 to 6
carbon atoms and comprising from 1 to 6 identical
or different halogen atoms, the polyhaloalkyl
group is, for example, trifluoromethyl,
- the cyclic or heterocyclic part of a nonaromatic
radical may be substituted with at least one
substituent borne by a carbon atom, chosen from the
groups:
• hydroxy1,
• C1-C4 alkoxy,
• C2-C4 (poly)hydroxyalkoxy,
• a C1-C2 alkylthio radical,
• RC(0)-N(R')- in which the radical R' is a hydrogen
atom or a C1-C4 alkyl radical optionally bearing at
least one hydroxyl group and the radical R is a
C3.-C2 alkyl radical or an amino radical substituted
with two identical or different C1-C4 alkyl groups,
optionally bearing at least one hydroxyl group,
• RC(0)-O- in which the radical R is a C1-C4 alkyl
radical or an amino radical substituted with one
or two identical or different C1-C4 alkyl groups
optionally bearing at least one hydroxyl group,
said alkyl radicals possibly forming with the
nitrogen atom to which they are attached a
saturated or unsaturated, optionally substituted
5- to 7-membered heterocycle, optionally
comprising at least one other heteroatom identical
to or different from nitrogen,
• RO-C(O)- in which the radical R is a C1-C4 alkyl
radical optionally bearing at least one hydroxyl
group,

- a cyclic or heterocyclic radical, or a nonaromatic
portion of an aryl or heteroaryl radical, may also be
substituted with one or more oxo or thioxo groups,
- an "aryl" radical represents a fused or nonfused
monocyclic or polycyclic carbon-based group
containing from 6 to 22 carbon atoms, and in which at
least one ring is aromatic, preferentially, the aryl
k ^r^agicaii jifs -, a{ -j phenyl.,, -biphenyl, naphthyl, mdenyl,

anthracenyl or tetrahydronaphthyl,
- a "diarylalkyl" radical represents a group comprising
on the same carbon atom of an alkyl group two
identical or different aryl groups such as
diphenylmethyl or 1,l-diphenylethyl,
- a "heteroaryl radical" represents a fused or
nonfused, optionally cationic, 5- to 22-membered
monocyclic or polycyclic group, comprising from 1 to
6 heteroatoms chosen from nitrogen, oxygen, sulfur
and selenium, and at least one ring of which is
aromatic, preferentially, a heteroaryl radical is
chosen from acridmyl, benzimidazolyl,
benzobistriazolyl, benzopyrazolyl, benzopyridazmyl,
benzoqumolyl, benzothiazolyl, benzotriazolyl,
benzoxazolyl, pyridyl, tetrazolyl, dihydrothiazolyl,
lmidazopyridyl, lmidazolyl, indolyl, isoquinolyl,
naphthoimidazolyl, naphthooxazolyl, naphthopyrazolyl,
oxadiazolyl, oxazolyl, oxazolopyridyl, phenazmyl,
phenoxazolyl, pyrazinyl, pyrazolyl, pyrilyl,
pyrazoyltriazyl, pyridyl, pyridmoimidazolyl,
pyrrolyl, quinolyl, tetrazolyl, thiadiazolyl,
thiazolyl, thiazolopyridyl, thiazoylimidazolyl,
thiopyrylyl, triazolyl, xanthylyl and the aminonium
salt thereof,
- a "diheteroarylalkyl" radical represents a group
comprising on the same carbon atom of an alkyl group
two identical or different heteroaryl groups, such as
difurylmethyl, 1,1-difurylethyl, dipyrrolylmethyl or
dithienylmethyl,
- a "cyclic radical" is a fused or nonfused monocyclic
or polycyclic nonaromatic cycloalkyl radical
containing from 5 to 22 carbon atoms, which may
comprise one or more unsaturations, the cyclic
radical is particularly a cyclohexyl,
- a "sterically hindered cyclic" radical is an aromatic
or nonaromatic, substituted or unsubstituted, 6- to
14-membered cyclic radical, which may be bridged,
hindered by a steric effect or constraint -sterically
t, ^hinde-redf f;raC1-icais -j fehati %may be mentioned include

bicyclo[l 1 0]butane, mesityls such as 1,3,5-
trimethylphenyl, 1, 3 , 5-tri-tert-butylphenyl, 1,3,5-
lsobutylphenyl and 1,3,5-tnmethylsilylphenyl, and
adamantyl;
- a "heterocyclic radical or heterocycle" is a fused or
nonfused, 5- to 22-membered monocyclic or polycyclic
nonaromatic radical, comprising from 1 to 6
heteroatoms chosen from nitrogen, oxygen, sulfur and
selenium,
- an "alkyl radical" is a linear or branched C1-C16,
preferably C1-Cs hydrocarbon-based radical,
- the term "optionally substituted" attributed to the
alkyl radical implies that said alkyl radical may be
substituted with one or more radicals chosen from the
following radicals: I) hydroxyl, n) C1-C4 alkoxy,
m) acylamino, IV) amino optionally substituted with
one or two identical or different C1-C4 alkyl
radicals, said alkyl radicals possibly forming with
the nitrogen atom that bears them a 5- to 7-membered
heterocycle optionally comprising another heteroatom
identical to or different from nitrogen, v) or a
quaternary aminonium group -N+R'R' ' R' ' ' , M" for which
R' , R' ' and R'", which may be identical or
different, represent a hydrogen atom or a C!-C4 alkyl
group, or alternatively -N+R'R' 'R' ' ' forms a
heteroaryl such as lmidazolium optionally substituted
with a C1-C4 alkyl group, and M" represents the
counterion of the organic or mineral acid or of the
corresponding halide,
- an "alkoxy radical" is an alkyl-oxy or alkyl-O-
radical for which the alkyl radical is a linear or
branched C1-C16 and preferentially C1-C8 hydrocarbon-
based radical,
- an "alkylthio radical" is an alkyl-S- radical for
which the alkyl radical is a linear or branched C;L-CI6
and preferentially QL-CB hydrocarbon-based radical,
when the alkylthio group is optionally substituted,
this implies that the alkyl group is optionally
. ,, substituteC1-as-tdefin&d previously,

- an "alkylene chain" represents a divalent C1-Ci8,
particularly C1-C6 and more particularly C1-C2 chain
when the chain is linear, optionally substituted with
one or more identical or different halogen atoms or
groups chosen from hydroxyl, alkoxy, (d1) (Cj.-
C4) (alkyl)amino, Ra-Za-C(Zb)- with Za and Zb, which may
be identical or different, representing an oxygen or
sulfur atom or a group NRa', and Ra representing an
alkali metal, a hydrogen atom or an alkyl group and
Ra' representing a hydrogen atom or an alkyl group;
- an "optionally substituted, saturated or unsaturated
C1-C20 hydrocarbon-based chain" represents a
hydrocarbon-based chain, particularly a C1-C8 chain,
optionally comprising one or more conjugated or
unconjugated K double bonds, the hydrocarbon-based
chain particularly being saturated, said chain is
optionally substituted with one or more identical or
different halogen atoms or groups chosen from
hydroxyl, alkoxy, (d1) (C0.-C4) (alkyl) amino and Rb-Zb-
C(ZC)- with Zb and Zc, which may be identical or
different, representing an oxygen or sulfur atom or a
group NRb', and Rb representing an alkali metal, a
hydrogen atom or an alkyl group and Rb| representing a
hydrogen atom or an alkyl group,
- the limit values delimiting the extent of a range of
values are included in this range of values,
- an "organic or mineral acid salt" is more
particularly chosen from a salt derived from 1)
hydrochloric acid HC1, 11) hydrobromic acid HBr, 111)
sulfuric acid H2SO4, IV) alkylsulfonic acids Alk-
S(0)2OH such as methanesulfonic acid and
ethanesulfonic acid, v) arylsulfonic acids Ar-S(0)20H
such as benzenesulfonic acid and toluenesulfonic
acid, vi) citric acid, vii) succinic acid, vin)
tartaric acid, IX) lactic acid, x) alkoxysulf mic
acids Alk-O-S(0)OH such as methoxysulfmic acid and
ethoxysulfmic acid, xi) aryloxysulfmic acids such
as tolueneoxysulfmic acid and phenoxysulfmic acid,
I AX-I.L) -J. phos(phor-iQ- aoid 71 -JH3PO4, xm) acetic acid

CH3C(0)OH, xiv) triflic acid CF3SO3H, and xv)
tetrafluoroboric acid HBF4,
- 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. 1) halides such as chloride and bromide, 11)
nitrates, m) sulfonates, including C1-C6
alkylsulfonates Alk-S(0)20" such as methanesulfonate
or mesylate, and ethanesulfonate, IV) arylsulfonates•
Ar-S(0)20~ such as benzenesulfonate and
toluenesulfonate or tosylate, v) citrate, vi)
succinate, vn) tartrate, vni) lactate, IX) alkyl
sulfates Alk-O-S(0)0~ such as methane sulfate and
ethane sulfate, x) aryl sulfates: Ar-O-S(0)0" such as
benzene sulfate and toluene sulfate, xi) alkoxy
sulfates Alk-O-S(0)20~ such as methoxy sulfate and
ethoxy sulfate; xn) aryloxy sulfates Ar-O-S (0) 2C>~,
xni) phosphate, xiv) acetate, xv) triflate, and xvi)
borates such as tetrafluoroborate,
- the "solvates" represent hydrates and also the
combination with linear or branched C1-C4 alcohols
such as ethanol, isopropanol or n-propanol.
The fluorescent dyes derived from the precursors (I)
and (II), or the chromophores derived from precursors
(I) and (II) as defined above are fluorescent dyes or
chromophores, i.e. they are capable of absorbing UV or
visible radiation at a wavelength AabS of between 250
and 800 nm and capable of re-emitting in the visible
region at an emission wavelength Aem of between 400 and
8 00 nm
Preferably, the fluorescent compounds or chromophores
derived from the precursors of formulae (I) and (II)
are dyes or chromophores capable of absorbing in the
visible region Aabs between 400 and 800 nm and re-
emitting in the visible region Aem between 400 and
800 nm More preferentially, the dyes or chromophores
I dgB-ijfedi f rpmt --fchq Epreicur:sqars of formulae (I) and (II)

