The present invention relates to a cosmetic treatment process especially for depigmenting and/or bleaching the skin, using at least one compound of dithiolane type.
The colour of human skin depends on many factors and especially on the seasons of the year, race and sex; it is mainly determined by the nature and concentration of melanin produced by the melanocytes. Melanocytes are specialized cells that synthesize melanin, by means of particular organelles, the melanosomes. At different periods in their life, certain people develop darker and/or more coloured marks on their skin and especially on the hands, giving the skin a heterogeneous appearance. These marks are also due to a large concentration of melanin in the keratinocytes located at the surface of the skin.
The use of highly effective, harmless topical depigmenting substances is most particularly sought in order to treat regional hyperpigmentations caused by melanocyte hyperactivity, such as idiopathic melasmas, occurring during pregnancy (“pregnancy mask” or chloasma) or oestro-progestative contraception, localized hyperpigmentations caused by benign melanocytic proliferation and hyperactivity, such as senile pigmentation marks known as actinic lentigo, accidental hyperpigmentations, possibly due to post-lesional cicatrization or photosensitization, and also certain leukodermias, such as vitiligo. For the latter (cicatrizations that may result in a scar, giving the skin a whiter appearance), failing the possibility of repigmenting the damaged skin, depigmentation of the areas of residual normal skin is completed in order to give the skin as a whole a uniform white complexion.
The mechanism of formation of skin pigmentation, i.e. the formation of melanin, is particularly complex and schematically involves the following main steps:

Tyrosine ---> Dopa ---> Dopaquinone ---> Dopachrome ---> Melanin
Tyrosinase (monophenol dihydroxyl phenylalanine: oxygen oxidoreductase EC 1.14.18.1) is the essential enzyme participating in this sequence of reactions. It especially catalyses the reaction for the conversion of tyrosine into dopa (dihydroxyphenylalanine) by virtue of its hydroxylase activity, and the reaction for the conversion of dopa into dopaquinone by virtue of its oxidase activity. This tyrosinase acts only when it is in the mature form, under the action of certain biological factors.
A substance is recognized as being depigmenting if it acts directly on the vitality of the epidermal melanocytes in which melanogenesis takes place and/or if it interferes with one of the steps in the biosyn-thesis of melanin either by inhibiting one of the en-zymes involved in melanogenesis or by inserting itself as a structural analogue of one of the chemical com-pounds of the melanin synthesis chain, which chain may then become blocked and thus ensure depigmentation.
The substances most commonly used as depigmenting agents are, more particularly, hydroquinone and its de-rivatives, in particular its ethers such as hydro-quinone monomethyl ether and monoethyl ether. Although they have a certain level of efficacy, these compounds are, unfortunately, not free of side effects on account of their toxicity, which may make them difficult or even hazardous to use. This toxicity arises from the fact that they participate in fundamental mechanisms of melanogenesis by killing cells which then run the risk of disturbing their biological environment and which consequently oblige the skin to eliminate them by pro-ducing toxins.
Thus, hydroquinone is a compound that is particu-larly irritant and cytotoxic to melanocytes, and whose total or partial replacement has been envisaged by many authors.
Substances are thus sought, which do not participate in the melanogenesis mechanism, but which act upstream of tyrosinase by preventing its activation, and which are consequently much less toxic. Kojic acid, which complexes the copper present in the active site of tyrosinase, is commonly used as a tyrosinase activation inhibitor. Unfortunately, this compound is unstable in solution, which somewhat complicates the manufacture of the composition.
There is still a need for a novel human skin-bleaching agent whose action is just as efficient as the known agents, but which does not have their drawbacks, i.e. which is non-irritant, non-toxic and/or non-allergenic to the skin, while at the same time being stable in a composition, or alternatively which has reinforced action so as to be able to be used in smaller amount, which considerably reduces the observed side effects.
In this regard, the Applicant has found, surprisingly and unexpectedly, that certain dithiolane compounds have good depigmenting activity, even at low concentration.
One subject of the invention is thus a cosmetic process for depigmenting, lightening and/or bleaching keratin materials, comprising the application of a cosmetic composition comprising, in a physiologically acceptable medium, at least one compound of formula (I) as defined below.
The invention also relates to the cosmetic use of a compound of formula (I) as an agent for bleaching, lightening and/or depigmenting keratin materials.
The invention also relates to the use of a compound of formula (I) for the manufacture of a dermatological composition for depigmenting, lightening and/or bleaching keratin materials.
The compounds used according to the invention allow the efficient depigmenting and/or lightening, or even the bleaching, of human skin. They are especially intended to be applied to the skin of individuals presenting brownish pigmentation marks or senescence marks, or to the skin of individuals who wish to combat the appearance of a brownish colour arising from melanogenesis, for example following exposure to ultraviolet radiation.
They can also depigment and/or lighten bodily hair, the eyelashes, head hair, and also the lips and/or the nails.
The compounds used according to the invention thus correspond to formula (I) below:

(I)
in which:
Y denotes O, NR1 or S
R1 denotes a hydrogen atom; a saturated linear C1-C20 or branched C3-C20 or unsaturated C2-C20 alkyl hydrocarbon-based group; a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals;
R denotes a hydrogen atom; or a saturated linear C1-C20 or branched C3-C20 or unsaturated C2-C20 alkyl hydrocar-bon-based group; or a phenyl group optionally substi-tuted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals; or a saturated C1-C8 alkyl group containing a phenyl substituent optionally sub-stituted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals;
R optionally bears one or more substituents chosen from OR2, SR2, NR2R3, COOR2 in which:
R2 denotes a hydrogen atom or a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group, or a phenyl group
R3 denotes a hydrogen atom; a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group; a phenyl group; an acetyl group;
when Y = NR1, R and R1 may form a ring chosen from pyr-rolidine, pyrroline, piperidine, piperazine, mor-pholine, thiomorpholine and azepine;
n = 0 or 1 or 2,
and also the salts thereof, chelates thereof, solvates thereof and optical isomers thereof.
The salts of the compounds described in the pre-sent invention include conventional non-toxic salts of the said compounds, such as those formed from organic or mineral acids. Examples that may be mentioned in-clude the salts of mineral acids such as sulfuric acid, hydrochloric acid, hydrobromic acid, hydriodic acid, phosphoric acid or boric acid. Mention may also be made of the salts of organic acids, which may comprise one or more carboxylic, sulfonic or phosphonic acid groups. They may be linear, branched or cyclic aliphatic acids, or alternatively aromatic acids. These acids may also comprise one or more heteroatoms chosen from O and N, for example in the form of hydroxyl groups. Mention may be made especially of propionic acid, acetic acid, terephthalic acid, citric acid and tartaric acid.
Mention may also be made of the salts of organic or mineral bases such as triethanolamine, aminopro-panediol, sodium or zinc salts.
The solvates that are acceptable for the non-therapeutic use of the compounds described in the pre-sent invention include conventional solvates such as those formed during the final step of preparation of the said compounds, due to the presence of solvents. Examples that may be mentioned include the solvates due to the presence of water or of linear or branched alco-hols such as ethanol or isopropanol.
The optical isomers are especially enantiomers and diastereoisomers.
The alkoxy groups are preferentially linear C1-C4 groups and more preferentially methoxy, ethoxy, propoxy or butoxy and even more preferentially methoxy.
Preferentially, the hydrocarbon-based groups are linear or branched alkyls and may be chosen from: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl and eico-syl.
Preferentially, the hydrocarbon-based groups are saturated, linear or branched C1-C8 alkyl radicals: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl.
Preferably, the compounds of formula (I) have the following meanings:
Y denotes S, O, NR1
R1 denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group;
R denotes a hydrogen atom; a saturated linear C1-C20 or branched C3-C20 alkyl hydrocarbon-based group; a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C1-C3 alkoxy radicals; a satu-rated C1-C5 alkyl group containing a phenyl substituent optionally substituted with one or more hydroxyls and/or with one or more C1-C3 alkoxy radicals; a linear C1-C5 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OR2, SR2, NR2R3, COOR2 in which:
R2 denotes a hydrogen atom or a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group,
R3 denotes a hydrogen atom; a saturated linear C1-C5 or branched C3-C5 hydrocarbon-based group; a phenyl group; an acetyl group;

when Y = NR1, R and R1 may form a pyrrolidine ring,

n = 0 or 1 or 2

and also the acid or base salts thereof, chelates thereof, solvates thereof and optical isomers thereof.
Preferentially, the compounds of formula (I) have the following meanings:

Y denotes O or NR1;
R1 denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group;
R denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group; a phenyl group optionally substituted with one or more hydroxyls and/or with one or more methoxy radicals; a saturated C1-C3 alkyl hydrocarbon-based group containing a phenyl substituent optionally substituted with one or more hy-droxyls and/or with one or more methoxy radicals; a linear C1-C4 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OR2, SR2, NR2R3, COOR2 in which:
R2 denotes a hydrogen atom or a saturated linear C1-C5 or branched C3-C5 hydrocarbon-based group,
R3 denotes a hydrogen atom; a saturated linear C1-C5 or branched C3-C5 hydrocarbon-based group;

n = 0 or 1 or 2

and also the acid or base salts thereof, chelates thereof, solvates thereof and optical isomers thereof.
More preferentially, the compounds of formula (I) have the following meanings:
Y denotes NR1

