STABILIZATION OF THIOPYRIDINONE COMPOUND AND COMPOSITION COMPRISING SAID COMPOUND

Abstract

STABILIZATION OF THIOPYRIDINONE COMPOUND AND COMPOSITION COMPRISING SAID COMPOUND The present invention relates to a composition comprising: (1) at least one thiopyridinone compound; and (2) at least one lipophilic antioxidant. The present invention can provide a composition including (1) thiopyridinone compound(s) with increased stability of the thiopyridinone compound(s) (1) over time, particularly even when the composition is maintained for a relatively long period of time at elevated temperature. Figure for abstract: None

Description

Title of the invention: STABILIZATION OF THIO-PYRIDINONE COMPOUND AND COMPOSITION COMPRISING SAID COMPOUND Technical field

[0001] The present invention relates to the stabilization of a thiopyridinone compound in a composition including the thiopyridinone compound.

[0002] CONTEXT OF ART

[0003] At various times in their lives, some people notice the appearance on their skin, and more particularly on their face and hands, of darker and / or more colored spots, which give a heterogeneous appearance to their skin. These spots are in particular due to a high concentration of melanin in the keratinocytes located on the surface of the skin.

[0004] The use of harmless topical depigmenting substances having good efficacy is particularly desired for the purpose of treating pigmentation spots.

[0005] For example, arbutin, niacinamide and kojic acid are known as skin depigmenting agents.

[0006] Furthermore, WO2017 / 102349 discloses a novel depigmenting or whitening agent, namely, a thiopyridinone compound. The thiopyridinone compound can exhibit strong depigmenting or whitening effects by reducing melanin production. DISCLOSURE OF THE INVENTION

[0007] However, it has been discovered that a thiopyridinone compound tends to destabilize in a composition over time, particularly when the composition including the thiopyridinone compound is maintained for a relatively long period under an elevated temperature.

[0008] Thus, an object of the present invention is to provide a composition including thiopyridinone compound(s) with increased stability of the thiopyridinone compound(s) over time, particularly when the composition is maintained for a relatively long period of time at elevated temperature.

[0009] The above objective can be achieved by a composition comprising:

[0010] (1) at least one compound chosen from the compounds of formula (I) below, the tautomers of formula (T) below, salts thereof, solvates, such as hydrates, thereof, optical isomers thereof, racemates thereof, and mixtures thereof:

[0011] (I)(D

[0012] in which

[0013] Ri denotes a radical chosen from

[0014] a) a hydrogen atom, and

[0015] b) a linear C1-C10 or branched C3-C10 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, chosen from

[0016] i) -O-R3, and

[0017] ii) -S-R3,

[0018] and

[0019] R2 denotes a radical chosen from

[0020] a) a hydrogen atom,

[0021] b) a linear C1-C12 or branched C3-C12 or cyclic C3-C8 saturated hydrocarbon group optionally substituted by one or more groups, which may be the same or different, chosen from

[0022] i) -O-R3,

[0023] ii) -S-R3,

[0024] iii) -C(O)-O-R3, and

[0025] iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals, and

[0026] c) a C5-C12 aryl group, optionally substituted by one or more hydroxyls and / or by one or more CrC8 alkoxy radicals

[0027] in which

[0028] R3 denotes a radical chosen from

[0029] a) a hydrogen atom, and

[0030] b) a linear C1-C10 or branched C3-C10 saturated alkyl group;

[0031] and

[0032] (2) at least one lipophilic antioxidant.

[0033] It may be preferable that:

[0034] Ri of formula (I) and (!') represents a hydrogen atom;

[0035] or

[0036] R 1 of formula (I) and (!') represents a linear alkyl group (C 1 -C 10) or a branched alkyl group (C 3 -C 10), in particular a linear alkyl group (C 1 -C 6) or a branched alkyl group (C 3 -C 6), such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably ethyl, in particular said alkyl group of R 1 is not substituted.

[0037] It may be preferable that:

[0038] R2 of formula (I) and (I') represents a hydrogen atom;

[0039] or

[0040] R2 of formula (I) and (I') represents a linear alkyl group (C1-C10) or a branched alkyl group (C3-C10), in particular a linear alkyl group (C1-C6) or a branched alkyl group (C3-C6), such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably a methyl or ethyl group; said alkyl group of R2 not being substituted.

