The present invention relates to cosmetic compositions for topical use, in particular intended for photo-protecting the skin and/or the hair, comprising an effective amount of at least one aromatic amide, sulphonamide or carbamate derivative of acrylonitrile, to novel aromatic amide, sulphonamide or carbamate derivatives of acrylonitrile and to a non-therapeutic process for treating the skin using these compositions. 
It is known that radiation with wavelengths of between 280 nm and 400 nm permit tanning of the human epidermis and that radiation with wavelengths of between 280 and 320 nm, known as UV-B radiation, cause skin burns and erythema that may be harmful to the development of a natural tan.  For these reasons, and also for aesthetic reasons, there is increasing demand for means for controlling this natural tanning.  This UV-B radiation should thus be screened out. 
It is also known that UV-A rays, with wavelengths of between 320 and 400 nm, which cause tanning of the skin, are liable to induce adverse changes therein, especially in the case of sensitive skin and/or skin that is continually exposed to solar radiation.  In particular, UV-A rays bring about a loss of elasticity of the skin and the appearance of wrinkles, leading to premature ageing of the skin.  They promote the onset of the erythemal reaction or amplify this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions.  Thus, for aesthetic and cosmetic reasons such as maintenance of the natural elasticity of the skin, an increasingly large number of people wish to control the effect of UV-A rays on their skin.  It is thus desirable also to screen out UV-A radiation. 
UV-A rays are divided into UV-A-1 rays known as xe2x80x9clong WV-Axe2x80x9d with wavelengths of between 340 and 400 nm, and UV-A-2 rays known as xe2x80x9cshort UV-Axe2x80x9d with wavelengths of between 320 and 340 nm.  A good UV-A screening agent should cover these two ranges of wavelengths as much as possible, i.e. it should be a broad UV-A screening agent, without, however, having an intrinsic coloration due to the absorption of light at wavelengths in the visible range.  Specifically, an important problem associated with the cosmetic use of coloured screening agents is the staining of fabrics liable to come into contact with these screening agents, such as towels and clothing. 
Many compounds intended for protecting the skin against UV-A and/or UV-B radiation have been proposed to date. 
Most of these are aromatic compounds that absorb UV radiation in the region between 280 nm and 315 nm, or in the region between 315 nm and 400 nm and above, or alternatively in both these regions.  They are usually formulated in antisun compositions that are in the form of oil-in-water emulsions, the lipophilic or hydrophilic organic screening agents being present in dissolved form, in one or other of these phases, in amounts that are suitable to obtain the desired sun protection factor (SPF). 
The expression xe2x80x9csun protection factorxe2x80x9d means the ratio of the irradiation time required to reach the erythema-forming threshold in the presence of the test screening agent to the irradiation time required to reach this same threshold in the absence of screening agent. 
Besides their screening power on solar radiation, photoprotective compounds must also have good cosmetic properties, good resistance to water and perspiration (remanence) and also satisfactory photostability. 
Among all the aromatic compounds derived from 2-cyano-acrylic acid that have been proposed for this purpose, mention may be made of the compounds described in patent FR 1 368 808, international patent applications WO 99/36049 and WO 97/15279, and those described in European patent applications EP-A-0 911 020, EP-A-0 716 089 and EP-A-0 005 182.  However, none of these screening agents simultaneously satisfies the three conditions of being a broad UV screening agent, that is to say of screening out both long UV-A and short UV-A, and of being uncoloured and photostable. 
Mention may also be made of 4-(tert-butyl)-4xe2x80x2-methoxy-dibenzoylmethane, sold under the trade name Parsol(copyright) 1789 by the company Hoffman Laroche, which is an uncoloured long UV-A screening agent with a broad spectrum of absorption in the UV-A range, but which has the major drawback of degrading under the effect of solar radiation, that is to say of not being photostable. 
The Applicant has discovered, surprisingly, that a particular family of aromatic amide, sulphonamide or carbamate derivatives of acrylonitrile have, simultaneously:
a broad spectrum of UV-A absorption, while at the same time being long UV-A screening agents,
an absence of coloration,
satisfactory photostability, and
good cosmetic properties,
and thus constitute excellent sunscreens that may be used, in replacement for Parsol(copyright) 1789, in cosmetic compositions, in particular to protect the skin and the hair against the harmful effects of sunlight. 
One subject of the present invention is, consequently, a cosmetic composition for topical use, in particular intended for photoprotecting the skin and/or the hair, containing, in a cosmetically acceptable support, at least one compound chosen from the aromatic amide, sulphonamide or carbamate derivatives of acrylonitrile of formula (1) below or the corresponding dimers of formula (2) below. 