are dyes capable of absorbing at a Aabs of between
420 nm and 550 nm and of re-emitting in the visible
region at a Aera of between 4 70 and 600 nm
The nonfluorescent dyes derived from precursors (I) and
(II), or the chromophores derived from precursors (I)
and (II) as defined above are dyes or chromophores
capable of absorbing UV or visible radiation at a
wavelength Aabs of between 4 00 and 8 00 nm but of not re-
emitting visible light
The dye precursors of the invention of formula (I) when
x and y are 1, contain a function SY, which may be in covalent form -S-Y or ionic form -S~ Y+ depending on the
nature of Y and of the pH of the medium
One subject of the invention concerns a process for
dyeing keratin fibers, which consists in applying to
said fibers, optionally pretreated with a reducing
agent
I) a cosmetically acceptable composition comprising at
least one colorless thiol/disulfide dye precursor
of formula (I), and
11) a cosmetically acceptable composition comprising at
least one colorless dye precursor of formula (II) ,
part B of which reacts chemically with part A to
form a colored or colored and fluorescent
chromophore B-X'-A-,
with the compounds of formulae (I) and (II) which are
as defined previously
One particular mode concerns a dyeing process using a
colorless dye precursor (I) with x and y equal to 1,
and comprising a radical Y representing a hydrogen atom
or an alkali metal Advantageously, Y represents a
hydrogen atom

protecting group known to those skilled in the art, for
instance these described in the publications
"Protective Groups in Organic Synthesis", T W Greene,
published by John Wiley & Sons, NY, 1981, pp 193-217;
"Protecting Groups", P Kocienski, Thieme, 3rd edition,
2005, chapter 5 In particular, when Y represents a
protecting group for the thiol function, Y is chosen
from the following radicals
■ (C1-C4) alkylcarbonyl,
■ (C1-C4) alkylthiocarbonyl,
■ (C1-C4) alkoxycarbonyl,
■ (C1-C4) alkoxythiocarbonyl,
■ (C1 - C4)alkyltniothiocarbonyl;
■ (d1) (C1-C4) (alkyl) aminocarbonyl,
■ (d1) (C1-C4) (alkyl)aminothiocarbonyl,
■ arylcarbonyl, for instance phenylcarbonyl,
■ aryloxycarbonyl,
■ aryl (C1 - C4) alkoxycarbonyl,
■ (d1) (C1-C4) (alkyl) aminocarbonyl, for instance
dimethylaminocarbonyl,

■ (C1-C4) (alkyl) arylaminocarbonyl,
■ SO3"; M+ with M+ representing an alkali metal such as
sodium or potassium, or alternatively An or An1" of
formula (I) cr (II) and M+ are absent,
■ optionally substituted aryl such as phenyl,
dibenzosuberyl or 1,3,5-cycloheptatrienyl,
■ optionally substituted heteroaryl, especially
including the following cationic or noncationic
heteroaryl radicals comprising from 1 to 4
heteroatoms
1) 5-, 6- or 7-membered monocyclic radicals 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,
!, ftTft pyryl2j\im,f-f-rthiopyrj-dyl;, pyndinium, pyrimidmyl,

pyrimidimum, pyrazmyl, pyrazinium, pyridazmyl,
pyridazinium, triazinyl, triazimum, tetrazinyl,
tetrazmium, azepme, azepmium, oxazepinyl,
oxazepinium, thiepmyl, thiepinium, ltnidazolyl,
lmidazolxum,
11) 8- to 11-membered bicyclic radicals 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 (C1-
C4)alkyl, for instance methyl, or polyhalo(C1-
C4)alkyl, for instance trifluoromethyl,
optionally cationic, optionally substituted
heterocycloalkyl, the hetercycloalkyl group
especially represents 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,
piperazmyl, piperidinyl, tetramethylpiperidyl,
morpholmyl, di/tetra/hexahydroazepmyl,
di/tetrahydrcpyrimidmyl, these groups being
optionally substituted with one or more groups such
as (C1-C4) alkyl, oxo or thioxo, or the heterocycle
represents the following group

m which R,c, R'd, R,e, R'f, R'9 and R'h, which may be
identical or different, represent a hydrogen atom or
a (C1-C4) alkyl group, or alternatively two groups R,g
with Jl'h, ,-anC1-/orr R'*e ->w„ith-, R'f, form an oxo or thioxo

group, or alternatively R'g with R'e together form a
cycloalkyl, and v represents an integer between 1 and
3 inclusive, preferentially, R,c to R'h represent a
hydrogen atom, and An'''- represents a counterion,
■ isothiouronium;
■ -C(NR'cR,d)=N+R,eR,f, An'11" with R,c, R,d, R,e and R,f,
which may be identical or different, representing a
hydrogen atom or a (C1-C4)alkyl group, preferentially,
R'c to R'f represent a hydrogen atom, and An' ' '"
represents a counterion;
■ iscthiourea,
■ -C(NR,cR,d)=NR,e, with R,c, R,d and R,e as defined
previously,
■ optionally substituted (d1) aryl (C!-C4) alkyl such as 9-
anthracenylmethyl, phenylmethyl or diphenylmethyl
optionally substituted with one or more groups
especially chosen from (C1-C4) alkyl, (C!-C4) alkoxy
such as methoxy, hydroxyl, alkylcarbonyl or (d1) (C1-
C4) (alkyl) amino such as dimethylamino;
■ optionally substituted (d1) heteroaryl (C1-C4) alkyl, the
heteroaryl group especially being a cationic or
noncationic, 5- or 6-membered monocyclic radical
comprising from 1 to 4 heteroatoms chosen from
nitrogen, oxygen and sulfur, such as pyrrolyl,
furanyl, thiophenyl, pyridyl, pyridyl N-oxide such as
4-pyridyl or 2-pyridyl-N-oxide, pyrylium, pyridmium
or triazmyl groups, optionally substituted with one
or more groups such as alkyl, particularly methyl,
advantageously, the (d1) heteroaryl (C1-C4) alkyl is
(d1)heteroarylmethyl or (d1)heteroarylethyl,
■ CR1R2R3 with R1, R2 and R3, which may be identical or
different, representing a halogen atom or a group
chosen from

- (C1-Cj alkyl,
- (C1-C4) alkoxy,
- optionally substituted aryl such as phenyl
optionally substituted with one or more groups, for
instance (C1-C4) alkyl, (C1-C4) alkoxy or hydroxyl,
l: a T gptuona^-ly n 1 substituted heteroaryl such as

thiophenyl, furanyl, pyrrolyl, pyranyl or pyridyl,
optionally substituted with a (C1-C4)alkyl group,
- P(Z1)R,1R,2R'3 with R'1 and R'2, which may be
identical or different, representing a hydroxyl,
(C1.-C4) alkoxy or alkyl group, R'3 representing a
hydroxyl or (C1-C4) alkoxy group, and Z1 representing
an oxygen or sulfur atom,
■ a sterically hindered ring; and
■ optionally substituted alkoxyalkyl, such as
methoxymethyl (MOM), ethoxyethyl (EOM) and
1sobutoxymethy1
One particular mode of the invention concerns the
dyeing process in which the chromophore of the final
product B-X'-A- derived from the precursors of formulae
(I) and (II) contains a group X' that represents an
lmine, (poly)methme, styryl, azomethme or azo group,
more particularly styryl.
The colorless dye precursors are chosen, for example,
from:
- the precursor (I) which represents [H2N-A-L-S] x- (Y)y,
and the dye precursor (II) of formula B-C(G)-H to
give the chromophore B-X'-A- which represents B-CH=N-
A-, with G representing an oxygen or sulfur atom,
this reaction is described, for example, in the
literature J Heterocyclic Chem , 44(3), 617-626,
2007,
- the precursor (I) which represents [H-C(G)-A-L-S]x-
(Y)y, and the dye precursor (II) of formula B-NH2 to
give the chromophore B-X'-A- which represents B-N=CH-
A-, with G as defined above,
this reaction is described, for example, in the
literature Huaxue shijie 46(6), 352-3, 357, 2005,
- the precursor (I) which represents [H3C-A-L-S]x-(Y) y,
y ix,9p.d the 1 dye ^precursor j(II) of formula B-C(G')- to

give the chromophore B-X'-A- which represents
B-CH=CH-A-, with G' representing an oxygen or sulfur
atom or NH,
this reaction is known to those skilled in the art as
the Knoevenagel reaction, which is detailed
herembelow,
- the precursor (I) which represents [H-C(G1)-A-L-S]x-
(Y)y, and the dye precursor (II) of formula B-CH3 to
give the chromophore B-X'-A- which represents B-
CH=CH-A-, with G' as defined above,
this reaction is described, for example, in the
literature Chemische Berichte 113(2), 457-70,1980,
J Heterocyclic Chem , 16(8), 1583-7, 1979,
- the precursor (I) which represents [G1 '-A-L-S]x-(Y)y,
and the nitroso-derived dye precursor (II) of formula
B-NO to give the chromophore B-X'-A- which represents
B-N=A'-, with A' representing an aryl or heteroaryl
group derived from A, comprising an oxo function if
G' ' represents a hydroxyl group, or alternatively an
imino group if G' ' represents a (C1-C6) (alkyl)amino
group,
this reaction is described, for example, in the
literature J" Amer Chem Soc. , 68, 2641-3, 1946,
ibid 71, 3260-2, 1949, Heterocycles 12(3), 323-7,
1979,
- the precursor (I) which represents a nitroso
derivative [ON-A-L-S] x-(Y)y, and the dye precursor
(II) of formula B-G'' to give the chromophore B-X'-A-
which represents B'=N-A-, with B' representing an
aryl or heteroaryl group derived from B, comprising
an oxo function if G' ' represents a hydroxyl group,
or alternatively an imino group if G' ' represents a
(C1-C6) (alky 1) amino group,
this reaction is described, for example, in the
literature J" .Amer Chem Soc , 68, 2641-3, 1946,
: ^i-bid f71,i ri3-2 6;P j-2^, f%££;2 '\Heterocycles 12(3), 323-7,

