# Patent

## Title
Sulphurated derivatives of resorcinol, preparation of same and cosmetic uses thereof

## Abstract

The present invention relates to a compound of the general formula (I) where: X═S, SO or SO2; and one of the radicals R1 and R2 is a hydrogen atom and the other is a radical: a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atom(s); a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atom(s); an aralkyl, optionally substituted by one or more C1 to C6 alkoxy group(s); or a COR3 or CONHR3, but not simultaneously, where R3 is a radical: a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atom(s); a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atom(s); an aralkyl, optionally substituted by one or more C1 to C6 alkoxy group(s); an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy groups and/or one or more OH group(s); or an aryl radical, optionally substituted by one or more C1 to C6 alkoxy group(s).

## Background
The present invention relates to novel analogues of resorcinol sulphide, resorcinol sulphoxide and resorcinol sulphone corresponding to the generic formula (I):




in which:

    X═S, SO or SO2, and;
    one of the radicals R1 and R2 represents a hydrogen atom and the other a radical:
    
        a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atom(s),
        a C2 to C18 linear or branched alkenyl, in particular an allyl group, or a 3,3 dimethylallyl group, or a geranyl group or a farnesyl group, optionally substituted by one or more halogen atom(s),
        an aralkyl, in particular benzyl, optionally substituted by one or more C1 to C6 alkoxy group(s), or
        COR3 or CONHR3, but not simultaneously, where R3 represents a radical:
        
            a C1 to CH linear or branched alkyl, optionally substituted by one or more halogen atom(s),
            a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atom(s),
            an aralkyl, in particular benzyl, optionally substituted by one or more C1 to C6 alkoxy group(s),
            an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy group(s), and/or OH group(s), or instead
            an aryl radical, in particular phenyl, optionally substituted by one or more C1 to C6 alkoxy group(s).
        
        
    
    


The term “alkyl” represents linear or branched saturated aliphatic hydrocarbon chains and comprising the specified number of carbon atoms.
The term “alkenyl” represents linear or branched unsaturated aliphatic hydrocarbon chains and comprising the specified number of carbon atoms, for example an allyl group or a 3,3 dimethylallyl group or a geranyl group or a farnesyl group.
The term “alkoxy” represents a linear or branched hydrocarbon chain comprising the specified number of carbon atoms and an oxygen atom, for example a methoxy group, or an ethoxy group, or a propoxy group or a butoxy group.
The term “aryl” represents any monocyclic or bicyclic aromatic carbon ring, such as for example phenyl or naphthyl.
The term “aralkyl” designates an aryl bonded by an alkyl, for example a benzyl, ethylphenyl, propylphenyl.
The term “aralkenyl” designates an aryl bonded by an alkenyl, for example a phenyl acrylate or (4-methoxyphenyl)acrylate or (3, 4-dimethoxyphenyl)acrylate.
The term “halogen” represents fluorine, chlorine, bromine or iodine.
The term “oleoyl” represents the univalent radical derived from oleic acid by the loss of the OH group.
The term “linoleoyl” represents the univalent radical derived from linoleic acid by the loss of the OH group.
The term “alpha-linolenoyl” represents the univalent radical derived from alpha-linolenic acid by the loss of the OH group.
The term “gamma-linolenoyl” represents the univalent radical derived from gamma-linolenic acid by the loss of the OH group.
The term “coumaroyl” represents 4-hydroxycinnamoyl.
The term “caffeoyl” represents 3,4-dihydroxycinnamoyl.
The term “feruoyl” represents 4-hydroxy-3-methoxycinnamoyl.
The term “sinapoyl” represents 4-hydroxy-3,5-dimethoxycinnamoyl.
Among the compounds of generic formula (I) belonging to the present invention, a particularly appreciated class of compounds corresponds to compounds of generic formula (I) in which X═S. Similarly, the present invention particularly relates to compounds of generic formula (I) in which X═S and R2═H.
In a preferred manner, the compounds according to the invention correspond to compounds of formula (I) in which X═S, R2═H and R1 is selected from the group consisting in: a C1 to C18 linear or branched alkyl or a C2 to C18 linear or branched alkenyl or COR3 and CONHR3.
According to an embodiment of the present invention, the compounds of generic formula (I) are those for which R1 represents:

    
    
        a C1 to C8 linear or branched alkyl and in particular C4 to C8; or
        a C2 to C18 linear or branched alkenyl chosen from an allyl group or a 3,3 dimethylallyl group or a geranyl group or a farnesyl group; or
        a benzyl.
    
    


According to the invention, a particularly appreciated class of compounds of generic formula (I) corresponds to compounds for which R3 represents:

    
    
        a C7 to C15 linear or branched alkyl and in particular C11 to C15; or
        a C10 to C18 linear or branched alkenyl, or
        a benzyl; or
        an aralkenyl chosen from phenyl acrylate or (4-methoxyphenyl)acrylate or (3,4-dimethoxyphenyl)acrylate; or
        a phenyl.
    
    


According to a specific embodiment of the invention, the compounds of generic formula (I) are those in which COR3 represents:

    
    
        an oleoyl or a linoleoyl or an alpha-linolenoyl or a gamma-linolenoyl.
    
    


According to another specific embodiment of the invention, the compounds of formula (I) are those for which COR3 represents:

    
    
        a cinnamoyl substituted by one or more C1 to C6 alkoxy group(s) and/or OH group(s) chosen from coumaroyl or 4-methoxycinnamoyl or 3,4-dimethoxycinnamoyl or caffeoyl or feruoyl or sinapoyl.
    
    


According to an embodiment of the invention, the compounds of generic formula (I) may be chosen from the following compounds:

    4-(4-hydroxy-2-((2E,6E)-3,6,11-trimethyldodeca-2,6,10-5 trienyloxy)phenylthio)benzene-1,3-diol,
    4-(4-hydroxy-2-(3-methylbut-2-enyloxy)phenylthio)benzene-1,3-diol,
    (E)-4-(2-(3,7-dimethylocta-2,6-dienyloxy)-4-hydroxyphenylthio)benzene-1,3-diol,
    4-(2-butoxy-4-hydroxyphenylthio)benzene-1,3-diol,
    4-(4-butoxy-2-hydroxyphenylthio)benzene-1,3-diol,
    4-(4-hydroxy-2-(octyloxy)phenylthio)benzene-1,3-diol,
    4-(2-hydroxy-4-(octyloxy)phenylthio)benzene-1,3-diol,
    4-(2-(benzyloxy)-4-hydroxyphenylthio)benzene-1,3-diol,
    4-(4-(benzyloxy)-2-hydroxyphenylthio)benzene-1,3-diol,
    4-(4-hydroxy-2-(4-methoxybenzyloxy)phenylthio)benzene-1,3-diol,
    4-(2-(decyloxy)-4-hydroxyphenylthio)benzene-1,3-diol,
    4-(2-(hexadecyloxy)-4-hydroxyphenylthio)benzene-1,3-diol,
    2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyldodecanoate,
    2-(2,4-dihydroxyphenylthio)-5-hydroxyphenylpalmitate,
    2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyloctanoate,
    4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyloctanoate,
    2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl3-phenylpropanoate,
    4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyl3-phenylpropanoate,
    2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl3-methylbutanoate,
    4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyl3-methylbutanoate,
    (9Z, 12Z)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl octadeca-9,12-dienoate
    (E)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl3-(4-methoxyphenyl)acrylate,
    (E)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl3-(3,4-dimethoxyphenyl)acrylate,
    2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyloctylcarbamate,
    2-(2,4-dihydroxyphenylsulphinyl)-5-hydroxyphenyldodecanoate,
    (9Z, 12Z)-2-(2,4-dihydroxyphenylsulphinyl)-5-hydroxyphenyl octadeca-9,12-dienoate
    4-(2-(decyloxy)-4-hydroxyphenylsulphinyl)benzene-1,3-diol,
    4-(2-(decyloxy)-4-hydroxyphenylsulphonyl)benzene-1,3-diol,


The invention also relates to the cosmetic use of compounds of formula (I′), which include, in addition novel analogues of formula (I), resorcinol sulphide, resorcinol sulphoxide and resorcinol sulphone, and in particular their use for the depigmentation of the skin, for the implementation of a method of cosmetic treatment of skin ageing. Generic formula (I′):




in which the radicals X, R1 and R2 have significations identical to those given with regard to formula (I), but where R1 and R2 can also represent simultaneously a hydrogen atom.

