Purification process comprising one or more cosmetic ingredients with at least one electrodialysis

Abstract

The present invention relates to a purification (PU) process for at least one aqueous medium based on at least one C-glycoside derivative corresponding to formula (I), as described below, preferably corresponding to formula (I') or (I''), and their optical isomers, geometric isomers, and / or their solvates such as hydrates, and at least one salt, comprising at least one electrodialysis step (PU1) of said aqueous medium. The invention also relates to a preparation (PR) process for at least one C-glycoside derivative, as described below, comprising at least one purification step (PU) by electrodialysis of at least one aqueous medium comprising at least said C-glycoside derivative and at least one salt.

Description

Title of the invention: Purification process comprising one or more cosmetic ingredients with at least one electrodialysis

[0001] The present invention relates to a purification process (PU) of at least one aqueous medium based on at least one cosmetic ingredient, in particular at least one C-glycoside derivative corresponding to formula (I), as described below, preferably corresponding to formula (!') or (I”), and their optical isomers, geometric isomers, and / or their solvates such as hydrates, and at least one salt, comprising at least one electrodialysis step (PU1) of said aqueous medium.

[0002] The invention also relates to a preparation process (PR) of at least one cosmetic ingredient, in particular at least one C-glycoside derivative, as described below, comprising at least one purification step (PU) by electrodialysis of at least one aqueous medium comprising at least said cosmetic ingredient and in particular at least one C-glycoside derivative and at least one salt.

[0003] The processes for preparing organic, water-soluble ingredients with interesting cosmetic properties, for example on keratin materials, can result in the formation of one or more impurities, found in an ionic form, which most often prove to be tedious to minimize, or even to eliminate, without having a more or less significant impact on the yield of the synthesized cosmetic ingredient.

[0004] Furthermore, such impurities, when present with the final cosmetic ingredient, can generate a color, a change in texture or an odor that is not desired in the cosmetic compositions using said ingredient. Thus, such impurities can be the cause of an unpleasant and marked odor, for example a pungent and strongly vinegary odor, likely to appear, even after the implementation of one or more purification operations, and to prove unpleasant and persistent even after formulation for consumers, especially since the current trend is to use fewer and fewer perfumes in cosmetic products to mask or neutralize this type of odor.

[0005] Such impurities can also cause compatibility problems with other additives possibly present in the final cosmetic formulations.

[0006] Such impurities can also be salts of acids or bases which will have an effect on the pH in an aqueous medium. This effect is all the more troublesome when the cosmetic active ingredient is isolated in the form of a concentrated aqueous solution.

[0007] Furthermore, the presence of such impurities, in particular inorganic and / or organic salts, can induce a significant increase in the viscosity of the aqueous reaction medium comprising the cosmetic ingredient(s), thus making it difficult, in certain cases, to obtain concentrated solutions of cosmetic ingredients intended for formulation.

[0008] For example, C-glycoside derivatives are organic compounds, soluble in water, whose properties are generally of interest in the field of cosmetics, in particular in care compositions, in order to be used to stimulate the synthesis of glycosaminoglycans present in the dermis and in particular to provide density and firmness to the skin (see for example the scientific article entitled “Synthesis of Pro-XylaneTM: A new biologically active C-glycoside in aqueous media”, M.Dalko-Csiba et al., Bioorganic & Medicinal Chemistry Letters 19 (2009) 845-849).

[0009] C-glycoside derivatives, such as xylose C-glycoside derivatives, are generally synthesized by means of a reaction, called the Lubineau reaction (Rodrigues, F., Canac, Y. and Lubineau, A., A convenient, one-step, synthesis of [3-Cglycosidic ketones in aqueous media. - Chemical Communications - 2000, (20), 2049-2050), from an unprotected monosaccharide or polysaccharide, for example D-xylose, and a beta-dicarbonyl compound, for example acetylacetone, in an aqueous medium in the presence of alkaline agent(s).

[0010] The Lubineau reaction is carried out with at least one alkaline agent, such as sodium bicarbonate or soda, present in an equimolar or excess quantity relative to the monosaccharide or polysaccharide, preferably in excess, for a reaction time which may vary from 5 minutes to 20 hours depending on the nature of the alkaline agent and / or the reaction parameters such as the concentration and / or the temperature.

[0011] However, such a synthesis reaction presents in particular the major pitfall of leading to the formation of impurities, found in particular in the form of salts, for example in the form of an organic salt, such as sodium acetate, the residual quantities of which can prove significant and difficult to reduce even by implementing several conventional purification and / or washing operations.

[0012] At the end of this reaction, the aqueous reaction medium can be neutralized with at least one mineral acidifying agent, in particular hydrochloric acid, to convert the organic acid salt into organic acid, in particular by transforming the sodium acetate into acetic acid, then several cycles of adding water and distillations are then carried out, in order to reduce the quantities of organic acid to contents likely to be commercially acceptable.

[0013] However, neutralization of the reaction medium with at least one acidifying agent mineral, such as hydrochloric acid, also leads to the formation of salts, in particular sodium chloride, which can be eliminated by precipitation through the addition of water-miscible solvents such as alcohols, in particular isobutanol or ethanol. To do this, successive distillation operations to eliminate water in particular, then the addition of alcohol can cause crystallization of salts, followed by possible washing(s), carried out with several cycles of water addition, to reduce the quantity of salts to acceptable levels within commercial solutions intended for use in the cosmetic field.

[0014] At the end of these different washing and / or purification operations, the C-glycoside derivatives obtained can be pure without solvent and then undergo, in certain cases, a hydrogenation reaction aimed at reducing the ketone function of the C-glycoside derivative and resulting from the beta-dicarbonyl derivative, into a hydroxyl function.

[0015] In particular, cosmetic ingredients and in particular C-glycoside derivatives of xylose, such as CBD-xylopyranoside-n-propan-2-one, may subsequently undergo a reduction reaction to lead to CBD-xylopyranoside-2-hydroxy-propane.

[0016] However, the washing and / or purification operations, including those carried out several times in succession, do not make it possible to satisfactorily reduce the quantities of impurities in ionic form and / or originating from an ionic form which are generated during the synthesis step, in particular on an industrial scale.

[0017] In particular, such washing and / or purification operations have the disadvantage of having to be carried out several times to sufficiently reduce the impurity content in a satisfactory manner and, when the impurities are malodorous, to minimize the odors generated by certain impurities such as acetic acid which are unpleasant and should be avoided for cosmetic use.

[0018] The successive implementation of these purification and / or washing operations thus has the disadvantage of reducing the yield, of generating additional organic effluents, of increasing the number of steps and / or of being tedious to implement on an industrial level both to reduce the organic acid content, in particular acetic acid, and to reduce the salt content, for example sodium chloride, in the final cosmetic ingredient intended for the formulation of cosmetic products for cosmetic use.

[0019] Furthermore, the use of organic solvents, in particular (a)polar aprotic organic solvents, during washing operations often has the disadvantage of not sufficiently reducing impurities and of inducing the implementation of additional washing or neutralization operations, or even purification by chromatography and / or crystallization, which are likely to harm the yield. Such additional operations are also tedious to implement on a large scale. industrial. In addition, residual levels of organic solvent(s) may persist in cosmetic ingredient solutions used in final cosmetic formulations, which is not desirable.

[0020] Furthermore, disadvantages similar to those described above are also found when it is desired to reduce, or even minimize, the salt content in aqueous formulations based on one or more cosmetic ingredients, in particular one or more C-glycoside derivatives.

[0021] As a result, the washing and / or purification operations conventionally implemented to reduce the salt content in media comprising at least one C-glycoside derivative do not lead to satisfactory results, particularly in terms of yield and degree of purity, in particular for industrial-scale, reproducible and robust manufacturing, for use in the field of cosmetics.

[0022] There is a need for improved industrializable processes for separating and recovering a C-glycoside derivative from an aqueous composition.

[0023] In view of the above, there is therefore a real need to implement a new method for purifying at least one aqueous medium comprising at least one cosmetic ingredient and in particular at least one C-glycoside derivative and at least one salt, which does not have the drawbacks mentioned above, leading in particular to an improved degree of purity, a higher yield and the implementation of which is more optimized, specifically on an industrial level, in terms of product quality on an industrial scale, number of purification steps, implementation and / or organic effluents generated.

[0024] In other words, one of the aims of the present invention is in particular to propose a method capable of treating at least one aqueous medium comprising at least one cosmetic ingredient, in particular at least one C-glycoside derivative and at least one salt, on an industrial scale for cosmetic applications.

[0025] In particular, one of the aims of the present invention is to propose a process for preparing one or more cosmetic ingredients, in particular one or more C-glycoside derivatives, during which the impurities, including those likely to generate an unpleasant or unpleasant odor, for example a pungent and strongly vinegary odor, in particular resulting from the synthesis step, are minimized in order to be able to be effectively implemented on an industrial scale for cosmetic applications.

[0026] Another aim of the invention is to provide a process for separating and recovering the free acid generated during the synthesis of cosmetic ingredient(s) and in particular of C-glycoside derivative(s) in an aqueous solution comprising at least one acid salt, in particular at least one acetic acid salt.

[0027] The present invention therefore relates in particular to a purification process (PU) of at least one aqueous medium comprising: - at least one cosmetic ingredient, in particular at least one compound of the following formula (I):

[0028]

[0029]

[0030]

[0031] (I) Formula (I) in which: - SA' represents a monosaccharide group or a polysaccharide group comprising up to 20 sugar units, in particular up to 6 sugar units, preferably a monosaccharide, disaccharide or trisaccharide, more preferably a monosaccharide, in pyranose and / or furanose form and of L and / or D series, said monosaccharide group or polysaccharide group being substituted by at least one free hydroxy group, and optionally at least one amine group optionally protected, in particular by an acetyl group R'-C(Y)- with R' representing a hydrogen atom, or a (Ci-C6)alkyl group such as methyl, and Y represents O, S, preferably O; - the bond between SA' and -CH2X is a C-anomeric bond, - X represents a divalent radical -C(O)- or -CH(OR)-, - R represents a hydrogen atom, a C1-C10 alkyl group, preferably C1-C4, such as methyl, or a C1-C4 alkylcarbonyl group such as acetyl, preferably a hydrogen atom; - Ri represents a hydrocarbon chain, saturated or unsaturated, linear or branched, cyclic or acyclic, preferably acyclic, in C1-C10, preferably in C1-C4, more preferably saturated; as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates, and - at least one salt; said method comprising at least one electrodialysis step (PU1) of said aqueous medium. The purification process (PU) according to the invention thus makes it possible to effectively reduce the quantity of salt(s) and / or the conjugated acid form(s) of said salts found in a mixture with at least one cosmetic ingredient and in particular at least one compound of formula (I) in an aqueous medium. The salt(s) may be derived from at least one step of preparation of said cosmetic ingredient and / or be derived from one or more washing operations and / or one or more neutralization operations carried out after at least one of the steps of a process for preparing said cosmetic ingredient(s).

[0032] The purification process (PU) according to the invention thus makes it possible to effectively reduce the quantity of salt(s) found in a mixture with at least one cosmetic ingredient, in particular at least one compound of formula (I) in an aqueous medium.

[0033] The salt(s) may be derived from at least one step of preparation of said cosmetic ingredient and / or be derived from one or more washing operations and / or one or more neutralization operations carried out after at least one of the steps of a process for preparation of said cosmetic ingredient.

[0034] The salt(s) present in the aqueous medium may be derived from at least one of the steps of a process for preparing at least one cosmetic ingredient and in particular at least one compound of formula (I) and / or be derived from one or more washing operations and / or one or more neutralization operations carried out after at least one of the steps of a process for preparing a cosmetic ingredient and in particular a process for preparing the compound of formula (I).

[0035] The salt(s) present in the aqueous medium may also result from an addition to said aqueous medium. These include in particular mineral acids such as hydrogen halides, in particular hydrochloric acid, sulfonic acids, and carboxylic acids such as acetic acid.

[0036] In other words, the purification process (PU) according to the invention makes it possible to treat any aqueous medium comprising at least one cosmetic ingredient and at least one compound of formula (I) and at least one salt, which may or may not be an impurity, with a view to at least one cosmetic use, preferably for the care of keratin materials, such as the skin.

[0037] The purification process (PU) makes it possible to advantageously reduce the presence of at least one salt, which may or may not be an impurity, in an aqueous medium without significantly impacting the quality and / or the degree of purity of the cosmetic ingredient.

[0038] The purification process (PU) makes it possible to advantageously reduce the presence of at least one salt, which may or may not be an impurity, in an aqueous medium without significantly impacting the quality and / or the degree of purity of a compound of formula (I).

[0039] The purification process (PU) makes it possible in particular to significantly reduce the content of one or more ionic impurities, including those causing an unpleasant odor, found in a mixture with at least one compound of formula (I) in an aqueous medium.

[0040] The purification process (PU) further facilitates the preparation of commercial solutions, based on at least one cosmetic ingredient and in particular at least one compound of formula (I), intended for at least one cosmetic use, preferably for the care of keratinous materials, such as skin.