[0041] It may be preferable that:

[0042] R2 of formula (I) and (I') represents a linear alkyl group (C1-C10) or a branched alkyl group (C3-C10), in particular a linear alkyl group (C1-C6) or a branched alkyl group (C3-C6), such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl; said alkyl group being substituted by one or more groups chosen from i), ii), iii) and iv) as defined above, preferably said alkyl group being substituted by one or two groups chosen from i), ii) and iii), more preferably by one or two groups chosen from i) and iii), better substituted by a group iii) such as carboxy.

[0043] It may be preferable that:

[0044] R2 of formula (I) and (I') represents a cycloalkyl group (C3-C8), preferably a cycloalkyl group (C5-C7) such as cyclohexyl;

[0045] or

[0046] R2 of formula (I) and (I') represents a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals, preferably a phenyl group in particular unsubstituted.

[0047] It may be preferable that:

[0048] R3 of formula (I) and (I') represents a hydrogen atom;

[0049] or

[0050] R3 of formula (I) and (I') represents a linear C1-C10 or branched C3-C10 saturated alkyl group; in particular a linear (C1-C6) alkyl group or a branched (C3-C6) alkyl group, preferably a (C1-C4) alkyl group such as a group methyl.

[0051] It may be more preferable that:

[0052] Ri of formula (I) and (!') represents a radical chosen from

[0053] a) a hydrogen atom, and

[0054] b) a linear C1-C6 or branched C3-C6 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, chosen from

[0055] i) -O-R3, and

[0056] ii) -S-R3,

[0057] preferably optionally substituted with one or more groups i);

[0058] R2 of formula (I) and (!') represents a radical chosen from

[0059] a) a hydrogen atom, and

[0060] b) a linear C1-C10 or branched C3-C10 or cyclic C3-C8 such as C5-C6 saturated hydrocarbon group, optionally substituted by one or more groups, which may be the same or different, chosen from

[0061] i) -O-R3,

[0062] ii) -S-R3,

[0063] iii) -C(O)-O-R3, and

[0064] iv) a phenyl group optionally substituted by one or more hydroxyls and / or by one or more C1-C4 alkoxy radicals such as methoxy,

[0065] preferably substituted by one or more groups chosen from i) and iii), preferably iii) such as carboxy; and

[0066] R3 of formula (I) and (!') represents a radical chosen from

[0067] a) a hydrogen atom, and

[0068] b) a linear C1-C6 or branched C3-C6 saturated alkyl group,

[0069] preferentially, the compounds of formula (I) and the tautomer (I'), the salts thereof, the solvates, such as the hydrates, of these, the optical isomers of these, the racemates of these, and the mixtures of these, have the following meanings:

[0070] Ri of formula (I) and (!') represents a radical chosen from:

[0071] a) a hydrogen atom, and

[0072] b) a linear C1-C4 or branched C3-C4 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, selected from i) -OR3, more preferably unsubstituted;

[0073] R2 of formula (I) and (!') represents a radical chosen from

[0074] a) a hydrogen atom, and

[0075] b) a linear C1-C10 or branched C3-C10 or cyclic C3-C8 saturated hydrocarbon group such as C5-C6, optionally substituted by one or more groups, which may be the same or different, chosen from

[0076] i) -O-R3,

[0077] iii) -C(O)-O-R3, and

[0078] iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C4 alkoxy radicals; and

[0079] R3 of formula (I) and (!') represents a radical chosen from:

[0080] a) a hydrogen atom;

[0081] b) a linear C1-C4 or branched C3-C4 saturated alkyl group such as methyl or ethyl.