A subject of the present invention is also the novel compounds of formula (2) below. 
Finally, a subject of the present invention is a non-therapeutic process for protecting the skin and/or the hair against solar radiation, which consists in applying to the skin and/or the hair an effective amount of the cosmetic composition defined above. 
The aromatic amide, sulphonamide or carbamate derivatives of acrylonitrile used as broad-spectrum UV-A screening agents in the cosmetic compositions of the present invention are compounds corresponding to the general formula (1) 
or dimers of such compounds, corresponding to formula (2): 
in which
X1 represents a radical R3xe2x80x94(Cxe2x95x90O)xe2x80x94, R3xe2x80x94SO2xe2x80x94 or R3xe2x80x94Oxe2x80x94(Cxe2x95x90O)xe2x80x94,
X2 represents a divalent radical of formula xe2x80x94(Cxe2x95x90O)xe2x80x94Rxe2x80x23xe2x80x94(Cxe2x95x90O)xe2x80x94, xe2x80x94SO2xe2x80x94Rxe2x80x23xe2x80x94SO2xe2x80x94 or xe2x80x94(Cxe2x95x90O)xe2x80x94Oxe2x80x94Rxe2x80x23xe2x80x94Oxe2x80x94(Cxe2x95x90O)xe2x80x94,
Y represents a radical xe2x80x94(Cxe2x95x90O)xe2x80x94R4 or xe2x80x94SO2R5,
R2 represents a linear or branched C1-8 alkyl group,
n is 0, 1 or 2,
R3 represents a linear or branched C1-30 alkyl or C3-30 alkenyl radical, possibly bearing one or more hydroxyl substituents and possibly containing, in the carbon chain, one or more hetero atoms chosen from oxygen, nitrogen and silicon atoms,
Rxe2x80x23 represents a single bond or a linear or branched divalent C1-30 alkylene or C3-30 alkenylene radical, possibly bearing one or more hydroxyl substituents and possibly containing, in the carbon chain, one or more hetero atoms chosen from oxygen, nitrogen and silicon atoms,
R4 represents a radical xe2x80x94OR6 or xe2x80x94NHR6,
R5 represents a linear or branched C1-30 alkyl radical or a phenyl nucleus that is unsubstituted or substituted with C1-4 alkyl or alkoxy radicals,
R6 represents a linear or branched C1-30 alkyl or C3-30 alkenyl radical, possibly bearing one or more hydroxyl substituents and possibly containing, in the carbon chain, one or more hetero atoms chosen from oxygen, nitrogen and silicon atoms. 
Although, in formula (1) above, only the isomers in which the cyano substituent is in the cis position relative to the para-aminophenyl substituent have been represented, this formula should be understood as also encompassing the corresponding trans isomer.  This is likewise the case for formula (2) in which, for each of the two double bonds, and independently, the cyano and para-aminophenyl substituents may be in a cis or trans configuration relative to each other. 
The compounds of formula (2) above are novel compounds. 
As mentioned above, the compounds of formulae (1) and (2) have excellent screening power in the broad UV-A range, i.e. in the wavelength range from 320 nm to 400 nm, show satisfactory photostability and are substantially colourless. 
Among the compounds of formulae (1) and (2) that are particularly preferred are those in which:
X1 represents a radical R3xe2x80x94(Cxe2x95x90O)xe2x80x94 or R3xe2x80x94Oxe2x80x94(Cxe2x95x90O)xe2x80x94,
X2 represents a radical xe2x80x94(Cxe2x95x90O)xe2x80x94CH2xe2x80x94CH2xe2x80x94(Cxe2x95x90O)xe2x80x94,
Y represents a radical xe2x80x94(Cxe2x95x90O)xe2x80x94R4,
n is 0,
R3 represents a linear or branched C1-10 alkyl radical,
R4 represents a radical xe2x80x94Oxe2x80x94R6, and
R6 represents a linear or branched C1-30 alkyl group optionally containing one or more silicon atoms. 
The derivatives of formulae (1) and (2) may be prepared according to known methods. 
To prepare the derivatives of formula (1), 1 mol of a derivative of formula (3) may be reacted with 1 mol of an acyl chloride, a sulphonyl chloride or a chloroformate of formula (4) in the presence of solvent and of a hydrochloric acid trapping agent, according to the following reaction scheme: 
Y, R2, R3 and n having the meanings given above for formula (1).  The derivative of formula (3) may be prepared by coupling a compound of formula (5) below with a cyano derivative of formula (6) below according to the reaction scheme: 
in which R2, Y and n have the meanings given above. 