1979,
- the precursor (I) which represents [G''-A-L-S]x-(Y)y,
and the dye precursor (II) of formula B-N2+ to give
the chromophore B-X'-A- which represents B-N=N-A with
G'' representing a hydrogen atom,
this reaction is described, for example, in the
literature Color Chemistry, Ed H Zollinger ISBN 3-
906390-23-3 pages 172-186,
- the precursor (I) which represents [N2+-A-L-S] x- (Y) y,
and the dye precursor (II) of formula B-G' ' to give
the chromophore B-X'-A- which represents B-N=N-A. G'1
represents a hydrogen atom,
this reaction is described in the literature Color
Chemistry, Ed H Zollinger ISBN 3-906390-23-3 pages
172-186,
- the precursor (I) which represents [H-C(G)-A-L-S]x-
(Y)y, and the dye precursor (II) of formula B-N(R)-NH2
to give the chromophore B-X'-A- which represents B-
N(R)-N=CH-A-, with G as defined above and R
representing a hydrogen atom or a (polyhydroxy)(C1-
C4)alkyl group;
this reaction is described in the literature
J Amer. Chem Soc , 62,3522,1940, Chemische Berichte
95,562-70, 1962,
- the precursor (I) which represents [H3C-A-L-S]x-(Y)y,
and the dye precursor (II) of formula B-N2+ to give
the chromophore B-X'-A- which represents B-N(R)-N=CH-
A-, with G' representing an oxygen or sulfur atom or
NH and R as defined above,
this reaction is described in the literature Jpn
Kokai TOKKYO Koho 2001019866 23/01/2001, Zhurnal
Obshchei Khimn 48(8), 1793-8, 1978, Khimiko-
farmatseuticheskn Zhurnal 12(11), 48-53, 1978
Agqor^ding,! t (t^O} n P^e 7 particular embodiment of the

invention, the dye precursors of formula (I) that are
useful for the dyeing process according to the
invention comprise
- either a group A representing an aryl group such as
phenyl, naplithyl, mdolyl or pyridyl, optionally
substituted with a (C1-C^) alkyl, (C1-C6) alkoxy, (C1-
C6) alkylthio, (d1) (C1-C6) (alkyl) amino, (C1-
C6)polyhaloalkyl, hydroxyl, (C1-C6) polyhydroxyalkyl,
polyhydroxy (C1-C6) alkoxy, cyano, R-G-C(G')-, R-C(G')-
G-, R'S(0)2-N(R) -, RR'N-S(0)2- group, with G or G',
which may be identical or different, representing an
oxygen or sulfur atom or a group NR1 , and R and R',
which may be identical or different, representing a
hydrogen atom or a (C^d) alkyl group, and in this
case the group B of the precursor of formula (II)
represents a cationic heteroaryl group such as
lmidazolium, pyridimum, qumolmium or mdolmium
optionally substituted with a (C1-C6) alkyl, (C1-
C6) alkoxy, (C1-C6) alkylthio, (d1) (C1-C6) (alkyl) amino,
(C1-C6)polyhaloalkyl, hydroxyl, (C1-
C6) polyhydroxyalkyl, polyhydroxy (C1-C6) alkoxy, cyano,
R-G-C(G')-, R-C(G')-G-, R' S (0) 2-N (R) - , RR'N-S(0)2-
group with G or G', which may be identical or
different, representing an oxygen or sulfur atom or a
group NR' , and R and R1 , which may be identical or
different, representing a hydrogen atom or a (C1-
C6) alkyl group,
- or a group A representing a cationic heteroaryl group
such as lmidazolium, pyridimum, qumolmium or
mdolmium optionally substituted with a (C1-C6) alkyl,
(C1-C6) alkoxy, (C1-C6) alkylthio, (d1) (C1-
C6) (alkyl) amino, (d~C6) polyhaloalkyl, hydroxyl, (C1-
C6) polyhydroxyalkyl, polyhydroxy (C1-C6) alkoxy, cyano,
R-G-C(G')-, R-C(G')-G-, R ' S (0) 2-N (R) - , RR'N-S(0)2-
group with G or G', which may be identical or
different, representing an oxygen or sulfur atom or a
group NR1 , and R and R' , which may be identical or
different, representing a hydrogen atom or a (C1-
k ^G^^alky-l-ig-re-up-, a^iC1-j m. this case the group B of the

precursor of formula (II) represents an aryl group
such as pnenyl, naphthyl, indolyl or pyridyl
optionally substituted with a (C1-C6) alkyl, (C1-
C6)alkoxy, (C1-C6) alkylthio, (d1) (C1-C6) (alkyl) amino,
(C1-C6)polyhaloalkyl, hydroxyl, (C1-
C6)polyhydroxyalkyl, polyhydroxy (C1-C6) alkoxy, cyano,
R-G-C(G,)-/ R-C(G')-G-, R ' S (0) 2-N(R)-, RR'N-S(0)2-
group with G or G', which may be identical or
different, representing an oxygen or sulfur atom or a
group NR', and R and R', which may be identical or
different, representing a hydrogen atom or a (C1-
C6) alkyl group
One particular embodiment concerns a dyeing process
that consists in applying to keratin fibers, which have
optionally been reduced beforehand, a colorless
disulfide precursor containing activated methylene of
formula (I2) as defined previously, it being understood
that the term "activated methylene" is considered as
being a methylene group that is sufficiently
nucleophilic to react with an electrophilic group and
thus to form a bond allowing electron transfer from A
to B and vice-versa;

and a colorless aldehyde-based precursor of formula
(Hi) below

In which formula (Hi)
n represents 0 or 1,
Ar represents an optionally substituted aryl or
heteroaryl group, particularly aryl such as phenyl
optionally substituted with
• a C1-C4 alkyl group,

e a hydroxyl group,
« a C1-C4 alkoxy group,
• a C2-C4 (poly)hydroxyalkoxy group,
• an alkoxycarbonyl group (RaO-C(0)-) in which Ra
represents a C1-C4 alkyl radical,
• an alkylcarbonyloxy group (RaC(0)-O-) in which Ra
represents a C1-C4 alkyl radical,
• an amino group optionally substituted with one or
more C1-C4 alkyl radicals, which may be identical or
different, optionally bearing at least one hydroxyl
group, the two alkyl radicals possibly forming with
the nitrogen atom to which they are attached a
substituted or unsubstituted 5- or 6-membered
heterocycle optionally bearing another heteroatom
identical to or different from nitrogen, for example
oxygen,
• an alkylcarbonylamino group (RaC(0)-NR'a-) in which Ra
represents a C1-C4 alkyl radical and R'a represents a
hydrogen atom or a C1-C4 alkyl radical,
• a (di-) (alkyl) aminocarbonyl group ( (Ra) 2N-C (0) ) in
which the radicals Ra, independently of each other,
which may be identical or different, represent a
hydrogen atom or a C1-C4 alkyl radical,
• a ureido group ( (Ra) 2N-C0-NRb-) in which the radicals
Ra and Rb, independently of each other, represent a
hydrogen atom or a C1-C4 alkyl radical,
• a halogen atom, preferably chlorine, fluorine or
bromine
Another particular embodiment of the invention concerns
a process that consists in applying to keratin fibers,
which have optionally been reduced beforehand, a
colorless disulfide precursor containing an aldehyde
function of formula (Ii)

in which formula (I^
B Ar represents an optionally substituted arylene or
heteroarylene group such as phenylene, naphthylene,
pyridmylene or pyrazolene, and particularly
phenylene,
■ L is as defined previously,
and a colorless precursor containing an activated
methyl of formula (II2) below

m which formula (II2)
■ R represents an optionally substituted (C1-C6)alkyl
group;
■ represents a 5- to 13-membered cationic
heteroaryl group, possibly comprising, besides the
cationic nitrogen atom, from 1 to 3 heteroatoms
chosen from nitrogen, oxygen and sulfur, and which
bears on a carbon atom a methyl group, such as
pyndinium or quinolimum, the methyl group
particularly being in position 2 or 4 of the
pyndinium or of the quinolimum
For example, the dyeing process may consist:
I) IN a first stage, in applying a cosmetic
composition comprising an aromatic dialdehyde
disulfide compound belonging to the general
formulae (I) and (Ii) , of the following structure

optionally of adding a fixing agent such as an
oxidizing agent, to improve the fixing of the
disulfide precursor to the keratin fibers which
have optionally been reduced beforehand, and then
n) of applying a composition comprising a precursor
containing activated methylene belonging to
formulae (II) and (II2) , such as 1,4-dimethyl

pyridinium This process may be represented
schematically as follows

During the first step, the cosmetic composition
comprising the colorless precursor belonging to
formulae (I) and (lx) is applied to keratin fibers,
which are advantageously pre-reduced, and during step 2
the cosmetic composition comprising the colorless
precursor belonging to formulae (II) and (II2) is
applied to the keratin fibers
Another particular embodiment concerns a dyeing process
that consists in applying to keratin fibers, which have
optionally been reduced beforehand, a colorless
heterocyclic disulfide precursor containing activated
methylene of formula (I) with a colorless aldehyde-
based precursor of formula (II)
For example, the dyeing process may consist
1) in a first stage, in applying a cosmetic
composition comprising a bispyridinium disulfide
compound containing activated methylene belonging
to the general formulae (I) and (I2) of the
following formula

optionally of adding a fixing agent such as an
oxidizing agent, to improve the fixing of the
disulfide precursor to the keratin fibers which
have pptt-ion^lly been, reduced beforehand, and then

ii) of applying a composition comprising a precursor
containing an aldehyde function belonging to
formulae (II) and (Hi), such as 4-{N,N-
dimethylamino) benzaldehyde This process may be
represented schematically as follows.