[0082] Compound (1) may be selected from compounds 1 to 24 below, tautomers thereof, salts thereof, solvates, such as hydrates, thereof, optical isomers thereof, racemates thereof, and mixtures thereof, in particular compounds 1, 2, 4, 6, 7, 9, 11, 12, 14, 15, 16, 17, 18, 19, 20 or 21, more particularly 1, 9, 16, 18, 19, 20 or 21, preferably 18, 19, 20 or 21, and more preferably 20: No. Structure Chemical Name 1 h 1 H N-ethyl-2-thioxo-1,2-dihydropyridi ne-3-carboxamide 2 / ;........., x \\ N-methyl-2-thioxo-1,2-dihydropyri dine-3-carboxamide 3 [1 ' [l N-octyl-2-thioxo-1,2-dihydropyridi ne-3-carboxamide 4 L. ..As. N-benzyl-2-thioxo-1,2-dihydropyri dine-3-carboxamide 5 ?.........X y's > / S. X / Sa N-phenyl-2-thioxo-1,2-dihydropyri dine-3-carboxamide 6 h J H N-cyclohexyl-2-thioxo-1,2-dihydro pyridine-3-carboxamide 7 .K ;< N- [2-(4-méthoxyphényl)éthyl] -2-th il ioxo-1,2-dihydropyridine-3-carbox il V ? amide 8 x^K N-(2-méthylpropyl)-2-thioxo-1,2-d Jk A, ...-' X<*’ * x.--'* V\m ihydropyridine-3-carboxamide 9 fs N-pentyl-2-thioxo-1,2-dihydropyri li H dine-3-carboxamide ’X. 10 N-nonyl-2-thioxo-1,2-dihydropyrid ine-3-carboxamide ? •^X 11 s I N-(2-hydroxyéthyl)-2-thioxo-1,2-d 'k* 'X> x' \ 'Hk S OH ihydropyridine-3-carboxamide ^'N” H / * <x„. 12 0 N,N-diéthyl à 'y yf / XH-; "XH, 2-mercaptonicotinamide 13 i fl; V y 'V'" Y.........K ■ X x XY^s 'v N-ethyl-N-(2-hydroxyethyl)-2-thio 15 UX OH yy^ 'Y ""'■""" XY $ N-(13-dihydroxypropan-2-yl)-2-th ioxo-1,2-dihydropyridine-3-carbox amide 16 -s ■-yY xy \ H / ÿ' N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]alaninate ethyl 17 ■X, Y N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]phenyl ethyl alaninate 18 G --'■ '"Ciy'" '"tr'' x ,..¼. CH. x .>■ >. x . • > \ N" \ si : CM, N-methyl-N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycinate ethyl 19 <-xv ..« f Y y T N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycinate ethyl 20 T c f'' \ / JO N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycine 21 O xx- A 'y H N-methyl-N- [(2-thioxo-1,2-dihydr opyridin-3-yl)carbonyl]glycine 22 £...... ss \___ / \ '•.......à AN,N-bis(2-hydroxyethyl)-2-thioxo-1,2-dihydropyridine-3-carboxamide e 23 A-'--r N-(3-methoxypropyl)-2-thioxo-1,2 -dihydropyridine-3-carboxamide 24 si N-butyl-2-thioxo-1,2-dihydropyrid ine-3-carboxamide

[0083] The amount of the compound(s) (1) in the composition according to the present invention may be from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1% to 3% by weight, relative to the total weight of the composition.

[0084] The lipophilic antioxidant (2) may be selected from the group consisting of dibutylhydroxytoluene, ethylhexyl methoxycrylene, tocopheryl acetate, oryzanol, pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, dilauryl thiopropionate, and mixtures thereof.

[0085] The amount of the lipophilic antioxidant(s) (2) in the composition according to the present invention may be from 0.01% to 10% by weight, preferably from 0.05% to 5%. by weight, more preferably from 0.1% to 3% by weight, relative to the total weight of the composition.

[0086] The composition according to the present invention may be for the whitening of a keratinous material, preferably the skin.

[0087] The present invention also relates to a cosmetic process, preferably a bleaching process, for a keratinous material, preferably the skin, comprising the step of:

[0088] application to keratinous material of the composition according to the present invention.

[0089] Another aspect of the present invention is a use of (2) at least one lipophilic antioxidant in a composition comprising (1) at least one compound selected from the compounds of formula (I) below, the tautomers of formula (I) below, the salts thereof, the solvates, such as hydrates, thereof, the optical isomers thereof, the racemates thereof, and the mixtures thereof:

[0090] (I) (D

[0091] in which

[0092] Ri denotes a radical chosen from

[0093] a) a hydrogen atom, and

[0094] b) a linear C1-C10 or branched C3-C10 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, chosen from

[0095] i) -O-R3, and

[0096] ii) -S-R3,

[0097] and

[0098] R2 denotes a radical chosen from

[0099] a) a hydrogen atom,

[0100] b) a linear C1-C12 or branched C3-C12 or cyclic C3-C8 saturated hydrocarbon group optionally substituted by one or more groups, which may be

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110] [YES]

[0112]