The present invention relates to the cosmetic use of compounds of generic formula (I′) or formula (I) as antioxidant active ingredient or as depigmenting active ingredient.
The subject matter of the present invention is also the use of compounds of generic formula (I) as medicine and in particular as antibacterial active ingredient.
The invention also relates to pharmaceutical or cosmetic compositions comprising at least one of the compounds of formula (I) or formula (I′) in association with at least one pharmaceutically or cosmetically acceptable excipient.
In the present invention, “pharmaceutically or cosmetically acceptable” is taken to designate that which is useful in the preparation of a pharmaceutical or cosmetic composition, which is generally safe, non toxic and neither biologically or otherwise undesirable and which is acceptable for therapeutic or cosmetic use, particularly by topical application.
The subject matter of the invention relates to a cosmetic composition characterised in that the quantity of compound of formula (I) or formula (I′) varies between 0.01% and 10% and preferably from 0.1% to 5% by weight with respect to the total weight of the composition.
The present invention relates to a method of bleaching and/or lightening of the human skin and/or body hair and/or head hair comprising the application on the skin and/or body hair and/or head hair of a cosmetic composition containing at least one compound of formula (I) or formula (I′).
The present invention relates to a method of cosmetic treatment and/or prevention of the ageing of the skin comprising the application on the skin of a cosmetic composition containing at least one compound of formula (I) or formula (I′)
The subject matter of the invention also extends to the method of synthesising novel compounds of formula (I).
According to another characteristic of the present invention, it also relates to a method of preparing a compound of generic formula (I) characterised in that 4,4′-thiodibenzene-1,3-diol or 4,4′-sulphinylbis-1,3-benzenediol is made to react with a halide of formula II:

Hal-R1   (II)

in which:

Hal represents a halogen atom, and R1 has the same signification as that given previously regarding formula (I) with the exception of a hydrogen atom.

According to another characteristic of the present invention, it also relates to a method of preparing a derivative of resorcinol of formula (I) in which X represents SO or SO2, characterised in that a compound of formula (I), in which X represents a sulphur atom, is oxidised in particular by means of an aqueous solution of hydrogen peroxide.
The present invention will be better understood with respect to the examples given hereafter for purely illustrative purposes.


I. SYNTHESIS OF COMPOUNDS OF THE INVENTION
1) Synthesis of Analogues of Resorcinol Sulphide
Example 1 (Resorcinol Sulphide)
4,4′-thiodibenzene-1,3-diol




1H NMR (400 MHz, DMSO-d6): 6: 6.19 (dd, 2H); 6.34 (d, 2H); 6.87 (d, 2H); 9.41 (wide s, 2H); 9.50 (wide s, 2H).
13C NMR (100 MHz, DMSO d6): 8: 102.58; 107.52; 111.46; 133.90; 157.04; 158.37.
MS (ESI−): 249.1 [M−H]−
A) Synthesis of Ethers: Synthesis of Ethers by Coupling of Resorcinol Sulphide with an Alkyl Halide.
To a suspension of 4,4′-thiodibenzene-1,3-diol (resorcinol sulphide, 3 g, 12 mmol, 4 eq.) and potassium carbonate (497 mg, 3.6 mmol, 1.2 eq.) in 20 ml of anhydrous DMF (=dimethylformamide) and under nitrogen, are added 856 mg of farnesyl bromide (3 mmol, 1 eq.) then the mixture is stirred at 80° C. for 6 hours. The reaction is followed by TLC (=thin layer chromatography).
After returning to room temperature, the solvent is evaporated then the residue is extracted with an ethyl acetate/water mixture. The organic phase is washed twice with water then with a saturated NaCl solution. After drying over magnesium sulphate, a solid is obtained after evaporation of the solvent. The solid is washed with DCM (=dichloromethane) then collected to provided 2 g of starting resorcinol sulphide that has not reacted.
The filtrate (DCM) is then evaporated to lead to an oil purified on silica by a heptane/ethyl acetate mixture (95/5 to 50/50) or by preparative HPLC. The product obtained in the form of a colourless oil is dried under vacuum overnight. 730 mg are then obtained with a yield of 55%.
The structure is determined by proton NMR, carbon NMR, HMBC, HMQC and NOESY analyses.
Example 2
4-(4-hydroxy-2-((2E,6E)-3,6,11-trimethyldodcca-2,6,10-trienyloxy)phenylthio)benzene-1,3-diol




1H NMR (500 MHz, CDCl3): 8: 1.58 (s, 3H); 1.60 (s, 3H); 1.66 (s, 3H); 1.73 (s, 3H); 1.96 (m, 2H); 2.04 (m, 2H); 2.09 (m, 2H); 2.14 (m, 2H); 4.56 (d, j=6.4 Hz, 2H); 5.01 (s, 1H, OH para S); 5.06 (s, 1H, OH para S); 5.07 (m, 1H); 5.11 (m, 1H); 5.51 (t, 1H); 6.29 (d, j=8.5-2.4 Hz, 1H); 6.32 (d, j=8.2-2.7 Hz, 1H); 6.38 (d, j=2.4 Hz, 1H); 6.42 (d, j=2.7 Hz, 1H); 7.08 (d, j=8.5 Hz, 1H); 7.33 (s, 1H, OH ortho S); 7.38 (d, j=8.5 Hz, 1H).
13C NMR (125 MHz, CDCl3): 8: 16.04; 16.75; 17.69; 25.70; 26.20; 26.70; 39.54; 15 39.66; 65.99; 100.68; 102.31; 108.18; 108.33; 110.79; 115.32; 118.49; 123.62; 124.34; 131.38; 133.99; 135.50; 137.54; 142.24; 156.88; 158.09; 158.48; 158.73.
MS (APCI): 455.2 [M+H]+
Rf (1/1; Heptane/EtOAc): 0.75
Example 3
4-(4-hydroxy-2-(3-methylbut-2-enyloxy)phenylthio)benzene-1,3-diol
From 1-bromo-3-methylbut-2-ene (=alkyl halide)




1H NMR (400 MHz, CDCl3): 5: 1.76 (s, 3H); 1.82 (s, 3H); 4.56 (d, 2H); 5.07 (m, 2H, 2×OH para S); 5.53 (t, 1H); 6.30-6.45 (m, 4H); 7.09 (d, 1H); 7.32 (s, 1H); 7.40 (d, 1H).
MS (APCI+): 319.0 [M+H]+
Example 4
(E)-4-(2-(3,7-dimethylocta-2,6-dienyloxy)-4-hydroxy phenylthio)benzene-1,3-diol
From geranyl chloride




1H NMR (400 MHz, CDCl3): 6: 1.62 (s, 3H); 1.68 (s, 3H); 1.75 (s, 3H); 2.13 (m, 2H); 4.59 (d, 2H); 4.80 (s, 1H); 4.85 (s, 1H); 5.11 (s, 1H); 5.53 (t, 1H); 6.30-6.45 15 (m, 4H); 7.09 (d, 1H); 7.32 (s, 1H); 7.41 (d, 1H).
MS (APCI+): 386.9 [M+H]+
Example 5
4-(2-butoxy-4-hydroxyphenylthio)benzene-1,3-diol
From 1-bromo-butane. Majority product (590 mg)




1H NMR (400 MHz, CDCl3): 8: 1.01 (t, 3H); 1.53 (m, 2H); 1.88 (m, 2H); 4.02 (t, 2H); 4.78 (wide s, 2H, 2 OH para S); 6.32 (m, 2H); 6.36 (s, 1H); 6.45 (s, 1H); 7.08 (d, 1H); 7.29 (s, 1H, OH ortho S); 7.40 (d, 1H).
MS (APC1+): 307.0 [M+H]+
Example 6
4-(4-butoxy-2-hydroxyphenylthio)benzene-1,3-diol
From 1-bromo-butane. Minority product (18 mg)




1H NMR (400 MHz, CDCl3): 8: 1.02 (t, 3H); 1.44 (m, 2H); 1.72 (m, 2H); 3.90 (t, 2H); 6.34 (d, 1H); 6.41 (d, 1H); 6.43 (s, 1H); 6.49 (s, 1H); 7.25 (m, 3H).
MS (APCI+): 307.1 [M+H]+
Example 7
4-(4-hydroxy-2-(octyloxy)phenylthio)benzene-1,3-diol
From 1-bromo-oetane. Majority product (1.3 g)