During the first step, the cosmetic composition
comprising the colorless precursor belonging to
formulae (I) and (I2) is applied to keratin fibers,
which are advantageously pre-reduced, and during step 2
the cosmetic composition comprising the colorless
precursor belonging to formulae (II) and (Hi) is
applied to the keratin fibers.
According to one particular embodiment in the process
of the invention, a reducing agent may be applied to
the keratin fibers as a pretreatinent before application
of the dye precursor of formula (I) This reducing
agent may be chosen from thiols, for instance cysteine,
homocysteine, thiolactic acid, salts of these thiols,
phosphmes, bisulfite, sulfites, thioglycolic acid, and
also esters thereof, especially glyceryl
monothioglycolate, and thioglycerol This reducing
agent may also be chosen from borohydrides and
derivatives thereof, for instance salts of borohydride,
of cyanoborohydride, of triacetoxyborohydride or of
trimethoxyborohydride sodium, lithium, potassium,
calcium, or ^quaternary-, aminonium (tetramethylaminonium,

tetraethylaminonium, tetra-n-butylaminonium or
benzyltriethylaminonium) salts, catecholborane
This pretreatinent may be of short duration, especially
from 1 second to 3 0 minutes and preferably from
1 minute to 15 minutes, with a reducing agent as
mentioned previously.
According to cne variant, the reducing agent is added
to the dye composition containing at least the
colorless precursor of formula (I) at the time of use
According to another variant, the reducing agent is
applied as a post-treatinent, after applying the dye
composition containing at least the colorless precursor
of formula (I) The duration of the post-treatinent with
the reducing agent may be short, for example from
0 1 second to 3 0 minutes and preferably from 1 minute
to 15 minutes, with a reducing agent as described
previously According to one particular embodiment, the
reducing agent is an agent of thiol or borohydride type
as described previously
When the dye precursor of formula (I) for which x and y
are 1 comprises a protecting group Y for the thiol
function, the process of the invention may be preceded
by a deprotection step for restoring m-situ the SH
function
By way of example, it is possible to deprotect the
function S-Y of the dyes of the invention with Y being
a protecting group, by adjusting the pH as follows



The deprotection step may also be performed during a
step of pretreatinent of the hair, for instance the hair
reducing pretreatinent.
One particular embodiment of the invention concerns a
process in which the colorless thiol or thiol-protected
precursor of formula (I) may be applied directly to the
hair without reducing agents, free of pretreatinent or
post-treatinent reducing agents
A treatinent with an oxidizing agent may optionally be
combined Any type of oxidizing agent that is
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 uncases, and 4-electron oxygenases such as
laccases The use of hydrogen peroxide is particularly
preferred The leave-on time of the oxidizing agent may
be between 1 second and 10 minutes
The dye composition according to the invention is
generally applied at room, temperature However, it may

be applied at temperatures ranging from 20 to 180°C
As indicated previously, another subject of the
invention is the colorless disulfide dye precursor of
formula di) or (I2) , or a colorless thiol or thiol-
protected dye precursor of formula (I3) , (I4) or (I5) ,
with the exception of compounds (1) to (xxvm) as
defined previously
According to one preferred variant of the invention,
the precursors of formula (I) for which x=y=l, the
radical Y represents a hydrogen atom or a group chosen
from (C1-C6)alkylcarbonyl, particularly acetyl,
optionally substituted arylcarbonyl, isothiourea or
isothiouronium, the group is particularly a group
C(NH2)=NH or -C (=N+H2) NH2, and SO3"
One particular embodiment of the invention concerns the
precursors of formula (Ii) for which Ar represents a
phenylene group
More particularly, these dye precursors are of formula
(Is)

in which formula (I6)
■ Ar represents a phenylene group such as 1,4 or 1,2-
phenylene,
■ T represents an amino group NR or amido group -NR-
C(O)- or -C(0)-NR- with R representing a hydrogen
atom or a (C1-C^alkyl group,
B ALK represents a divalent C1-Ci0 alkylene chain,
optionally interrupted with one or more divalent
groups or combinations thereof chosen from -N(Ra)-,
-N+(Ra) (Rb)-/ An", -CO- and with Ra and Rb, which may
be identical or different, chosen from a hydrogen and
a (C1-C6)alkyl radical, and An" representing an
_kftT A 12 1 rj 2 0 15 L 3 '- 2 3

anionic counterion, or 11) with a catiomc
heterocycle or catiomc heteroaryl Het+, An", with An"
representing an anionic counterion and Het+
representing a saturated or unsaturated 5- to 10-
membered heterocycle, or a 5- to 10-membered
heteroaryl such as iraidazolium, piperazinium or
piperidmium, with An" representing an anionic
counterion, and
■ n is 0.
One particular embodiment of the invention also
concerns the precursors of formula (I2) for which L
represents a C1-Ci0 alkylene chain, particularly
ethylene; optionally interrupted with a sulfonamide
group
More particularly, the compounds of formula (I2)
contain a group bearing an activated methylene
which represents a catiomc heteroaryl group chosen
from pyridmium, particularly 2- or 4-pyridmium,
benzoxazolium, benzimidazolium, benzothiazolium,
thiazolium, mdolmium, mdolyl and qumolmium,
particularly 2- or 4-qumolmium
Examples that may be mentioned include the precursors
of formula (I) , (Ii) or (I6) below


Examples that may be mentioned include the precursors
of formula (I) or (I2) below


Examples that may be mentioned include the precursors
of formula (I3) or (I4) below


Examples that may be mentioned include the precursors
of formula (I5) below


With An- representing an anionic counterion
Examples that may be mentioned include the precursors
of formula (II), containing an electrophilic group,
below
Vanillin (4-hydroxy-3-methoxybenzaldehyde), isovanillin
(3-hydroxy-4-methoxybenzaldehyde), 3,4-
dihydroxybenzaldehyde, 4-hydroxybenzaldehyde, 3,5-
dimethoxy-4-hydroxybenzaldehyde, 4-hydroxybenzaldehyde,
4 -dimethylaminobenzaldehyde, 4 -methyl - 5 -
lmidazolecarboxaldehyde, 4-dimethyl-
aminocmnamaldehyde, 4 -hydroxy- 2 -methoxybenzaldehyde,
3,5-dimethyl-4-hydroxybenzaldehyde, 4-dimethylamino-2-
methoxybenzaldenyde, 2-hydroxybenzaldehyde, 4-hydroxy-

1-naphthaldehyde, 4-methoxy-l-naphthaldehyde, 4-
dimethylamino-1-naphthaldehyde, 4'-hydroxybiphenyl-1-
carboxaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2,4-
dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, 2,5-
dihydroxybenzaldehyde, 2,3,4-trihydroxybenzaldehyde,
3,4,5-trihydroxybenzaldehyde, 2,4,6-
trihydroxybenzaldehyde, 2,4-dimethoxybenzaldehyde, 2,3-
dimethoxybenzaldehyde, 2,5-dimethoxybenzaldehyde, 3,5-
dimethoxybenzaldehyde, 3,4-dimethoxybenzaldehyde,
indole-3 -carboxaldehyde, benzene-1,4-dicarboxaldehyde,
4-ethoxybenzaldehyde, 2-methy1-1,4-naphthoquinone, 4-
carboxybenzaldehyde, 4-hydroxy-3-methoxycmnamaldehyde,
3,5-dimethoxy-4-hydroxycinnamaldehyde, 3-methoxy-4-(1-
pyrrclidmyl) benzaldehyde, 4 -dimethylamino- 3 -methoxy-
benzaldehyde, 1, 2,-phthalaldehyde, pyrrole-2-aldehyde,
thiophene-2-aldehyde, thiophene-3-aldehyde, chromone-3-
carboxaldehyde, 6-methyl-4-oxo-l(4H)-benzopyran-3-
carboxaldehyde, N-methylpyrrole-2-aldehyde, 5-
methylfurfural, 6-hydroxychromene-3-carboxyaldehyde, 6-
methylmdole - 3 - carboxaldehyde, 4 -dibutyl -
aminobenzaldehyde, N-ethylcarbazole-3-aldehyde, 4-
diethylamino-2-hydroxybenzaldehyde, 3,4-dimethoxy-5-
hydroxybenzaldehyde, 5- [4- (dimethylamino) phenyl] -2,4-
pentadienal, 2,3-thiophenecarboxaldehyde, 2,5-
thiophenedicarboxaldehyde, 2-methoxy-1-naphthaldehyde,
3-ethoxy-4-hydroxybenzaldehyde
These compounds react with the compounds of formula
(I2) or (I5)
Examples that may be mentioned include the precursors
of formula (II), containing a nucleophilic group,
below
1,4-dimethylquinolinium, 1,2-dimethylquinolinium, 1,4-
dimethylpyridmium, 1,2-dimethylpyridimum, 2,4,6-
trimethylpyrilium, 2-methyl-1-ethylquinolinium, 2,3-
dimethylisoqumolmium, 1,2,3,3-tetramethyl-3H-
mdolium, 2,3-dimethylbenzothiazolium, 3-benzyl-2-
t bgn-zgthiazol-ium^ { 2— mesthyl-3-propylbenzothiazolium, 2,4-

dimethyl- 3 -ethylthiazolium, 3-(2-carboxyethyl)-2,5-
dimethylbenzothiazolium, 1,2,3-tnmethyl-benz-imiC1-
azolium, 5,6-dichloro-l,3-diethyl-2-methylbenz-
lmidazolium, 3-ethyl-2-methyl-benzothiazolium, 5-
chloro-3-ethyl-2-methyl-benzo-thiazolium, 3-ethyl-2-
methylbenzoxazolium salts, rhodanme,
2-methyl-3-(3-sulfopropyl)benzothiazolium hydroxide
(inner salt), 4-methyl-l-(3-sulfopropyl) pyridmium
hydroxide (inner salt), 4-methyl-l-(3-sulfo-propyl)-
quinolinium hydroxide (inner salt), 5-methoxy-2-methyl-
s' (3-sulfopropyl) benzothiazolium hydroxide (inner
salt);
These compounds reacting with the compounds of formula
(Ii), (I3), (I4) or (I6)
The compounds of formula (Ii) may be especially
obtained from similar preparation processes described,
for example, in the documents Justus Liebigs Annalen
der Chemie (1978), (7), 1123-8; ibid (1974), (5), 734-
40, Chemical Communications (Cambridge) (1996), (10),
1193-1194 or Organic Letters (2000), 2(26), 4141-4144
with Gp representing a leaving group such as halide,
for instance bromide or chloride, a mesylate or a
According to a first embodiment, the process for
synthesizing the compounds of formula (Ii) used in the
invention consists in performing the following step-


tosylate, L and Ar are as defined previously and Nuc
representing a group of primary or secondary amine type
or of alcohol type
According to this process, a step of nucleophilic
substitution (SNAr) of an arylaldehyde (al) with a
compound (a2) is performed in a manner known to those
skilled in the art
Certain reagents of type (al) are commercial reagents
As a guide, mention may be made of 4-
fluorobenzaldehyde, isonicotinaldehyde and 6-
fluoronicotinic acid
Certain reagents of type (a2) are commercial reagents.
As a guide, mention may be made of cysteamme, N,N'-
dimethylcysteamme and N,N,N',N'-tetramethylcystine .
This reaction usually takes place at a temperature of
between 20°C and 120°C and preferably between 50°C and
100 °C in the presence of a suitable solvent, among
which mention may be made of water, alcohols,
especially aliphatic alcohols containing up to 4 carbon
atoms, dimethylformamide or N-methylpyrrolidmone
The product may be isolated via the techniques known to
those skilled in the art (precipitation, evaporation,
chromatography, etc ).
Reference may be made to the book Advanced Organic
Chemistry Reactions, Mechanisms and Structures,
J March, 4th edition,, John Wiley & Sons, 1992, for
further details regarding the operating conditions used
for the process mentioned above
The compounds of formula (I2) may especially be
obtained via preparation processes similar to those
described, for example, in the documents Molecular
^CgySjtals -y and -tL-iqi l -?