R1 denotes a hydrogen atom; a saturated linear C1-C4 al-kyl hydrocarbon-based group;

R denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group; a phenyl group; a saturated linear C1-C4 alkyl group substituted with a phenyl optionally substituted with one or more identical or different groups chosen from OH, OMe; a linear C1-C4 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OH, NHAc, SR2, COOR2 with R2 being a hydrogen or a linear C1-C4 alkyl group;

n = 0 or 1 or 2

and also the acid or base salts thereof, chelates thereof, solvates thereof and optical isomers thereof.
Preferentially, the compounds of formula (I) have the following meanings:
Y denotes NH

R denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group; a phenyl group; a saturated linear C1-C4 alkyl group substituted with a phenyl optionally substituted with one or more identical or different groups chosen from OH, OMe; a linear C1-C4 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OH, NHAc, SR2, COOR2 with R2 being a hydrogen or a linear C1-C4 alkyl group;

n = 0 or 1 or 2;

and also the acid or base salts thereof, chelates thereof, solvates thereof and optical isomers thereof.
Preferentially, the compounds of formula (I) have the following meanings:
Y denotes NH

R denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group;

n = 0 or 1 or 2;

and also the acid or base salts thereof, chelates thereof, solvates thereof and optical isomers thereof.
Preferentially, Y = O, NR1.
More preferentially, Y = NR1.
Even more preferentially, Y = NH.
Most preferentially, R = H or a C1-C8 alkyl radi-cal.
Among the compounds of formula (I), the following compounds will preferably be used:

No. Structure Chemical name
1
4-methyl-1,2-dithiolane-4-carboxylic acid
2
4-methyl-1,2-dithiolane-4-carboxamide
3
methyl 4-methyl-1,2-dithiolane-4-carboxylate
4
ethyl 4-methyl-1,2-dithiolane-4-carboxylate
5
propyl 4-methyl-1,2-dithiolane-4-carboxylate
6
benzyl 4-methyl-1,2-dithiolane-4-carboxylate
7
N-methyl-4-methyl-1,2-dithiolane-4-carboxamide
8
{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]amino}¬acetic acid
9
octyl 4-methyl-1,2-dithiolane-4-carboxylate

No. Structure Chemical name
10
N-heptyl-4-methyl-1,2-dithiolane-4-carbox¬amide
11
N-butyl-4-methyl-1,2-dithiolane-4-carbox¬amide
12
methyl 2-{[(4-methyl-1,2-dithio¬lan-4-yl)carbonyl]¬amino}-4-(methylsulfan- yl)butanoate
13
S-[2-(acetylamino)ethyl] 4-methyl-1,2-dithiolane-4-carbothioate
14
N-(2-hydroxyethyl)-4-methyl-1,2-dithiolane-4-carboxamide
15
N-(2,3-dihydroxypropyl)-4-methyl-1,2-dithiolane-4-carboxamide
16
N-(4-hydroxy-3-methoxy¬benzyl)-4-methyl-1,2-dithiolane-4-carbox¬amide
17
N-[2-(4-hydroxy-3-methoxy-phenyl)ethyl]-4-methyl-1,2-dithiolane-4-carboxamide

No. Structure Chemical name
18
N,N-diethyl-4-methyl-1,2-dithiolane-4-carboxamide
19
methyl 2-(acetylamino)-3-{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]sulfanyl}¬propanoate
20
S-(2-hydroxyethyl) 4-methyl-1,2-dithiolane-4-carbothioate
21
ethyl {[(4-methyl-1,2-dithio¬lan-4-yl)carbonyl]¬sulfanyl}¬acetate
22
[(4-methyl-1,2-dithiolan-4-yl)carbonyl]pyrrolid-ine
23
4-methyl-1,2-dithiolane-1-oxo-4-carboxylic acid
24
4-methyl-1,2-dithiolane-1,1-dioxo-4-carboxylic acid
25
ethyl 4-methyl-1,2-dithio¬lane-1-oxo-4-carboxylate

No. Structure Chemical name
26
4-methyl-1,2-dithiolane-4-carboxamide 1-oxide
27
4-methyl-1,2-dithiolane-4-carboxamide 1,1-dioxide
28
4-methyl-N-(1-methylethyl)-1,2-dithiolane-4-carbox¬amide
29
4-methyl-N-phenyl-1,2-dithiolane-4-carboxamide
30
N-[2-(4-hydroxyphenyl)¬ethyl]-4-methyl-1,2-dithiolane-4-carboxamide
31
N-propyl-4-methyl-1,2-dithiolane-4-carboxamide
32
N-pentyl-4-methyl-1,2-dithiolane-4-carboxamide
33
N-hexyl-4-methyl-1,2-dithiolane-4-carboxamide

No. Structure Chemical name
34 N-octyl-4-methyl-1,2-dithiol¬ane-4-carboxamide
35
N-propyl-4-methyl-1,2-dithiol¬ane-4-carboxamide
36
butyl 4-methyl-1,2-dithiol¬ane-4-carboxylate
37
isopropyl 4-methyl-1,2-dithiolane-4-carboxylate
38
pentyl 4-methyl-1,2-dithiol¬ane-4-carboxylate
39
hexyl 4-methyl-1,2-dithiol¬ane-4-carboxylate
40
heptyl 4-methyl-1,2-dithiol¬ane-4-carboxylate
41
N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
1-oxide
42
N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
1-dioxide

Among these compounds, the following compounds are more particularly preferred:

No. Structure Chemical name
2
4-methyl-1,2-dithiolane-4-carboxamide
10
N-heptyl-4-methyl-1,2-dithiolane-4-carboxamide
11
N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
23
4-methyl-1,2-dithiolane-1-oxo-4-carboxylic acid
24
4-methyl-1,2-dithiolane-1,1-dioxo-4-carboxylic acid
26
4-methyl-1,2-dithiolane-4-carboxamide 1-oxide
27
4-methyl-1,2-dithiolane-4-carboxamide 1,1-dioxide
41
N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
1-oxide
42
N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
1-dioxide

and also the acid or base salts thereof, optical iso-mers thereof and solvates thereof.

Some of the compounds in accordance with the in-vention are known per se. These are compounds 1 to 8 below:

No. Structure Chemical name CAS
1
4-methyl-1,2-dithiolane-4-carboxylic acid 208243-72-5

2
4-methyl-1,2-dithiolane-4-carboxamide 208243-73-6

3
methyl 4-methyl-1,2-dithiol¬¬ane-4-carboxylate 208243-88-3
4
ethyl 4-methyl-1,2-dithiol¬ane-4-carboxylate 208243-89-4
5
propyl 4-methyl-1,2-dithiol¬ane-4-carboxylate 208243-90-7
6
benzyl 4-methyl-1,2-dithiol¬ane-4-carboxylate 208243-73-6
7
N-methyl-4-methyl-1,2-dithiolane-4-carboxamide 208243-91-8
8
{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]amino}acetic acid 208243-74-7

These compounds have been described in patent ap-plication WO 98/23606 and used in pharmacology as agents for reducing glucose or fat in the blood.
The compounds of formula (I) may be obtained ac-cording to one of the routes described below and docu-mented
- in the review by Lene Teuber, Sulfur reports, 9(4), 257-349, 1990 Naturally occurring 1,2-dithiolanes and 1,2,3-trithianes. Chemical and Biological Properties,
- in patent application EP 0 869 126 A1.
Starting with 2,2-bis(hydroxymethyl)propionic acid (CAS:4767-03-7), by functionalization of the hydroxyls to leaving groups X (alkyl or aryl sulfonates such as mesylates or tosylates, or halogens such as iodine, bromine or chlorine) followed by the introduction of sulfur according to the following reaction scheme:

This introduction of sulfur may be performed:
(i) in a single step using a metal disulfide (for instance Na2S2) or tetrathiomolybdate salts in polar protic or aprotic solvents (for example water, DMF, methanol or acetonitrile) to give the dithiolane,
(ii) or in two steps by forming a dithiol interme-diate, which, in the presence of an oxidizing agent (oxygen, DMSO, FeCl3, I2, Br2, sodium iodide, thallium trifluoroacetates, silver triflates, aqueous hydrogen peroxide solution, sodium iodate and periodate, sodium hypochlorite, potassium ferricyanide or chromium oxide) in neutral or basic medium, leads to the formation of the dithiolane. In this case, the dithiol is obtained by conversion (in basic or acidic medium) in a polar or apolar solvent of an intermediate species via deriva-tives of thioacetic acid CH3COSH (in the presence of base), with thiourea or NaSH, via the formation of di-thiosulfonates (Bunte salts).
Functionalization of the carboxylic acid COOH into a function COYR may be performed according to the con-ventional acid activation methods (described in Compre-hensive Organic Transformations by R. Larock, Wiley VCH Ed. in the chapter: Interconversion of nitriles, car-boxylic acids and derivatives). Preferably, the methods used favour proceeding via the acid chloride (by using thionyl or oxalyl chloride, or 1-chloro-N,N,2-trimethyl-1-propenamine) or via the formation of a mixed anhydride (using alkyl chloroformates) or the use of carbodiimides or diethyl cyanophosphate (Phosphorus in organic synthesis - XI, Amino acids and peptides - XXI, Reaction of diethyl phosphorocyanidate with car-boxylic acids. A new synthesis of carboxylic esters and amides, Tetrahedron, 32, 1976, 2211-2217).*
The solvents used may be polar or apolar, and protic or aprotic (for example toluene, dichloro-methane, THF, DMF, acetonitrile, water, methanol or isopropanol).
All these reactions may be performed at tempera-tures of between -20 and 100°C.
The production of the products of oxidation of the sulfur atoms of the dithiolanes of formula (I) (n other than zero) may be performed according to the following reaction scheme:

using oxidizing agents such as oxygen, hydrogen perox-ide, DMSO, sodium periodate, organic peracids, inor-ganic persulfates or inorganic permanganates in the presence or absence of a catalyst (for example Na2WO4, MoO2Cl2 or trichlorooxobis(triphenylphosphine)rhenium). The various oxidation steps depend on the stoichiometry of the oxidizing agents used. The solvents that may be used may be water, acetone, dichloromethane or metha-nol.
These oxidations have been described in the fol-lowing documents:
- Oxidation of 1,2-Dithiolanes, Bernt Lindberg, Göran Bergson, Arkiv För Kemi, 1965, 23(31), 319-333;
- Selective oxidation of sulfides to sulfoxides and sulfones at room temperature using H2O2 and an Mo(VI) salt as catalyst, Kandasamy Jeyakumar, Dillip Kumar Chand, Tetrahedron Letters 47(2006), 4573-4576;
- Rhenium-Catalyzed Oxidation of Thiols and Disul-fides with Sulfoxides, Jeffrey B. Arterburn, Marc C. Perry, Sherry L. Nelson, Benjamin R. Dible, Mylena S. Holguin, J. Am. Soc., 119, 9309-9310, 1997.
Advantageously, compound 1 may be obtained accord-ing to the route described below starting with di-chloropivalic acid according to a one-pot process, end-ing with a precipitation.

Advantageously, compound 2 may be obtained from compound 1, preferentially using isobutyl chloroformate or oxalyl chloride.

The compounds according to the invention find a most particular use in the cosmetic or pharmaceutical field, in particular the dermatological field.
They may be present in cosmetic compositions, in an amount that may be between 0.01% and 10% by weight, preferably between 0.1% and 5% by weight and especially from 0.5% to 3% by weight relative to the total weight of the composition. Preferably the compounds are pre-sent in the compositions alone or as a synergistic mix-ture.
The composition also comprises a physiologically acceptable medium, which will preferably be a cosmeti-cally or pharmaceutically acceptable medium, especially a dermatologically acceptable medium, i.e. a medium that has no unpleasant odour, colour or appearance, and that does not cause the user any unacceptable stinging, tautness or redness. In particular, the composition is suitable for topical application to the skin.
The term “physiologically acceptable medium” means a medium that is compatible with human keratin materi-als such as bodily or facial skin, the lips, mucous membranes, the eyelashes, the nails, the scalp and/or the hair.
The composition according to the invention may then comprise any adjuvant commonly used in the envis-aged application field.
Mention may be made especially of water; organic solvents, especially C1-C6 alcohols and C2-C10 carboxylic acid esters; carbon-based and/or silicone oils, of min-eral, animal and/or plant origin; waxes, pigments, fillers, colorants, surfactants, emulsifiers, co-emulsifiers; cosmetic or dermatological active agents, UV-screening agents, polymers, hydrophilic or lipo-philic gelling agents, thickeners, preserving agents, fragrances, bactericides, ceramides, odour absorbers, antioxidants.
These optional adjuvants may be present in the composition in a proportion of from 0.001% to 80% by weight and especially from 0.1% to 40% by weight rela-tive to the total weight of the composition. Depending on their nature, these adjuvants may be introduced into the fatty phase or into the aqueous phase of the compo-sition, or into lipid vesicles. In any case, these ad-juvants, and the proportions thereof, will be chosen by a person skilled in the art such that the advantageous properties of the compounds according to the invention are not, or are not substantially, adversely affected by the envisaged addition.
As active agents, it will be advantageous to in-troduce into the composition used according to the in-vention at least one compound chosen from: desquamating agents; calmatives, organic or mineral photoprotective agents, moisturizers; depigmenting or propigmenting agents; anti-glycation agents; NO-synthase inhibitors; agents for stimulating the synthesis of dermal or epi-dermal macromolecules and/or for preventing their deg-radation; agents for stimulating fibroblast and/or keratinocyte proliferation or for stimulating keratino-cyte differentiation; muscle relaxants and/or dermo-decontracting agents; tensioning agents; anti-pollution agents and/or free-radical scavengers; agents acting on the capillary circulation; agents acting on the energy metabolism of cells; and mixtures thereof.
Examples of such additional compounds are: retinol and derivatives thereof such as retinyl palmitate; ascorbic acid and derivatives thereof such as magnesium ascorbyl phosphate and ascorbyl glucoside; tocopherol and derivatives thereof such as tocopheryl acetate; nicotinic acid and precursors thereof such as nicotina-mide; ubiquinone; glutathione and precursors thereof such as L-2-oxothiazolidine-4-carboxylic acid; plant extracts and especially plant proteins and hydrolysates thereof, and also plant hormones; marine extracts such as algal extracts; bacterial extracts; sapogenins such as diosgenin and wild yam extracts containing them; ce-ramides; hydroxy acids such as salicylic acid and 5-n-octanoylsalicylic acid; resveratrol; oligopeptides and pseudodipeptides and acyl derivatives thereof; manga-nese and magnesium salts, in particular the gluconates; and mixtures thereof.
The term “desquamating agent” means any compound capable of acting:
- either directly on desquamation by promoting ex-foliation, such as ?-hydroxy acids, in particular sali-cylic acid and derivatives thereof (including 5-n-octanoylsalicylic acid); ?-hydroxy acids, such as gly-colic acid, citric acid, lactic acid, tartaric acid, malic acid or mandelic acid; urea; gentisic acid; oli-gofucoses; cinnamic acid; Saphora japonica extract; resveratrol;
- or on the enzymes involved in the desquamation or degradation of corneodesmosomes, glycosidases, stra-tum corneum chymotryptic enzyme (SCCE) or other prote-ases (trypsin, chymotrypsin-like). Mention may be made of agents for chelating mineral salts: EDTA; N-acyl-N,N’N’-ethylenediaminetriacetic acid; aminosulfonic compounds and in particular (N-2-hydroxyethylpiperazine-N-2-ethane)sulfonic acid (HEPES); 2-oxothiazolidine-4-carboxylic acid (procys-teine) derivatives; derivatives of ? amino acids of glycine type (as described in EP-0 852 949, and also sodium methyl glycine diacetate sold by BASF under the trade name Trilon M); honey; sugar derivatives such as O-octanoyl-6-D-maltose and N-acetylglucosamine.
The desquamating agents are generally present in the composition according to the invention in propor-tions ranging from 0.01% to 15% by weight and prefera-bly ranging from 0.1% to 10% by weight relative to the total weight of the composition.
As calmatives that may be used in the composition according to the invention, mention may be made of: pentacyclic triterpenes and extracts of plants (e.g.: Glycyrrhiza glabra) containing them, for instance ?-glycyrrhetinic acid and salts and/or derivatives thereof (glycyrrhetinic acid monoglucuronide, stearyl glycyrrhetinate or 3-stearoyl¬oxyglycyrrhetic acid), ur-solic acid and its salts, oleanolic acid and its salts, betulinic acid and its salts, an extract of Paeonia suffruticosa and/or lactiflora, salicylic acid salts and in particular zinc salicylate, the phycosaccharides from the company Codif, an extract of Laminaria sac-charina, canola oil, bisabolol and camomile extracts, allantoin, Sepivital EPC (phosphoric diester of vita-mins E and C) from SEPPIC, omega-3 unsaturated oils such as musk rose oil, blackcurrant oil, ecchium oil, fish oil, plankton extracts, capryloylglycine, Seppi-calm VG (sodium palmitoylproline and Nymphea alba) from SEPPIC, a Pygeum extract, an extract of Boswellia ser-rata, an extract of Centipeda cunninghami, an extract of Helianthus annuus, an extract of Linum usitatis-simum, tocotrienols, extracts of Cola nitida, piper-onal, an extract of clove, an extract of Epilobium An-gustifolium, Aloe vera, an extract of Bacopa monieri, phytosterols, cortisone, hydrocortisone, indomethacin and betamethasone.
The calmatives are generally present in the compo-sition according to the invention in proportions rang-ing from 0.01% to 15% by weight and preferably ranging from 0.1% to 10% by weight relative to the total weight of the composition.
The organic photoprotective agents are chosen es-pecially from anthranilates; cinnamic derivatives; dibenzoylmethane derivatives; salicylic derivatives; camphor derivatives; triazine derivatives such as those described in patent applications US 4 367 390, EP 863 145, EP 517 104, EP 570 838, EP 796 851, EP 775 698, EP 878 469, EP 933 376, EP 507 691, EP 507 692, EP 790 243, EP 944 624; benzophenone derivatives; ?,? diphenylacrylate derivatives; benzotriazole deriva-tives; benzalmalonate derivatives; benzimidazole de-rivatives; imidazolines; bis-benzazolyl derivatives as described in patents EP 669 323 and US 2 463 264; p aminobenzoic acid (PABA) derivatives; methylene¬bis(hydroxyphenylbenzotriazole) derivatives as de-scribed in patent applications US 5 237 071, US 5 166 355, GB 2 303 549, DE 197 26 184 and EP 893 119; screening polymers and screening silicones such as those described especially in patent applica-tion WO 93/04665; ? alkylstyrene-based dimers, such as those described in patent application DE 198 55 649.
The mineral photoprotective agents may be chosen especially from pigments or even nanopigments (mean size of the primary particles: generally between 5 nm and 100 nm and preferably between 10 nm and 50 nm) of coated or uncoated metal oxides, for instance nanopig-ments of titanium oxide (amorphous or crystallized in rutile and/or anatase form), of iron oxide, of zinc ox-ide, of zirconium oxide or of cerium oxide, which are all UV photoprotective agents that are well known per se. Standard coating agents are, moreover, alumina and/or aluminium stearate. Such coated or uncoated metal oxide nanopigments are described in particular in patent applications EP 518 772 and EP 518 773.
The photoprotective agents are generally present in the composition according to the invention in pro-portions ranging from 0.1% to 20% by weight and pref-erably ranging from 0.2% to 15% by weight relative to the total weight of the composition.
This composition may be in any galenical form nor-mally used in the cosmetic or pharmaceutical field, and especially in the form of an optionally gelled aqueous or aqueous-alcoholic solution, a dispersion, optionally a two-phase dispersion, of the lotion type, an oil-in-water or water-in-oil or multiple emulsion (for example W/O/W or O/W/O), an aqueous gel, a dispersion of oil in an aqueous phase with the aid of spherules, these spherules possibly being polymer nanoparticles such as nanospheres and nanocapsules or, better still, lipid vesicles of ionic and/or nonionic type; aqueous or oily gels. These compositions are prepared according to the usual methods. According to this invention, a composi-tion in the form of an emulsion, especially an oil-in-water emulsion, is preferably used.
The composition may be more or less fluid and may have the appearance of a white or coloured cream, an ointment, a milk, a lotion, a serum, a paste, a gel or a mousse. It may optionally be applied in aerosol form. It may also be in solid form, in particular in the form of a stick.
When the composition is an emulsion, the propor-tion of the fatty phase may range from 5% to 80% by weight and preferably from 8% to 50% by weight relative to the total weight of the composition. The emulsifier and the co-emulsifier may be present in a proportion ranging from 0.3% to 30% by weight and preferably from 0.5% to 20% by weight relative to the total weight of the composition.
The composition used according to the invention may constitute a skincare composition, and especially a cleansing, protecting, medicated or care cream for the face, the hands, the feet, the major anatomical folds or the body (for example day creams, night creams, makeup-removing creams, foundation creams or antisun creams); a fluid foundation, a makeup-removing milk, a protective or care body milk or an antisun milk; a skincare lotion, gel or mousse, such as a cleansing lo-tion.
The invention is illustrated in greater detail by the non-limiting examples that follow.