The compound of formula (1) may also be prepared by coupling a compound of formula (7) below with a cyano derivative of formula (6) below according to the following reaction scheme: 
in which Y, R2, X and n have the meanings given above; the derivative (7) may be prepared by coupling a derivative of formula (5) below with an acyl chloride, a sulphonyl chloride or a chloroformate of formula (4) below in the presence of a solvent and of a hydrochloric acid trapping agent, according to the following reaction scheme: 
in which R2, R3 and n have the meanings given above. 
To prepare the derivatives of formula (2), two moles of a derivative of formula (3), prepared in the manner described above, may be reacted with one mole of a dicarboxylic or disulphonic acid dichloride or a dichloroformate of formula (8) below in the presence of a solvent and of a hydrochloric acid trapping agent, according to the following reaction scheme: 
in which Y, R2, Rxe2x80x23 and n have the meanings given above. 
The compounds of formula (2) may also be prepared by coupling one mole of a derivative of formula (9) below with two moles of a cyano derivative of formula (6) below: 
in which Y, R2, Rxe2x80x23 and n have the meanings given above. 
The derivative of formula (9) may be prepared by coupling two moles of a derivative of formula (5) below with one mole of a dicarboxylic or disulphonic acid dichloride or a dichloroformate of formula (8) below in the presence of a solvent and of a hydrochloric acid trapping agent, according to the following reaction scheme: 
in which R2, Rxe2x80x23 and n have the meanings given above. 
The compound(s) of formula (1) or (2) is(are) preferably present in the cosmetic compositions for topical use of the present invention in a proportion of 0.1% and 20% by weight and in particular in a proportion of from 0.5% to 10% by weight, relative to the total weight of the cosmetic composition. 
The cosmetic compositions, in particular the antisun compositions, of the present invention can also contain one or more organic sunscreens that are active in the UV-A and/or UV-B range, other than the broad-spectrum UV-A screening agents of formula (1) or (2) described above. 
These sunscreens may be chosen especially from cinnamic derivatives, salicylic derivatives, benzylidenecamphor derivatives, triazine derivatives such as those described in the patents or patent applications U.S. Pat.  No.  4,367,390, EP 0 863 145, EP 0 517 104, EP 0 570 838, EP 0 796 851, EP 0 775 698, EP 0 878 469, EP 0 933 376 and EP 0 893 119, benzophenone derivatives, xcex2,xcex2xe2x80x2-diphenylacrylate derivatives, phenylbenzimidazole derivatives, anthranilic derivatives, imidazoline derivatives, methylenebis(hydroxyphenylbenzotriazole) derivatives such as those described in the patents or patent applications U.S. Pat.  No.  5,237,071, U.S. Pat.  No.  5,166,355, GB 2 303 549, DE 19726184 and EP 0 893 119, p-aminobenzoic acid derivatives, and screening hydrocarbon polymers and screening silicones such as those described especially in patent application WO 93/04665. 
Examples of such additional UV-A-active and/or UV-B-active sunscreens that may be mentioned include the following compounds, denoted by their NCI name, and also mixtures thereof:
Para-Aminobenzoic Acid Derivatives:
PABA
ethyl PABA
ethyl dihydroxypropyl PABA
ethylhexyl dimethyl PABA sold especially under the trade name Escalol(copyright) 507 by ISP,
glyceryl PABA,
PEG-25 PABA sold under the trade name Uvinul(copyright) P25 by BASF,
Salicylic Derivatives:
homosalate sold under the trade name Eusolex(copyright) HMS by Rona/EM Industries,
ethylhexyl salicylate sold under the trade name Neo Heliopan(copyright) OS by Haarmann and Reimer,
dipropylene glycol salicylate sold under the trade name Dipsal(copyright) by Scher,
TEA salicylate sold under the trade name Neo Heliopan(copyright) TS by Haarmann and Reimer,
Cinnamic Derivatives:
ethylhexyl methoxycinnamate sold especially under the trade name Parsol(copyright) MCX by Hoffmann Laroche,
isopropyl methoxycinnamate
isoamyl methoxycinnamate sold under the trade name Neo Heliopan(copyright) E 1000 by Haarmann and Reimer,
cinoxate,