method consisting in 1) generating the thiol dyes of
formula (13') via reduction of a dye containing two
chromophores, bearing a disulfide function -S-S- such
as di) and 11) protecting according to the standard
methods said thiol function of (I31) with the reagent 1_
Y'R to gam access to the thiol-protected dyes of
formula (13''). The thiol compound (I31) may also be
metallated witn an alkali metal or alkaline-earth metal
Met* to give the thiolate dye of formula ((I3'-Met).

with Y' representing a protecting group for a thiol
function, Met representing an alkali metal or alkaline-
earth metal, particularly sodium or potassium, it being
understood that when the metal is an alkaline-earth
metal, 2 chromophores containing a thiolate function
-S" may be combined with 1 Metal2+; L is as defined
previously, and R represents a nucleofugal leaving
group, for instance mesylate, tosylate, triflate or
halide
According to another possibility, a thiol-protected
compound (a6) may be reacted with a protecting group Y'
as defined previously prepared according to one of the
procedures described in the books mentioned previously,
said thiol-protected compound comprising at least one
nucleophilic function with a sufficient amount,
preferentially an equimolar amount, of a compound (a) ,
^•tjhe ^aldehyde^ fufi-pt;ion of which is protected, and which

comprises an electrophilic function to form a covalent
S bond, see below the preparation of dyes of formula
(Is1 ' ') •

with Nu representing a nucleophilic group, E
representing an electrophilic group; £ the bond
generated after attack of the nucleophile on the
electrophile, m' and n' representing an integer between
1 and 6 inclusive with m'+n' between 2 and 10, R
representing a C1-C2 alkyl group, and together may form
a 5-membered heterocycle
By way of example, the covalent bonds or £ bonding
group that may be generated are listed in the table
below, from condensation of electrophiles with
nucleophiles
Electrophiles E Nucleophiles Nu Covalent bonds E
Activated esters* Amines Carboxamides
Acyl azides** Amines Carboxamides
Acyl halides Amines Carboxamides
Acyl halides Alcohols Esters
Acyl cyanides Alcohols Esters
Acyl cyanides Amines Carboxamides
Alkyl halides Amines Alkylammes
Alkyl halides Carboxylic Esters

acids
Alkyl halides Thiols Thioesters
Alkyl halides Alcohols Ethers
Sulfonic acids and Thiols Thioethers
salts thereof
Sulfonic acids and Carboxylic Esters
salts thereof acids
Sulfonic acids and Alcohols Ethers
salts thereof
Anhydrides Alcohols Esters
Anhydrides Amines Carboxamides
Aryl halides Thiols Thioethers
Aryl halides Amines Arylammes
Aziridines Thiols Thioethers
Carboxylic acids Amines Carboxamides
Carboxylic acids Alcohols Esters
Carbodnmides Carboxylic N-acylureas
acids
Diazoalkanes Carboxylic Esters
acids
Epoxides Thiols Thioethers
Haloacetamides Thiols Thioethers
Imide esters Amines Amidines
Isocyanates Amines Ureas
Isocyanates Alcohols Urethanes
Isothiocyanates Amines Thioureas
Maleimides Thiols Thioethers
Sulfonic esters Amines Alkylammes
Sulfonic esters Thiols Thioethers
Sulfonic esters Carboxylic Esters
acids
Sulfonic esters Alcohols Ethers
Sulfonyl halides Amines Sulfonamides

*the activated esters of general formula -CO-LG with LG
representing a leaving group such as oxysuccimmidyl,
oxybenzotriazolyl or aryloxy, optionally substituted,
**the acyl azides can rearrange to give isocyanates
One variant to this process is to use a chromophore
containing an electrophilic acrylate function (-OCO-
C=C-) on which is performed an addition reaction that
will generate a S bond.
It is also possible to use a thiol reagent (a7) : Y'-SH
comprising a group Y' as defined previously, the SH
nucleophilic function of which can react on the carbon
atom of the radical L alpha to the halogen atom borne
by an arylaldehyde compound, to give the thiol-
protected dye of formula (I3'')-

with Hal representing a nucleofugal halogen atom such
as bromine, iodine or chlorine
More particularly, a nucleofugal leaving group may be
replaced with a thiourea group (S=C(NRR)NRR) to
generate isothiouroniums For example, if the thiourea
group is a thioimidazolinium (a8) , to give the dye S-
protected with an lmidazolium group (I3111)


Another variant may allow access to compound (I3' ' ')
from a thioimidazole (a9), followed by alkylation of
said thioimidazole using R'C1-Gp with Gp being a leaving
group such as chloride, bromide or tosylate

One variant is to use, instead of the halide comprising
compound (a'), a compound comprising another type of
nucleofuge such as tosylate or mesylate
In accordance with another possibility, certain thiol-
protected compounds (la''11) may be obtained by
reacting a thiol-protected compound with a compound
bearing two carboxylic acid functions activated
according to the standard methods (for example reaction
with a carbodnmide or with thionyl chloride) The
resulting product (alO) is then reacted with a compound
(c) bearing a nucleophilic function, for example of
primary or secondary amine type, or of aliphatic
alcohol type Next, the aldehyde is regenerated by
deprotection using the methods known to those skilled
in the art


Another variant is to use a thiolactone derivative as
represented by the scheme below:

with G' representing an oxygen or sulfur atom or a
group NR1 with R1 representing a hydrogen atom or an
alkyl radical, and R representing a hydrogen atom or a
C1-C4 alkyl, C!-C4 hydroxyalkyl or aryl (C1-C4) alkyl
radical. The tniolactone derivative is preferentially
chosen with n'=3 and G' represents an oxygen atom
One synthetic variant is to react two equivalents of
the nucleophilic reagent (c' ' ') with a disulfide

dielectrophilic reagent (j) it is possible to generate
after condensation the disulfide compound (I'-S) After
deprotection of the aldehydes, this compound may
undergo a reduction to form the thiol compound (I'-H),
which may be protected to form the thiol-protected dye
(I''-Y) or may be metallated with an alkali metal to
give the metallated compound (II1 ' "Metai)

The thiol-protected disulfide compounds of formulae

(Ii) , (I3) and (I4) may be synthesized in two steps. The
first steps consist in preparing disulfide (Ii-aid) or
thiol-protected (14-aid) compounds via methods described
above and 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, Wemheim, 2005. The
second step consists of a step of formylation of the
aryl ring
The step of formylation of the aryl ring is known to
those skilled in the art as the Vilsmeier-Haak
reaction This process avoids the steps of protection
and then deprotection of the aldehyde group in the
processes described above

The compounds of formulae (Ii-aid) and (13-aid) may be
obtained via the processes described above and known to
those skilled in the art
The compounds of formula (I5) may especially be
obtained by reduction of the disulfide group of
compounds of the type (I2)


These synthetic processes have been described above
One synthetic variant is to react one equivalent of a
compound comprising a thiol-protected group and a
leaving group (al2) with a heterocycle (al3) to give
the compounds (Is11)

According to this process, a step of quaternization of
a heterocycle (al3) with a thiol-protected compound
(al2) is performed in a manner known to those skilled
in the art
Usually, this reaction takes place at a temperature of
between 20°C and 120°C and preferably between 50°C and
100 °C in the presence of a suitable solvent, among
which mention may be made of water, alcohols,
j^egpeciaijLly f aliphatic alcohols containing up to 4 carbon

atoms, dimethylformamide or N-methylpyrrolidmone
The products may be isolated via the techniques known
to those skilled in the art (precipitation,
evaporation, chromatography, etc )
Certain reagents of the type (al3) are commercial
reagents As a guide, mention may be made of 4-
methylqumolme, 2-methylquinolme, 4-methylpyridine,
2-methylpyridine, 2-methylqumolme, 3-
methylisoqumolme, 2 , 3 , 3-tetramethyl-3H-indole, 2-
methylbenzothiazole, 2,4-dimethylthiazole, 2,5-
dimethylbenzothiazole, 1,2-dimethylbenzimidazole, 5,6-
dichloro-1-ethyl-2-methylbenzimidazole, 5-chloro-2 -
methylbenzothiazole, 2-methylbenzoxazole salts,
rhodanme; 5 -methoxy-2 -methylbenzothiazole
Another subject of the present invention is a cosmetic
composition comprising at least one thiol or thiol-
protected disulfide compound of formula (Ii) , (I2) ,
(I3) , (I4) or (I5) as defined previously, said compound
being different from compounds (1) to (xxvin) as
defined previously.
The cosmetic compositions that are useful in the
invention generally contain an amount of thiol or
thiol-protected disulfide precursor of formula (Ix) ,
(I2) , (I3) , (I4) or (I5) of between 0 001% and 50%
relative to the total weight of the composition and
preferably between 0 01% and 5% relative to the total
weight of the composition.
The cosmetic medium that is suitable for dyeing, also
known as the dye support, is a cosmetic medium
generally containing water or a mixture of water and of
at least one organic solvent Examples or organic
solvents that may be mentioned include C1-C4 lower
alkanols, such as ethanol and isopropanol, polyols and
(j?glpy©l 1 2 etfhejtTjS^f c for- 2 -instance 2-butoxyethanol,

propyleneglycol, propyleneglycol monomethyl ether and
diethyleneglycol monoethyl ether and monomethyl ether,
and also aromatic alcohols, for instance benzyl alcohol
or phenoxyethanol, and mixtures thereof
When they are present, the solvents are preferably
present in proportions preferably of between 1% and 99%
by weight approximately and even more preferentially
between 5% and 95% by weight approximately relative to
the total weight of the dye composition
The dye composition may also contain various adjuvants
conventionally used in hair dye compositions, such as
anionic, cationic, nonionic, amphoteric or zwitterionic
surfactants or mixtures thereof, anionic, cationic,
nonionic, amphoteric or zwitterionic polymers or
mixtures thereof, mineral or organic thickeners, and in
particular anionic, cationic, nonionic and amphoteric
polymeric associative thickeners, antioxidants,
penetrants, sequestrants, fragrances, buffers,
dispersants, conditioning agents, for instance volatile
or nonvolatile, modified or unmodified silicones such
as amino silicones, film-forming agents, ceramides,
preserving agents, opacifiers and conductive polymers.
The above adjuvants are generally present in an amount
for each of them of between 0 01% and 20% by weight
relative to the weight of the composition
Needless to say, a person skilled in the art will take
care to select this or these optional additional
compound(s) such that the advantageous properties
intrinsically associated with the dye composition in
accordance with the invention are not, or are not
substantially, adversely affected by the envisaged
addition(s)