Examples of synthesis:

Example 1: synthesis of 4-methyl-1,2-dithiolane-4-carboxylic acid (compound 1)

8 g of dichloropivalic acid are placed in a 250 ml three-necked flask on which are mounted a condenser and a dropping funnel. The acid is dissolved in 80 ml of water, and 4.6 g of Na2CO3 are slowly added. A solution of 10.7 g of potassium thioacetate is added dropwise, and the reaction medium is brought to reflux. 14.9 g of Na2CO3 are added and the medium is again refluxed. After disappearance of the starting material, 7.3 ml of DMSO are added, followed by refluxing. The dithiolane is ob-tained after acidification by precipitating and drying the solid under vacuum. A pale yellow solid is ob-tained.
1H NMR (400 MHz, DMSO-d6): d ppm 3.69 (d, 2H), 2.95 (d, 2H), 1.53 (s, 3H), ESI-:
[(M, H) -] = 163 m/z

Example 2: synthesis of octyl 4-methyl-1,2-dithiolane-4-carboxylate (compound 9)

1 g of acid (24) and then 0.8 ml of 1-chloro-N,N,2-trimethylpropenylamine (27) are placed in 20 ml of dichloromethane in a 100 ml three-necked flask using a syringe. The mixture is stirred for 1 hour, followed by dropwise addition via an additional funnel to a re-action medium at -5°C containing 1.28 ml of triethyl-amine, 0.96 ml of octanol and 20 ml of dichloromethane. The mixture is stirred. The reaction medium is then washed with water (3 × 30 ml). The aqueous phase is ex-tracted with 3 × 10 ml of EtOAc. The combined organic phases are washed with 30 ml of saturated aqueous NaCl solution and then dried over Na2SO4, filtered and then concentrated under vacuum (500 mbar, T = 40°C) on a ro-tavapor. The crude product obtained is a yellow oil (m = 1.25 g). Purification is performed by flash chroma-tography on a column of silica (m SiO2 = 40 g, eluting with a 100/0 and then 98/2 heptane/EtOAc gradient).
After concentrating the fractions on a rotavapor (P = 100 mbar, T = 40°C), 1.08 g of yellow oil are ob-tained.
Yield = 66%; Rf (ester) = 0.16 (eluent: cyclohex-ane);
1H NMR (400 MHz, DMSO-d6): d ppm 4.08 (t, 2H), 3.57 (d, 2H), 3.02 (d, 2H), 1.58 (m, 2H), 1.40 (s, 3H), 1.29 (m, 10H), 0.86 (t, 3H)
MS m/z (M+, 277; M+23, 299).
The following manipulations were performed under the same conditions described previously, with only the nucleophile varying.

Example 3: synthesis of S-[2-(acetylamino)ethyl] 4-methyl-1,2-dithiolane-4-carbothioate (compound 13)

Method identical to that of Example 2: the nucleo-phile used is N-acetylcysteamine (0.64 ml).
Purification is performed by flash chromatography on a column of silica (m SiO2 = 40 g; eluting with a linear gradient of 100/0 and then 98/2 DCM/MeOH).
After concentrating the fractions on a rotavapor (P = 200 mbar, T = 40°C), 0.32 g of a mixture compris-ing the expected compound and N,N,2-trimethylpropionamide is obtained. After evaporating under vacuum, the expected final compound is obtained in the form of a thick yellow liquid.
Yield = 10%; Rf (expected)= 0.3; eluent: 95/5 DCM/MeOH; 1H NMR (DMSO-d6): d ppm 8.03 (t, NH), 3.57 (d, 2H), 3.18 (dt 2H), 3.10 (d, 2H), 2.96 (m, 2H), 1.79 (s, 3H), 1.43 (s, 3H); MS m/z (M+, 266; M+23, 288).

Example 4: synthesis of N-(2-hydroxyethyl)-4-methyl-1,2-dithiolane-4-carboxamide (compound 14)

Method identical to that of Example 2: the nucleo-phile used is ethanolamine (0.36 ml). After filtering the reaction medium, a crude yellow oil is obtained (m = 1.850 g).
Purification is performed by flash chromatography on a column of silica (eluting with a linear gradient of 100/0 and then 98/2 DCM/MeOH).
After concentrating the fractions on a rotavapor (P = 500 mbar, T = 40°C), 800 mg of a yellow oil (pure compound) are obtained; yield = 65%.
Rf (expected)= 0.43; eluent: 9/1 DCM/MeOH;
1H NMR (DMSO-d6): d ppm 7.80 (t, NH), 4.64 (t, OH), 3.53 (d, 2H), 3.40 (dt, 2H), 3.14 (m, 2H), 2.99 (d, 2H), 1.34 (s, 3H); MS m/z (M+, 208; M+23, 230).