1H NMR (400 MHz, CDCl3): 8: 0.91 (t, 3H); 1.30 (m, 8H); 1.47 (m, 2H); 1.88 (m, 2H); 3.99 (t, 2H); 4.90 (wide s, 2H); 6.30 (d, 1H); 6.35 (d, 1H); 6.36 (s, 1H); 6.45 (s, 1H); 7.07 (d, 1H); 7.32 (wide s, 1H); 7.41 (d, 1H).
MS (APCI+): 363.2 [M+H]+
Example 8
4-(2-hydroxy-4-(octyloxy)phenylthio)benzene-1,3-diol
From 1-bromo-octane. Minority product (100 mg)




1H NMR (400 MHz, CDCl3): 8: 0.87 (t, 3H); 1.27 (m, 8H); 1.41 (m, 2H); 1.72 (m, 2H); 3.90 (t, 2H); 6.34 (d, 1H); 6.41 (d, 1H); 6.44 (s, 1H); 6.48 (s, 1H); 7.25 (m, 3H)
MS (APCI+): 363.1 [M+H]+
Example 9
4-(2-(benzyloxy)-4-hydroxyphenylthio)benzene-1,3-diol
From benzyl bromide. Majority product (600 mg)




1H NMR (400 MHz, CDCl3): 8: 4.80 (m wide, 2H); 5.14 (s, 2H); 6.34 (m, 2H); 6.44 (s, 2H); 7.02 (d, 1H); 7.08 (s, 1H); 7.34-7.41 (m, 6H).
MS(APCI+): 341.1 [M+H]+
Example 10
4-(4-(benzyloxy)-2-hydroxyphenylthio)benzene-1,3-diol
From benzyl bromide. Minority product (28 mg)




1H NMR (400 MHz, CDCl3): 8: 5.00 (s, 2H); 6.34-6.57 (m, 4H); 7.28-7.39 (m, 7H).
MS (APCI+): 341.1 [M+H]+
Example 11
4-(4-hydroxy-2-(4-methoxybenzyloxy)phenylthio)benzene-1,3-diol
From 4-methoxybenzyl bromide. Majority product (600 mg)




1H NMR (400 MHz, CDCl3): 8: 3.82 (s, 3H); 5.04 (s, 2H); 5.24 (m wide, 2H); 6.34 (m, 2H); 6.44 (m, 2H); 6.92 (d, 2H); 7.03 (d, 1H); 7.14 (wide s, 1H); 7.37 (m, 3H).
MS (APCI+): 371.0 [M+H]+
Example 12
4-(2-(decyloxy)-4-hydroxyphenylthio)benzene-1,3-diol
Procedure of example 2 but with 2 equivalents of resorcinol sulphide, 1 equivalent of 1-iododecane, 16 hours at room temperature. The product is obtained in the form of a white solid after purification with a yield of 83%.




1H NMR (400 MHz, CDCl3): 8: 0.91 (t, 3H); 1.25 (m, 12H); 1.47 (m, 2H); 1.88 (m, 2H); 3.99 (t, 2H); 4.90 (wide s, 2H); 6.30 (d, 1H); 6.35 (d, 1H); 6.36 (s, 1H); 6.45 10 (s, 1H); 7.07 (d, 1H); 7.32 (wide s, 1H); 7.41 (d, 1H).
13C NMR (100 MHz, DMSO): 8:13.89; 22.04; 25.39; 28.56; 28.65; 28.70; 28.89; 28.94; 31.24; 67.76; 100.18; 102,66; 107.47; 107.62; 107.98; 113.65; 130.42; 135.21; 156.83; 157.34; 158.20; 158.81
MS (APCI+): 391.1 [M+H]+
Example 13
4-(2-(hexadecyloxy)-4-hydroxyphenylthio)benzene-1,3-diol
Same synthesis as SP02-131 from 1-iodo-hexadecane Product obtained in the form of a white solid with a yield of 84%.




1H NMR (400 MHz, CDCl3): 8: 0.88 (t, 3H); 1.2 (m, 24H); 1.47 (m, 2H); 1.84 (m, 2H); 3.92 (t, 2H); 5.31 (wide s, 2H); 6.27 (dd, 1H); 6.33 (s, 1H); 6.36 (d, 1H); 6.45 (s, 1H); 7.05 (d, 1H); 7.38 (wide s, 1H); 7.41 (d, 1H).
13C NMR (100 MHz, CDCl3): 6: 14.11; 22.68; 25.95; 28.89; 29.35; 29.56; 29.61; 29.66; 29.70; 31,91; 69.22; 100.39; 102,29; 108.19; 108.54; 110.89; 115.01; 133.93; 137.49; 156.88; 158.19; 158.40; 158.44.
MS (ESI−): 473.2 [M−H]
B) Synthesis of Esters
a) Route 1: Coupling from Resorcinol Sulphide
To a solution of 4,4′-thiodibenzene-1,3-diol (resorcinol sulphide, 1 g, 4 mmol, 4 eq.) and triethylamine (177 μl, 1.2 mmol, 1.2 eq.) in 20 ml of anhydrous THF (tetrahydrofuran) and under nitrogen, are added drop by drop 219 mg of lauroyl chloride (1 mmol, 1 eq.) then the mixture is stirred at room temperature for 1 hour. The reaction is followed by TLC.
After returning to room temperature, the solvent is evaporated then the residue extracted with an ethyl acetate/water mixture. The organic phase is washed twice with water then with a saturated NaCl solution. After drying over magnesium sulphate, a solid is obtained after evaporation of the solvent. The solid is washed with DCM then collected to provide 510 mg of starting resorcinol sulphide that has not reacted.
The filtrate (DCM) is then evaporated to lead to an oil purified on silica by a cyclohexane/ethyl acetate mixture (9/1) or by preparative HPLC (high performance liquid chromatography). The product obtained in the form of a colourless oil is dried under vacuum overnight. The product solidifies when cold. 260 mg are then obtained in the form of a white solid with a yield of 60%.
Example 14
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl dodecanoate




1H NMR (500 MHz, CDCl3): 6: 0.86 (t, J =7 Hz, 3H); 1.32 (m, 17H); 1.79 (q, J=7.6 Hz, 2H); 2.63 (t, J=7.5 Hz, 2H); 5.30 (s, 1H); 5.35 (s, 1H); 6.38 (dd, J=8.4 and 2.6 Hz, 1H); 6.45 (d, J=2.7 Hz, 1H); 6.48 (dd, J=8.5 and 2.7 Hz, 1H); 6.50 (d, J=2.4 Hz, 1H); 6.73 (d, J=8.5 Hz, 1H); 6.76 (s, 1H); 7.35 (d, j=8.5 Hz, 1H).
13(NMR (125 MHz, CDCl3): 8: 14.12; 22.67; 24.83; 29.13; 29.22; 29.32; 29.44; 29.59; 31.89; 34.24; 103.01; 107.84; 108.72; 110.12; 114.67; 120.06; 130.45; 137.96; 148.93; 155.48; 158.48; 159.03; 172.98.
MS (APCI): 433.1 [M+H]+
Rf (7/3; Heptane/EtOAc): 0.58
Example 15
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl octanoate
From octanoyl chloride




1H NMR (400 MHz, CDCl3): 8: 0.82 (t, 3H); 1.29 (m, 8H); 1.63 (m, 2H); 2.35 (t, 2H); 6.41 (d, 1H); 6.49 (s, 1H); 6.56 (s, 1H); 6.57 (d, 1H); 6.81 (d, 1H); 7.39 (d, 20 1H).
MS (APCI+): 377.1 [M+H]+
Example 16
4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyl octanoate
From octanoyl chloride




1H NMR (400 MHz, CDCl3): 5: 0.88 (t, 3H); 1.33 (m, 8H); 1.72 (m, 2H); 2.3 (t, 2H); 6.36 (d, 1H); 6.41 (s, 1H); 6.58 (d, 1H); 6.71 (s, 1H); 7.31 (m, 2H). 5
MS (APCI+): 377.1 [M+H]+
Example 17
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-phenylpropanoate
From hydro-cinnamoyl chloride




1H NMR (400 MHz, CDCl3): 6: 2.98 (t syst AB, 2H); 3.13 (t syst AB, 2H); 5.40 (wide s, 2H); 6.41 (d, 1H); 6.46 (s, 1H); 6.48 (s, 1H); 6.54 (d, 1H); 6.79 (d, 1H); 7.22-15 7.38 (m, 6H).
MS (APCI+): 383.1 [M+H]+
Example 18
4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyl 3-phenylpropanoate
From hydro-cinnamoyl chloride