DEA methoxycinnamate,
diisopropyl methylcinnamate,
glyceryl ethylhexanoate dimethoxycinnamate
xcex2,xcex2-Diphenylacrylate Derivatives:
octocrylene sold especially under the trade name Uvinul(copyright) 539 by BASF,
etocrylene sold especially under the trade name Uvinul(copyright) N-35 by BASF,
Benzophenone Derivatives:
benzophenone-1 sold under the trade name Uvinul(copyright) 400 by BASF,
benzophenone-2 sold under the trade name Uvinul(copyright) D-50 by BASF,
benzophenone-3 or oxybenzone sold under the trade name Uvinul(copyright) M-40 by BASF,
benzophenone-4 sold under the trade name Uvinul(copyright) MS-40 by BASF,
benzophenone-5,
benzophenone-6 sold under the trade name Helisorb(copyright) 11 by Norquay,
benzophenone-8 sold under the trade name Spectrasorb(copyright) UV-24 by American Cyanamid
benzophenone-9 sold under the trade name Uvinul(copyright) DS-49 by BASF,
benzophenone-12
Benzylidenecamphor Derivatives:
3-benzylidenecamphor manufactured under the name Mexoryl(copyright) SD by Chimex,
4-methylbenzylidenecamphor sold especially under the trade name Eusolex(copyright) 6300 by Merck,
benzylidenecamphorsulphonic acid manufactured under the name Mexoryl(copyright) SL by Chimex,
camphorbenzalkoniummethosulphate manufactured under the name Mexoryl(copyright) SO by Chimex,
terephthalylidenedicamphorsulphonic acid manufactured under the name Mexoryl(copyright) SX by Chimex,
polyacrylamidomethylbenzylidenecamphor manufactured under the name Mexoryl(copyright) SW by Chimex,
Phenylbenzimidazole Derivatives:
phenylbenzimidazolesulphonic acid sold especially under the trade name Eusolex(copyright) 232 by Merck
benzimidazilate sold under the trade name Neo Heliopan(copyright) AP by Haarmann and Reimer
Triazine Derivatives:
anisotriazine sold under the trade name Tinosorb(copyright) S by Ciba Geigy,
ethylhexyltriazone sold especially under the trade name Uvinul(copyright) T150 by BASF,
diethylhexylbutamidotriazone sold under the trade name Uvasorb(copyright) HEB by Sigma 3V,
Phenylbenzotriazole Derivatives:
drometrizole trisiloxane sold under the trade name Silatrizole(copyright) by Rhodia Chimie,
methylenebis(benzotriazolyl)tetramethylbutylphenol sold in solid form under the trade name Mixxim(copyright) BB/100 by Fairmount Chemical or in micronized form as an aqueous dispersion under the trade name Tinosorb(copyright) M by Ciba Speciality Chemicals,
Anthranilic Derivatives:
menthylanthranilate sold under the trade name Neo Heliopan(copyright) MA by Haarmann and Reimer,
Imidazoline Derivatives:
ethylhexyl dimethoxybenzylidene dioxoimidazoline propionate
Benzalmalonate Derivatives:
polyorganosiloxane containing benzalmalonate functions, sold under the trade name Parsol(copyright) SLX by Hoffmann Laroche
The organic UV screening agents that are more particularly preferred are chosen from the following compounds:
ethylhexyl salicylate,
ethylhexyl methoxycinnamate,
octocrylene,
phenylbenzimidazolesulphonic acid,
terephthalylidenedicamphorsulphonic acid,
benzophenone-3,
benzophenone-4,
benzophenone-5,
4-methylbenzylidenecamphor,
benzimidazilate,
anisotriazine,
ethylhexyltriazone,
diethylhexylbutamidotriazone,
methylenebis(benzotriazolyl)tetramethylbutylphenol,
drometrizoletrisiloxane,
and mixtures thereof. 
The cosmetic compositions according to the invention may also contain agents for artificially tanning and/or browning the skin (self-tanning agents) such as dihydroxyacetone (DHA). 
The cosmetic compositions according to the invention may also contain one or more mineral pigments and in particular metal oxide nanopigments, that are coated or uncoated, such as, for example, nanopigments of titanium oxide in amorphous or crystallized (rutile and/or anatase) form, of iron oxide, of zinc oxide, of zirconium oxide or of cerium oxide.  These nanopigments have a mean particle size of between 5 nm and 100 nm and preferably between 10 nm and 50 nm and are all known UV photoprotective agents. 
These nanopigments may be coated with known coating agents such as, for example, alumina and/or aluminium stearate. 
Such coated or uncoated nanopigments are described, for example, in patent applications EP-A-0 518 772 and EP-A-0 518 773. 