approximately It may be adjusted to the desired value
by means of acidifying or basifymg agents usually used in the dyeing of keratin fibers, or alternatively using
standard buffer systems
Among the acidifying agents that may be mentioned, for
example, are mineral or organic acids, for instance
hydrochloric acid, orthophosphoric acid or sulfuric
acid, carboxylic acids, for instance acetic acid,
tartaric acid, citric acid and lactic acid, and
sulfonic acids
Among the basifymg agents that may be mentioned, for
example, are aqueous aminonia, alkali metal carbonates,
alkanolammes such as monoethanolamme, diethanolamine
and triethanolamme, and also derivatives thereof,
sodium hydroxide, potassium hydroxide and the compounds
of formula (y) below:

in which Wa is a propylene residue optionally
substituted with a hydroxyl group or a C!-C4 alkyl
radical; Ral, Ra2, Ra3 and Ra4, which may be identical or
different, represent a hydrogen atom or a C1-C4 alkyl or
C1-C4 hydroxyalkyl radical
The dye compositions may be in various forms, such as
in the form of a liquid, cream or gel, or in any other
form that is suitable for dyeing keratin fibers, and
especially the hair
A subject of the invention is also a multi-compartinent
device or dyeing "kit" in which a first compartinent
contains a dye composition comprising at least one
colorless disulfide/thiol .precursor of formula (I) as

defined previously and a second compartinent contains a
colorless precursor of formula (II) as defined
previously. Optionally, the device also contains a
compartinent comprising a reducing agent capable of
reducing the disulfide bridges of keratin fibers and/or
capable of reducing the disulfide functions of the dye
precursor (I) bearing a disulfide group when x = 2 and
y=0
The invention also relates to a multi-compartinent
device in which a first compartinent contains a
colorless disulfide/thiol precursor of formula (I) as
defined previously, a second compartinent contains a
colorless precursor of formula (II) as defined
previously, a third compartinent contains a reducing
agent capable of reducing the disulfide bond of keratin
materials and/or of the dye precursor (I) bearing a
disulfide group when x = 2 and y=0, and a fourth
compartinent contains an oxidizing agent
Alternatively, the dyeing device contains a first
compartinent containing a dye composition which
comprises at least one dye precursor (I) bearing a
thiol-protected group with x = 1 and y=l, a second
compartinent containing a colorless precursor of formula
(II) as defined previously, a third compartinent
containing an agent capable of deprotecting the thiol-
protected of formula (I) to release the thiol, and
optionally a fourth compartinent comprising an oxidizing
agent
Each of the devices mentioned above may be equipped
with a means for applying the desired mixture to the
hair, for instance the devices described in patent
FR 2 586 913
The examples that follow serve to illustrate the
invention without, however, being limiting in nature
LAI A. L 1 L 0 2 0 t S 1 * r > ^
* The dyes iri the examples herembelow were fully

characterized by the standard spectroscopic and
spectrometric methods
The examples that follow illustrate the invention
without, however, limiting its scope
EXAMPLE OF SYNTHESIS
Example 1: Synthesis of 1,1'-(disulfanediyldiethane-
2,l-diyl)bis(4-methylpyridinium)
dimethanesulfonate

Procedure
Step 1: Synthesis of disulfanediyldiethane-2,1-diyl
dimethanesulfonate:
10 g of 2,2'-dithiodiethanol and 14 44 g of
triethylamme (TEA) are diluted in 100 mL of ethyl
acetate (EtOAc) At 0°C, 16 35 g of methanesulfonyl
chloride diluted in 35 mL of EtOAc are added dropwise
to the reaction medium with rapid stirring 7 22 g of
TEA are introduced and stirring is continued at room
k & T A f 1 r n ; a r '=: t J - 2 )
^temperature "for' 4 hours 30 minutes 8.2 g of

methanesulfonyl chloride are added dropwise at 15°C and
stirring is continued at room temperature for 17 hours
The precipitate is filtered off and washed with three
times 50 mL of EtOAc The organic phases are extracted
with 100 mL of ice-water, 100 mL of water, three times
5 0 mL of saturated sodium hydrogen carbonate solution
(NaHC03) , twice 20 mL of saturated sodium chloride
solution (NaCl), and then dried over anhydrous sodium
sulfate (Na2SO4) The EtOAc is evaporated off, and
17 49 g of a clear pale yellow oil are collected and
stored at -25°C. The analyses indicate that the product
is in accordance and pure
Step 2: Synthesis of 1,1'-(disulfanediyldiethane-2,1-
diyDbis(4-methylpyridinium) dimethanesulfonate
3 51 g of 4-picolme and 5 g of disulfanediyldiethane-
2,1-diyl dimethanesulfonate are diluted in 5 mL of N-
methylpyrrolidmone (NMP) and then heated at 80°C with
stirring for 2 hours Stirring is continued at room
temperature for 17 hours The reaction medium is made
up with 50 mL of ethyl acetate and then filtered,
washed with three times 100 mL of EtOAC and dried under
vacuum over P205 7.29 g of brown powder are collected
The analyses indicate that the product is in accordance
and pure
EXAMPLES OF DYEING
Compositions 1 to 4 comprising the dye precursors of
formulae (I) and (II) versus the comparative:


Example 1 - Dyeing of the invention:
Composition 1 was applied to a lock of grey hair
containing 90% natural grey (NG) hairs and permanent-
waved grey (PWG) hairs, at room temperature (about
20°C) The leave-on time after application is
15 minutes The lock is rinsed with water. Composition
2 is then applied to this lock, comprising the
colorless disulfide precursor according to the
invention, with a leave-on time after application of
3 0 minutes The lock is then rinsed with water and a
composition 4 is then applied to this lock, comprising
the other colorless precursor according to the
invention The leave-on time after application is
3 0 minutes The lock is rinsed with water and then air-
^drfed

We observed that the dyeing and rinsing liquors are not
colored.
Example 2 - Dyeing with the comparative
Composition 1 was applied to a lock of grey hair at
room temperature (about 20°C) The leave-on time after
application is 15 minutes The lock is rinsed with
water Composition 3 is then applied to this lock,
comprising the non-disulfide precursor of the
comparative, with a leave-on time after application of
3 0 minutes The lock is then rinsed with water, and a
composition 4 is then applied to this lock, comprising
the other colorless precursor according to the
invention The leave-on time after application is
3 0 minutes The lock is rinsed with water and then air-
dried
It is observed that the dyeing and rinsing liquors are
colored.
Shampooing
The locks thus dyed are subjected to a wash-fastness
test, which consists in performing five shampoo washes
(with a standard shampoo) and in evaluating the color
after these five shampoo washes
It is found that, for Example 1, the rinsing liquors
are not colored On the other hand, for the
comparative, the liquors are always colored after the
fifth shampoo wash
After dyeing, the color of the locks is measured with a
Minolta CM2600d spectrocolorimeter (specular components
included, 10° angle, lllummant D65) in the CIEL*a*b*
system In this system, L* represents the intensity of
the color, a* indicates the green/red color axis and b*
i & r /v 1 1 r L> *■ n '< >~ * > « 2 ^
'"'the "blue/yellow cdlor axis

AE represents the variation in color between a lock of
"pre-shampooed" hair and a lock of "post-shampooed"
dyed hair, and is determined from the following
formula:

in which L*, a* and b* represent the values measured on
the "pre-shampooed" lock and L0*, a0* and b0* represent
the values measured on the "post-shampooed" lock
The colorimetric results obtained are given in the
table below

These results show that the dyeing of the invention
(Example 1) makes it possible to obtain improved dyeing in terms of shampoo fastness relative to the
comparative composition (Example 2)

CLAIMS
1 A process for dyeing keratin fibers, which
consists in applying to said fibers, which have
optionally been pretreated with a reducing agent
i) a cosmetically acceptable composition
comprising at least one colorless
thiol/disulfide dye precursor of formula (I).
formula (I) [Z-A-L-S]x-(Y)y
ii) and a cosmetically acceptable composition
comprising at least one colorless dye
precursor of formula (II)
formula (II) B-X
in which the portion B of the precursor of formula
(II) reacts chemically with portion A of the
precursor of formula (I) to form a colored or
colored and fluorescent chromophore B-X'-A-,
in which formulae (I) and (II)
> x represents 0 or 1,
> y represents 1 or 2,
> L represents an optionally substituted divalent
C1-C20 hydrocarbon-based chain, optionally
interrupted and/or optionally ending at one or
other of its ends 1) with one or more divalent
groups or combinations thereof chosen from.
-N(Ra)-, -N+(Ra) (Rb)-, An", -O-, -S-, -CO- and
-SO2- with Ra and Rb, which may be identical or
different, chosen from a hydrogen and a (C1-
C6)alkyl, hydroxy (C1-C6) alkyl or (d1) (C1-
C6) (alkyl) amino (C1-C6) alkyl radical and An-
representing an anionic counterion, or 11) with
a cationic heterocycle or cationic heteroaryl
Het+, An", with An" as defined above and Het+
representing a saturated or unsaturated 5- to
10-membered heterocycle, or a 5- to 10-membered
heteroaryl,
> A and B, which may be identical or different,
represent a colorless chromophore,
> X and Z {Represent a chemical function capable

of reacting together to form a group X1,
X' representing a chain allowing the electron
transfer between chromophore A and chromophore
B,
> Y represents 1) a hydrogen atom, 11) an alkali
metal, 111) an alkaline-earth metal, IV) an
aminonium group N^R^R^R5, An1'" or a
phosphonium group P+RaRpRYRS, An''" with Ra, Rp,
RY and R , which may be identical or different,
representing a hydrogen atom or a (C1-C4)alkyl
group, and An''" being an anionic counterion; or
v) a protecting group for a thiol function,
it being understood that when x is 2, then y is
zero, and when x is 1, then y is 1
2 The dyeing process as claimed in the preceding
claim, in which the radicals X and Z of the dye
precursors (I) and (II) represent a chemical
function capable of reacting together to form a
group X' chosen from nine, (poly)methme, styryl,
azomethme and azo groups.
3. The dyeing process as claimed in either of the
preceding claims, in which the precursors (I) and
(II) are chosen from:
- the precursor (I) which represents [H2N-A-L-S]x-
(Y)y, and the dye precursor (II) of formula B-
C(G)-H to give the chromophore B-X'-A- which
represents B-CH=N-A-, with G representing an
oxygen or sulfur atom,
- the precursor (I) which represents [H-C(G)-A-L-
S]x-(Y)y, and the dye precursor (II) of formula
B-NH2 to give the chromophore B-X'-A- which
represents B-N=CH-A-, with G as defined above,
- the precursor (I) which represents [H3C-A-L-S] x-
(Y)y, and the dye precursor (II) of formula B-
C(G')- to give the chromophore B-X'-A- which
represents B-CH=CH-A-, with G' representing an
oxygen or sulfur atom or NH,