1H NMR (400 MHz, CDCl3): 8: 2.86 (t syst AB, 2H); 3.04 (t syst AB, 2H); 6.36 (d, 1H); 6.42 (s, 1H); 6.50 (d, 1H); 6.61 (s, 1H); 7.22-7.38 (m, 7H).
MS (APCI+): 383.1 [M+H]+
Example 19
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-methylbutanoate
From isovaleroyl chloride




1H NMR (400 MHz, CDCl3): 8: 1.10 (d, 6H); 2.31 (m, 1H); 2.53 (d, 2H); 4.79 (wide s, 1H); 4.87 (wide s, 1H); 6.42 (d, 1H); 6.49 (s, 1H); 6.56 (s, 1H); 6.58 (d, 1H); 6.76 (s, 1H); 6.82 (d, 1H); 7.40 (d, 1H).
MS (APCI+): 335.0 [M+H]+
Example 20
4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyl 3-methylbutanoate
From isovaleroyl chloride




1H NMR (400 MHz, CDCl3): 5: 1.03 (d, 6H); 2.22 (m, 1H); 2.40 (d, 2H); 4.75 (wide s, 2H); 6.38 (d, 1H); 6.46 (s, 1H); 6.57 (d, 1H); 6.69 (s, 1H); 7.30 (m, 3H).
MS (APCI+): 335.1 [M+H]+
Example 21
(9Z, 12Z)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl octadeca-9,12-dienoate
From linoleoyl chloride




1H NMR (400 MHz, CDCl3): 8: 0.88 (t, 3H); 1.32 (m, 14H); 1.80 (m, 2H); 2.04 (m, 4H); 2.63 (t, 2H); 2.79 (t, 2H); 5.35 (m, 4H); 6.38 (d, 1H); 6.45 (s, 1H); 6.51 (m, 2H); 6.73 (d, 1H); 7.35 (d, 1H).
MS (ESI): 513.2 [M+H]+
Rf (1/1; Heptane/EtOAc): 0.75
b) Route 2: Coupling via Carbodiimide
To a solution of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (960 mg, 5 mmol) and 4-DMAP (4-dimethylaminopyridine) (0.5 mmol) in 20 ml of anhydrous DMF under N2 are added 620 mg of 4-methoxycinnamic acid (3.5 mmol) then the mixture is stirred for 15 minutes. 3.5 g of 4,4′-thiodibenzene-1,3-diol (resorcinol sulphide, 14 mmol, 4 eq.) are added then the mixture is stirred at room temperature for 4 days.
The solvent is evaporated then the residue purified over silica CHCl3/MeOH (95/5) to provide 320 mg of pure product in the form of a white solid after evaporation and drying in the vacuum oven. Yield: 22%
Example 22
(E)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-(4-metoxyphenyl)acrylate




1H NMR (400 MHz, CDCl3): 8: 3.86 (s, 3H); 5.00 (wide s, 1H); 5.07 (wide s, 1H); 6.40 (dd, 1H); 6.48 (d, 1H); 6.60 (m, 2H); 6.64 (d, 1H); 6.85 (d, 1H); 6.95 (d, 2H); 7.40 (d, 1H); 7.58 (d, 2H); 7.91 (d, 1H).
MS (APCI+): 411.0 [M+H]+
Rf (1/1; Heptane/EtOAc): 0.14
Example 23
(E)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-(3,4-dimethoxyphenyl)acrylate
From 3,4-dimethoxycinnamic acid




1H NMR (400 MHz, DMSO-d6): 8: 3.82 (s, 3H); 3.84 (s, 3H); 6.22 (d, 1H); 6.37 (d, 1H); 6.61 (s, 1H); 6.64 (d, 1H); 6.77 (d, 1H); 6.92 (m, 2H); 7.01 (d, 1H); 7.31 (d, 1H); 7.43 (s, 1H); 7.72 (d, 1H); 9.58 (m, 2H); 9.78 (m, 1H).
MS (EST+): 441.0 [M+H]+
Rf (95/5; DCM/MeOH): 0.66
C. Synthesis of Carbamates
To a solution of 4,4′-thiodibenzene-1,3-diol (resorcinol sulphide, 5 g, 20 mmol, 4 eq.) in 40 ml of anhydrous THF and under nitrogen, are added drop by drop 0.88 ml of octyl isocyanate (5 mmol, 1 eq.) then the mixture is stirred for 9 hours under reflux. The reaction is followed by TLC.
After returning to room temperature, the solvent is evaporated then the residue extracted with an ethyl acetate/water mixture. The organic phase is washed twice with water then with a saturated NaCl solution. After drying over magnesium sulphate, a solid is obtained after evaporation of the solvent. The solid is washed with DCM then collected to provide starting resorcinol sulphide that has not reacted.
The filtrate (DCM) is then evaporated to lead to an oil purified on silica by a cyclohexane/ethyl acetate mixture or by preparative HPLC. The product obtained in the form of a colourless oil is dried under vacuum overnight. 540 mg are then obtained in the form of a colourless oil with a yield of 27%.
Example 24
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl octylcarbamate




1H NMR (400 MHz, CDCl3): 5: 0.86 (t, 3H); 1.26 (m, 8H); 1.35 (m, 2H); 1.59 (m, 2H); 3.32 (m, 2H); 5.30 (t, 1H); 5.93 (wide s, 1H); 6.23 (wide s, 1H); 6.35 (m, 2H); 6.41 (s, 1H); 6.52 (s, 1H); 6.63 (d, 1H); 7.32 (wide s, 1H); 7.35 (d, 1H).
MS (ESI+): 406.1 [M+H]+
2) Synthesis of Analogues of Resorcinol Sulphoxide
Example 25(Resorcinol Sulphoxide)
4,4′sulphinyldibenzene-1,3-diol




1H NMR (400 MHz, DMSO-d6): 8: 6.32 (m, 4H); 7.10 (d, 2H); 9.82 (wide s, 2H); 10.13 (wide s, 2H).
MS (APCI): 267.0 [M+H]+
A) Synthesis of Esters
A suspension of 4,4′-sulphinylbis-1,3-benzenediol (resorcinol sulphoxide, 2.66 g, 10 mmol, 4 eq.) in 100 ml of anhydrous THF is solubilised hot and under nitrogen then are added after 5 minutes at room temperature, 420 μL of triethylamine (12 mmol, 1.2 eq.). A rapid precipitation is observed then 547 mg of lauroyl chloride (2.5 mmol, 1 eq.) are added drop by drop. The mixture is stirred for 2 hours at room temperature. The reaction is followed by TLC.
After returning to room temperature, the solid is filtered then the filtrate is evaporated to lead to an oil purified on silica by a heptane/ethyl acetate mixture (80/20 to 50/50) or by preparative HPLC. The product obtained in the form of a white solid is dried under vacuum overnight. 511 mg are then obtained with a yield of 46%.
Example 26
2-(2,4-dihydroxyphenylsulphinyl)-5-hydroxyphenyl dodecanoate




1H NMR (400 MHz, DMSO-d6): 8: 0.86 (t, 3H); 1.24 (m, 16H); 1.53 (m, 2H); 2.45 (m, 2H); 6.28 (d, 1H); 6.33 (dd, 1H); 6.53 (s, 1H); 6.83 (dd, 1H); 7.12 (d, 1H); 7.43 (d, 1H); 9.88 (s1, 1H); 10.19 (s1, 1H); 10.27 (s1, 1H).
MS (APCI+): 449.2 [M+H]+
Rf (1/1; Heptane/EtOAc): 0.42
Example 27
(9Z,12Z)-2-(2,4-dihydroxyphenylsulphinyl)-5-hydroxyphenyl octadeca-9,12-dienoate
From linoleoyl chloride