[0041] The purification process (PU) according to the invention can be carried out after one or more steps of synthesis of at least one cosmetic ingredient and in particular at least one compound of formula (I) and / or after at least one step of washing and / or neutralization of an aqueous reaction medium comprising at least said compound of formula (I).

[0042] The purification process (PU) according to the invention can thus be implemented during a process for preparing one or more cosmetic ingredients preferably chosen from the compounds of formula (I), for example at the end of the preparation process or after one of the steps of the process, for example between one of the steps of the process.

[0043] Another object of the present invention is further to provide a preparation process (PR) of one or more cosmetic ingredients preferably chosen from the compounds of formula (I), comprising at least one purification (PU) comprising at least one electrodialysis step (PU1) of at least one aqueous medium comprising at least said cosmetic ingredient, preferably said compound of formula (I), and at least one salt.

[0044] In other words, the invention relates to a preparation process (PR) of one or more cosmetic ingredient(s) preferably chosen from the compounds of formula (I), comprising at least one purification (PU) during which at least one aqueous medium comprising at least said at least one cosmetic ingredient preferably chosen from the compound(s) of formula (I) and at least one salt is subjected to at least one electrodialysis (PU1).

[0045] In other words, the invention relates in particular to a process for the preparation (PR) of one or more cosmetic ingredients preferably chosen from the compounds of formula (I), comprising: - at least one synthesis step (PRi) of at least one cosmetic ingredient preferably chosen from at least one compound of formula (I), leading to the formation of at least said cosmetic ingredient preferably said compound of formula (I), and at least one salt in an aqueous medium, • optionally, at least one washing and / or neutralization step (PR0), preferably at least one neutralization step (PR0) of the aqueous reaction medium resulting from at least one of the synthesis steps (PRi), - at least one purification (PU) comprising at least one electrodialysis step (PU1) of at least said aqueous reaction medium comprising: at least said cosmetic ingredient preferably chosen from the compounds of formula (I), and at least one salt.

[0046] According to a preferred embodiment, the invention relates in particular to a process for the preparation (PR) of one or more compounds of formula (I), comprising: - at least one synthesis step (PRi) of at least one compound of formula (I), leading to the formation of at least one compound of formula (I), and of at least one salt in an aqueous medium, • optionally, at least one washing and / or neutralization step (PRO), preferably at least one neutralization step (PRO) of the aqueous reaction medium resulting from at least one of the synthesis steps (PRi), - at least one purification (PU) comprising at least one electrodialysis step (PU1) of at least said aqueous reaction medium comprising at least said compound of formula (I), and at least said salt.

[0047] The preparation process (PR) according to the invention thus makes it possible to achieve the objectives as described above, that is to say that it leads to one or more cosmetic ingredients preferably chosen from the compounds of formula (I), having a high degree of purity with a satisfactory yield while presenting an industrially optimized implementation, in particular robust and reproducible, in particular compared to the processes conventionally implemented in the prior art.

[0048] In particular, the preparation process (PR) according to the invention has the advantage of minimizing impurities in ionic form, and / or their non-ionic conjugated forms, including those usually causing a marked and unpleasant odor, such as a pungent and strongly vinegary odor, which are particularly long and difficult to eliminate with conventional washing and / or purification operations.

[0049] In particular, the preparation process (PR) according to the invention has the advantage of minimizing impurities in ionic form such as their acid form, including those usually causing a marked and unpleasant odor, such as a pungent and strongly vinegary odor, which are particularly long and difficult to eliminate with conventional washing and / or purification operations.

[0050] The electrodialysis step (PU1) advantageously makes it possible to eliminate very large quantities of impurity(ies) in ionic form, resulting from at least one synthesis step (PRi), and possibly resulting from at least one neutralization step (PRO) carried out with at least one mineral or organic acidifying agent, preferably organic.

[0051] The electrodialysis step (PU1) also advantageously makes it possible to eliminate very large quantities of impurity(ies) in ionic form and / or in non-ionic conjugated form such as their acid form, resulting from at least one synthesis step (PRi), said impurity(ies) and possibly resulting from at least one neutralization step lization (PRO) implemented with at least one mineral or organic acidifying agent, preferably organic.

[0052] The process (PR) according to the invention then advantageously makes it possible to reduce the quantities of perfumes used and / or to increase the range of perfume(s) which can be envisaged to mask or neutralize odors which may be unpleasant during the preparation of a cosmetic formulation based on at least one cosmetic ingredient, preferably a compound of formula (I).

[0053] The process (PR) according to the invention also makes it possible to effectively reduce organic effluents at the reactor outlet and to limit the numerous solvent change and / or washing operations conventionally implemented in the processes described in the prior art.

[0054] The process (PR) according to the invention notably presents an implementation that is easier to optimize on an industrial level than the conventional processes of the prior art, notably those involving a successive implementation of several distillations to reduce as much as possible the impurities in ionic form, which makes it possible to treat the synthesis reaction as well as the purification and / or washing steps in the same reactor having a format adapted to the batch treated.

[0055] The electrodialysis step (PU1) allows the process according to the invention to be implemented in any reactor, which makes it industrially versatile and flexible.

[0056] In particular, the synthesis step(s) (PR1) of the compound(s) of formula (I) can be carried out in any reactor.

[0057] The process (PR) according to the invention also has the advantage of not using an organic solvent to reduce the impurities resulting from at least one of the synthesis steps, which improves its environmental footprint.

[0058] The preparation process (PR) according to the invention thus makes it possible to achieve a gain in the number of steps to be implemented at the end of the synthesis reaction to reduce the impurity content and facilitates, on an industrial level, the implementation of additional reactions of the cosmetic ingredient such as the additional reactions implemented in the process for preparing cosmetic ingredient(s), in particular the compound of formula (I), for example a step of reduction of the compound of formula (I).

[0059] The preparation process (PR) according to the invention also has the advantage of efficiently leading to several grades of a cosmetic ingredient depending on the desired content of impurities thanks to the use of electrodialysis.

[0060] The preparation process (PR) according to the invention thus also has the advantage of efficiently leading to several grades of a cosmetic ingredient and in particular of the compound of formula (I) depending on the desired content of impurities thanks to the use of electrodialysis.

[0061] The preparation process (PR) according to the invention thus makes it easier to control the impurity contents in the final solution obtained intended for cosmetic use.

[0062] Other objects, characteristics, aspects and advantages of the invention will appear even more clearly on reading the description and the example which follows.

[0063] In what follows, and unless otherwise indicated, the limits of a domain of values ​​are included in this domain, in particular in the expressions “between” and “ranging from ... to ...”.

[0064] Furthermore, the expression “at least one” used in the present description is equivalent to the expression “one or more”.

[0065] Furthermore, the expression "at least" used in the present description is equivalent to the expression "greater than or equal to". Finally, in a manner known per se, the term "Cn" or "Cn" compound or group denotes a compound or group containing "n" carbon atoms in its chemical structure.

[0066] For the purposes of the present invention, the term "cosmetic ingredient" is equivalent to "cosmetic active ingredient" and designates any compound possessing an activity of interest in the cosmetic field such as an active ingredient having a biological action after application to keratin materials such as non-therapeutic active ingredients intended to prevent or treat the signs of aging, such as moisturizers, humectants, such as active ingredients having an action on the barrier function, such as UV filters, and / or any compound modifying the appearance of keratin materials such as coloring materials.

[0067] For the purposes of the present invention, keratin materials are understood to mean skin such as the skin of the body, hands, legs, face, décolleté, and keratin fibers, preferably hair, more preferably skin.

[0068] For the purposes of the present invention, the terms “purification (P)” and “purification step (P)” are used interchangeably.

[0069] For the purposes of the present invention, the terms “alkaline agent” or “alkalizing agent” are used interchangeably.

[0070] The alkalizing agent(s) may be mineral alkaline agents, preferably selected from the group consisting of alkali metal hydroxides or alkaline earth metal hydroxides, such as lithium hydroxides, sodium hydroxide, potassium hydroxide, alkali or alkaline earth metal (bi)carbonates such as sodium or potassium (bi)carbonates, and mixtures thereof. The alkalizing agent(s) may be organic alkaline agents, preferably selected from the group consisting of mono(Ci-C6)(hydroxy)alkylamine, di(Ci-C6)(hydroxy)alkylamine, tri(Ci-C6)(hydroxy)alkylamine (preferably tri(Ci-C6)(hydroxy)alkylamine), amines saturated or unsaturated cyclic, aromatic such as pyridine, or non-aromatic, optionally substituted by one or more (Ci-C4)alkyl groups such as tetrahydropyridine optionally substituted by one or more (C1-C4)alkyl groups, piperidine optionally substituted by one or more (Ci-C4)alkyl groups, or piperazine optionally substituted by one or more (Ci-C4)alkyl groups. Preferably the alkaline agents of the invention are tertiary amines.

[0071] Preferably, the alkalizing agents are chosen from the group consisting of alkali or alkaline earth metal hydroxides, in particular sodium hydroxide, alkali or alkaline earth metal (bi)carbonates, in particular sodium or potassium (bi)carbonates and tri(Ci-C6)(hydroxy)alkylamines, in particular tri(Ci-C6)alkylamines, in particular triethylamine.

[0072] Preferably, the alkalizing agents are minerals.

[0073] More preferably, the alkalizing agents are mineral and are chosen from the group consisting of alkali or alkaline-earth metal hydroxides, alkali or alkaline-earth metal (bi)carbonates, and mixtures thereof, in particular alkali or alkaline-earth metal hydroxides, in particular sodium hydroxide.

[0074] The acidifying agents that may be used in the process according to the invention may be any acidification means known to those skilled in the art, such as the use of acid resins or the addition of organic or mineral, preferably mineral, acidifying agent(s).

[0075] The acidifying agents may be mineral, such as sulfuric acid, phosphoric acid, sulfonic acid, phosphonic acid, hydrogen halide acids H+Hal with Hal representing a halogen atom chosen from the group consisting of chlorine, bromine and iodine, preferably H+Hal acids with Hal preferably representing a chlorine atom,; preferably by adding mineral acidifying agents, in particular of the mineral acid type such as sulfuric acid, phosphoric acid, sulfonic acid, phosphonic acid, H+Hal acids with Hal representing a halogen atom chosen from the group consisting of chlorine, bromine and iodine, preferably H+Hal acids with Hal preferably representing a chlorine atom.

[0076] The organic acidifying agents may be chosen from the group consisting of i) carboxylic acids, in particular (poly)hydroxy(Ci-C6)alkyl(poly)carboxylic acids, such as, for example, acetic acid, tartaric acid, citric acid, lactic acid, and ii) sulfonic acids, in particular (Ci-C6)alkylsulfonic acids. Purification process (PU)

[0077] As previously indicated, the purification process (PU) is carried out in an aqueous medium comprising at least one cosmetic ingredient, preferably at least one compound of formula (I), and at least one salt.

[0078] In other words, the process (PU) is a process for treatment by electrodialysis of at least one aqueous medium comprising at least one cosmetic ingredient, preferably at least one compound of formula (I) and at least one salt.

[0079] Thus the process (PU) makes it possible to treat an aqueous solution comprising at least one cosmetic ingredient, preferably at least one compound of formula (I) and at least one salt. Aqueous medium

[0080] The treated aqueous medium comprises at least one cosmetic ingredient and at least one salt.

[0081] Preferably, the aqueous medium comprises at least one compound of formula (I) and at least one salt.

[0082] As indicated above, the compound of formula (I) corresponds to the following formula (I): (I)

[0083] Formula (I) in which: - SA' represents a monosaccharide group or a polysaccharide group comprising up to 20 sugar units, in particular up to 6 sugar units, preferably a monosaccharide, disaccharide or trisaccharide, more preferably a monosaccharide, in pyranose and / or furanose form and of L and / or D series, said monosaccharide or polysaccharide being substituted by at least one free hydroxyl group, and optionally at least one amine group optionally protected in particular by an acetyl group R'-C(Y)- with R' representing a hydrogen atom, or a (Ci-C6)alkyl group such as methyl, and Y represents O, S, preferably O, - the bond between SA' and -CH2X is a C-anomeric bond, - X represents a divalent group chosen from: -C(O)- or -CH(OR)-, - R represents a hydrogen atom, a C1-C10 alkyl group, preferably CrC4, such as methyl, or an alkyl(Ci-C4)carbonyl group such as acetyl, preferably a hydrogen atom; - Ri represents a hydrocarbon chain, saturated or unsaturated, linear or branched, cyclic or acyclic, preferably acyclic, in C1-C10, preferably in C1-C6, more preferably in C1-C4, more preferably saturated, in particular in C1;

[0084] as well as one of its optical isomers, geometric isomers, and / or one of its solvated such as hydrates.

[0085] By "bond between SA' and CH2-X" which "is a bond of C-anomeric nature" is meant that the part of the sugar unit SA' is connected to the rest of the molecule via the methylene group -CH2- by a carbon-carbon bond CC (i.e. carbon of the sugar SA'-carbon of the methylene -CH2-) and not by an oxygen-carbon bond OC (i.e. not by an oxygen bond of the sugar SA' - carbon of the methylene -CH2-).