- the precursor (I) which represents [H-C (G')-A-L-
S]x-(Y)y, and the dye precursor (II) of formula
B-CH3 to give the chromophore B-X'-A- which
represents B-CH=CH-A-, with G' as defined above,
- the precursor (I) which represents [G' '-A-L-S]x-
(Y)y, and the nitroso-derived dye precursor (II)
of formula B-NO to give the chromophore B-X'-A-
which represents B-N=A'-, with A1 representing
an aryl or heteroaryl group derived from A,
comprising an oxo function if G' ' represents a
hydroxyl group, or alternatively an imino group
if G" represents a (C1-C6) (alkyl) amino group;
- the precursor (I) which represents a nitroso
derivative [ON-A-L-S] x-(Y)y, and the dye
precursor (II) of formula B-G'' to give the
chromophore B-X'-A- which represents B'=N-A-,
with B' representing an aryl or heteroaryl group
derived from B, comprising an oxo function if
G' ' represents a hydroxyl group, or
alternatively an imino group if G1 ' represents a
(C1-C6) (alkyl) amino group,
- the precursor (I) which represents [G''-A-L-S]x-
(Y)y, and the dye precursor (II) of formula B-N2+
to give the chromophore B-X'-A- which represents
B-N=N-A with G'' representing a hydrogen atom;
- the precursor (I) which represents [N2+-A-L-S]x-
(Y)y, and the dye precursor (II) of formula B-G1'
to give the chromophore B-X'-A- which represents
B-N=N-A G'' represents a hydrogen atom;
- the precursor (I) which represents [H-C(G)-A-L-
S]X-(Y)>, and the dye precursor (II) of formula
B-N(R)-NH2 to give the chromophore B-X'-A- which
represents B-N(R)-N=CH-A-, with G as defined
above and R representing a hydrogen atom or a
(polyhydroxy) (C!-C4)alkyl group,
- the precursor (I) which represents [H3C-A-L-S]x-
(Y)y, and the dye precursor (II) of formula B-N2+
to give the chromophore B-X'-A- which represents
B-2N|(Ri) ■iN=GH?-A-^, Jwitte G' representing an oxygen

or sulfur atom or NH and R as defined above
4 The dyeing process as claimed in any one of the
preceding claims, in which the precursor (I)
contains
- either a group A representing an aryl group
optionally substituted with a (C1-C6) alkyl, (C1-
C6)alkoxy, (C1-C6) alkylthio, (d1) (C1-
Cs) (alkyl) amino, (C1-C6)polyhaloalkyl, hydroxyl,
(C1 - C6) polyhydroxyalky 1, polyhydroxy (C1 - C6) alkoxy,
cyano, R-G-C(G')-, R-C(G')-G-, R»S(0)2-N (R)-,
RR'N-S(0)2- group, with G or G', which may be
identical or different, representing an oxygen
or sulfur atom or a group NR', and R and R',
which may be identical or different,
representing a hydrogen atom or a (C!-C6) alkyl
group, and in this case the group B of the
precursor of formula (II) represents a cationic
heteroaryl group optionally substituted with a
(C1-C6) alkyl, (C1-C6) alkoxy, (C1-Ce) alkylthio,
(d1) (C1-C6) (alkyl) amino, (C1-C6)polyhaloalkyl,
hydroxyl, (C1-C6) polyhydroxyalky 1,
polyhydroxy (C1-C6) alkoxy, cyano, R-G-C(G')-, R-
C(G')-G-, R'S(0)2-N(R)-, RR'N-S(0)2- group with G
or G', which may be identical or different,
representing an oxygen or sulfur atom or a group
NR', and R and R', which may be identical or
different, representing a hydrogen atom or a (C1-
C6) alkyl group;
- or a group A representing a cationic heteroaryl
group optionally substituted with a (C1-C6) alkyl,
(C1-C6) alkoxy, (C1-C6) alkylthio, (d1) (C1-
Cs) (alkyl) amino, (C!-C6) polyhaloalkyl, hydroxyl,
(C1 - C6) polyhydroxyalky 1, polyhydroxy (C1 - C6) alkoxy,
cyano, R-G-C(G')-, R-C(G')-G-, R'S(0)2-N(R)-,
RR'N-S(0)2- group with G or G', which may be
identical or different, representing an oxygen
or sulfur atom or a group NR', and R and R',
whach-i T r->may ^be _; identical or different,

representing a hydrogen atom or a (C1-C6) alkyl
group and in this case the group B of the
precursor of formula (II) represents an aryl
group optionally substituted with a (C1-C6)alkyl,
(C1-C6) alkoxy, (C1-C6) alkylthio, (d1) (C1-
C6) (alkyl) amino, (C1-C6) polyhaloalkyl, hydroxy 1,
(C!-C6) polyhydroxyalkyl, polyhydroxy (C1-C6) alkoxy,
cyano, R-G-C(G')-, R-C(G')-G-, R'S(0)2-N(R)-,
RR'N-S(0)2- group with G or G1 , which may be
identical or different, representing an oxygen
or sulfur atom or a group NR1 , and R and R1 ,
which may be identical or different,
representing a hydrogen atom or a (C1-C6) alkyl
group
5. The dyeing process as claimed in any one of the
preceding claims, which consists in applying to
the keratin fibers
l) a colorless disulfide precursor containing
activated methylene of formula (I2)
m which formula (I2) :
■ represents a 5- to 13-membered cationic
heteroaryl group, which may comprise, besides
the cationic nitrogen atom, from 1 to 3
heteroatoms chosen from nitrogen, oxygen and
sulfur, and which bears on a carbon atom a
methyl group,
■ L is as defined in claim 1;
n) and a colorless aldehyde-based precursor of
formula (Hi) below

. in whicth, fprmula (III,) .

o n represents 0 or 1,
H Ar represents an aryl or heteroaryl group
optionally substituted with one or more groups
chosen from:
• a C1-C4 alkyl group,
• a hydroxyl group,
• a C1-C4 alkoxy group,
• a C2-C4 (poly)hydroxyalkoxy group,
• an alkoxycarbonyl group (RaO-C(0)-) in which Ra
represents a C1-C4 alkyl radical,
• an alkylcarbonyloxy group (RaC(0)-O-) in which
Ra represents a C1-C4 alkyl radical,
• an amino group optionally substituted with one
or more C1-C4 alkyl radicals, which may be
identical or different, optionally bearing at
least one hydroxyl group, the two alkyl
radicals possibly forming with the nitrogen
atom to which they are attached a substituted
or unsubstituted 5- or 6-membered heterocycle
optionally bearing another heteroatom
identical to or different from nitrogen,
• an alkylcarbonylamino group (RaC (0) -NR'a-) in which Ra represents a C1-C4 alkyl radical and
R'a represents a hydrogen atom or a C1-C4 alkyl
radical,
• a (di-) (alkyl) aminocarbonyl group ( (Ra) 2N-C (0) )
in which the radicals Ra, independently of each
other, which may be identical or different,
represent a hydrogen atom or a Q1.-C4 alkyl
radical,
• a ureido group ( (Ra) 2N-C0-NRb-) in which the
radicals Ra and Rb, independently of each
other, represent a hydrogen atom or a C;L-C4
alkyl radical, and
• a halogen atom.
6. The dyeing process as claimed in the preceding
claim, in which the precursor of formula (I2)
r ^contains ?a radical -Ljrepresenting a C^-Cio alkylene

chain
7 The dyeing process as claimed in any one of claims
1 to 3, which consists in applying to the keratin
• fibers
I) a colorless disulfide precursor containing an
aldehyde function of formula (Ii)
in which formula (Ii)
■ Ar represents an optionally substituted arylene
or heteroarylene group,
■ L is as defined in claim 1,
n) and a colorless precursor containing an
activated methyl of formula (II2) below.

in which formula (II2)
■ R represents a hydrogen atom or a (C1-C6)alkyl
group,
■ represents a 5- to 13-membered catiomc
heteroaryl group, possibly comprising, besides
the cationic nitrogen atom, from 1 to 3
heteroatoms chosen from nitrogen, oxygen and
sulfur, and which bears on a carbon atom a
methyl group
8 The dyeing process as claimed in the preceding
claim, in which the colorless precursor containing
an aldehyde function is of formula (I6)

in which formula (I6)
a Ar represents a phenylene group,
>-' ,r r /xH fT "• ^egr^se,njts an ..amino group NR or amido group