Example 5: synthesis of 4-methyl-1,2-dithiolane-4-carboxamide (compound 2)

Method (Ex. 5-a) identical to that of Example 2: the nucleophile used is ammonia in isopropanol (9.5 ml). After filtering the reaction medium, a crude yellow oil is obtained (m = 1.853 g).
Purification is performed by flash chromatography on a column of silica (eluent: DCM).
After concentrating the fractions on a rotavapor (P = 600 mbar, T = 40°C), 500 mg of pure expected yel-low solid are obtained. Yield = 52%.
Alternatively, method (Ex. 5-b), 1.2 equivalents of isobutyl chloroformate are added, at 0°C, to a solu-tion of 1 g of compound 1 in THF with 1.2 equivalents of triethylamine. After 2 hours at room temperature, the reaction medium is added to a cooled solution of ammonia, either at 28% in water or at 2N in isopropa-nol. The medium is stirred at room temperature for the time required, and then concentrated under vacuum. The crude product is then taken up in toluene, to give com-pound 2 after precipitation. Yield = 60%
Rf (expected)= 0.45; eluent: 95/5 DCM/MeOH; 1H NMR (DMSO-d6): d ppm 7.38 (s, NH), 7.13 (s, NH), 3.53 (d, 2H), 2.97 (d, 2H), 1.34 (s, 3H); ESI-: [(M, H) -] = 162 m/z; ESI+: [(M, Na) +] = 186 m/z; ESI+: [(M, H) +] = 164 m/z; ESI+: [(M, Na, MeOH) +] = 218 m/z

Example 6: synthesis of N-(2,3-dihydroxypropyl)-4-methyl-1,2-dithiolane-4-carboxamide (compound 15)

Method identical to that of Example 2: the amount of starting acid used is 0.25 g and the nucleophile used is dimethyldioxalanemethanamine (0.2 ml).
110 mg of pure expected yellow oil are obtained. Yield = 26%
Rf (expected)= 0.51; eluent: 95/5 DCM/MeOH; 1H NMR (DMSO-d6): d ppm 7.77 (t, 1H: NH), 3.55 (dd 4H, H3: diastereoisomers), 3.5 (m, 4H, H7: diastereoisomers), 3.20 (m, 2H, H8: diastereoisomers), 3.05 (dd, 2H: H9 and H9’), 2.99 (dd, 4H, H5), 1.35 (s, 12H, H10+H11: di-astereoisomers), 0.9 (d, 3H, H6); MS m/z (M+23, 300).
70 mg of the pure product protected in acetonide form and about 5 g of Dowex resin are used in a solu-tion of 3 ml of water and 2 ml of THF. The reaction mixture is stirred at room temperature for 20 hours and then at 40°C for 40 hours.
The reaction medium with the resin is filtered un-der vacuum and washed with 3 × 10 ml of water and then 2 × 10 ml of EtOH. The filtrate is then concentrated on a rotavapor (P = 200 mbar, T = 40°C). 30 mg of a yellow oil containing two diastereoisomers are obtained.
Rf (expected)= 0.24; eluent: 9/1 DCM/MeOH; 1H NMR (DMSO-d6): d ppm 7.80 (t, 1H: NH), 4.73 (d, OH), 4.50 (t, OH), 3.55 (d, 4H), 3.4 (m, 2H), 3.2 (m, 1H), 3.1 (m, 2H), 2.99 (d, 4H), 1.35 (s, 3H); MS m/z (M+, 208; M+23, 230).

Example 7: synthesis of N-heptyl-4-methyl-1,2-dithiolane-4-carboxamide (compound 10)

Method identical to that of Example 2: the nucleo-phile is 0.22 ml of n-heptylamine.
The crude product obtained is a yellowish oil (m = 0.27 g).
Purification is performed by flash chromatography on a column of silica (m SiO2 = 12 g; eluent: 99/1 DCM/MeOH).
After concentrating the fractions on a rotavapor (P = 500 mbar, T = 40°C), 0.21 g of a yellow oil (pure compound 10) is obtained. Yield = 54%.
Rf (expected)= 0.5; eluent: 99/1 DCM/MeOH; 1H NMR (DMSO-d6): d ppm 7.78 (t, NH), 3.53 (d, 2H), 3.1 (dt, 2H), 2.97 (d, 2H), 1.41 (tt, 2H), 1.34 (s, 3H), 1.23 (m, 8H), 0.85 (t, 3H); MS m/z (M+, 262; M+23, 284)

Example 8: synthesis of methyl 2-{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]amino}-4-(methylsulfanyl)¬butanoate (compound 12)

Method identical to that of Example 2: the nucleo-phile is L-methionine methyl ester. 140 mg of a yellow oil are obtained (7% yield).
1H NMR (DMSO-d6): d ppm 8.13 (d, NH), 4.4 (m, 1H), 3.63 (s, 3H), 3.58 (m, 2H), 3.02 (m, 2H), 2.5 (m, 2H), 2.04 (s, 3H), 1.96 (m, 2H), 1.38 (s, 3H); MS m/z (M+, 310; M+23, 332)

Example 9: synthesis of N-butyl-4-methyl-1,2-dithiolane-4-carboxamide (compound 11)

1.1 equivalents of triethylamine and 1 equivalent of diethyl cyanophosphate are added to 1 g of 1,2-dithiolane-4-methyl-4-carboxylic acid in ml of anhy-drous THF, at 0°C. 1.1 equivalents of n-butylamine are added at 0°C and the medium is stirred for 1 hour while warming to room temperature. After evaporation and aqueous work-up by extraction, the concentrated crude reaction product is purified on a column of silica (eluent: dichloromethane). After evaporating the frac-tions of interest, a yellow oil is obtained.
1H NMR (DMSO-d6): d ppm 7.79 (t, NH), 3.53 (d, 2H), 3.1 (dt, 2H), 2.97 (d, 2H), 1.41 (tt, 2H), 1.34 (s, 3H), 1.23 (m, 8H), 0.85 (t, 3H); MS m/z (M+, 262; M+23, 284)
1H NMR (DMSO-d6): d ppm 7.79 (t, NH), 3.54 (d, 2H), 3.08 (dt, 2H), 2.98 (d, 2H), 1.40 (q, 2H), 1.34 (s, 3H), 1.27 (m, 4H), 0.87 (t, 3H); ESI+: [(M, Na) +] = 242 m/z

Example 10: synthesis of 4-methyl-1,2-dithiolane-4-carboxylic acid 1-oxide (compound 23)

1 equivalent of aqueous 30% hydrogen peroxide so-lution is added to 100 mg of 4-methyl-1,2-dithiolane-4-carboxylic acid in 2 ml of acetone. The reaction medium is stirred at 20°C overnight. After concentrating under vacuum, the thiosulfinate is obtained quantitatively in the form of a white solid as a mixture of two di-astereoisomers in proportions of 70/30.
1H NMR (DMSO-d6): d ppm
major diastereoisomer: 4.38 (d, 1H), 3.78 (q, 2H), 3.11 (d, 1H), 1.57 (s, 3H)
minor diastereoisomer: 4.36 (d, 1H), 3.96 (d, 1H), 3.42 (d, 1H), 3.31 (d, 1H), 1.51 (s, 3H)
13C NMR (DMSO-d6): d ppm: 174.95; 174.63; 71.96; 70.85; 58.98; 56.73; 46.53; 45.03; 23.77; 21.96
ESI-: [(M, H) -] = 179 m/z

Example 11: synthesis of 4-methyl-1,2-dithiolane-4-carboxylic acid 1,1-dioxide (compound 24)

2 equivalents of aqueous 30% hydrogen peroxide so-lution and 0.15 equivalent of sodium tungstate Na2WO4 are added to 100 mg of 4-methyl-1,2-dithiolane-4-carboxylic acid in 2 ml of acetone. The reaction medium is stirred at 20°C overnight. After filtering and con-centrating under vacuum, the crude product is purified on a column of silica to give the thiosulfonate in the form of a white solid.
1H NMR (DMSO-d6): d ppm 4.14 (d, 1H), 4.05 (d, 1H), 3.69 (d, 1H), 3.66 (d, 1H), 1.51 (s, 3H);
13C NMR (DMSO-d6): d ppm 173.90; 65.86; 50.26; 44.58; 23.59
ESI-: [(M, H) -] = 195 m/z

Example 12: synthesis of ethyl 4-methyl-1,2-dithiolane-4-carboxylate (compound 4)

Sulfonic resin Dowex 50 WX8 (sold by Aldrich) is added to 1 g of 4-methyl-1,2-dithiolane-4-carboxylic acid in 20 ml of ethanol. The mixture is refluxed for 24 hours and then filtered and evaporated to give the pure ethyl ester.
1H NMR (DMSO-d6): d ppm 4.13 (q, 2H), 3.58 (d, 2H), 3.02 (d, 2H), 1.40 (s, 3H), 1.20 (t, 3H)
ESI+: [(2M, Na) +] = 407 m/z

Example 13: synthesis of ethyl 4-methyl-1,2-dithiolane-4-carboxylate 1-oxide (compound 25)

Oxidation of the ethyl ester is performed in the same manner as for the acid.
175 mg of a pale yellow oil are obtained.
1H NMR (DMSO-d6): d ppm
major diastereoisomer: 4.4 (d, 1H), 4.11 (q, 2H), 3.8 (d, 1H), 3.75 (d, 1H), 3.17 (d, 1H), 1.59 (s, 3H), 1.53 (t, 3H)
minor diastereoisomer: 4.2 (d, 1H), 4.11 (q, 2H), 3.98 (d, 1H), 3.8 (d, 1H), 3.42 (d, 1H), 3.32 (d, 1H), 1.51 (s, 3H)
13C NMR (DMSO-d6): d ppm 174.95, 174.63, 71.96, 70.85, 58.98, 56.73, 46.53, 45.03, 23.77, 21.96
ESI+: [(M, Na) +] = 231 m/z; ESI+: [(M, Na, MeOH) +] = 263 m/z; ESI+: [(2M, Na) +] = 439 m/z
ESI+: [(M, Na) +] = 231 m/z; ESI+: [(M, Na, MeOH) +] = 263 m/z; ESI+: [(2M, Na) +] = 439 m/z