1H NMR (400 MHz, DMSO-d6): 8: 0.84 (t, 3H); 1.29 (m, 14H); 1.55 (m, 2H); 2.00 (m, 4H); 2.42 (t, 2H); 2.76 (t, 2H); 5.33 (m, 4H); 6.28 (s, 1H); 6.35 (ds, 1H); 6.53 (s, 15 1H); 6.82 (d, 1H); 7.12 (d, 1H); 7.43 (d, 1H); 9.88 (s, 1H); 10.19 (s, 1H); 10.27 (s, 1H).
MS (ESI): 529.2 [M+H]+
Rf (7/3; Heptane/EtOAc): 0.45
B) Synthesis of Ethers by Oxidation of Analogues of Resorcinol Sulphide
To a solution of example 12 (=4-(2-(decyloxy)-4-hydroxyphenylthio)benzene-1,3-diol) (320 mg) in 10 ml of acetic acid are added 260 μL of a solution of 30% hydrogen peroxide in H2O (2.5 mmol, 3 eq.) then the mixture is stirred for 3 hours at room temperature.
50 mL of water are added to precipitate the product. The solid obtained is collected, then taken up in ethyl acetate then this organic phase is washed with water then with a saturated sodium chloride solution. After drying over MgSO4, the solvent is evaporated to lead to a beige solid dried overnight in the vacuum oven (50 mbar, 50° C.). 310 mg of product are obtained with a yield of 90%.
Example 28
4-(2-(decyloxy)-4-hydroxyphenylsulphinyl)benzene-1,3-diol




1H NMR (400 MHz, DMSO d6): 8: 0.86 (t, 3H); 1.23 (m, 14H); 1.54 (m, 2H); 3.77-3.92 (m, 2H); 6.26 (d, 1H); 6.29 (s, 1H); 6.40 (d, 1H); 6.49 (dd, 1H); 6.98 (d, 1H); 6.76 (s, 1H); 7.28 (d, 1H); 9.80 (s, 1H); 9.98 (s, 1H); 10.06 (s, 1H).
13C NMR (100 MHz, DMSO d6): 8: 13.89; 22.03; 25.14; 25.38; 28.29; 28.64; 28.66; 28.90; 28.93; 31.25; 67.86; 99.86; 102,38; 107.12; 107.49; 120.17; 121.72; 127.19; 127.68; 156.82; 157.07; 160.95; 161.18.
MS (ESI+): 407.2 [M+H]+
Rf (1/1; Heptane/EtOAc): 0.12
3) Synthesis of Analogues of Resorcinol Sulphone
A) Synthesis of Resorcinol Sulphone
To a solution of 4,4′-thiodibenzene-1,3-diol (resorcinol sulphide, 10 mmol, 2.5g) in an acetone/acetic acid mixture (1/1, 60 mL) are added 5.12 mL of a 30% solution of hydrogen peroxide in H20 (30 mmol) then the mixture is stirred for 72 hours at room temperature.
The solvent is evaporated then the solid obtained is taken up in ethyl acetate to obtain a white solid. Filtration of the solid then the filtrate is evaporated then the residue thereby obtained is purified on silica to lead to 320 mg of a white solid.
Example 29
4,4′-sulphonyldibenzene-1,3-diol (Resorcinol Sulphone)




1H NMR (400 MHz, DMSO-d6): 6: 6.24 (d, 2H); 6.33 (dd, 2H); 7.61 (d, 2H); 10.06 5 (s, 1H); 10.16 (s, 1H).
13C NMR (100 MHz, DMSO d6): 5:102.73; 106.41; 117.98; 131.54; 157.14; 162.86.
Rf (9/1; DCM/MeOH): 0.6
B) Synthesis of Analogues of Resorcinol Sulphone by Oxidation of Analogues of Resorcinol Sulphide into Resorcinol Sulphone
To a solution of example 12 (=4-(2-(decyloxy)-4-hydroxyphenylthio)benzene-1,3-diol) (195 mg, 0.5 mmol) in 10 ml of acetic acid are added 2.8 mL of a 30% solution of hydrogen peroxide in H20 (25 mmol, 50 eq.) then the mixture is stirred for 48 hours at room temperature.
50 mL of water are added to precipitate the product. The solid obtained is collected on sinter, then washed twice with water then twice with n-pentane. The solid is then dried overnight in the vacuum oven (50 mbar, 50° C.) to lead to a white solid. 135 mg of product are obtained with a yield of 64%.
Example 30
4-(2-(decyloxy)-4-hydroxyphenylsulphonyl)benzene-1,3-diol




1H NMR (400 MHz, DMSO d6): 5: 0.87 (tl, 3H); 1.26 (m, 14H); 1.44 (ml, 2H); 3.77 (ml, 2H); 6.22 (s, 1H); 6.30 (d, 1H); 6.35 (s, 1H); 6.44 (d, 1H); 7.59 (d, 1H); 7.74 (d, 1H); 9.97 (s, 1H); 10.10 (s, 1H); 10.30 (s, 1H).
13C NMR (100 MHz, DMSO d6): 6:13.89; 22.02; 25.29; 28.25; 28.64; 28.75; 28.88; 28.92; 31.24; 67.96; 99.78; 102.66; 106.04; 106.28; 117.91; 119.88; 131.65; 131.82; 156.97; 157.69; 162.77; 163.15.
II Results of Biological Tests
1) Protocols
A) Determination of the Depigmenting Activity in an in vitro Acellular Test: Tyrosinase Inhibition Test)
Principle:
This test is used to evaluate the depigmenting activity of the molecules tested. Tyrosinase is a limiting enzyme in melanogenesis.
It belongs to the family of oxydoreductases. It has in particular the function: monophenol monooxygenase (MPMO) and polyphenol oxidase (PPO).
It is synthesised at the level of the melanocytes. It is activated during its migration towards melanosome keratinocytes. It transforms tyrosine into DOPA then dopaquinone, which leads in fine to a polymerisation, i.e. a production of pigments (see diagram below).


















 













Tyrosinase





O2

O2




Slow

Rapid



Tyrosine
Monophenol
DOPA
Polyphenol
Dopaquinone



mono oxygenase

oxidase




MPMO

PPO









The substrate: L-tyrosine, is transformed into L-DOPA by the monophenol mono oxygenase function which is transformed by the polyphenol oxidase function from tyrosinase into dopaquinone. The latter is going to self-oxidise into dopachrome which is measured by spectrophotometry at 490 nm.
More precisely, it is the overall tyrosinase activity (MPMOg) which is measured since it is the dopachrome in fine that is assayed. Thus the products tested on MPMOg (=measurement of the activity on PPO and MPMO) can cumulate the inhibition of the 2 functions,

    
    
        inhibiting uniquely the MPMO function stricto sensus (transformation of tyrosine into DOPA) as a complement to the PPO test,
        could inhibit PPO uniquely.

General Experimental Conditions:

    
    


Reader: Synergy HT programme: tyrosinase 280-490 kinetic: kinetic over 45 min, reading at t=10 minutes, Tests in 96 transparent wells, Phosphate buffer—pH 6.8, Enzyme: mushroom tyrosinase—Sigma=T-3824 Substrate: L-Tyrosine—Sigma=T-3754, Positive control: Kojic acid (KA)—Fluka=60890 (reference inhibitor)
Reference Molecules for the Test:
Kojic acid: 9 μM<IC 50<20 μM (PPO), 3 μM<IC 50<7 μM (MPMO)
Vitamin C: 20 μM<IC 50<40 μM (PPO)
Reduced glutathion: 55% inhibition at 25 μM (PPO), IC 50=1-2 μM (MPMO)
Hydroquinone: IC 50=3-4 μM (MPMO)
Arbutin: 57% inhibition at 88 μM (MPMO)
These exogenous molecules are known to regulate negatively melanogenesis. Hydroquinone inhibits the synthesis of melanin by presenting itself as tyrosinase substrate in order to divert its activity. Arbutin containing hydroquinone acts in the same way. Kojic acid reduces the activity of tyrosinase by inhibiting the hyperpigmentation induced by the UV. Vitamin C would inhibit tyrosinase but would also behave as a powerful reducer by preventing the coloration of the melanin through oxidation. Vitamin A decreases the expression of tyrosinase.
B) Melanin Assay Test in B16-F10 Cells:
Principle:
This involves a test of measuring the synthesis of melanin by colorimetric assay on a murine melanoma cell line: the B16-F10 line. This test makes it possible to evaluate the depigmenting power of active ingredients.
The B16-F10 cells are cultured in 96-well plates in DMEM medium supplemented with FCS (foetal calf serum), and incubated for 24 hours at 37° C., 5% CO2. The cells are then stimulated with 0.1 μM α-MSH (to stimulate the synthesis of melanin, the stimulation observed is around 150%) and treated for 72 hours with the active ingredients to be tested. Each concentration of active ingredient is tested at least in triplicate. The total melanin followed by the intracellular melanin dissolved in the lysis buffer are then assayed by absorbance reading at 405 nm. The total proteins are assayed in the lysate and the results are expressed in mg melanin/mg proteins. The percentage of activity is calculated as follows:




  
    %
    ⁢
    
      
    