-NR-C(O)- or -C(0)-NR- with R representing a
hydrogen atom or a (C1-C6) alkyl group,
■ ALK represents a divalent C1-C10 alkylene chain,
optionally interrupted with one or more divalent
groups or combinations thereof chosen from.
-N(Ra)-, -N+(Ra) (Rb) ", An", -CO- and with Ra and
Rb, which may be identical or different, chosen
from a hydrogen and a (C!-C6) alkyl radical, and
An" representing an anionic counterion, or 11)
with a cationic heterocycle or cationic
heteroaryl Het+, An", with An" representing an
anionic counterion and Het+ representing a
saturated or unsaturated 5- to 10-membered
heterocycle, or a 5- to 10-membered heteroaryl,
and
■ n is 0.
9 The dyeing process as claimed in any one of claims
1, 7 and B, which consists
I) ma first stage, in applying a cosmetic
composition comprising an aromatic dialdehyde
disulfide compound belonging to the general
formulae (I) , (II) and (16) , of the following
structure

optionally of adding a fixing agent such as an
oxidizing agent, to improve the fixing of the
disulfide precursor to the keratin fibers,
which have optionally been reduced beforehand,
and then
n) of applying a composition comprising at least
1, 4 -dimethyl pyndinium
10 The dyeing process as claimed in any one of the
preceding claims, in which the keratin fibers have
been pretreated with a reducing agent chosen from
_ thiols,_ .homocysteineA „thiolactic acid, salts of

these thiols, phosphines, bisulfite, sulfites,
thioglycolic acid, and esters thereof, and
borohydrides and derivatives thereof, for instance
catecholborane
11 A disulfide compound of formula (Ii) or (I2) , or
thiol or thiol-protected compound of formula (I3),
(I4) or (I5)

the organic or mineral acid salts, optical
isomers, geometrical isomers, and solvates such as
hydrates thereof,
in which formulae (Ii) , (I2) , (I3) , (I4) and (I5) :
■ Ar represents an optionally substituted arylene
or heteroarylene group,
■ R represents a hydrogen atom or a (C!-C6) alkyl
group,
■ Y represents 1) a hydrogen atom, 11) an alkali
metal, 111) an alkaline-earth metal; IV) an
aminonium group N+RaRpRYR , An" or a phosphonium
group P+RaRpRYR5, An" with Ra, Rp, RY and R5, which
may be identical or different, representing a
hydrogen atom or a (C1-C4) alkyl group and An"

representing an anionic counterion, or v) a
protecting group for a thiol function,
a L is as defined previously,
■ n is 0 or 1,
■ 3 \^_y represents a 5- to 13-membered cat ionic
heteroaryl group which may comprise, besides the
cationic nitrogen atom, from 1 to 3 heteroatoms
chosen from nitrogen, oxygen and sulfur, and
which bears on a carbon atom a methyl group,
■ Het+ represents a cationic heteroarylene group
bearing at least one methyl group chosen from

in which radicals (A) to (E).
- the methyl group of the Het+ groups (C) and (D)
is in position 2 or 4,
- R1 represents a halogen atom or a (C1-C6) alkyl,
(C1-C6) alkoxy, (C1-C6) alkylthio, (d1) (C1-
C6) (alkyl) amino, (C1-C6)polyhaloalkyl,
hydroxy1, (C1- C6)polyhydroxyalky1,
polyhydroxy (C1-C6) alkoxy, cyano, R-G-C(G')-, R-
C(G')-G-, R'S(0)2-N(R)-, RR'N-S(0)2- group with
G or G', which may be identical or different,
representing an oxygen or sulfur atom or a
group NR' , and R and R' , which may be
identical or different, representing a
hydrogen atom or a (C1-C6) alkyl group,
- R represents a hydrogen atom or a
(polyhydroxy) (C1-C4) alkyl group,

- or alternatively two contiguous groups R1 form
with the two carbon atoms that bear them an
optionally substituted benzo group;
- t represents an integer between 0 and 4
inclusive,
- t1 represents an integer between 0 and 2
inclusive;
- Z' represents an oxygen or sulfur atom or a
methylene group -C(R2)(R3)- with R2 and R3,
which may be identical or different,
representing a hydrogen atom or a (C1-C6) alkyl
group;
An- represents an anionic counterion,
it being understood that the compounds of formula
(I1) , (I2) , (I3) , (I4) or (I5) cannot represent the
following compounds (1) to (xxviii)

with Ac representing an acetyl group (xxn) ,
An=MeSO4- or N03-or pTSA- (xxvi) ,

12. The disulfide compound as claimed in the preceding
claim, of formula (I6)
0
Hk >^ >A|\ /-ALK-S^ /ALK r^. i J]
I [ X Jn T S ^T^T ^IrT ^H
0 (I«)
m which formula (I6)
B Ar represents a phenylene group,
■ T represents an amino group NR or amido group
7NR7„Q(0);-, , or -C(ph-NR- with R representing a

hydrogen atom or a (C1-C6)alkyl group,
■ ALK represents a divalent C1-C10 alkylene chain,
optionally interrupted with a cationic
heteroaryl group Het+, An", with Het+
representing a saturated or unsaturated 5- to
10-membered heterocycle or a 5- to 10-membered
heteroaryl and An" represents an anionic
counterion, and
■ n is 0
L3 A compound as claimed in either of claims 11 and
12, chosen from the precursors of formula (I), (Ii)
or (I6) below



, ,,the precursors of formula (I3) or (I4) below:

with An- representing an anionic countenon;
the following precursors of formula (II) ,
containing an electrophilic group.
vanillin (4-hydroxy-3-methoxybenzaldehyde),
isovanillin (3-hydroxy-4-methoxybenzaldehyde),
3,4-dihydroxybenzaldehyde, 4-hydroxybenzaldehyde,
3,5-dimethoxy-4-hydroxybenzaldehyde, 4-
hydroxybenzaldehyde, 4-dimethylaminobenzaldehyde,
4-methyl-5-lmidazolecarboxaldehyde, 4 -dimethyl-
aminocmnamaldehyde, 4-hydroxy-2-
methoxybenzaldehyde, 3, 5-dimethyl-4-hydroxy-
benzaldehyde , 4 -dimethylamino - 2 -
methoxybenzaldehyde, 2-hydroxybenzaldehyde, 4-
hydroxy-1-naphthaldehyde, 4-methoxy-1-
naphthaldehyde, 4 - dimethylamino -1 - naphthaldehyde,
4'-hydroxybiphenyl-1-carboxaldehyde, 2-hydroxy-3-
methoxybenzaldehyde, 2,4-dihydroxybenzaldehyde,
3,4-dihydroxybenzaldehyde, 2,5-
dihydroxybenzaldehyde, 2,3,4-
trihydroxybenzaldehyde, 3,4,5-trihydroxy-
benzaldehyde, 2,4,6-trihydroxybenzaldehyde, 2,4-
dimethoxybenzaldehyde, 2,3-dimethoxybenzaldehyde,
2,5-dimethoxybenzaldehyde, 3,5-
dimethoxybenzaldehyde, 3,4-dimethoxybenzaldehyde,
mdole-3-carboxaldehyde, benzene-1,4-
dicarboxaldehyde, 4-ethoxybenzaldehyde, 2-methyl-
1,4-naphthoquinone, 4-carboxybenzaldehyde, 4-
hydroxy-3-methoxycmnamaldehyde, 3,5-dimethoxy-4-
hydroxy-cmnamaldehyde, 3-methoxy-4- (1-
pyrrolidmyl) benzaldehyde, 4-dimethyl-amino-3-
methoxybenzaldehyde, 1,2,-phthalaldehyde, pyrrole-

2-aldehyde, thiophene-2-aldehyde, thiophene-3-
aldehyde, chromone-3-carboxaldehyde, G-methyl-4-
oxo-l(4H)-benzopyran-3-carboxaldehyde, N-
methylpyrrole-2-aldehyde, 5-methylfurfural, 6-
hydroxychromene-3-carboxyaldehyde, 6-methyl-
indole-3 -carboxaldehyde, 4 -dibuty 1 -
aminobenzaldehyde, N-ethylcarbazole-3-aldehyde, 4-
diethylamino-2-hydroxybenzaldehyde, 3,4-dimethoxy-
5-hydroxybenzaldehyde, 5-[4-
(dime thylamino) phenyl] -2 , 4-pentadienal, 2,3-
thiophenecarboxaldehyde, 2,5-
thiophenedicarboxaldehyde, 2-methoxy-1-
naphthaldehyde, 3-ethoxy-4-hydroxybenzaldehyde;
the following precursors of formula (II) ,
containing a nucleophilic group.
1, 4-dimethylquinolmium, 1, 2-dimethylquinolmium,
1,4-dimethylpyridinium, 1,2-dimethylpyridmium,
2,4,6-trimethylpyrilium, 2-methyl-1-
ethylqumolinium, 2,3-dimethylisoquinolmium,
1,2,3,3-tetramethyl-3H-mdolium, 2,3-
dimethylbenzothiazolium, 3-benzyl-2-
benzothiazolium, 2-methyl-3-propylbenzothiazolium,
2,4-dimethyl-3-ethylthiazolium, 3-(2-
carboxyethyl)-2,5-dimethylbenzothiazolium, 1,2,3-
trimethylbenzimidazolium, 5 , 6-dichloro-l,3-
diethyl-2-methylbenzlmidazolium, 3 -ethyl-2-methyl-
benzothiazolium, 5-chloro-3-ethyl-2-
methylbenzothiazolium, 3-ethyl-2-methyl-
benzoxazolium salts, rhodanme,
2-methyl-3 -(3 -sulfopropyl)benzothiazolium
hydroxide (inner salt), 4-methyl-1- (3-
sulf opropyl) pyridmium hydroxide (inner salt), 4-
methyl-1- (3-sulf opropyl) qumolinium hydroxide
(inner salt), 5-methoxy-2-methyl-3-(3-
sulfopropyl)benzothiazolium hydroxide (inner
salt).
14. A cosmetic composition comprising at least one
- ^-w ^colorless ,thiol „or~ thiol -protected disulfide dye

precursor as defined in any one of claims 11
to 13
15. The composition according to the preceding claim,
in which the thiol or thiol-protected disulfide
compound is present in an amount of between 0.001%
and 50% by weight relative to the total weight of
the composition
16 A multi-compartinent device comprising in a first
compartinent a cosmetic composition containing at
least one colorless thiol/disulfide precursor of
formula (I) as defined in claim 1, a second
compartinent comprising a cosmetic composition
containing at least one colorless precursor of
formula (II) as defined in claim 1, optionally,
another compartinent comprising a reducing agent
capable of reducing keratin fibers and/or the
disulfide precursor of formula (I) , and/or
optionally another compartinent containing an
oxidizing agent capable of fixing the precursor of
formula (I) to the keratin fibers

ABSTRACT

DYE COMPOSITION COMPRISING AT LEAST ONE COLORLESS
DISULFIDE/THIOL PRECURSOR, AND DYEING PROCESS USING THE
COMPOSITION
The present invention relates to the dyeing of keratin
materials using two colorless dye precursors, at least
one of which contains a disulfide/thiol unit, said
precursors reacting together chemically to form the
color in situ
The process according to the invention makes it
possible in the context of certain variants to solve
the problems caused by the color generated during the
process, while at the same time not degrading the
efficacy of the coloration, and especially of the
lightening effect
The colorations obtained are moreover powerful,
chromatic, sparingly selective, and fast with respect
to external agents such as sunlight, perspiration and
especially shampoo