The cosmetic compositions may also contain adjuvants usually used in cosmetics, such as fatty substances, organic solvents, silicones, surfactants, anionic, cationic, nonionic or amphoteric polymers or mixtures thereof, thickeners, antioxidants, opacifiers, stabilizers, antifoams, fragrances, preserving agents, fillers, sequestering agents, propellants, pH regulators and colorants, and mixtures thereof. 
They may also contain one or more cosmetic active principles chosen, for example, from softeners, hydroxy acids, vitamins, moisturizers, emollients, free-radical scavengers, substance P antagonists and anti-inflammatories, and mixtures of these compounds. 
The fatty substances may consist of an oil or a wax or mixtures thereof, and they also comprise fatty acids, fatty alcohols and fatty acid esters.  The oils may be chosen from animal, plant, mineral or synthetic oils and especially from hydrogenated palm oil, hydrogenated castor oil, liquid petroleum jelly, liquid paraffin, purcellin oil, volatile or non-volatile silicone oils, isoparaffins, polyolefins, fluoro oils and perfluoro oils.  Similarly, the waxes may be chosen from animal, fossil, plant, mineral and synthetic waxes that are known per se, for instance petroleum jelly, paraffin, lanolin, hydrogenated lanolin and acetylated lanolin. 
Among the organic solvents that may be mentioned are lower alcohols and polyols such as ethanol, isopropanol, propylene glycol, glycerol and sorbitol. 
The thickeners may be chosen especially from modified or unmodified guar gums and cellulose gums, such as hydroxypropyl guar gum, methylhydroxyethylcellulose, hydroxypropylmethylcellulose or hydroxyethylcellulose. 
Needless to say, a person skilled in the art will take care to select this or these optional additional compound(s) and/or the amounts thereof such that the advantageous properties intrinsic to the compounds and compositions according to the invention are not adversely affected by the envisaged addition(s). 
The cosmetic compositions for topical use of the invention may be prepared according to techniques that are well known to those skilled in the art, in particular those intended for preparing emulsions of oil-in-water or water-in-oil type. 
These compositions may be in particular in the form of a lotion, a thickened lotion, a simple or complex emulsion (O/W, W/O, O/W/O or W/O/W emulsion), such as a cream or a milk, in the form of a gel or cream-gel, or in the form of a powder or a solid tube, and may optionally be packaged as an aerosol and may be in the form of a mousse or a spray. 
When it is an emulsion, the aqueous phase of this emulsion may comprise a nonionic vesicular dispersion prepared according to known processes (Bangham, Standish and Watkins, J. Mol.  Biol.  13, 238 (1965), FR 2 315 991 and FR 2 416 008). 
The cosmetic composition of the invention may be used as a composition for protecting the human epidermis or the hair against ultraviolet rays, as an antisun composition or as a makeup product. 
When the cosmetic composition according to the invention is used for protecting the human epidermis against UV rays or as an antisun composition, it may be in the form of a lotion, a suspension or a dispersion in solvents or fatty substances, in the form of a nonionic vesicular dispersion or in the form of an emulsion, preferably oil-in-water type, such as a cream or a milk, or in the form of an ointment, a gel, a cream-gel, a solid tube, an aerosol mousse or a spray. 
When the cosmetic composition according to the invention is used for protecting the hair against UV rays, it may be in the form of a shampoo, a lotion, a gel, a rinse-out composition, to be applied before or after shampooing, before or after dyeing or bleaching, or before, during or after permanent-waving or straightening the hair, a styling or treating lotion or gel, a lotion or gel for blow-drying or hairsetting, a permanent-waving, straightening, dyeing or bleaching composition for the hair or a hair lacquer. 
When the composition is used as a makeup product for the eyelashes, the eyebrows, the skin or the hair, such as an epidermal treatment cream, a foundation, a tube of lipstick, an eyeshadow, a face powder, a mascara, an eyeliner or a colouring gel, it may be in solid or pasty, anhydrous or aqueous form, for instance an oil-in-water or water-in-oil emulsion, a suspension or a gel. 
As a guide, for the antisun formulations in accordance with the invention, which contain a support of oil-in-water emulsion type, the aqueous phase generally represents from 50% to 95% by weight and preferably from 70% to 90% by weight, relative to the total formulation, the oily phase from 5% to 50% by weight and preferably from 10% to 30% by weight, relative to the total formulation, and the (co)emulsifier(s) from 0.5% to 20% by weight and preferably from 2% to 10% by weight, relative to the total formulation. 
The examples that follow illustrate the invention