[0086] For the purposes of the present invention, SA' comprises a monosaccharide or polysaccharide SA group comprising up to 20 sugar units, as defined above; SA being substituted by at least one free hydroxy group.

[0087] In other words, SA' has the same meaning as SA and comprises at least one free hydroxy group (-OH).

[0088] SA' may represent a monosaccharide group or a polysaccharide group comprising up to 20 sugar units, in particular up to 6 sugar units, in pyranose and / or furanose form and of L and / or D series, of anomer a or b, and- said monosaccharide or polysaccharide comprising at least one free hydroxy group and optionally at least one optionally protected amine group.

[0089] According to one embodiment, SA' is a monosaccharide group selected from the group consisting of glucose, galactose, mannose, xylose, fucose, arabinose, rhamnose, glucuronic acid, galacturonic acid, iduronic acid, N-acetyl-glucosamine, N-acetyl-galactosamine and more particularly SA is a monosaccharide selected from the group consisting of D-glucose, D-galactose, D-mannose, D-xylose, L-fucose, L-arabinose, L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-iduronic acid, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine.

[0090] Preferably, SA' is a monosaccharide selected from the group consisting of glucose, xylose, N-acetyl-galactosamine or fucose, in particular glucose, xylose or fucose, more particularly xylose

[0091] More preferably, SA' is a monosaccharide group chosen from the group consisting of D-glucose, D-xylose, N-acetyl-D-galactosamine or L-fucose, in particular D-glucose, D-xylose or L-fucose, more particularly D-xylose.

[0092] According to one embodiment, SA' is a polysaccharide group comprising up to 6 sucrose units and chosen from the group consisting of D-maltose, D-lactose, D-cellobiose, D-maltotriose, a disaccharide combining a uronic acid chosen from D-iduronic acid or D-glucuronic acid with a hexosamine chosen from D-galactosamine, D-glucosamine, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, an oligosaccharide containing at least one xylose advantageously chosen from xylobiose, methyl-beta-xylobioside, xylotriose, xylo- tetraose, xylopentaose and xylohexaose and preferentially xylobiose which is composed of two xylose molecules linked by a 1-4 bond.

[0093] Preferably, SA' represents a monosaccharide group.

[0094] Preferably, SA' represents a monosaccharide group chosen from the group consisting of glucose, in particular D-glucose, xylose, in particular D-xylose, fucose, in particular L-fucose, arabinose, in particular L-arabinose, rhamnose, in particular L-rhamnose, glucuronic acid, in particular D-glucuronic acid, galacturonic acid, in particular D-galacturonic acid, iduronic acid, in particular D-iduronic acid, N-acetyl glucosamine, in particular N-acetyl-D-glucosamine, N-acetyl-galactosamine, in particular N-acetyl-D-galactosamine, and preferably SA is chosen from D-glucose, D-xylose, L-fucose, L-arabinose, L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-iduronic acid

[0095] Preferably, SA' represents a monosaccharide group chosen from the group consisting of glucose, xylose, N-acetyl-galactosamine or fucose, more preferably SA' is chosen from the group consisting of glucose, xylose or fucose.

[0096] Preferably, SA' represents a monosaccharide group chosen from the group consisting of D-glucose, D-xylose, N-acetyl-D-galactosamine or L-fucose, more preferably SA' is chosen from the group consisting of D-glucose, D-xylose or L-fucose.

[0097] More preferably, SA' represents a xylose group and even more preferably D-xylose.

[0098] As indicated previously, Ri represents a hydrocarbon chain, linear or branched, saturated or unsaturated, cyclic or acyclic, in C1-C10, preferably in C1-C6, more preferably in C1-C4, in particular in C1.

[0099] According to one embodiment, Ri represents a linear or branched, saturated or unsaturated, cyclic or acyclic, preferably acyclic, C1-C6, more preferably C1-C4, in particular Cp, hydrocarbon chain.

[0100] According to one embodiment, Ri represents a linear or branched, saturated or unsaturated, preferably saturated, cyclic alkyl chain such as cyclohexyl or cyclopentyl, or acyclic in C1-C6, more preferably in C1-C4, in particular in C1-

[0101] Preferably, Ri represents a linear or branched, preferably linear, saturated or unsaturated, acyclic, preferably saturated, C1-C10, preferably C1-C6, more preferably C1-C4, in particular C1, hydrocarbon chain.

[0102] Preferably, Ri represents a linear, saturated or unsaturated, acyclic, preferably saturated, C1-C10, preferably C1-C6, more preferably C1-C4, in particular C1 alkyl chain.

[0103] Preferably, Ri represents a linear, saturated or unsaturated, acyclic, C1-C4, in particular Cp, alkyl chain.

[0104] Preferably, X represents a divalent radical -C(O)- or -CH(OH)-.

[0105] Advantageously, in formula (I): - X represents a divalent radical -C(O)- or -CH(OH)-, - SA represents a monosaccharide group selected from the group consisting of D-glucose, D-galactose, D-mannose, D-xylose, L-fucose, L-arabinose, L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-iduronic acid, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, preferably selected from D-glucose, D-galactose, D-mannose, D-xylose, L-fucose, L-arabinose, L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-iduronic acid, more preferably selected from D-glucose, D-xylose or L-fucose; - Ri represents a linear, saturated or unsaturated, acyclic, preferably saturated, C1-C10, preferably C1-C6, more preferably C1-C4 hydrocarbon chain, in particular a methyl group.

[0106] Preferably, the compound of formula (I) is a compound corresponding to the following formula (!): O Rs (HGL (D

[0107] Formula (!') in which: - n is equal to 0 or 1, preferably is equal to 1, - p is an integer ranging from 1 to 4, preferably the index p is equal to 3, - Ri has the same meaning as in formula (I), preferably represents a linear alkyl chain, preferably acyclic, in C1-C10, preferably in C1-C6, more preferably in C1-C4, in particular in C1; - X represents a divalent radical -C(O)- or -CH(OR)-, - R represents a hydrogen atom, a C1-C10 alkyl group, preferably C1-C4, such as methyl, or an alkyl(Ci-C4)carbonyl group such as acetyl; preferably R represents a hydrogen atom;

[0108] as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates.

[0109] In other words, the compound of formula (I) is preferentially chosen from the group consisting of the compounds of formula (!') as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates, and their mixtures.

[0110] Preferably, in the formula (!'), the index n is equal to 1 and the index p is an integer varying from 1 to 4, preferably the index p is equal to 3.

[0111] Preferably, the compound of formula (I) is a compound corresponding to the following formula (I”): O. A HOZ ^OH OH (I”)

[0112] Formula (I”) in which: - Ri has the same meaning as in formula (I), preferably represents a linear alkyl chain, preferably acyclic, in C1-C10, preferably in C1-C6, more preferably in C1-C4, in particular in C1; - X represents a divalent radical -C(O)- or -CH(OR)-, preferably -C(O)- - R represents a hydrogen atom, a C1-C10 alkyl group, preferably C1-C4, such as methyl, or an alkyl(CrC4)carbonyl group such as acetyl; preferably R represents a hydrogen atom;

[0113] as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates.

[0114] In other words, the compound of formula (I) is more preferably chosen from the group consisting of the compounds of formula (I”) and their mixtures.

[0115] Preferably, in formula (I”), R is a hydrogen atom.

[0116] Preferably, the compound of formula (I) is a compound corresponding to the formula (!”') next: 1 1 HO'" "V" "OH OH (I'”)

[0117] Formula (!”') in which:

[0118] X corresponds to a divalent radical -C(O)- or -(CH)OH-, preferably -C(O)-

[0119] as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates.

[0120] The cosmetic ingredient(s), and preferably the compound(s) of formula (I) as described above, may be present in a content of at least 25% by weight of active material of cosmetic ingredient and in particular of formula (I), preferably in a content ranging from 25% to 80% by weight, more preferably ranging from 25 to 75% by weight, more preferably ranging from 30% to 70% relative to the total weight of the aqueous medium.

[0121] Preferably, the aqueous medium comprises at least one compound of formula (F) in a content of at least 25% by weight, preferably in a content ranging from 25 to 80% by weight, more preferably in a content ranging from 28 to 75% by weight, relative to the total weight of the aqueous medium.

[0122] More preferably, the aqueous medium comprises at least one compound of formula (I”) or (F”) in a content of at least 25% by weight, preferably in a content ranging from 40 to 80% by weight, more preferably in a content ranging from 50% to 75% by weight, relative to the total weight of the aqueous medium. Salt

[0123] According to a general characteristic of the present invention, said at least one salt is in particular different from a surfactant.

[0124] Preferably, said at least one salt is chosen from the group consisting of inorganic salts, organic salts and their mixtures.

[0125] Preferably, said at least one salt is chosen from the compounds of formula (IV):

[0126] ZZW(IV)

[0127] Formula (IV) in which:

[0128] y is an integer ranging from 1 to 3,

[0129] w is an integer ranging from 1 to 3,

[0130] A is an organic or inorganic anion, preferably organic,

[0131] D is an organic or inorganic cation, preferably inorganic,

[0132] The salt respects electroneutrality, that is to say that the absolute value of the sum of the negative charges of the anions is equal to the sum of the positive charges of the cations.

[0133] Preferably, in formula (IV),

[0134] w is equal to 1 or 2, preferably 1,

[0135] y is equal to 1 or 2, preferably 1.

[0136] Preferably, in formula (IV), w is equal to 1 and y is equal to 1.

[0137] Aw may be an inorganic anion selected from the group consisting of nitrate (NO3 ), carbonate (CO32 ), halides, in particular chloride (Cl ), more preferably in the group consisting of nitrate (NO3) and halides, in particular chloride (Cl ).

[0138] Aw may be an organic anion chosen from the group consisting of CrCi8, preferably Ci-Cio, preferentially Ci-C6, more preferentially Ci-C4, even more preferentially Ci-C2, better still C2, in particular from a group consisting of Ci-C6 carboxylic acids.

[0139] Preferably, Aw is an organic anion, preferably chosen from the group consisting of linear or branched, cyclic or non-cyclic, preferably C1-C10, more preferably C1-C6 carboxylic acids.

[0140] Preferably, Aw is an organic anion chosen from the group consisting of linear CrCi8 carboxylic acids, more preferably Ci-C6.

[0141] Preferably, Aw is an organic anion chosen from the group consisting of C1-C4 carboxylic acids, preferably C1-C2, better still C2 such as acetate (CH3COO).

[0142] According to one embodiment, D'+ may be an organic cation, preferably chosen from the group consisting of ammonium, phosphonium, imadazolium, pyrazolium, piperidinium, piperazinium ions.

[0143] According to one embodiment, D'+ is an inorganic cation chosen from the group consisting of alkali metal cations and alkaline earth metal cations.

[0144] Advantageously, D'+ is a cation chosen from the group consisting of alkali metal cations, alkaline earth metal cations, the ammonium ion (NH4+), in particular alkali metal cations, alkaline earth metal cations.

[0145] Preferably, D'+ is a cation selected from the group consisting of calcium ion (Ca 2+), magnesium ion (Mg2+), sodium ion (Na+) and potassium ion (K+), in particular calcium ion and sodium ion, more particularly sodium ion.

[0146] Preferably, the salt corresponds to the following formula (IV1): (IV1)

[0147] Formula (IV1) in which:

[0148] D+ has the same meaning as that given in formula (IV) with y=l,

[0149] R2 represents an alkyl chain, saturated or unsaturated, linear or branched, cyclic or acyclic, preferably acyclic, C1-C10, preferably C1-C6, more preferably- mainly in C1-C4, especially in Cp

[0150] Preferably, R2 represents a linear or branched, saturated or unsaturated, cyclic or acyclic, preferably acyclic, C1-C6, more preferably C1-C4, in particular Cp alkyl chain.

[0151] According to one embodiment, R2 represents a linear or branched, saturated or unsaturated, cyclic alkyl chain such as cyclohexyl or cyclopentyl, or acyclic in C1-C6, more preferably in C1-C4, in particular in Cp

[0152] Preferably, R2 represents a linear or branched, preferably linear, saturated or unsaturated, acyclic, C1-C10, preferably C1-C6, more preferably C1-C4, in particular Cp alkyl chain.

[0153] Preferably, R2 represents a linear, saturated or unsaturated, acyclic, C1-C10, preferably C1-C6, more preferably C1-C4, in particular Cp alkyl chain.

[0154] Preferably, R2 represents a linear, saturated or unsaturated, acyclic, C1-C4, in particular Cp, alkyl chain.

[0155] Preferably, in formula (IV1), D+ represents an inorganic cation chosen from the group consisting of alkali metal cations and alkaline earth metal cations.