Example 14: synthesis of 4-methyl-1,2-dithiolane-4-carboxamide 1-oxide (compound 26)

1 equivalent of aqueous 30% hydrogen peroxide so-lution is added to 100 mg of 4-methyl-1,2-dithiolane-4-carboxamide in 2 ml of acetone. The reaction medium is stirred at 20°C overnight. After concentrating under vacuum and purifying on a column of silica, the thi-osulfinate is obtained in the form of a white solid as a mixture of two diastereoisomers.
1H NMR (DMSO-d6): d ppm
major diastereoisomer: 7.40 (bd, 2H), 4.31 (d, 1H), 3.78 (bs, 2H), 3.04 (d, 1H), 1.49 (s, 3H)
minor diastereoisomer: 7.32 (bd, 2H), 4.21 (d, 1H), 3.92 (d, 1H), 3.42 (d, 1H), 3.34 (d, 1H), 1.40 (s, 3H)
ESI-: [(M, H) -] = 178 m/z

Example 15: synthesis of 4-methyl-1,2-dithiolane-4-carboxamide 1,1-dioxide (compound 27)

2 equivalents of aqueous 30% hydrogen peroxide so-lution and 0.15 equivalent of sodium tungstate Na2WO4 are added to 100 mg of 4-methyl-1,2-dithiolane-4-carboxamide in 2 ml of acetone. The reaction medium is stirred at 20°C overnight. After filtering and concen-trating under vacuum, the crude product is purified on a column of silica to give the thiosulfonate in the form of a white solid.
1H NMR (DMSO-d6): d ppm 7.50 (bd, 2H), 4.21 (d, 1H), 4.08 (d, 1H), 3.66 (d, 1H), 3.59 (d, 1H), 1.49 (s, 3H);
ESI-: [(M, H) -] = 194 m/z

Example 16: synthesis of N-(4-hydroxy-3-methoxybenzyl)-4-methyl-1,2-dithiolane-4-carboxamide (compound 16)

24.3 mmol of N-hydroxysuccinimide are added to 24.3 mmol of dithiolane acid dissolved in 60 ml of di-chloromethane cooled to 0°C (on an ice bath). The reac-tion medium is stirred for 30 minutes at 0°C. A solu-tion of 24.3 mmol of DCC in 50 ml of dichloromethane is added and the mixture is then stirred at 20°C for 4 hours. The reaction medium is filtered and washed, and the filtrate is then evaporated to dryness on a rota-vapor at 40°C under vacuum to give 1-{[(4-methyl-1,2-dithiolan-4-yl)¬carbonyl]oxy}pyrrolidine-2,5-dione (m = 7 g, quanti¬ta¬tive yield). 10 ml of MeTHF, 3.16 mmol of 4-(aminomethyl)-2-methoxyphenol hydrochloride and 3.16 mmol of triethylamine are added to 1.58 mmol of 1-{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]oxy}pyr¬roli¬dine-2,5-dione. After stirring overnight, the mixture is filtered, rinsed with MeTHF and then evaporated. Flash chromatography, eluting with 98/2 dichloro-methane/methanol, gives compound 16 in the form of a yellow oil (84% yield).
1H NMR (DMSO-d6): d ppm 1.39 (s, 3H); 3.03 (d, 2H); 3.56 (d, 2H), 3.63 (s, 3H, OCH3), 4.21 (d, 2H), 6.64 (dd, 1H, Ar), 6.69 (d, 1H, Ar), 6.80 (d, 1H, Ar), 8.31 (t, 1H, NH), 8.79 (s, 1H, OH)
ESI+: [(M, H)+] = 300 m/z

Example 17: synthesis of N-[2-(4-hydroxy-3-methoxyphenyl)ethyl]-4-methyl-1,2-dithiolane-4-carbox¬amide (compound 17)

Same method as for compound 16 with 4-(2-aminoethyl)-2-methoxyphenol hydrochloride. 320 mg of a yellow solid are obtained (yield = 64%).
1H NMR (DMSO-d6): d ppm 1.31 (s, 3H); 2.63 (t, 2H), 2.97 (d, 2H); 3.24 (m, 2H, NCH2) 3.53 (d, 2H), 3.75 (s, 3H, OCH3), 6.57 (dd, 1H, Ar), 6.67 (d, 1H, Ar), 674 (d, 1H, Ar), 8.86 (t, 1H, NH), 8.67 (s, 1H, OH)
ESI+: [(M, H)+] = 314 m/z

Example 18: synthesis of N,N-diethyl-4-methyl-1,2-dithiolane-4-carboxamide (compound 18)

5 ml of anhydrous dichloromethane and 0.1 ml of anhydrous DMF are added to 2.26 mmol of compound 1. The mixture is cooled to 0°C and 2.7 mmol of oxalyl chlo-ride are added. The mixture is stirred at 20°C and then added at 0°C to a mixture of 2.26 mmol of diethylamine, 5 ml of anhydrous dichloromethane and 6.8 mmol of diisopropylethylamine. The reaction medium is stirred for 3 hours at 20°C. When the reaction is complete, the medium is diluted in 50 ml of dichloromethane and then washed with 2 × 30 ml of water and 1 × 50 ml of satu-rated NH4Cl solution, dried over Na2SO4 and evaporated to dryness on a rotavapor. After flash chromatography (eluent: heptane/EtOAc), compound 18 is isolated in the form of a yellow oil (48% yield).
1H NMR (DMSO-d6): d ppm 1.36 (s, 3H); 3.15 (d, 2H); 3.50 (d, 2H), 3.3 (m, 2 × 2H), 1.07 (m, 2 × 3H)
ESI+: [(M, H)+] = 220 m/z

Example 19: synthesis of methyl 2-(acetylamino)-3-{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]sulfanyl}¬propanoate (compound 19)

Same method as in Example 18 with N-acetylcysteine methyl ester.
90 mg of a yellow oil are obtained (12% yield).
1H NMR (DMSO-d6): d ppm 1.42 (s, 3H); 1.84 (s, 3H, OCH3); 3.15 (d, 2H); 3.56 (d, 2H), 3.38-3.12 (dd, 2H), 3.65 (s, 3H, COCH3), 8.42 (d, 1H, NH)
ESI+: [(M, H)+] = 324 m/z

Example 20: synthesis of S-(2-hydroxyethyl) 4-methyl-1,2-dithiolane-4-carbothioate (compound 20)

Same method as in Example 18 with sulfanylethanol.
130 mg of a yellow oil are obtained (26% yield).
1H NMR (DMSO-d6): d ppm 1.43 (s, 3H); 3.1 (d, 2H); 3.56 (d, 2H), 2.99 (t, 2H: CH2S), 3.48 (q, 2H: CH2OH)
ESI+: [(M, Na)+] = 247 m/z

Example 21: synthesis of ethyl {[(4-methyl-1,2-dithiolan-4-yl)carbonyl]sulfanyl}acetate (compound 21)

Same method as in Example 17 with ethyl thioglyco-late.
30 mg of a virtually colourless oil are obtained (7% yield).
1H NMR (DMSO-d6): d ppm 1.53 (s, 3H); 1.28 (t, 3H), 2.99 (d, 2H); 3.65 (d, 2H), 3.71 (s, 2H, SCH2), 4.20 (q, 2H)

Example 22: synthesis of [(4-methyl-1,2-dithiolan-4-yl)carbonyl]pyrrolidine (compound 22)

Same method as for Example 5-b with pyrrolidine.
130 mg of a yellow solid are obtained (38% yield).
1H NMR (DMSO-d6): d ppm 1.36 (s, 3H); 1.81 (m, 2 × 2H); 3.10 (d, 2H); 3.30 (m, 2 × 2H); 3.58 (d, 2H),
ESI+: [(M, H)+] = 218 m/z

Example 23: synthesis of 4-methyl-N-(1-methylethyl)-1,2-dithiolane-4-carboxamide (compound 28)

Same method as in Example 18 with isopropylamine.
250 mg of a beige-coloured solid are obtained (54% yield).
1H NMR (DMSO-d6): d ppm 1.06 (d, 2 × 3H); 1.33 (s, 3H, Hc); 2.99 (d, 2H, Hb); 3.56 (d, 2H, Ha); 3.88 (m, 1H),
ESI+: [(M, H)+] = 206 m/z

Example 24: synthesis of 4-methyl-N-phenyl-1,2-dithiolane-4-carboxamide (compound 29)

Same method as in Example 18 with aniline.
380 mg of a yellow oil are obtained (70% yield).
1H NMR (DMSO-d6): d ppm 1.51 (s, 3H, Hc); 2.99 (d, 2H, Hb); 3.75 (d, 2H, Ha), 7.08 (t, 1H, Ar), 7.3 (t, 2H, Ar), 7.60 (d, 2H, Ar), 9.56 (s, 1h, NH)
ESI+: [(M, H)+] = 240 m/z

Example 24bis : Synthesis of N-butyl-4-methyl-1,2-dithiolane-4-carboxamide 1-oxide (compound 41)

To 6g of N- butyl -4-methyl-1,2-dithiolane-4-carboxamide (example 9 ; compound 11), dissolved in ethanol (30ml) and acetone (60ml) was added 15 ml of acetic acid before adding dropwise 3 equivalents of hy-drogen peroxide. The reaction mixture is stirred at room temperature overnight. After stripping down all the solvents, the crude material is purified by silica gel chromatrography (Ethyl acetate/Heptane 60/40 to 80/20) to afford the desired thiosulfinate as a white solid as a mixture of diastereoisomers.