    ⁢
    activity
  
  =
  
    
      
        
          Normalised
          ⁢
          
            
          
          ⁢
          average
          ⁢
          
            
          
          ⁢
          of
          ⁢
          
            
          
          ⁢
          control
        
        -
        
          Normalised
          ⁢
          
            
          
          ⁢
          average
          ⁢
          
            
          
          ⁢
          of
          ⁢
          
            
          
          ⁢
          treated
        
      
      
        Normalised
        ⁢
        
          
        
        ⁢
        average
        ⁢
        
          
        
        ⁢
        of
        ⁢
        
          
        
        ⁢
        control
      
    
    ×
    100
  




A negative value indicates an inhibition, whereas a positive value indicates an induction of the synthesis of melanin.
General Experimental Conditions:
Equipment:
CO2 cell incubator (Heraeus), Oven, Centrifuge (Heraeus), Laminar air flow fume hood, 96-well clear bottomed plates—Falcon, sterile cones—Treff Lab, Polylabo, Mithras LB940 (Berthold Technologies)—154/MIPA/003
Biological Equipment:


    
    
        B16-F10 cell line between P10 and P20 (murine melanocytes) (ATCC, CRL-6475)
    
    


Reagents:

    
    
        DMEM without phenol red (GibcoBRL, 31053-028), 200 mM Glutamax-I Supplement (GibcoBRL, 35050-038), D-PBS (GibcoBRL, 14190-094), Foetal calf serum (Invitrogen, 10270-098), Trypsine-EDTA (GibcoBRL, 25300-054), NaOH (Sigma, S8045-500G), DMSO (Sigma, 471267-1L), Nle, Phe—Melanocyte Stimulating Hormone (Sigma, M-8764), Melanin (Sigma, M-0418), BCA-Copper (Sigma, B9643 and C2284), BSA (Sigma, P0914)

C) Test for the Study of the Antioxidant Capacity by Chemiluminescence (Photochem Analytik Jena)

Principle:

    
    


This test is used to determine the antioxidant capacity of the molecules. It is a method that generates free radicals by a photochemical signal. The intensity of the oxidation is 1000 times greater than that obtained under normal conditions.
The detection is carried out by chemiluminescence. It enables the evaluation of hydrosoluble and liposoluble anti-oxidant molecules or extracts.
The results are expressed respectively in equivalent quantity of vitamin C or Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid). The sensitivity is of the order of a nanomole.
The antioxidant activity studied in this test represents the capacity to trap specifically superoxide anions by chemiluminescence.
The quantified results are expressed in Trolox equivalent (standard), i.e. in “μg of product for 1 μg of Trolox”. This signifies that a quantity×of sample is needed to obtain an activity equivalent to the activity detected for 1 μg of standard. It is an anti-oxidant power relative to a reference, which makes it possible to disregard the concentration tested.
Generation of Oxygenated Free Radicals:
The superoxide radical: 020− is generated by a photochemical reaction:

L+hv (UV)+O2→L*O2→L0++O20−

L*: luminol in the excited state
L0+: luminol radical
Detection of the Signal:
A part of the superoxide anions is quenched by the anti-oxidants. The remaining free radicals are quantified by chemiluminescence.

L0++O20−→N2+AP*2−→AP2−+hv (luminescence)

AP*2−: aminophthalate in the excited state


















Photo-




Name
Conditions
sensitising
Antioxidant









Blank
100% O2
+
—




generated



Standards
Standard range:
+
Vitamin C or




from 1 to 3

Trolox




nmol



Test
+/−O20−
+
Molecule x to be




generated

tested










D) Test of Protection of Linoleic Acid Following a UV Stress.

Target: Protection of Linoleic Acid Under Fenton Conditions, UV Irradiation

Linoleic acid belongs to the family of polyunsaturated fatty acids (PUFA) (AGPI). Sensitive to oxidation, linoleic acid is a favoured target for oxygenated free radicals (OFR) in biological media. When biological membranes are exposed to an oxidative stress, the components the most affected are the phospholipids constituted of PUFA and cholesterol. Their degradation leads to lipidic peroxidation and generally to destructuring. Lipidic peroxidation is a self-catalysing process which generally involves OFR. Lipidic peroxidation is in part responsible for skin ageing.
The method employed to evaluate lipid peroxidation is based on the coupling of thiobarbituric acid (TBA) and secondary degradation products leading to coloured compounds detectable by spectrofluorometry. The essential secondary compound of final degradation is malondialdehyde, MDA. MDA is a carcinogenic and mutagenic aldehyde, it acts on proteins and DNA.
Principle of the Test:
The sample to be tested is placed in contact with linoleic acid in a weight/weight ratio. The sample undergoes an MED (Minimal Erythemal Dose) irradiation under Fenton conditions, namely in the presence of H202 and iron II in a solar simulator.
Following irradiation, the reaction mixture is taken up in methanol and derivatised at 90° C. with TBA. Chromogene, the MDA-TBA complex, representative of the equimolar production of MDA is assayed by fluorimetry (excitation at 525 nm, emission at 549 nm).
The results are expressed in fluorescence units, as a function of a MDA-TBA control range then expressed as concentration of the MDA-TBA complex. Then, the percentage of the starting MDA/linoleic acid (LA) ratio is determined. Then the percentage of protection of linoleic acid is determined.
E) Determination of the Minimal Inhibitory Concentration (MIC):
This test is used to determine the antibacterial activity of a compound. Tests are carried out with 4 bacterial strains using the principle of microdilution. The MIC are determined by micromethod in liquid medium. The successive dilutions according to the products tested in the culture broth (Trypcase soy) are carried out on 96 well microplates in a final volume of 0.1 ml. The wells are seeded with 0.01 ml of bacterial suspensions titrated at around 107 UFC/ml. The microplates are incubated under optimal growth conditions and the MIC is read visually.
2) Results
A) Determination of the Depigmenting Activity in an in vitro Acellular Test: Tyrosinase Inhibition Test.
All of the results have been grouped together in summary Table 1 inserted hereafter.
Caption of results for tyrosinase test:

















Interesting
Very good
>80% assay from 250



activity+++
activity
to 150 μM



Interesting
Good activity
>30% assay from 250



activity++

to 150 μM










B) Melanin Assay Test in B16-F10 Cells:

The results have also been grouped together in summary Table 1 below.
Interpretation of results:
A negative value indicates an inhibition, whereas a positive value indicates an induction of the synthesis of melanin.
It may be noted that the majority of the compounds tested exhibit good inhibition capacity of the synthesis of melanin. The invention thus relates to the cosmetic use for the depigmentation of the skin of compounds of generic formula (I) or (I′).
C) Test for the Study of the Antioxidant Capacity by Chemiluminiscence (Photochem Analytic Jena)
The results have also been grouped together in summary Table 1 below.
The majority of the compounds have good antioxidant activity. The scale for interpreting the results is the following:
















μg of sample





for 1 μg of



Products
Trolox
Activity









Vitamin C
0.1 to 3.0
Very good



BHT
3.01 to 50
Good



Cysteine
50.1 to 1000
Medium



Albumin
>1000
Low



Lipoic
NEGATIVE
None



acid










Most of the compounds exhibit results comparable to vitamin C. All of the compounds show results less than 1000 μg of Trolox (301 μg being the lowest result obtained with resorcinol sulphone); they thus all have interesting anti-oxidant activity. The invention also relates to the cosmetic use for the prevention and/or treatment of the ageing of the skin of compounds of generic formula (I) or (I′).
D) Test of Protection of Linoleic Acid Following a UV Stress
The results have also been grouped together in summary Table 1 below. The negative control is linoleic acid non stressed by UV radiation and chemically: thus not irradiated (NI). It is representative of the basal oxidation linked to the environment. It corresponds to the basal non specific production of MDA, and is very low (of the order of 7 10E-7 M).
The positive control is quercetin which has an almost total protection at 1% and which protects partially (around 50%) at 0.1%.
The product assay is expressed as weight/weight ratio, in other words in weight percentage with respect to the total quantity of linoleic acid. The maximal MDA level is determined by the condition UV+H202+iron II (F).
The percentage of protection of linoleic acid represents: the % ratio of MDA under maximal stress conditions untreated over the % of MDA under stress conditions treated by the product.
A molecule is considered as significantly active if its percentage of protection of linoleic acid is greater than 20%. All of the molecules tested are thus significantly active.