[0156] Advantageously, in formula (IV1), D+ is a cation chosen from the group consisting of alkali metal cations, alkaline earth metal cations, the ammonium ion (NH4+), in particular alkali metal cations, alkaline earth metal cations, in particular the sodium ion (Na+), the potassium ion (K+) or an ammonium (NH4+).

[0157] More preferably, in formula (IV1), D+ represents the sodium ion (Na+).

[0158] Preferably, said at least one salt is chosen from the group consisting of salts of alkali metals, alkaline earth metal salts, ammonium salts and their mixtures.

[0159] Preferably, said at least one salt is chosen from the group consisting of calcium salts, magnesium salts, sodium salts, potassium salts and mixtures thereof, more preferably chosen from the group consisting of calcium salts, sodium salts and mixtures thereof.

[0160] Preferably, said at least one salt is chosen from the group consisting of alkali metal salts of C1-C6, preferably C1-C4, more preferably C1-C2, better still C2, carboxylic acids, such as sodium acetate.

[0161] Preferably, said at least one salt is chosen from the group consisting of alkali metal salts, alkaline earth metal salts, ammonium salts and mixtures thereof.

[0162] Preferably, said at least one salt is chosen from the group consisting of salts of calcium, magnesium salts, sodium salts, potassium salts and their mixtures, more preferably chosen from the group consisting of calcium salts, sodium salts and their mixtures.

[0163] Preferably, said at least one salt is chosen from the group consisting of alkali metal salts of C1-C6, preferably C1-C4, more preferably C1-C2, better still C2, carboxylic acids, such as sodium acetate.

[0164] Salt may or may not be an impurity.

[0165] Preferably, the salt may be an impurity, for example resulting from at least one of the steps of a process for preparing at least one cosmetic ingredient, preferably at least one compound of formula (I) and / or resulting from at least one step of at least one washing and / or purification process(es) carried out before, after or during, preferably after, at least one of the steps of a process for preparing said at least one cosmetic ingredient, preferably said at least one compound of formula (I).

[0166] Preferably, the salt is an impurity.

[0167] The salt, preferably of formula (IV), more preferably of formula (IV1), can be present in a content ranging from 0.05% to 50% by weight, in particular in a content ranging from 0.1% to 40% by weight, more particularly in a content ranging from 0.5% to 30% by weight, relative to the total weight of the aqueous medium.

[0168] More preferably, the salt corresponding to formula (IV1) may be present in a content ranging from 0.05% to 45% by weight, in particular in a content ranging from 0.1% to 35% by weight, more particularly in a content ranging from 0.5% to 25% by weight, relative to the total weight of the aqueous medium by weight, relative to the total weight of the aqueous medium.

[0169] Preferably, the aqueous medium comprises: - at least one compound of formula (I) as defined above, and - at least one salt corresponding to formula (IV), as defined above, more preferably to formula (IV1), as defined previously.

[0170] Advantageously, the aqueous medium comprises: - at least one compound of formula (I') as defined above, and - at least one salt corresponding to formula (IV1), as defined previously in particular chosen from the group consisting of alkali metal salts, alkaline earth metal salts, ammonium salts and their mixtures.

[0171] More preferably, the aqueous medium comprises: - at least one compound of formula (I”) as defined above, and - at least one salt corresponding to formula (IV1) as defined previously, in particular chosen from the group consisting of alkali metal salts, alkaline earth metal salts, ammonium salts and their mixtures. Electrodialysis step (PU1)

[0172] As indicated previously, the purification process (PU) according to the invention comprises at least one electrodialysis step (PU1) of at least one aqueous medium comprising at least said cosmetic ingredient, preferably said compound of formula (I) and at least one salt, as defined previously.

[0173] In other words, the method (PU) according to the invention comprises at least one step (PU1) during which at least the aqueous medium, as defined above, is subjected to at least one electrodialysis, preferably to one electrodialysis.

[0174] In other words, the aqueous medium, as defined above, is conveyed into an electrodialyzer to separate said salt(s) from said aqueous medium.

[0175] Preferably, the purification process (PU) according to the invention comprises at least one electrodialysis step (PU1) of at least one aqueous medium comprising at least said compound of formula (I) and at least one salt of formula (IV1) as defined above.

[0176] The method of the invention implements an electrolysis step. Electrodialysis is a method known to those skilled in the art; it is an electrochemical process which makes it possible to extract ions (anions or cations) contained in a solution (see, for example, chemical news, Electrodialysis and its numerous applications, F. Lutin - no. 327-328, February-March 2009).

[0177] The principle of the process is to use electrically charged membranes (cationic or anionic) used to separate the medium ions from the solution, in particular aqueous, using the driving force of the potential difference. The electrodialysis device is often built on the principle of a filter press of stacking successive membranes which can include several tens or even hundreds of cationic and anionic membranes alternating between two electrodes, the solution, in particular aqueous, arriving in the device (feed solution) flows through the different cells (i.e. space between 2 successive membranes also pair of membranes). When an electrical potential difference is applied between 2 electrodes the positively charged cations in the feed solution move towards the cathode.These ions easily pass through negatively charged cation exchange membranes, but are retained by positively charged anion exchange membranes. And conversely, negatively charged anions migrate to the anode, pass through the anion exchange membrane, and are retained by the cation exchange membrane. Thus, the arrangement of ion-selective membranes causes the migrating ions to concentrate in each alternating cell of the stack. Thus, the ions removed from the aqueous feed solution are concentrated into two separate streams.

[0178] In summary, the extraction of ions is done by migration of ions through at least two selective membranes (anionic or cationic) under the action of an electric field. Only anions can cross an anionic membrane and only cations can cross a cationic membrane. By placing several membranes in parallel, allowing positive ions and negative ions to pass alternately, certain ions can be eliminated from the solution, particularly aqueous.

[0179] Thus, electrodialysis can separate, concentrate and / or purify a C-glycoside derivative such as a compound of formula (I), from aqueous solutions.

[0180] In some compartments there is concentration of ions and in others the ions are eliminated. Particles not carrying an electrical charge are not eliminated.

[0181] In the method of the invention, conventional electrodialysis (ED) or bipolar electrodialysis (BPED) can be used.

[0182] According to one embodiment of the invention, the method implements conventional electrodialysis.

[0183] By "conventional electrodialysis" or ED or concentration electrodialysis is meant a device implementing the electrochemical separation of ions of a composition, in particular aqueous, transferred from one membrane to another by selective exchange using a continuous electrical voltage. Conventional electrodialysis therefore makes it possible to purify, concentrate and demineralize.

[0184] By "bipolar electrodialysis" or BPED is meant an ion exchange device by electrodialysis membranes that uses at least one bipolar membrane to split water into proton and hydroxide ion, i.e. generating acid and alkali flows. Under the driving force of an electric field, a bipolar membrane dissociates water into hydrogen ions (H+) and hydroxide (OH ). A bipolar membrane is formed of an anion and cation exchange layer that are bonded together, and a very thin interface where water diffuses from external aqueous saline solutions. With the anion exchange side facing the anode and the cation exchange side facing the cathode, hydroxyl anions will be transported through the anion exchange layer and hydrogen cations through the cation exchange layer. A bipolar membrane allows the generation and concentration of hydroxyl and hydrogen ions on its surface.These ions can be used in an electrodialysis stack to combine with the cations and anions of the salt to produce acids and bases (or alkaline agent).

[0185] This process allows the pH of a solution to be adjusted without having to add an alkaline or acid agent.

[0186] The membranes of the electrolysis device are anionic or cationic. Cationic membranes are often made of sulfonated or phosphonated polymers such as sulfonated polystyrenes, while cationic membranes Anionic membranes are often made of quaternary ammonium polymer, phosphonium such as polystyrenes with quaternary ammonium. Preferably the membranes are sulfonated and quaternary ammonium. Pre-treatment may be necessary before electrodialysis. Suspended solids with a diameter greater than 10 mm must be removed, otherwise they may clog the membrane pores. There are also substances that can neutralize the membrane, such as large organic anions, colloids, iron and manganese oxides. They disrupt the selective effect of the membrane.

[0187] Before electrolysis the composition can be filtered or passed through an ion exchange resin.

[0188] Before electrodialysis, the pH of the aqueous composition comprising the cosmetic ingredient(s) has a pH greater than the pKa of the salt of the conjugate acid (weak acid). Preferably before electrolysis the pH of the aqueous composition comprising the C-glycoside derivatives is preferably at least 4, more preferably at least 5, even more preferably at least 6, even more preferably at least 7. The pH can be adjusted using an alkaline or acidic agent such as acetic acid, sodium hydroxide or (bi)carbonates of alkaline agents.

[0189] Anion exchange membranes or cation exchange membranes suitable for concentration by electrodialysis may be used in the methods of the present invention. Such membranes are commercially available from Astom Corp. (Tokyo, Japan), for example Neosepta membranes, Tokuyama Co., Ltd. (Tokyo, Japan), Ameridia (Somerset).

[0190] The conventional electrodialysis step can be performed with any commercially available electrodialysis unit. Such units are commercially available from various suppliers such as Valeo (France), Eurodia Industrie SA (France). Eet Corporation (US), Ameridia (US), or Mega AS (Czech Republic).

[0191] Concentrating electrodialysis is preferably carried out using a configuration known as an electrodialysis cell. The cell consists of a feed (diluate) compartment and a concentrate (brine) compartment formed by an anion exchange membrane and a cation exchange membrane placed between two electrodes. The electrodialysis process preferably uses multiple electrodialysis cells arranged in a configuration known as an electrodialysis stack, with alternating anion and cation exchange membranes forming the multiple electrodialysis cells. The number of cells can range from a few cells, for example ten cells, to hundreds of cells in a stack.

[0192] The parameters of electrodialysis include current density, voltage cell, current efficiency, diluate concentration and concentrate concentration.

[0193] The amount (density) of current determines the amount in equivalent grams of product transported across the membranes. Operation at high current density can reduce the required surface area of ​​electrodialysis cells. The current density is preferably balanced with increasing cell voltage, which nevertheless can result in higher energy consumption.

[0194] By "limiting current" is meant the maximum current density allowed to avoid an abrupt increase in the cell voltage. The limiting current may depend on parameters such as the design of the battery, the concentrations of the composition, particularly aqueous, the temperature, etc.

[0195] The current efficiency also determines the surface area of ​​the membranes required for the process of the present invention.

[0196] By "current efficiency" we mean the efficiency of an electrochemical process.

[0197] Current efficiency takes into account all potential parasitic phenomena occurring in the membrane stack (e.g. membrane permselectivity < 100%, physical leakage (leading to impurities in the products, which can be reduced by optimized stack design and membrane selection).

[0198] According to a particular embodiment of the invention, the ratio of electrical energy consumed / kg is between 0.01 kW / h and 0.2 kW / h / kg, better between 0.03 kW / h / kg and 0.1 kW / h / kg.

[0199] Another important parameter is the concentrations (conductivities) of the two streams. The ratio of the conductivities affects the efficiency of the current, limiting the maximum concentration for the concentrate (brine) stream. In general, the minimum diluate concentration is limited by conductivity considerations due to the ohmic resistance of the diluate cells and the low limiting currents at low conductivities. The minimum conductivity that can be considered is about 0.5 mS / cm. The minimum starting concentration of salts / cosmetic ingredient, in particular C-glycoside derivative, for carrying out the concentration electrodialysis is one whose conductivity is preferably at least 10 mS / cm, more preferably at least 20 mS / cm, even more preferably at least 30 mS / cm.

[0200] According to a particular embodiment of the invention, the composition, in particular aqueous, is preferably pretreated to remove impurities and particles, in particular to remove acetic acid. Any pretreatment method known to those skilled in the art may be used, such as centrifugation, microfiltration, nanofiltration, ion exchange or distillation, in particular by distillation, preferably under reduced pressure.

[0201] When the membranes are fouled by impurities, they can be cleaned using conventional methods known to those skilled in the art such as the use of current reversal solutions or dilute, caustic and / or enzymatic acid.

[0202] The temperature range in conventional or bipolar electrodialysis stacks is preferably between 10°C and 50°C, in particular at a temperature between 35°C and 40°C.

[0203] The pH range in electrodialysis stacks, particularly conventional ones, is preferably between 3 and 8, more preferably between 4 and 7.

[0204] According to a particular embodiment, the conventional or bipolar electrodialysis of the method of the invention is carried out at a temperature between 10°C and 50°C, particularly between 15°C and 40°C, preferably the temperature is between 20°C and 35°C such as 25°C.

[0205] According to one embodiment, the method of the invention implements a conventional electrolysis step, in particular carried out at a pH of at least 4, preferably at least 5, more preferably at least 6 and preferably at a pH less than or equal to 8.

[0206] According to a particular embodiment of the invention in the electrodialysis step of the process, the composition, in particular aqueous, comprising the salt(s) / cosmetic ingredient(s), in particular the C-glycoside derivatives, are introduced into the electrodialysis cell through the diluate compartment.