RMN 1H (DMSO-d6): ? ppm
Main Diastereoisomer : 8 (t, 1H), 4.21 (d, 1H), 3.94 (d, 1H), 3.55 (d, 1H), 3.36 (d, 1H), 3.07 (q, 2H), 1.49 (s, 3H)
ESI+ : [(M, H) +] = 236 m/z

Example 24 ter : Synthesis of N-butyl-4-methyl-1,2-dithiolane-4-carboxamide 1-dioxide (compound 42)

To a mixture of 10.35 g of N- butyl -4-methyl-1,2-dithiolane-4-carboxamide (example 9 ; compound 11), in 400 ml of methanol were added 58g of Oxone® (Aldrich CAS : 10058-23-8). The reaction mixture is stirred at room temperature for 1 hour before filtration. The fil-trate is concentrated under vacuum and purified by by silica gel chromatrography (Ethyl acetate/Heptane 60/40 to 80/20) to afford 5g of the desired thiosulfonate as a white solid.

RMN 1H (DMSO-d6): ? ppm 8 (t, 1H), 4.23 (d, 1H), 4.09 (d, 1H), 3.66 (d, 1H), 3.63 (d, 1H), 3.10 (q, 2H), 1.49 (s, 3H), 1.40 (m, 2H), 1.25 (m, 2H), 0.87 (t, 3H);
ESI+ : [(M, H) +] = 252 m/z

Example 25: Demonstration of the activity on con-stitutive melanogenesis
A biological test demonstrated the depigmenting activity of the compounds according to the invention. The modulatory effect of the compounds on constitutive melanogenesis was measured according to the method de-scribed in patent FR-A-2 734 825 and also in the arti-cle by Schmidt et al., Anal. Biochem., 235(2), 1996, pp.113-118. This test is performed on a co-culture of keratinocytes and melanocytes.
For the test compounds, the inhibitory activity on melanin synthesis was determined, by estimating the ra-tio of incorporation of thiouracil to the incorporation of leucine, relative to 100% of the control (the con-trol corresponds to the test performed without test compound).
The results are collated in the following table:

Cytotoxicity on a co-culture Maximum Activ-ity
Compound 2 (Example 5) 100 µM -76%
Arbutin Non-cytotoxic -44%
Kojic acid 100 µM -30%

The results obtained show that compound 2 used ac-cording to the invention has greater depigmenting ac-tion than arbutin and kojic acid.

Example 26
A bleaching facial care cream of oil-in-water emulsion type is prepared, comprising (weight %):

compound 2 (Example 5) 2%
glyceryl stearate 2%
Polysorbate-60 (Tween 60 from ICI) 1%
stearic acid 1.4%
triethanolamine 0.7%
carbomer 0.4%
liquid fraction of shea butter 12%
perhydrosqualene 12%
antioxidant qs
fragrance, preserving agent qs
water qs 100%

A similar composition is prepared with the com-pound of Example 9 (compound 11) or of Example 14 (com-pound 26).

Example 27
A skin depigmenting gel is prepared, comprising (weight %):

compound 2 (Example 5) 2%
hydroxypropylcellulose (Klucel H from Hercules) 1%
antioxidant qs
fragrance, preserving agent qs
isopropanol 40%
water qs 100%

A similar composition is prepared with the com-pound of Example 15 (compound 27).

WE CLAIM
1. Cosmetic process for depigmenting, lightening and/or bleaching keratin materials, comprising the ap-plication of a cosmetic composition comprising, in a physiologically acceptable medium, at least one com-pound of formula (I):

(I)
in which:
Y denotes O, NR1 or S
R1 denotes a hydrogen atom; a saturated linear C1-C20 or branched C3-C20 or unsaturated C2-C20 alkyl hydrocarbon-based group; a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals;
R denotes a hydrogen atom; or a saturated linear C1-C20 or branched C3-C20 or unsaturated C2-C20 alkyl hydrocar-bon-based group; or a phenyl group optionally substi-tuted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals; or a saturated C1-C8 alkyl group containing a phenyl substituent optionally sub-stituted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals;
R optionally bears one or more substituents chosen from OR2, SR2, NR2R3, COOR2 in which:
R2 denotes a hydrogen atom or a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group, or a phenyl group
R3 denotes a hydrogen atom; a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group; a phenyl group; an acetyl group;
when Y = NR1, R and R1 may form a ring chosen from pyr-rolidine, pyrroline, piperidine, piperazine, mor-pholine, thiomorpholine and azepine;
n = 0 or 1 or 2,
and also the salts thereof, chelates thereof, solvates thereof and optical isomers thereof.
2. Process according to Claim 1, in which:
Y denotes S, O, NR1
R1 denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group;
R denotes a hydrogen atom; a saturated linear C1-C20 or branched C3-C20 alkyl hydrocarbon-based group; a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C1-C3 alkoxy radicals; a satu-rated C1-C5 alkyl group containing a phenyl substituent optionally substituted with one or more hydroxyls and/or with one or more C1-C3 alkoxy radicals; a linear C1-C5 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OR2, SR2, NR2R3, COOR2 in which:
R2 denotes a hydrogen atom or a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group,
R3 denotes a hydrogen atom; a saturated linear C1-C5 or branched C3-C5 hydrocarbon-based group; a phenyl group; an acetyl group;
when Y = NR1, R and R1 may form a pyrrolidine ring,
n = 0 or 1 or 2.
3. Process according to one of the preceding claims, in which:
Y denotes O or NR1;
R1 denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group;
R denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group; a phenyl group optionally substituted with one or more hydroxyls and/or with one or more methoxy radicals; a saturated C1-C3 alkyl hydrocarbon-based group containing a phenyl substituent optionally substituted with one or more hy-droxyls and/or with one or more methoxy radicals; a linear C1-C4 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OR2, SR2, NR2R3, COOR2 in which:
R2 denotes a hydrogen atom or a saturated linear C1-C5 or branched C3-C5 hydrocarbon-based group,
R3 denotes a hydrogen atom; a saturated linear C1-C5 or branched C3-C5 hydrocarbon-based group;
n = 0 or 1 or 2.
4. Process according to one of the preceding claims, in which
Y denotes NR1;
R1 denotes a hydrogen atom; a saturated linear C1-C4 al-kyl hydrocarbon-based group;
R denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group; a phenyl group; a saturated linear C1-C4 alkyl group substituted with a phenyl optionally substituted with one or more identical or different groups chosen from OH, OMe; a linear C1-C4 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OH, NHAc, SR2, COOR2 with R2 being a hydrogen or a linear C1-C4 alkyl group;
n = 0 or 1 or 2.
5. Process according to one of the preceding claims, in which
Y denotes NH
R denotes a hydrogen atom; a saturated linear C1-C10 or branched C3-C10 alkyl hydrocarbon-based group; a phenyl group; a saturated linear C1-C4 alkyl group substituted with a phenyl optionally substituted with one or more identical or different groups chosen from OH, OMe; a linear C1-C4 alkyl hydrocarbon-based group substituted with one or more identical or different groups chosen from OH, NHAc, SR2, COOR2 with R2 being a hydrogen or a linear C1-C4 alkyl group;
n = 0 or 1 or 2.
6. Process according to Claim 1, in which the com-pound of formula (I) is chosen from the following com-pounds:

- 4-methyl-1,2-dithiolane-4-carboxylic acid
- 4-methyl-1,2-dithiolane-4-carboxamide
- methyl 4-methyl-1,2-dithiolane-4-carboxylate
- ethyl 4-methyl-1,2-dithiolane-4-carboxylate
- propyl 4-methyl-1,2-dithiolane-4-carboxylate
- benzyl 4-methyl-1,2-dithiolane-4-carboxylate
- N-methyl-4-methyl-1,2-dithiolane-4-carboxamide
- {[(4-methyl-1,2-dithiolan-4-yl)carbonyl]amino}acetic acid
- octyl 4-methyl-1,2-dithiolane-4-carboxylate
- N-heptyl-4-methyl-1,2-dithiolane-4-carboxamide
- N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
- methyl 2-{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]amino}-4-(methylsulfanyl)¬butanoate
- S-[2-(acetylamino)ethyl] 4-methyl-1,2-dithiolane-4-carbothioate
- N-(2-hydroxyethyl)-4-methyl-1,2-dithiolane-4-carboxamide
- N-(2,3-dihydroxypropyl)-4-methyl-1,2-dithiolane-4-carboxamide
- N-(4-hydroxy-3-methoxybenzyl)-4-methyl-1,2-dithiolane-4-carboxamide
- N-[2-(4-hydroxy-3-methoxyphenyl)ethyl]-4-methyl-1,2-dithiolane-4-carboxamide
- N,N-diethyl-4-methyl-1,2-dithiolane-4-carboxamide
- methyl 2-(acetylamino)-3-{[(4-methyl-1,2-dithiolan-4-yl)carbonyl]sulfanyl}¬propanoate
- S-(2-hydroxyethyl) 4-methyl-1,2-dithiolane-4-carbothioate
- ethyl {[(4-methyl-1,2-dithiolan-4-yl)carbonyl]sulfanyl}acetate
- [(4-methyl-1,2-dithiolan-4-yl)carbonyl]pyrrolidine
- 4-methyl-1,2-dithiolane-1-oxo-4-carboxylic acid
- 4-methyl-1,2-dithiolane-1,1-dioxo-4-carboxylic acid
- ethyl 4-methyl-1,2-dithiolane-1-oxo-4-carboxylate
- 4-methyl-1,2-dithiolane-4-carboxamide 1-oxide
- 4-methyl-1,2-dithiolane-4-carboxamide 1,1-dioxide
- 4-methyl-N-(1-methylethyl)-1,2-dithiolane-4-carboxamide
- 4-methyl-N-phenyl-1,2-dithiolane-4-carboxamide
- N-[2-(4-hydroxyphenyl)ethyl]-4-methyl-1,2-dithiolane-4-carboxamide
- N-propyl-4-methyl-1,2-dithiolane-4-carboxamide
- N-pentyl-4-methyl-1,2-dithiolane-4-carboxamide
- N-hexyl-4-methyl-1,2-dithiolane-4-carboxamide
- N-octyl-4-methyl-1,2-dithiolane-4-carboxamide
- N-propyl-4-methyl-1,2-dithiolane-4-carboxamide
- butyl 4-methyl-1,2-dithiolane-4-carboxylate
- isopropyl 4-methyl-1,2-dithiolane-4-carboxylate
- pentyl 4-methyl-1,2-dithiolane-4-carboxylate
- hexyl 4-methyl-1,2-dithiolane-4-carboxylate
- heptyl 4-methyl-1,2-dithiolane-4-carboxylate
- N-butyl-4-methyl-1,2-dithiolane-4-carboxamide 1-oxide
- N-butyl-4-methyl-1,2-dithiolane-4-carboxamide 1-dioxide.
7. Process according to Claim 1, in which the com-pound of formula (I) is chosen from the following com-pounds:
- 4-methyl-1,2-dithiolane-4-carboxamide
- N-heptyl-4-methyl-1,2-dithiolane-4-carboxamide
- N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
- 4-methyl-1,2-dithiolane-4-carboxamide 1-oxide
- 4-methyl-1,2-dithiolane-4-carboxamide 1,1-dioxide
- 4-methyl-1,2-dithiolane-1-oxo-4-carboxylic acid
- 4-methyl-1,2-dithiolane-1,1-dioxo-4-carboxylic acid
- N-butyl-4-methyl-1,2-dithiolane-4-carboxamide 1-oxide
- N-butyl-4-methyl-1,2-dithiolane-4-carboxamide
1-dioxide.
8. Process according to one of the preceding claims, in which the compound of formula (I) is not one of the following compounds:
- 4-methyl-1,2-dithiolane-4-carboxylic acid
- 4-methyl-1,2-dithiolane-4-carboxamide
- methyl 4-methyl-1,2-dithiol¬¬ane-4-carboxylate
- ethyl 4-methyl-1,2-dithiol¬ane-4-carboxylate
- propyl 4-methyl-1,2-dithiol¬ane-4-carboxylate
- benzyl 4-methyl-1,2-dithiol¬ane-4-carboxylate
- N-methyl-4-methyl-1,2-dithiolane-4-carboxamide
- {[(4-methyl-1,2-dithiolan-4-yl)carbonyl]amino}acetic acid.
9. Process according to one of the preceding claims, in which the compound of formula (I) is pre-sent, alone or as a mixture, in the composition in an amount of between 0.01% and 10% by weight, preferably between 0.1% and 5% by weight and especially from 0.5% to 3% by weight relative to the total weight of the composition.
10. Process according to one of the preceding claims, in which the composition comprises at least one adjuvant chosen from the group formed by: water; or-ganic solvents, especially C1-C6 alcohols and C2-C10 car-boxylic acid esters; carbon-based and/or silicone oils, of mineral, animal and/or plant origin; waxes, pig-ments, fillers, colorants, surfactants, emulsifiers, co-emulsifiers; cosmetic or dermatological active agents, UV-screening agents, polymers, hydrophilic or lipophilic gelling agents, thickeners, preserving agents, fragrances, bactericides, ceramides, odour ab-sorbers, antioxidants.
11. Process according to one of the preceding claims, in which the composition comprises at least one active agent chosen from: desquamating agents; calma-tives, organic or mineral photoprotective agents, mois-turizers; depigmenting or propigmenting agents; anti-glycation agents; NO-synthase inhibitors; agents for stimulating the synthesis of dermal or epidermal macro-molecules and/or for preventing their degradation; agents for stimulating fibroblast and/or keratinocyte proliferation or for stimulating keratinocyte differen-tiation; muscle relaxants and/or dermo-decontracting agents; tensioning agents; anti-pollution agents and/or free-radical scavengers; agents acting on the capillary circulation; agents acting on the energy metabolism of cells; and mixtures thereof.
12. Process according to one of the preceding claims, for depigmenting, lightening and/or bleaching the skin.
13. Cosmetic use of a compound of formula (I) as defined according to any one of Claims 1 to 8, as an agent for bleaching, lightening and/or depigmenting keratin materials.
14. Use of a compound of formula (I) as defined according to any one of Claims 1 to 8, for the manufac-ture of a cosmetic dermatological composition for de-pigmenting, lightening and/or bleaching keratin materi-als.

15. A cosmetic composition comprising a compound(s) represented by general formula I from 0.01% to 10% by wt of the total composition alongwith a medium compatible to human keratin materials such as herein described, active agent and optionally adjuvants

Formula I
Wherein in which:
Y denotes O, NR1 or S
R1 denotes a hydrogen atom; a saturated linear C1-C20 or branched C3-C20 or unsaturated C2-C20 alkyl hydrocarbon-based group; a phenyl group optionally substituted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals;
R denotes a hydrogen atom; or a saturated linear C1-C20 or branched C3-C20 or unsaturated C2-C20 alkyl hydrocar-bon-based group; or a phenyl group optionally substi-tuted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals; or a saturated C1-C8 alkyl group containing a phenyl substituent optionally sub-stituted with one or more hydroxyls and/or with one or more C1-C8 alkoxy radicals;
R optionally bears one or more substituents chosen from OR2, SR2, NR2R3, COOR2 in which:
R2 denotes a hydrogen atom or a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group, or a phenyl group
R3 denotes a hydrogen atom; a saturated linear C1-C5 or branched C3-C5 or unsaturated C2-C5 hydrocarbon-based group; a phenyl group; an acetyl group;
when Y = NR1, R and R1 may form a ring chosen from pyr-rolidine, pyrroline, piperidine, piperazine, mor-pholine, thiomorpholine and azepine;
n = 0 or 1 or 2,
and also the salts thereof, chelates thereof, solvates thereof and optical isomers thereof.

16. A composition as claimed in claim 15, wherein the adjuvant is selected from a group comprising water, organic solvents, especially C1-C6 alcohols and C2-C10 carboxylic acid esters; carbon-based and/or silicone oils, of mineral, animal and/or plant origin; waxes, pigments, fillers, colorants, surfactants, emulsifiers, co-emulsifiers; cosmetic or dermatological active agents, UV-screening agents, polymers, hydrophilic or lipophilic gelling agents, thickeners, preserving agents, fragrances, bactericides, ceramides, odour absorbers, antioxidants.

17. A composition as claimed in claim 15 or 16, wherein the active agent chosen from: desquamating agents; calmatives, organic or mineral photoprotective agents, moisturizers; depigmenting or propigmenting agents; anti-glycation agents; NO-synthase inhibitors; agents for stimulating the synthesis of dermal or epidermal macromolecules and/or for preventing their degradation; agents for stimulating fibroblast and/or keratinocyte proliferation or for stimulating keratinocyte differentiation; muscle relaxants and/or dermo-decontracting agents; tensioning agents; anti-pollution agents and/or free-radical scavengers; agents acting on the capillary circulation; agents acting on the energy metabolism of cells; and mixtures thereof.

18. A composition as claimed in claim 15, 16 or 17, wherein the compound of formula (I) is as defined in any one of claims 2 to 8.

Dated this 27th Day of November, 2009