[0113] identical or different, chosen from i) -O-R3, ü) -S-R3, iii) -C(O)-O-R3, and iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals, and (c) a C5-C12 aryl group, optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals in which R3 denotes a radical chosen from a) a hydrogen atom, and b) a linear C1-C10 or branched C3-C10 saturated alkyl group in order to stabilize the compound(s) (1). Best mode for carrying out the invention After extensive research, the inventors have discovered that it is possible to provide a composition including a thiopyridinone compound or thiopyridinone compounds with increased stability of the thiopyridinone compound(s) over time, particularly even when the composition is maintained for a relatively long period of time at elevated temperature. Thus, the composition according to the present invention comprises: (1) at least one compound selected from the compounds of formula (I) below, the tautomers of formula (!') below, the salts thereof, the solvates, such as hydrates, of these, the optical isomers thereof, the racemates thereof, and the mixtures thereof (hereinafter, the compound is called "thiopyridinone compound"):

[0114]

[0115]

[0116] (i) (D in which Ri denotes a radical chosen from

[0117] a) a hydrogen atom, and

[0118] b) a linear C1-C10 or branched C3-C10 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, chosen from

[0119] i)-O-R3, and

[0120] ii) -S-R3,

[0121] and

[0122] R2 denotes a radical chosen from

[0123] a) a hydrogen atom,

[0124] b) a linear C1-C12 or branched C3-C12 or cyclic C3-C8 saturated hydrocarbon group optionally substituted by one or more groups, which may be the same or different, chosen from

[0125] i) -O-R3,

[0126] ii) -S-R3,

[0127] iii) -C(O)-O-R3, and

[0128] iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more CrC8 alkoxy radicals, and

[0129] c) a C5-C12 aryl group, optionally substituted by one or more hydroxyls and / or by one or more CrC8 alkoxy radicals

[0130] in which

[0131] R3 denotes a radical chosen from

[0132] a) a hydrogen atom, and

[0133] b) a linear C1-C10 or branched C3-C10 saturated alkyl group;

[0134] and

[0135] (2) at least one lipophilic antioxidant.

[0136] The composition according to the present invention can show increased stability of the thiopyridinone compound (1) therein.

[0137] In other words, the composition according to the present invention can increase the stability of the thiopyridinone compound (1) therein. The term "stability" of the thiopyridinone compound (1) can be determined by the change in the amount of the thiopyridinone compound (1) in the composition according to the present invention over a certain period of time. Increased "stability" means that the change in the amount of the thiopyridinone compound (1) over time is more limited.

[0138] The composition according to the present invention can show increased stability of the thiopyridinone compound (1) therein, even when the composition is maintained for a relatively long period of time such as two weeks at an elevated temperature such as 55°C.

[0139] Therefore, the composition according to the present invention can be stored for a long period of time even in hot conditions.

[0140] In addition, the increased stability of the thiopyridinone compound (1) may provide improved or increased bioavailability of the thiopyridinone compound (1) which may function as a depigmenting or bleaching agent. Therefore, the composition according to the present invention may provide increased or improved depigmenting or bleaching effects.

[0141] Hereinafter, the composition, use and others according to the present invention will be described in detail.

[0142] [Composition]

[0143] The composition according to the present invention comprises:

[0144] (1) at least one thiopyridinone compound; and

[0145] (2) at least one lipophilic antioxidant.

[0146] The thiopyridinone compound (1), and the lipophilic antioxidant (2), as well as other features of the composition according to the present invention will be explained below.

[0147] (Thiopyridinone compound)

[0148] The composition according to the present invention comprises (1) at least one thiopyridinone compound. Two or more thiopyridinone compounds (1) may be used in combination. Thus, a single type of thiopyridinone compound (1) or a combination of different types of thiopyridinone compounds (1) may be used.

[0149] The thiopyridinone compound (1) is selected from the compounds of formula (I) below, the tautomers of formula (!') below, the salts thereof, the solvates, such as hydrates, of these, the optical isomers of these, the racemates of these, and the mixtures of these:

[0150] (I) (!')

[0151] in which

[0152] Ri denotes a radical chosen from

[0153] a) a hydrogen atom, and

[0154] b) a linear C1-C10 or optionally branched C3-C10 saturated alkyl group substituted by one or more groups, which may be the same or different, chosen from

[0155] i) -O-R3, and

[0156] ii) -S-R3,

[0157] and

[0158] R2 denotes a radical chosen from

[0159] a) a hydrogen atom,

[0160] b) a linear C1-C12 or branched C3-C12 or cyclic C3-C8 saturated hydrocarbon group optionally substituted by one or more groups, which may be the same or different, chosen from

[0161] i) -O-R3,

[0162] ii) -S-R3,

[0163] iii) -C(O)-O-R3, and

[0164] iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more CrC8 alkoxy radicals, and

[0165] c) a C5-C12 aryl group, optionally substituted by one or more hydroxyls and / or by one or more CrC8 alkoxy radicals

[0166] in which

[0167] R3 denotes a radical chosen from

[0168] a) a hydrogen atom, and

[0169] b) a linear C1-C10 or branched C3-C10 saturated alkyl group.