[0207] When the solution reaches the active zone of the cells, the direct current (DC) voltage causes the positively charged cations to migrate toward the cathode and the negatively charged anions toward the anode. When the ions reach an ion exchange membrane, the properties of the membrane determine whether the ions are rejected or allowed to pass through. Ions that can pass through membranes are retained in the next compartment since the next membrane in its path will be of the opposite charge. Therefore, there are compartments from which ions are removed and compartments where they are concentrated. If the solutions are circulated rapidly through the cell, a diluate stream and a concentrate stream are obtained. The product can be the desalinated stream, the concentrated stream, or both. Bipolar membrane electrodialysis

[0208] According to a preferred embodiment of the invention, the method implements at least one bipolar or bipolar membrane electrodialysis step.

[0209] This bipolar electrodialysis may involve first bringing into contact the concentrate resulting from conventional electrodialysis followed by at least one bipolar membrane electrodialysis to convert the C-glycoside derivatives of formula (I).

[0210] According to a preferred embodiment of the invention, the method implements a bipolar electrodialysis step without first performing a conventional electrodialysis step.

[0211] Bipolar membrane electrodialysis can be performed with any available bipolar membrane electrodialysis unit. Such units are commercially available from suppliers such as The Electrosynthesis Company, Inc. (US), FuMA-Tech GmbH (Germany), Solvay SA (Belgium), Tokuyama Co., Ltd. (Japan), Graver Water Co. (US), Tianwei, Membrane Technology Co. Ltd. (China), Ameridia (US), Eurodia Industrie SA (France).

[0212] Any bipolar membrane suitable for bipolar membrane electrodialysis may be used in the methods of the present invention. Such membranes are commercially available from Astom Corp. (Tokyo, Japan), for example Neosepta membranes, Tokuyama Co., Ltd. (Tokyo, Japan), Ameridia (Somerset, NJ, USA), Eurodia Industrie SA (Wissous, France), CelTech, Inc. (Fayetteville, NC, USA), Eden Purification Systems (North Haven, CT, USA), Ion Power, Inc. (Bear, DE, USA), Minntech Corporation (Minneapolis, MN, USA) and GE Water & Process Technologies (Trevose, PA, USA), Veolia (France).

[0213] Examples of membranes marketed by Veolia are AR204; AR103, AR908, CR64, CR67, CR61. The membranes can be woven or the polymers can be cast onto a variety of fabrics. Each type of fabric is designated by a single letter:

[0214] R —> Woven acrylic fabric, H —> Heavy woven acrylic fabric, E —> Non-woven polyester fabric woven, T —> fine non-woven polyester fabric, U —> ultra-fine non-woven polyester fabric, P —> polypropylene woven fabric, N —> fine non-woven polypropylene fabric. The name of each membrane type can be the combination of membrane chemistry and support structure (e.g. AR103P, CR67T). Membranes have certain electrical resistance, and permselectivity

[0215] Ion exchange membranes such as lonics have certifications for example NSF 61 for drinking water, 21CFR175 176 177 178 182; EU 1935 / 2004 and EU 10 / 2001 for food contact materials

[0216] According to a particular embodiment, the bipolar membrane electrodialysis of the method of the invention is carried out at a temperature between 10°C and 40°C, particularly between 15°C and 35°C, preferably the temperature is between 20°C and 30°C such as 25°C.

[0217] It is understood herein that the concentrating electrodialysis unit and the bipolar membrane electrodialysis unit may be integrated into the same apparatus.

[0218] Different configurations of bipolar membrane electrodialysis are possible and described by the manufacturers.

[0219] A three-compartment cell is obtained by adding the bipolar membrane into a conventional electrodialysis cell. In such a case, the bipolar membrane is flanked on either side by the anion and cation exchange membranes described above to form three compartments: acid between the bipolar and anion exchange membranes, base between the bipolar and cation exchange membranes, and salt between the cation and anion exchange membranes.

[0220] A two-compartment cell can be obtained by adding bipolar and cation exchange membranes or by adding bipolar and anion exchange membranes.

[0221] According to one embodiment of the invention, an alternation of cation exchange membranes and bipolar membranes is used.

[0222] Advantageously, the electrodialysis step (PU1) is carried out at a pH ranging from 4 to 9, preferably at a pH ranging from 4.5 to 8.5, more preferably in a pH range from 5 to 8, more preferably at a pH ranging from 6.5 to 7.5.

[0223] The electrodialysis step (PU1) is preferably carried out at a pH of less than 8 so as to effectively reduce the contents of ionic impurities, i.e. the salt contents, preferably corresponding to formula (II), more preferably to formula (II').

[0224] The electrodialysis step (PU1) can be carried out at a temperature ranging from 20 to 50°C, preferably at a temperature ranging from 25°C to 45°C.

[0225] Preferably, the electrodialysis step (PU1) is carried out with conventional electrolysis, more preferably at a “product” conductivity (i.e. before treatment) ranging from 50 to 0.05 mS / cm, preferably ranging from 40 to 0.2 mS / cm, measured in particular at a temperature ranging from 20°C to 50°C.

[0226] According to one embodiment, the electrodialysis step (PU1) is carried out with a bipolar membrane electrolysis at a “product” conductivity (i.e. before treatment) ranging from 60 to 0.5 mS / cm, preferably ranging from 55 to 1 mS / cm, more preferably ranging from 50 to 10 mS / cm, even more preferably ranging from 45 to 20 mS / cm, measured in particular at a temperature ranging from 20°C to 50°C. Preferably the concentration of the cosmetic ingredient(s), in particular C-glycoside derivative, is between 10 and 70% by weight, particularly between 20 and 60% by weight, more particularly between 30 and 50% by weight.

[0227] Preferably, the electrodialysis step (PU1), in particular conventional electrodialysis, is carried out at a pH ranging from 5 to 8, more preferably at a pH ranging from 4 to 8, and at a temperature ranging from 20°C to 50°C, more preferably at a temperature ranging from 25°C to 45°C.

[0228] Preferably, the electrodialysis step (PU1) bipolar membrane electrodialysis, is carried out at an alkaline pH ie > 7, more preferably at a pH higher or equal to 8, better greater than or equal to 9, in particular between 9.5 and 12, and at a temperature in particular ranging from 20°C to 50°C, more preferably at a temperature ranging from 25°C to 45°C.

[0229] The electrodialyzer comprises in particular a first electrode, constituting the anode, and a second electrode, constituting the cathode, so that, when a direct current source is applied, an electric field is applied across all of the components of the electrodialyzer between the first electrode and the second electrode.

[0230] Between the first electrode and the second electrode, the electrodialyzer may comprise a series of compartments mounted in parallel and each formed of two membranes, in particular an anionic or anion exchange membrane, i.e. a membrane permeable to anions and impermeable to cations, and a cationic or cation exchange membrane, i.e. a membrane permeable to cations and impermeable to anions. The anionic and cationic membranes are arranged alternately within the electrodialyzer.

[0231] Thus each compartment is formed of an anionic membrane and a cationic membrane which are spaced from each other.

[0232] In other words, the electrodialyzer can be of the conventional type comprising a stack of membranes alternately exchanging cation and exchanging anion, placed in an electric field created by electrodes.

[0233] Between the first electrode and the second electrode, the electrodialyzer comprises a compartment, generally located in the center of the device, called the dilution compartment, in which the aqueous solution, as defined previously, circulates.

[0234] The dilution compartment is arranged between two adjacent compartments, called concentration compartments. In other words, the concentration compartments are located on either side of the dilution compartment. In other words, the dilution and concentration compartments are arranged alternately within the electrodialyzer. In yet other words, the dilution behavior is sandwiched between two concentration compartments.

[0235] Thus, during the circulation of an aqueous medium, as defined above, in the dilution compartment, on the one hand, under the effect of the electric current, the anions of the salt, attracted towards the anode, will migrate from the dilution compartment towards the concentration compartment by crossing the anionic membrane and will remain blocked in this concentration compartment because of the cationic membrane.

[0236] On the other hand, the cations of the salt, attracted by the cathode, will migrate from the dilution compartment to the concentration compartment by crossing the cationic membrane and will remain blocked in this concentration compartment because of the anionic membrane.

[0237] Thus the salt is extracted from the dilution compartment, in which the aqueous medium circulates, while the anions and cations of the salt are concentrated respectively in each adjacent concentration compartment.

[0238] The electrodialysis step (PU1) thus makes it possible to reduce the salt content in the aqueous medium as defined previously.

[0239] The aqueous medium according to the invention comprising at least the compound of formula (I), located in the dilution compartment is then recovered at the outlet of the electrodialysis via a conduit.

[0240] Electrodialysis advantageously makes it possible to eliminate very large quantities of impurities in ionic form from the aqueous medium comprising at least said cosmetic ingredient, preferably said compound of formula (I) as defined above.

[0241] The electrodialysis step (PU1) thus makes it possible to achieve a salt content likely to be less than or equal to 10% by weight, preferably less than or equal to 5% by weight, more preferably varying from 1 to 5% by weight, better still varying from 1.5 to 2% by weight, relative to the total weight of the dry extract containing said cosmetic active ingredient.

[0242] In other words, at the end of the purification process (PU), said cosmetic ingredient, preferably said compound of formula (I), is preferably in the form of a dry extract comprising a content of less than or equal to 10% by weight, preferably less than or equal to 5% by weight, more preferably varying from 1 to 5% by weight, better still varying from 1.5 to 2% by weight, of at least one salt, preferably of at least one compound of formula (IV) or (IV') relative to the total weight of the dry extract.

[0243] The aqueous medium or aqueous solution thus recovered can be used for cosmetic applications.

[0244] Preferably, the purification process (PU) comprises at least one electrodialysis step (PU1) of at least one aqueous medium comprising at least one cosmetic ingredient, preferably at least one compound of formula (I), as defined above, and at least one salt, preferably corresponding to formula (II), more preferably corresponding to formula (II').

[0245] According to one embodiment, the purification method (PU) according to the invention comprises at least one electrodialysis step (PU1) of at least one aqueous medium comprising: - at least one cosmetic ingredient, - at least one salt, preferably corresponding to formula (IV1).

[0246] Even more preferably, the purification process (P) according to the invention comprises at least one electrodialysis step (PI) of at least one aqueous medium comprising: - at least one cosmetic ingredient - at least one salt corresponding to formula (IV1), in particular chosen from the group consisting of alkali metal salts, alkaline earth metal salts, ammonium salts and their mixtures

[0247] More preferably, the purification process (PU) according to the invention comprises at least one electrodialysis step (PU1) of at least one aqueous medium comprising: - at least one compound of formula (I'), as defined above, • preferably, in formula (I'), Ri represents a linear alkyl chain of C1-C10, preferably C1-C6, more preferably C1-C4, in particular C1 - at least one salt, preferably corresponding to formula (IV1).

[0248] Even more preferably, the purification process (P) according to the invention comprises at least one electrodialysis step (PI) of at least one aqueous medium comprising: - at least one compound of formula (I”), as defined above, • preferably, in formula (I”), Ri represents a linear C1-C10, preferably C1-C6, more preferably C1-C4, in particular C1, alkyl chain. - at least one salt corresponding to formula (IV1), in particular chosen from the group consisting of alkali metal salts, alkaline earth metal salts, ammonium salts and their mixtures.

[0249] Preparation process (PR) of at least one cosmetic active ingredient

[0250] As indicated previously, the preparation process (PR) according to the invention is a preparation process (PR) of at least one cosmetic ingredient preferably chosen from the compounds corresponding to the following formula (I): ITS Z X ' (I)

[0251] Formula (I) in which: - SA' represents a monosaccharide group or a polysaccharide group comprising up to 20 sugar units, in particular up to 6 sugar units, in pyranose and / or furanose form and of L and / or D series, of anomer a or b, said monosaccharide or polysaccharide comprising at least one free hydroxy group, and optionally at least one optionally protected amine group, - the SA'-CH2-X bond represents a C-anomeric bond, - X represents a divalent radical -C(O)- or -CH(OR), preferably -C(O)- R represents a hydrogen atom, a C1-C10 alkyl group, preferably C1-C4, such as methyl, or a C1-C4 alkylcarbonyl group such as acetyl, preferably a hydrogen atom; Ri represents a hydrocarbon chain, saturated or unsaturated, linear or branched, cyclic or acyclic, preferably acyclic, in C1-C10, preferably in C1-C4, more preferably saturated

[0252] as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates;

[0253] said method comprising: at least one reaction step (PR1) taking place according to the following synthesis scheme (A): Agent aîcaSn iii) (iïVl) synthesis route (A) in which: • Ri and R2 are the same or different; with R2 having the same meaning as Ri in formula (I), • SA has the same meaning as in formula (I), • D+ is an organic or inorganic cation, derived from the alkaline agent, preferably D+ is an inorganic cation,

[0254] said reaction step (PR1) being carried out in aqueous media in the presence of: of at least one compound of formula (II), of at least one compound of formula (III), and of at least one alkaline agent in an equimolar or excess amount relative to the compound of formula (II), preferably in excess,

[0255] to lead to the formation of at least one compound of formula (IA) and at least one compound of formula (IV1) in an aqueous medium, optionally at least one neutralization step (PRO) comprising the addition of at least one acidifying agent, mineral or organic, preferably organic, in the aqueous reaction medium resulting from said step (PR1), optionally, at least one reduction step (PRii) of at least said compound of formula (IA) in a preferably aqueous medium to lead to the formation of at least one compound corresponding to the following formula (IB): ITS' GOLD (IB)

[0256] Formula (IB) in which: - SA', Ri and R have the same meanings as in formula (I); - at least one purification (PU) comprising at least one electrodialysis step (PU1), as defined previously, of at least one aqueous reaction medium comprising at least one compound of formula (IA) or (IB) and at least one compound of formula (IV1).