TABLE 1









%



Tyrosinase
B16

Protection



depigmenting
activity
μg of
Linoleic acid



activity
results -% at
sample for 1
under


Example
result
X μM
μg of Trolox
UV/Fenton



















Example
+ + +
−50% (61 μM)
23
90%


1
 1 μM


Example
+ +
−50% (14 μM)
9.7
92%


2


Example
+ + +
−41% (20 μM)
4.7
87%


3


Example
+ + +
−35% (10 μM)
5.2
89%


4


Example
+ + +
−27% (20 μM)
2.8
89%


5


Example
+ + +
−30% (20 μM)
14.9
—


6


Example
+ + +
−50% (10 μM)
3.4
92%


7


Example
+ + +
−40% (10 μM)
18.8
97%


8


Example
+ + +
−31% (20 μM)
3.2
85%


9


Example
+ + +
−20% (20 μM)
22
94%


10


Example
+ + +
−34% (20 μM)
3.5
91%


11


Example
+++
—
3.4
96%


12


Example
−
—
5.7
95%


13


Example
+ + +
−50% (48 μM)
4.8
—


14
 7 μM


Example
+ +
−20% (10 μM)
30
75%


15


Example
+ + +
—
33.2
91%


16


Example
+ + +
−50% (92 μM)
3.9
87%


17


Example
+ + +
−20% (50 μM)
24.1
90%


18


Example
+ + +
−20% (50 μM)
2.8
88%


19


Example
+ + +
−24% (50 μM)
25.6
91%


20


Example
+ + +
−50% (32 μM)
5.9
—


21
11 μM


Example
+ + +
—
2.5
97%


22


Example
+ + +
—
2.8
96%


23


Example
+ + +
−26% (50 μM)
3.8
97%


24


Example
+ + +
−50% (73 μM)
73
79%


25
12 μM


Example
+++
—
69
80%


26


Example
+++
—
40
78%


27


Example
++
—
28
94%


28


Example
−
—
301
25%


29


Example
−
—
147
34%


30









E) Determination of the Minimum Inhibitory Concentration (MIC):

The results have been grouped together in Table 2. A compound is considered to have very good antibacterial activity when it has an MIC below 1 ppm. The antibacterial activity is considered as good when the MIC is between 1 ppm and 100 ppm. The antibacterial activity of a compound is considered as average when it is between 100 ppm and 1000 ppm.











TABLE 2





Bacterial
Example
Example
Example
Example


strains
5
7
12
13







Staphylococcus
6 ppm
0.78 ppm
0.78 ppm
190 ppm


aureus IP4.83


ATCC6538


Staphylococcus
3 ppm
0.39 ppm
0.39 ppm
156 ppm


epidermidis


IP6821


P. acnes
3 ppm
0.09 ppm
0.09 ppm
 90 ppm


IP53.117


ATCC6919


Escherichia
—
 390 ppm
 780 ppm
—


coli IP53126


ATCC8739









The compounds tested exhibit significant antibacterial activity. In particular, examples 7 and 12 exhibit strong antibacterial activity against the strain Propionibacterium acnes. 
III. Composition According to the Invention













Ingredients
INCI
Percentage by



(trade name)
designation
weight
Function







I. Purified
Water
SQF 100%



water


Hydrolite 5
Pentylene
3
Humectant,



Glycol

Preservative


EDTA, 2Na
Disodium EDTA
0.1
Complexing





agent


Microcare PM4
Phenoxyethanol -
0.8
Preservatives



Parabene


Water soluble
Trideceth-9 &
1.5
Aqueous


PCL
PEG-5

emollient



Ethylhexanoate


II. Pemulen
Acrylates/C 10-
0.5
Gelifier,


TR-1
30 Alkyl

stabilising



Crosspolymer

agent


III. Stearine
Stearic acid
2
Emulsifier,


TP


consistency





factor


Liquid PCL
Cetearylethyl-
3
Emollient



hexanoate &



Isopropyl-



myristate


DC200
Dimethicone
0.3
Emollient


Myritol 318
Capric or
3
Emollient



caprylic



triglycerides


Primol 352
Liquid paraffin
2
Emollient


IV.


Active


Depigmenting


ingredient


active


ingredient


V. Sodium
NaOH
0.08
pH adjuster


hydroxide









In such a composition, the percentage of active ingredient can vary between 0.01% and 10% by weight and preferably from 0.1% to 5% by weight with respect to the total weight of the composition.
The invention also relates to pharmaceutical or cosmetic compositions comprising at least one of the compounds of formula (I) or formula (I′) in association with at least one pharmaceutically or cosmetically acceptable excipient.
According to a specific embodiment of the invention, the pharmaceutical or cosmetic compositions comprise at least one of the compounds of formula (I) or formula (I′) in association with at least one pharmaceutically or cosmetically acceptable excipient and a fatty phase.
According to a specific embodiment of the invention, the pharmaceutical or cosmetic compositions comprise at least one of the compounds of formula (I) or formula (I′) in association with at least one pharmaceutically or cosmetically acceptable excipient and an emollient.
The present invention relates to a cosmetic composition for depigmenting the skin and/or head hair and/or body hair characterised in that it comprises at least one compound of formula (I) or formula (I′).
The invention also relates to a cosmetic composition for anti-ageing of the skin, characterised in that it comprises at least one compound of formula (I) or formula (I′).
The invention also extends to a pharmaceutical composition for disinfecting the skin characterised in that it comprises at least one compound of formula (I).
The composition according to the invention may moreover comprise conventional cosmetic adjuvants especially chosen from fatty phases, organic solvents, thickeners, softeners, opacifiers, stabilisers, emollients, anti-foaming agents, hydrating agents, fragrances, preservatives such as parabenes, polymers, fillers, sequestering agents, bactericides, odour absorbers, alkalising or acidifying agents, surfactants, anti-free radicals, antioxidants, vitamins E and C, a-hydroxyacids, or thermal water such as Avène thermal water or any other ingredient normally used in cosmetics, in particular for the production of compositions of this type. The composition according to the invention may moreover comprise a fatty phase. The fatty phase may be constituted of an oil or a wax or mixtures thereof, and also comprise fatty acids, fatty alcohols, and fatty acid esters. The oils may be chosen from animal, plant, mineral or synthetic oils and especially from vaseline oil, paraffin oil, silicone oils, volatile or not, such as dimethicone; isoparaffins, polyolefins, fluorinated and perfluorinated oils. Similarly, the waxes may be chosen from animal, fossil, plant or synthetic waxes such as bee waxes, candelilla waxes, canauba waxes, karate butter, petroleum wax (or microcrystalline wax), paraffin, and mixtures thereof. The composition according to the invention may moreover comprise a polyol miscible in water at room temperature (around 25° C.), especially chosen from polyols having particularly from 2 to 20 carbon atoms, preferably having from 2 to 10 carbon atoms, and preferentially having 2 to 6 carbon atoms, such as glycerine; glycol derivatives such as propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol, diethylene glycol; glycol ethers such as C1-C4 mono-, di- or tri-propylene glycol alkyl ethers, C1-C4 mono-, di- or tri-ethylene glycol alkyl ethers; and mixtures thereof.
The composition according to the invention may also comprise thickening agents or rheology modification agents, such as for example non ionic ethoxylated hydrophobically modified urethanes, polycarboxylic acid thickeners such as copolymers of acrylates/steareth-20 methacrylate, carbomers, cured acrylate copolymers and mixtures thereof.
The composition according to the invention may also comprise acids and bases making it possible to adjust the pH range of said composition. The bases may be inorganic (sodium hydroxide, potassium hydroxide, aqueous ammonia, etc.) or organic such as mono-, di- or tri-ethanolamine, aminomethylpropanediol, N-methyl-glucamine, basic amino acids such as arginine and lysine, and mixtures thereof.
The composition according to the invention may also comprise skin conditioning agents. Examples of skin conditioning agents include, but are not limited to, anionic, cationic and non ionic emulsifiers such as sodium lauryl sulphate, sodium dioctyl sulphosuccinate, sodium stearate, sorbitan ester; ethoxylated fatty acids; ethoxylated fatty alcohols such as trideceth-9 and PEG-5 ethylhexanoate; stearic acid; any other emulsifier and conditioning agent known to those skilled in the art; and mixtures thereof.
The composition according to the invention may moreover contain other active ingredients leading to a complementary effect.
The composition according to the invention may be presented in any form appropriate for topical application, particularly on the skin and/or the hair. In particular, they can come in the form of emulsions obtained by the dispersion of an oil phase in an aqueous phase, for example an oil-in-water or water-in-oil or multiple emulsion, or in the form of a gel or a liquid, paste or solid anhydrous product, or in the form of a dispersion in the presence of spherules. The composition according to the invention may also be less fluid and come in the form of a white or coloured cream, an ointment, a milk, a lotion, a serum, a paste, a mask, a powder, a solid stick, or, optionally, an aerosol, a foam or a spray.