[0257] For the purposes of the present invention, SA' corresponds to SA-OH with SA having the same meaning as SA', as defined above, and the hydroxy -OH group is a free hydroxy group.

[0258] For the purposes of the present invention, a compound of formula (IA) is a compound of formula (I) in which X corresponds to a radical -C(O)-.

[0259] For the purposes of the present invention, a compound of formula (IB) is a compound of formula (I) in which X corresponds to a radical -CH(OR) with R as defined above.

[0260] The process (PR) according to the invention is particularly advantageous because the electrodialysis step (PU1) makes it possible to effectively reduce not only the content of salts resulting from the synthesis step (PR1) and / or the reaction step (PRii) but also the content of salts formed at the end of the neutralization step (PR0).

[0261] Advantageously, the reaction step (PR1) is carried out in an aqueous medium, in the presence of: • at least one compound of formula (II), • at least one compound of formula (III), preferably in an amount equimolar or in excess relative to the compound of formula (II), preferably in excess, • preferably the compound of formula (III) is in an amount greater than 1, preferably in an amount ranging from 1 to 5, more preferably ranging from 1 to 4, even more preferably ranging from 1 to 3, better still ranging from 1 to 2, in particular ranging from 1 to 1.5, molar equivalents relative to the compound of formula (II); • at least one alkaline agent, • preferably at least one alkaline agent as described above, preferably mineral, more preferably chosen from the group consisting of alkali or alkaline-earth metal hydroxides, alkali or alkaline-earth metal (bi)carbonates, and mixtures thereof; in particular alkali or alkaline-earth metal hydroxides, more preferably alkali metal hydroxides such as sodium hydroxide, • the alkaline agent being in an equimolar quantity or in excess relative to the compound of formula (II), preferably in excess, • preferably the alkaline agent is in an amount ranging from 1 to 5 molar equivalents, more preferably in an amount ranging from 1 to 4 molar equivalents, more preferably in an amount ranging from 1 to 3 molar equivalents, better still in an amount ranging from 1 to 2 molar equivalents, relative to the compound of formula (II), • preferably, reaction step (i) takes place: • at a temperature ranging from 30°C to 80°C, preferably at a temperature ranging from 30°C to 70°C, more preferably at a temperature ranging from 30°C to 60°C, better still at a temperature ranging from 30°C to 50°C, • preferably, the duration of the reaction varies: • from 10 minutes to 10 hours, preferably from 20 minutes to 5 hours, more preferably from 30 minutes to 4 hours.

[0262] Preferably, the reaction step (PR1) is carried out in an aqueous medium and successively comprises: • preferably the addition of at least one compound of formula (II) in an aqueous medium, in particular at a temperature ranging from 30 to 80°C, • preferably, after solubilization of the compound of formula (II) in the aqueous medium, the temperature is advantageously reduced, • preferably, the addition of at least one compound of formula (III) in the aqueous medium comprising at least the compound of formula (II), • preferably, the addition of at least one alkaline agent, preferably mineral, in an equimolar or excess quantity, preferably in excess, as described above, relative to the compound of formula (II), at a temperature preferably less than or equal to 45°C, • preferably, the reaction medium comprising at least the compound of formula (II), at least the compound of formula (III) and at least one alkaline agent, is heated to the reaction temperature as described above, • preferably, at the end of the reaction (PR1), the reaction medium can be cooled by at least 5°C, preferably by at least 10°C, more preferably by at least 15°C.

[0263] Preferably, at the end of the reaction step (PR1), the pH can be adjusted to a value less than or equal to 8.5, and even more preferably to a value greater than or equal to 2.5, preferably varying in a range from 2.5 to 8.5.

[0264] The neutralization step (PRO) can be carried out simultaneously or sequentially, preferably sequentially, preferably before the electrodialysis step (PU1).

[0265] The neutralization step (PRO) advantageously makes it possible to neutralize the excess alkaline agent present in the aqueous reaction medium resulting from step (PR1).

[0266] Preferably, the preparation process (PR) comprises at least one neutralization step (PRO) comprising at least one acidifying treatment as defined previously, such as the use of a resin or the addition of at least one acidifying agent as defined previously, preferably organic,

[0267] Preferably, the at least one electrodialysis step (PU1) is carried out after the reaction step (PR1) or after one of the reaction steps (PRii), or between the reaction step (PR1) and at least one reaction step (PRii), and optionally after the neutralization step (PRO).

[0268] Advantageously, the at least one electrodialysis step (PU1) is implemented after the reaction step (PR1).

[0269] Advantageously, the at least one electrodialysis step (PU1) is implemented between the reaction step (PR1) and at least one reaction step (PRii).

[0270] Thus, according to an advantageous embodiment, the method (PR) according to the invention comprises: - at least one reaction step (PR1) as defined previously, - at least one neutralization step (PRO), as defined previously, of the reaction medium resulting from step (PR1), - possibly at least one reaction step (PRii), as defined previously, - at least one purification step (PU), as described previously, preferably carried out after the reaction step (PR1) or optionally after the reaction step (PRii), more preferably between the reaction step (PR1) and the reaction step (PRii).

[0271] Advantageously, the at least one electrodialysis step (PU1) is implemented after the neutralization step (PRO).

[0272] According to one embodiment, the method according to the invention comprises an electrodialysis step (PU1).

[0273] According to another embodiment, the method according to the invention comprises several electrodialysis steps (PU1).

[0274] According to one embodiment, at least one electrodialysis step (PU1) is carried out after the reaction step(s) (PR1).

[0275] According to another embodiment, the electrodialysis step (PU1) is carried out at least once after the reaction step(s) (PRii).

[0276] According to a particular embodiment, the electrodialysis step (PU1) is carried out at least once after the step(s) (PR1) and the method of the invention does not include a step (PRii).

[0277] According to another embodiment, the method of the invention comprises at least one step (PR1), preferably one step (PR1), and at least one step (PRii), preferably one step (PRii), and the electrodialysis step (PU1) is carried out at least once after at least one step (PR1) without being carried out after the step(s) (PRii).

[0278] According to yet another embodiment, the method of the invention comprises at least one step (PR1), preferably one step (PR1), and at least one step (PR ii), preferably one step (PRii), and the electrodialysis step (PU1) is carried out at least once after at least one step (PRii) without being carried out at the end of the step(s) (PR1).

[0279] According to another embodiment, the method of the invention comprises at least one step (PR1), preferably one step (PR1), and at least one step (PRii), preferably one step (PRii), and the electrodialysis step (PU1) is carried out at least once after at least one step (PR1) and at least once after at least one step (PRii).

[0280] According to a preferred embodiment, the method of the invention comprises a step (PR1), and a step (PRii), and the electrodialysis step (PU1) is carried out at least once after step (PR1) without being carried out at the end of step(s) (PRii). Reaction step (PRii)

[0281] The preparation process (PR) may optionally further comprise at least one reaction step (PRii) of at least said cosmetic ingredient.

[0282] The preparation process (PR) may optionally further comprise at least one reaction step (PRii) of at least said compound of formula (I) in which X corresponds to a radical -C(O)- (i.e. a compound of formula (IA)) to form at least one compound of formula (I) in which X corresponds to a radical -CH(OR)- (i.e. a compound of formula (IB)).

[0283] According to an advantageous embodiment, the process (PR) according to the invention further comprises at least one reaction step (PRii) of at least said compound of formula (IA) to form at least one compound of formula (IB). Reduction step (PRii)

[0284] The reaction step (PRii) is preferably a reduction step (PR2) taking place in an aqueous medium according to the following synthesis route (B): Reduction its 1 ' (j _ s &r O OH (lAj (rB) synthesis route (B) in which: • SA' and RI have the same meanings as in formula (I).

[0285] For the purposes of the present invention, a compound of formula (IB) is a compound of formula (IB) in which R represents a hydrogen atom.

[0286] In other words, a compound of formula (I) is a compound of formula (I) in which X corresponds to a radical -CH(OR) with R representing a hydrogen atom.

[0287] Preferably, the preparation process according to the invention comprises: - at least one reaction step (PR1), as described previously, - optionally at least one neutralization step (PRO), as defined previously, of the reaction medium resulting from the reaction step (PR1), - at least one reduction step (PR2), taking place in an aqueous medium according to the synthesis route (B) as defined previously, - at least one purification step (PU), as described previously, carried out before and / or after the reduction step (PR2), preferably before the reduction step (PR2).

[0288] The step of reducing the carbonyl group to produce an alcohol group is carried out by a conventional reduction method known to those skilled in the art. For example, the work (Adv. Or g. Chem. J. Mardi, 4th ed. John Wiley & son, p. 910-919, (1992) can be cited.

[0289] The reduction step (PR2) may be a reduction carried out in the presence of one or more hydrides, in particular borohydrides such as NaBH4, NaBH3CN, an enzymatic reduction or a reduction by catalytic hydrogenation.

[0290] Preferably, the at least one reduction step (PR2) is a reduction by catalytic hydrogenation.

[0291] In other words, the at least one reduction step (PR2) is advantageously a hydrogenation carried out in the presence of at least one catalyst and optionally an acidifying agent. The hydrogenation can for example be carried out under conditions described in the literature Heterocycles M. Hashimoto, M. Takahashi 77 (1), 227-231 (2009).

[0292] The catalyst is preferably a metal catalyst, such as ruthenium (Ru), rhodium (Rh), platinum (Pt), iridium (Ir), nickel (Ni) or palladium (Pd), preferably ruthenium (Ru) more preferably a metal catalyst, chosen from ruthenium (Ru), rhodium (Rh), Platinum (Pt), Iridium (Ir), better ruthenium (Ru).

[0293] Preferably, the catalyst is supported, preferably is supported ruthenium, such as on carbon (or graphite), on alumina, on AISi, on zeolite, or on barium sulfate (BaSO4). According to one embodiment, the hydrogenation is catalyzed by Rh on carbon (Rh / C) or Ru on carbon (Ru / C).

[0294] Preferably, the catalyst is selected from the group consisting of ruthenium on carbon (Ru / C), ruthenium on alumina (Ru / Al), ruthenium on AISi, ruthenium on zeolite or ruthenium on barium sulfate (BaSO4).

[0295] Preferably, the catalyst is ruthenium (Ru), for example on carbon (Ru / C).

[0296] Preferably, at least one reduction step (PR2) is carried out under a hydrogen pressure ranging from 2 to 100 bars, preferably ranging from 3 to 50 bars, more preferably ranging from 4 to 25 bars, even more preferably ranging from 5 to 15 bars, better still ranging from 6 to 12 bars such as 10 bars.

[0297] Preferably, the at least one reduction step (PR2) is carried out at a temperature ranging from 20 to 150°C, preferably at a temperature ranging from 30 to 100°C, more preferably at a temperature ranging from 40°C to 100°C.

[0298] Preferably, the at least one reduction step (PR2) takes place for a period ranging from 30 minutes to 30 hours, preferably from 45 minutes to 10 hours, in particular ranging from 1 hour to 7 hours. Preferably, the at least one reduction step (PR2) is a reduction by catalytic hydrogenation in the presence of at least one catalyst, in particular ruthenium, under a hydrogen pressure ranging from 2 to 100 bars and at a temperature ranging from 30 to 150°C.

[0299] Preferably, the at least one reduction step (PR2) is a reduction by catalytic hydrogenation in the presence of at least one catalyst, in particular ruthenium, under a hydrogen pressure ranging from 4 to 50 bars and at a temperature ranging from 40 to 100°C.

[0300] Preferably, the at least one reduction step (PR2) is a reduction by catalytic hydrogenation in the presence of at least one catalyst, in particular ruthenium, under a hydrogen pressure ranging from 5 to 25 bars and at a temperature ranging from 40°C to 100°C.

[0301] Advantageously, the at least one reduction step (PR2) is carried out, in an aqueous medium: - in the presence of: • at least one compound of formula (I), in which X corresponds to a divalent radical -C(O)-, • at least one catalyst, more preferably chosen from the group consisting of palladium or ruthenium, in particular ruthenium on carbon, - under a hydrogen pressure varying from 2 to 50 bars, more preferably from 4 to 12 bars, - at a temperature ranging from 40 to 100°C.

[0302] At the end of at least the reduction step (PR2), the reaction medium can be cooled to a temperature varying from 15°C to 25°C and then purged under an inert atmosphere such as nitrogen.

[0303] The reaction medium from step (PR2) is then preferably filtered.