## Claims

1. Compound of generic formula (I)



in which:
X=S, SO or SO2 and;
one of the radicals R1 and R2 represents a hydrogen atom and the other a radical selected from:
a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms, or
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups, or
COR3 or CONHR3, but not simultaneously,
wherein R3 represents a radical selected from:

a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms,
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups,
an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy groups and/or one or more OH groups,

or
an aryl radical, optionally substituted by one or more C1 to C6 alkoxy groups.

2. Compound according to claim 1, wherein X=S.

3. Compound according to claim 1, wherein X=S and R2=H.

4. Compound according to claim 3, wherein X=S, R2=H and R1 is selected from the group consisting of: C1 to C18 linear or branched alkyl, C2 to C18 linear or branched alkenyl, COR3 and CONHR3 as defined in claim 1.

5. Compound according to claim 1, wherein R1 represents:
a C1 to C8 linear or branched alkyl; or
a C2 to C18 linear or branched alkenyl selected from an allyl group or a 3,3 dimethylallyl group or a geranyl group or a farnesyl group; or
a benzyl.

6. Compound according to claim 1, wherein R3 represents:
a C7 to C15 linear or branched alkyl; or
a C10 to C18 linear or branched alkenyl; or
a benzyl; or
an aralkenyl selected from phenyl acrylate or (4-methoxyphenyl)acrylate or (3,4-dimethoxyphenyl)acrylate; or
a phenyl.

7. Compound according to claim 1, selected from one of the following compounds:
4-(4-hydroxy-2-((2E,6E)-3,6,11-trimethyldodeca-2,6,10-trienyloxy)phenylthio)benzene-1,3-diol,
4-(4-hydroxy-2-(3-methylbut-2-enyloxy) phenylthio) benzene-1,3-diol,
(E)-4-(2-(3,7-dimethylocta-2,6-dienyloxy)-4-hydroxyphenylthio)benzene- 1,3-diol,
4-(2-butoxy-4-hydroxyphenylthio)benzene-1,3-diol,
4-(4-butoxy-2-hydroxyphenylthio)benzene-1,3-diol,
4-(4-hydroxy-2-(octyloxy)phenylthio)benzene-1,3-diol,
4-(2-hydroxy-4-(octyloxy)phenylthio)benzene-1,3-diol,
4-(2-(benzyloxy)-4-hydroxyphenylthio)benzene-1,3-diol,
4-(4-(benzyloxy)-2-hydroxyphenylthio)benzene-1,3-diol,
4-(4-hydroxy-2-(4methoxybenzyloxy) phenylthio) benzene-1,3-diol,
4-(2-(decyloxy)-4-hydroxyphenylthio)benzene-1,3-diol,
4-(2-(hexadecyloxy)-4-hydroxyphenylthio)benzene-1,3-diol,
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl dodecanoate,
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl octanoate,
4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyloctanoate,
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-phenylpropanoate,
4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyl 3-phenylpropanoate,
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-methylbutanoate,
4-(2,4-dihydroxyphenylthio)-3-hydroxyphenyl 3-methylbutanoate,
(9Z,12Z)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl octadeca-9,12-dienoate
(E)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-(4- methoxyphenyl)acrylate,
(E)-2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl 3-(3,4-dimethoxyphenyl)acrylate,
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl octylcarbamate,
2-(2,4-dihydroxyphenylsulphinyl)-5-hydroxyphenyl dodecanoate,
(9Z, 12Z)-2-(2,4-dihydroxyphenylsulphinyl)-5-hydroxyphenyl octadeca-9,12- dienoate
4-(2-(decyloxy)-4-hydroxyphenylsulfinyl)benzene-1,3-diol,
4-(2-(decyloxy)-4-hydroxyphenylsulphonyl)benzene-1,3-diol, or
2-(2,4-dihydroxyphenylthio)-5-hydroxyphenyl palmitate.

8. A method of bleaching and/or lightening of the human skin and/or body hair and/or head hair comprising the application on the skin and/or body hair and/or head hair of a compound of formula (I′)



in which X=S or SO and the radicals R1 and R2 simultaneously represent hydrogen or one of the radicals R1 and R2 represents a hydrogen atom and the other a radical selected from:
a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms, or
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups, or
COR3, or
CONHR3,
wherein R3 represents a radical selected from:

a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms,
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups,
an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy groups and/or one or more OH groups,

or
an aryl radical, optionally substituted by one or more C1 to C6 alkoxy groups.

9. A method of cosmetic treatment of the ageing of the skin comprising the application on the skin of a compound of formula (I′)
(I′)
in which X=S, SO or SO2 and;
R1 and R2 are simultaneously hydrogen or one of the radicals R1 and R2 represents a hydrogen atom and the other a radical selected from:
a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms, or
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups, or
COR3,or
CONHR3,
wherein R3 represents a radical selected from:

a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C1 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms,
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups,
an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy groups and/or one or more OH groups,

or
an aryl radical, optionally substituted by one or more C1 to C6 alkoxy groups.

10. A method of disinfecting the skin comprising the application on the skin of a person in need thereof of a compound of formula (I) as an antibacterial active ingredient



wherein X=S, one of the radicals R1 and R2 represents a hydrogen atom and the other a C1 to C18 linear alkyl.

11. Pharmaceutical or cosmetic composition comprising as active ingredient at least one compound of formula (I) as defined according to claim 1, in association with a pharmaceutically or cosmetically acceptable excipient.

12. Pharmaceutical or cosmetic composition according to claim 11, wherein the quantity of compound of formula (I) varies between 0.01% and 10% by weight with respect to the total weight of the composition.

13. A method of depigmenting the skin and/or head hair and/or body hair comprising the application on the skin of a cosmetic composition or a composition comprising at least one compound of formula (I′)



in which X=S or SO and;
R1 and R2 both represent a hydrogen atom or one of R1 and R2 represents a hydrogen atom and the other represents radical selected from:
a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atom(s),
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atom(s), or
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy group(s), or
COR3 or
CONHR3,
wherein R3 represents a radical selected from:

a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms,
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups,
an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy groups and/or one or more OH groups, or
an aryl radical, optionally substituted by one or more C1 to C6 alkoxy groups.

14. A method of cosmetic treatment of the ageing of the skin comprising the application on the skin of a composition comprising at least one compound of formula (I′)



in which X=S, SO or SO2 and;
R1 and R2 both represent a hydrogen atom or one of R1 and R2 represents a hydrogen atom and the other represents radical selected from:
a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms, or
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups, or
COR3 or
CONHR3,
wherein R3 represents a radical selected from:

a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms,
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups,
an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy groups and/or one or more OH groups, or

an aryl radical, optionally substituted by one or more C1 to C6 alkoxy groups.

15. A method of disinfecting the skin comprising the application on the skin of a pharmaceutical composition comprising a compound of formula



wherein X=S, one of the radicals R1 and R2 represents a hydrogen atom and the other a C1 to C18 linear alkyl to a person in need thereof.

16. Method of preparing a compound of generic formula (I) according to claim 1, wherein 4,4′-thiodibenzene-1,3-diol or
4,4′-sulphinylbis-1,3-benzenediol is reacted with a halide of formula II


Hal-R1  (II)


in which:
Hal represents a halogen atom, and
R1 represents a radical selected from:
a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms, or
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups, or
COR3 or
CONHR3,
wherein R3 represents a radical selected from:

a C1 to C18 linear or branched alkyl, optionally substituted by one or more halogen atoms,
a C2 to C18 linear or branched alkenyl, optionally substituted by one or more halogen atoms,
an aralkyl, optionally substituted by one or more C1 to C6 alkoxy groups,
an aralkenyl, optionally substituted by one or more C1 to C6 alkoxy groups and/or one or more OH groups, or

an aryl radical, optionally substituted by one or more C1 to C6 alkoxy groups.

17. Method of preparing, according to claim 16, a derivative of resorcinol of formula (I) in which X represents SO or SO2, wherein a compound of formula (I), in which X represents a sulphur atom, is oxidised by means of an aqueous solution of hydrogen peroxide.