[0304] Preferably, the preparation process according to the invention comprises succes sively: • at least one reduction step (PR2) as defined previously, • preferably, the reaction medium before, during or at the end of the reduction step (PR2) undergoes at least one treatment with carbon black, more preferably before or after the reduction step (PR2), • optionally, at least one step of adding at least one acidifying or alkalizing agent to the reaction medium resulting from the reduction step (PR2), • optionally, at least one concentration step (PR2) of the compound of formula (IB) in the reaction medium resulting from the reduction step (PR2), • preferably at least one concentration step (PC) is carried out, in particular by distillation, preferably under reduced pressure, • optionally, at least one purification step such as filtration • optionally, at least one step of adding at least one bac agent tericidal or bacteriostatic, preferably bacteriostatic, preferably derived from glycol such as propylene glycol, pentylene glycol, caprylyl glycol, more preferably propylene glycol; • preferably, the bacteriostatic agent, in particular propylene glycol, is present in a content ranging from 2 to 50% by weight, preferably from 5 to 40% by weight, relative to the total weight of the mixture comprising at least the compound of formula (IB), and the bacteriostatic agent, • possibly, at least one purification step such as distillation.

[0305] For the purposes of the present invention, the term “bio-sourced” means that the propylene glycol is derived from compounds of plant origin. Reaction step (PR3)

[0306] The reaction step (PRii) can also be an addition or O-alkoxylation step (PR3) taking place in an aqueous or non-aqueous medium according to the following synthesis route (Bl): synthesis route (Bl) in which:

[0307] R corresponds to a C1-C10 alkyl group, preferably C1-C4, such as methyl, or a (C1-C4)alkylcarbonyl group such as acetyl.

[0308] Advantageously, the method (PR) according to the invention comprises: - at least one reaction step (PR1) as defined previously, - at least one reaction step (PRii) corresponding to a reduction step (PR2), as defined previously, - at least one reaction step (PRiii) corresponding to an addition step (PR3) as defined previously, - at least one purification (PU), as defined previously, carried out between the reaction step (PR1) and the reduction step (PR2), and / or at least after the reduction step (PR2), preferably between the reduction step (PR2) and the addition step (PR3), and / or after the addition step (PR3).

[0309] According to another variant of the invention, the compounds (I”B) are obtained by addition of at least one molar equivalent of a nucleophilic compound RG to (IA), with R as defined previously and G represents an electron-deficient atom or group such as an alkali metal such as sodium, potassium, or lithium, or a magnesium halide such as MgCl in particular this reaction is carried out under an inert atmosphere and in a preferably polar aprotic organic solvent, particularly an ethereal solvent such as diethyl ether, THF, followed by a hydrolysis reaction.

[0310] Step of optional separation of an excess of compound of formula (III)

[0311] Preferably, the process (PR) may comprise at least one step of separating the excess compound of formula (III) from the reaction medium resulting from step (PR1), in particular carried out by distillation, for example by vacuum distillation.

[0312] The step of separating the excess of the compound of formula (III) can be carried out simultaneously or sequentially, preferably sequentially, preferably after the neutralization step (PR0).

[0313] According to an advantageous embodiment, the method (PR) comprises at least: - at least one reaction step (PR1) as defined previously, - at least one neutralization step (PRO) of the reaction medium resulting from step (PR1), - at least one step of separation of the excess of the compound of formula (III) carried out simultaneously or sequentially with the neutralization step (PRO), preferably after the neutralization step (PRO), - at least one reduction step (PR2) as defined previously, - at least one purification step (PU), as defined previously, of preferably implemented before and / or after the reduction step (PR2), preferably before or after the reduction step (PR2), more preferably before the reduction step (PR2). Packaging of the compound of formula (I)

[0314] At the end of the process according to the invention, the compound of formula (I), in which X corresponds to a divalent radical -C(O)- or -CH(OR)-, can be packaged in the form of a dry extract (without solvent).

[0315] Preferably, at the end of the process according to the invention, the compound of formula (I), in which X corresponds to a divalent radical -C(O)- or -CH(OR)-, is in solution in a liquid which comprises a content of at least 25% by weight of active material (cosmetic ingredient(s) preferably composed of formula (I)) preferably in a content ranging from 25% to 90% by weight, relative to the total weight of the solution.

[0316] Preferably, at the end of the process according to the invention, the compound of formula (I), in which X corresponds to a divalent radical -C(O)- or -CH(OR)-, is in solution in a liquid which comprises a content of at least 20% by weight of active material, more preferably in a content ranging from 20% to 90% by weight relative to the total weight of the solution.

[0317] Preferably, at the end of the process according to the invention, the compound of formula (I), in which X corresponds to a divalent radical -C(O)- or -CH(OR)-, is in solution in a liquid which comprises a content of at least 20% by weight of active material, more preferably in a content ranging from 20% to 90% by weight relative to the total weight of the solution.

[0318] According to one embodiment, the compound of formula (I) in which X corresponds to a divalent radical -C(O)- or -CH(OR)- is packaged in a liquid and the pH is adjusted to a target value, preferably between 3.5 and 7, by adding at least one alkalizing agent or at least one acidifying agent.

[0319] Process for the preparation of at least one compound of formula (D

[0320] Preferably, the process according to the invention is a process for the preparation (PR') of one or more compounds of formula (I') as defined above.

[0321] The process according to the invention is preferably a process for the preparation (PR') of at least one compound corresponding to the following formula (!'):

[0322]

[0323]

[0324]

[0325] (D Formula (!) in which: - n is equal to 0 or 1, preferably is equal to 1, - p is an integer ranging from 1 to 4, preferably the index p is equal to 3, - RI has the same meaning as in formula (I), preferably re has a linear alkyl chain, preferably acyclic, in CrCio, preferably in Ci-C6, more preferably in Ci-C4, in particular in Ci; - X represents a divalent radical -C(O)- or CH(OR)-, - R represents a hydrogen atom, a C1-C10 alkyl group, preferably C1-C4, such as methyl, or an alkyl(CrC4)carbonyl group such as acetyl; preferably R represents a hydrogen atom, as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates; said method comprising: - at least one reaction step (PR1) taking place according to the following synthesis scheme (A'): we yes w (tvi} synthesis route (A') in which: n is equal to 0 or 1, preferably is equal to 1, p is an integer ranging from 1 to 4, preferably the index p is equal to 3, Ri and R2 are the same or different, preferably the same; with R2 having the same meaning as Ri in the formula (!'), D+ is an organic or inorganic cation, preferably inorganic, more preferably chosen from the group consisting of alkali metal cations, alkaline earth metal cations and ammonium (NH4+); better still from the group consisting of alkali metal cations, alkaline earth metal cations and ammonium (NH4+); better still from the group consisting of alkali metal cations, alkaline earth metal cations and ammonium (NH4+). alkaline earth metals;

[0326] said reaction step (PR1) being carried out in an aqueous medium in the presence of: of at least one compound of formula (II'), of at least one compound of formula (III), preferably present in an equimolar amount or in excess relative to the compound of formula (II'), preferably, the compound of formula (III) is present in an amount greater than 1, preferably in an amount ranging from 1 to 5, more preferably ranging from 1 to 4, molar equivalents relative to the compound of formula (II'), of at least one alkaline agent in an equimolar amount or in excess relative to the compound of formula (II'), preferably in excess preferably, the alkaline agent is present in an amount ranging from 1 to 5 molar equivalents, more preferably in an amount ranging from 1 to 4 molar equivalents, relative to the compound of formula (II'), the alkaline agent preferably being mineral, more preferably chosen from the group consisting of alkali or alkaline earth metal hydroxides, alkali or alkaline earth metal (bi)carbonates, and mixtures thereof; in particular alkali or alkaline earth metal hydroxides, such as sodium hydroxide,

[0327] to lead to the formation of at least one compound of formula (Ai), and at least one compound of formula (IV1); preferably at least one neutralization step (PRO) comprising an acidification such as the addition of at least one acidifying agent, mineral or organic, preferably organic, in the aqueous reaction medium resulting from said step (PR1),

[0328] - optionally, at least one reaction step (PRii) of at least said compound of formula (l'Ai) to lead to at least one compound corresponding to the formula (l'B 1): (I'B1)

[0329] Formula (I'Bl) in which the indices n, p and RI have the same meanings as in formula (I); preferably, the reaction step (PRii) is a reduction step (PR2), as defined previously, • at least one purification (PU) comprising at least one electrodialysis step (PU1), as defined previously, of at least one aqueous reaction medium comprising at least one compound of formula (IA) or (IB 1) and at least one compound of formula (IV1).

[0330] The reaction step (PR1), the reduction step (PR2) and the purification (PU), in particular the electrodialysis step (PU1), are as defined previously.

[0331] Preferably, the purification (PU) is carried out after the reaction step (PR1), more preferably at least between the reaction step (PR1) and at least one reaction step (PRii), and / or at least after at least one reaction step (PRii), for example after the reduction step (PR2).

[0332] Preferably, the reaction step (PRii) is a reduction step (PR2) taking place in an aqueous medium according to the following synthesis route (Bl): XX ^R': Xx f Y "If Rêducêsn f YY I / f LH | | Au (tai) œBi) synthesis route (Bl) in which: - Ri has the same meaning as in formula (I).

[0333] Preferably, the reduction step (PR2) is a reduction by catalytic hydrogenation, as defined previously.

[0334] For the purposes of the present invention, a compound of formula (Ai) is a compound of formula (I') in which X corresponds to a divalent radical -C(O)-.

[0335] For the purposes of the present invention, a compound of formula (I'Bl) is a compound of formula (I') in which X corresponds to a divalent radical -CH(OH)-.

[0336] Preferably, in the reaction step (PR1), the molar ratio compound(s) of formula (III) / compound(s) of formula (II') is greater than or equal to 1, preferably between 1 and 5, more preferably between 1 and 4, even more particularly between 1 and 3, better still between 1 and 2, in particular ranging from 1 to 1.5; according to a particular embodiment, the molar ratio compound(s) of formula (III) / compound(s) of formula (II”) is greater than 1.

[0337] Preferably, the molar ratio of alkaline agent(s) / compound(s) of formula (II') is greater than or equal to 1, preferably between 1 and 5, more preferably between 1 and 4, even more particularly between 1 and 3, better still between 1 and 2; according to a particular embodiment, the molar ratio of alkaline agent / compound of formula (II') is greater than 1.

[0338] Process for the preparation of at least one compound of formula U'”)

[0339] Preferably, the process according to the invention is a process for the preparation (PR”) of one or more compounds corresponding to the following formula (!'”): (I'”)

[0340] Formula (I”') in which X represents a divalent radical -C(O)- or -(CH)OR- with R representing a hydrogen atom,

[0341] as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates;

[0342] said method comprising:

[0343] - at least one reaction step (PR1) taking place according to the synthesis scheme (A”) following:

[0344] synthesis route (A”) in which: • D+ is a cation chosen from the group consisting of alkali metal cations, alkaline earth metal cations and ammonium (NH4+);

[0345] said reaction step (PR1) being carried out in an aqueous medium, in the presence of: • at least one compound of formula (III'), preferably present in an equimolar or excess quantity, preferably in excess relative to the compound of formula (II”), • preferably, the compound of formula (III') is present in an amount greater than 1, preferably in an amount ranging from 1 to 5, more preferably ranging from 1 to 4, molar equivalents relative to the compound of formula (II”), • at least one alkaline agent in an equimolar or excess quantity, preferably in excess relative to the compound of formula (II”), • preferably, the alkaline agent is present in an amount ranging from 1 to 5 molar equivalents, more preferably in an amount ranging from 1 to 4 molar equivalents, relative to the compound of formula (II”), • the alkaline agent being preferably mineral, more preferably chosen from the group consisting of alkali or alkaline earth metal hydroxides, in particular chosen from alkali metal hydroxides such as sodium hydroxide,

[0346] to lead to the formation of at least one compound of formula (I”'A) and at least one compound of formula (IV2); - preferably at least one neutralization step (PRO) comprising at least one acidification such as the addition of at least one acidifying agent, mineral or organic, preferably organic, in the aqueous reaction medium resulting from said step (PR1),

[0347] - optionally, at least one reaction step (PRii) of at least said compound of formula (I'”A), to lead to at least one compound corresponding to the following formula (I”'B): OJ X 7 HO- y 'OH OH • preferably, the reaction step (PRii) is a reduction step (PR2), as defined previously, • at least one purification (PU) comprising at least one electrodialysis step (PU1), as defined previously, of at least one aqueous reaction medium comprising at least one compound of formula (I”A) or (I”B 1) and at least one compound of formula (IV2).

[0348] The reaction step (PR1) and the purification step (PU) are as defined previously.

[0349] Preferably, the purification (PU) is carried out at least between the reaction step (PR1) and at least one reaction step (PRii), and / or at least after at least one reaction step (PRii), for example after the reduction step (PR2).

[0350] Preferably the purification step PU1 is carried out after the reaction step (PR1) and before the reaction step (PRii).

[0351] For the purposes of the present invention, a compound of formula (I' ' ' A) is a compound of formula (!'”) in which X corresponds to a divalent radical -C(O)-.

[0352] For the purposes of the present invention, a compound of formula (I' ' 'B) is a compound of formula (!'”) in which X corresponds to a radical -CH(OH).

[0353] Preferably, the molar ratio compound(s) of formula (III) / compound(s) of formula (II”) is greater than or equal to 1, preferably between 1 and 5, more preferably particularly between 1 and 4, even more particularly between 1 and 3, better still between 1 and 2, in particular ranging from 1 to 1.5; according to a particular embodiment, the molar ratio compound(s) of formula (III) / compound(s) of formula (II”) is greater than 1.

[0354] Preferably, the molar ratio of alkaline agent(s) / compound(s) of formula (II') is greater than or equal to 1, preferably between 1 and 5, more preferably between 1 and 4, even more particularly between 1 and 3, better still between 1 and 2; according to a particular embodiment, the molar ratio of alkaline agent / compound of formula (II') is greater than 1.

[0355] Preferably, the reaction step (PRii) is a reduction step (PR2) taking place in an aqueous medium according to the following synthesis route (B”): - . ,-¾ . J f' Y 'Y' H Oh 4 H Preferably, the reduction step (PR2) is a reduction by catalytic hydrogenation, as defined previously.

[0356] Preferably, the purification (PU) is carried out at least between the reaction step (PR1) and the reduction step (PR2).

[0357] The process for preparing at least one compound of formula (I') or (I”) may further comprise the additional steps described for the process for preparing at least one compound of formula (I).

[0358] The invention is illustrated in more detail in the following non-limiting examples. EXAMPLE

[0359] Example 1 - Preparation of CBD-xvlopyranoside-2-hvdroxv-propan-2-one (35% by weight)

[0360] Step 1: Preparation of a compound of formula (!'”) oh om W in -w

[0361] Step 1: Lubineau reaction and purification by electrodialysis

[0362] Water (1.04 kg) is loaded into a reactor at 20°C. It is heated to 50°C and then xylose (700 g) is charged and stirred until the medium is homogeneous. Cool to 15 °C and acetylacetone (555 g) is charged. 50% sodium hydroxide solution (540 g) is charged at a temperature below 45 °C. Then heat to 30 °C to 50 °C for 30 min to 4 hours. Cool to 20 °C and then acidify to a pH below 6. The medium is concentrated to 30% to 60%.

[0363] A passage is then carried out on electrodialysis at a pH between 4.0 and 8.0 between 25°C and 45°C until an acetic acid content of less than 10,000 ppm or even less than or equal to 6000 ppm is obtained.

[0364] The solution is then brought into contact with carbon black and then optionally concentrated to a dry extract of 30% to 60% and then the pH is adjusted to 6.0-7.0. The product is isolated with a yield of 90-95%. Step 2: Hydrogenation

[0366] The compound of formula (!') (2.08 kg) in aqueous solution with the appropriate acetic acid content is introduced into a hydrogenator with ruthenium on carbon (catalytic quantity). The mixture is purged at least once with nitrogen and then with hydrogen. The mixture can be heated to a temperature above 25 °C and then pressurized hydrogen is introduced up to a pressure of about 10 bar.

[0367] The mixture is heated to a temperature less than or equal to 100°C for a period of time ranging from 2 to 7 hours under a pressure ranging from 8 to 12 bars. The hydrogenation reaction is carried out until the end of hydrogen consumption.

[0368] The reaction medium can be allowed to return to room temperature (20°C) and then is optionally purged with an inert gas (nitrogen). The catalyst is then filtered and the filtrate is then optionally brought into contact with carbon black. The solution is concentrated until a dry extract of 40 to 80% is obtained.

[0369] The pH of the filtrate is adjusted to an acidic pH (e.g. between 4 and 6). A glycol derivative as a solvent such as propylene glycol may be added to the previous solution to obtain a content of compound of formula (I) of 20 to 90%.

[0370] The product is isolated in solution with a good yield (between 90-95%) and an acetic acid content of the solution of less than 20,000 ppm.

Claims

Claims

1. Process for purifying (PU) at least one aqueous medium comprising: - at least one cosmetic ingredient, and - at least one salt; said process comprising at least one step of electrodialysis (PU1) of said aqueous medium.

2. Purification process (PU) according to the preceding claim in which the cosmetic active ingredient(s) is (are) chosen from the compounds of the following formula (I): XX"" SA' (I) Formula (I) in which: - SA' represents a represents a monosaccharide group or a polysaccharide group comprising up to 20 sugar units, in particular up to 6 sugar units, in pyranose and / or furanose form and of L and / or D series, said monosaccharide group or polysaccharide group having at least one free substituted hydroxy group, and optionally at least one optionally protected amine group, - the bond between SA' and CH2-X is a bond of C- anomeric nature, - X represents a divalent radical -C(O)- or -CH(OR)-, preferably -C(O)- or -CH(OH)-;- R represents a hydrogen atom, a C1-C10 alkyl group, preferably C1-C4, such as methyl, or a C1-C4 alkylcarbonyl group such as acetyl, preferably a hydrogen atom, - R1 represents a saturated or unsaturated, linear or branched, cyclic or acyclic, preferably acyclic, C1-C10, preferably C1-C4, more preferably saturated hydrocarbon chain; particularly R1 represents a linear or branched, saturated or unsaturated, cyclic or acyclic, C1-C10, more particularly C1-C6, even more preferably C1-C4, such as C1;

3.

4.

5.

6. as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates. Method according to the preceding claim, characterized in that SA' represents a monosaccharide group chosen from the group consisting of glucose, in particular D-glucose, xylose, in particular D-xylose, fucose, in particular L-fucose, arabinose, in particular L-arabinose, rhamnose, in particular L-rhamnose, glucuronic acid, in particular D-glucuronic acid, galacturonic acid, in particular D-galacturonic acid, iduronic acid, in particular D-iduronic acid, N-acetyl glucosamine, in particular N-acetyl-D-glucosamine, N-acetyl-galactosamine, in particular N-acetyl-D-galactosamine, and preferably SA is chosen from D-glucose, D-xylose, L-fucose, L-arabinose, L-rhamnose, D-glucuronic acid, D-galacturonic acid, acid D-iduronic. Process according to claim 2 or 3, characterized in that Ri represents a linear, saturated or unsaturated, acyclic hydrocarbon chain, in C1-C6, more preferably in C1-C4, in particular in G. Process according to any one of claims 2 to 4, characterized in that X represents a divalent radical -C(O)- or -CH(OH)-. Process according to any one of claims 2 to 5, characterized in that the cosmetic agent(s) represent a compound of formula (I”): * OH (I”) Formula (I”) in which RI and X are as defined in any one of claims 2, 4 or 5, as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates; preferably of formula (!”'):

7.

8.

9. (I'”) Formula (I'”) in which: X corresponds to a divalent radical -C(O)- or -(CH)OH-, preferably -C(O)- as well as one of its optical isomers, geometric isomers, and / or one of its solvates such as hydrates. Method according to any one of the preceding claims, characterized in that the cosmetic ingredient(s) is / are present in a content of at least 25% by weight of active material in cosmetic ingredient(s), preferably in a content ranging from 25% to 80% by weight, more preferably ranging from 25 to 75% by weight, more preferably ranging from 30% to 70% relative to the total weight of the aqueous medium. Process according to any one of the preceding claims, characterized in that said salt corresponds to the following formula (IV): Dy+Aw- (IV) Formula (II) in which: y is an integer ranging from 1 to 3, preferably 1; w is an integer ranging from 1 to 3, preferably 1; A is an organic or inorganic anion, preferably organic, more preferably chosen from the group consisting of CrCi8 carboxylic acids, even more preferably Ci-Cio, better still CrC6; D is an organic or inorganic cation, preferably inorganic, more preferably chosen from the group consisting of alkali metal cations, alkaline earth metal cations and ammonium (NH4+). Process according to the preceding claim, characterized in that said salt corresponds to the following formula (IV1): R< 'O 0' (IVl) Formula (II') in which: D is an organic or inorganic cationic, preferably inorganic, R2 represents a hydrocarbon chain, saturated or unsaturated, linear or branched, cyclic or acyclic, preferably acyclic, in C1-C10, preferably in C1-C6, more preferably in C1-C4, in particular in C1.

10. Process according to any one of the preceding claims, characterized in that the salt is present in a content ranging from 0.05% to 50% by weight, in particular in a content ranging from 0.1% to 40% by weight, more particularly in a content ranging from 0.5% to 30% by weight, relative to the total weight of the aqueous medium, relative to the total weight of the aqueous medium.

11. Method according to any one of the preceding claims, characterized in that the electrodialysis step (PU1) is carried out at a pH between 4 and 9, more preferably between 4.5 and 8.

5.

12. Method according to any one of the preceding claims, characterized in that the electrodialysis step (PU1) is carried out at a temperature ranging from 20°C to 50°C, preferably at a temperature ranging from 25°C to 45°C.

13. Method according to any one of the preceding claims, characterized in that the electrodialysis step (PU1) is carried out with conventional electrolysis, preferably at a product conductivity, before treatment, ranging from 50 to 0.05 mS / cm, preferably ranging from 40 to 0.2 mS / cm, measured in particular at a temperature ranging from 20°C to 50°C.

14. Method according to any one of the preceding claims, characterized in that the electrodialysis step (PU1) is carried out with a bipolar membrane electrolysis at a product conductivity (before treatment) ranging from 60 to 0.5 mS / cm, preferably ranging from 55 to 1 mS / cm, more preferably ranging from 50 to 10 mS / cm, even more preferably ranging from 45 to 20 mS / cm, measured in particular at a temperature ranging from 20°C to 50°C.

15. Method according to any one of the preceding claims, characterized in that, at the end of the electrodialysis step (PU1), the salt content is less than or equal to 10% by weight, preferably less than or equal to 5% by weight, more preferably varies from 1 to 5% by weight, better still varies from 1 to 2% by weight, relative to the total weight of the dry extract containing the cosmetic ingredient.

16. Process for the preparation (PR) of at least one compound of formula (I), as defined according to any one of claims 2 to 6, characterized in that it comprises: - at least one reaction step (PR1) taking place according to the following synthesis scheme (A): Cl GA x , s g R; (ïï> 0À}. (Klj synthesis route (A) in which: • Ri and R2 are the same or different; with R2 having the same meaning as Ri in formula (I), • SA has the same meaning as in formula (I), • D+ is an organic or inorganic cation, preferably inorganic, said reaction step (PR1) being carried out in aqueous media in the presence of: • at least one compound of formula (II), • at least one compound of formula (III), and • at least one alkaline agent in an equimolar or excess quantity relative to the compound of formula (II), to lead to the formation of at least one compound of formula (IA) and at least one compound of formula (IV1) in an aqueous medium, - optionally at least one neutralization step (PRO) comprising the addition of at least one acidifying agent, mineral or organic, preferably organic, in the aqueous reaction medium resulting from said step (PR1), optionally, at least one reaction step (PRii) of at least said compound of formula (IA) to lead to the formation of at least one compound corresponding to the following formula (IB): there it is GOLD (IB) Formula (IB) in which: - SA, Ri and R have the same meanings as in formula (i); - at least one purification (PU) comprising at least one electrodialysis step (PU1), as defined according to any one of claims 1 or 11 to 14, of at least one aqueous reaction medium comprising at least one compound of formula (IA) or (IB) and at least one compound of formula (IV1).

17.

18. Method according to the preceding claim, characterized in that the purification (PU) is carried out after at least the neutralization step (PRO). Process according to claim 16 or 17, characterized in that the reaction step (PRii) is a reduction step (PR2) taking place in an aqueous medium according to the following synthesis route (B): SA' y--y O GM (W (IW synthesis route (B) in which: - SA' and RI have the same meanings as in formula (I).

19. Process according to claim 16 or 18, characterized in that the reduction step (PR2) is a reduction by catalytic hydrogenation preferably with a metal catalyst, such as ruthenium (Ru), rhodium (Rh), Platinum (Pt), Iridium (Ir), Nickel (Ni) or palladium (Pd), preferably ruthenium (Ru) more preferably a metal catalyst, chosen from ruthenium (Ru), rhodium (Rh), Platinum (Pt), Iridium (Ir), better still ruthenium (Ru)

20. Method according to any one of claims 16 to 19, characterized in that the purification (PU) is carried out after the reaction step (PR1), or between the reaction step (PR1) and the reaction step (PRii), or after the reaction step (PRii), preferably between the reaction step (PR1) and the reaction step (PRii).

21. Process according to any one of claims 16 to 20, characterized in that the alkaline agent(s) of step (PRO) is or are mineral alkaline agents chosen from the group consisting of alkali or alkaline earth metal hydroxides, alkali or alkaline earth metal (bi)carbonates, and mixtures thereof, in particular alkali or alkaline earth metal hydroxides, in particular sodium hydroxide.