[0170] Hereinafter, for the purposes of the present invention and unless otherwise indicated:

[0171] - a “saturated linear C3-Ci2 or branched C3-Ci2” hydrocarbon group is equivalent to a “linear (CrCi2) or branched (C3-Ci2) alkyl group” which corresponds to a linear CrCi2 or branched C3-Ci2 saturated hydrocarbon group, preferably to a linear C1-Ci0 or branched C3-Ci0 hydrocarbon group, and more preferably to a linear C1-C6 or branched C3-C6 hydrocarbon group; preferably, the linear or branched groups may be chosen from methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl; more preferably, the linear or branched saturated alkyl groups may be chosen from methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl and octyl, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl;

[0172] - - a “C3-C8 cyclic” saturated hydrocarbon group is a cycloalkyl group mono or bicyclic containing from 3 to 8 carbon atoms, and in particular is a monocyclic C5 to C7 cycloalkyl group such as a cyclohexyl group,

[0173] - an “alkoxy radical” is an alkyloxy radical for which the alkyl radical is a linear or branched C1-C16 hydrocarbon radical, and preferably a hy- radical CrC8 drocarbon;

[0174] - when the alkoxy group is optionally substituted, this implies that the group alkyl is optionally substituted as defined above;

[0175] - an “aryl” group represents a carbon-based, monocyclic or bi- cyclic, fused or not, comprising from 5 to 12 carbon atoms, preferably from 6 to 10 carbon atoms, and in which at least one cycle is aromatic; preferably, the aryl radical is a phenyl, biphenyl, naphthyl group, more preferably a phenyl group;

[0176] - the term “at least one” is equivalent to the term “one or more”; and

[0177] - the term "inclusive" for a concentration range means that the limits of this range are included in the defined range.

[0178] Salts of compounds of formula (I), (I'), (II), or (II') as defined below include conventional non-toxic salts of said compounds, such as those formed from an organic or inorganic acid or an organic or inorganic base.

[0179] As salts of the compounds of formula (I), (I'), (II) or (II'), mention may be made of:

[0180] the salts obtained by addition of the compound of formula (I) or (II) to:

[0181] a mineral base, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonium hydroxide, magnesium hydroxide, lithium hydroxide, and sodium, potassium or calcium carbonate or hydrogen carbonate for example;

[0182] or

[0183] an organic base such as a primary, secondary or tertiary alkylamine, for example triethylamine or butylamine. This primary, secondary or tertiary alkylamine may comprise one or more nitrogen and / or oxygen atoms and may thus comprise, for example, one or more alcohol functions. Mention may be made in particular of 2-amino-2-methylpropanol, ethanolamine, triethanolamine, 2-dimethylaminopropanol, 2-amino-2-(hydroxymethyl)-1,3-propanediol and 3-(dimethylamino)propylamine.

[0184] Mention may also be made of amino acid salts, for example lysine, arginine, guanidine, glutamic acid and aspartic acid. Advantageously, the salts of the compounds of formula (I) or (II) (when they comprise a carboxy group) may be chosen from alkali or alkaline earth metal salts such as sodium, potassium, calcium or magnesium salts and ammonium salts.

[0185] An “organic or inorganic acid salt” is more particularly chosen from the salts chosen from a salt derived from i) hydrochloric acid HCl, ii) hydrobromide acid HBr, iii) sulfuric acid H2SO4, iv) alkylsulfonic acids: Alk-S(O)2OH such as methanesulfonic acid and ethanesulfonic acid; v) arylsulfonic acids: Ar-S(O)2OH such as benzenesulfonic acid and toluene- sulfonic acid; vi) citric acid; vii) succinic acid; viii) tartaric acid; ix) lactic acid; x) alkoxysulfinic acids: Alk-OS(O)OH such as methoxysulfinic acid and ethoxysulfinic acid; xi) aryloxysulfinic acids such as tolueneoxysulfinic acid and phenoxysulfinic acid; xii) phosphoric acid H3PO4; xiii) acetic acid CH3C(O)OH; xiv) triflic acid CF3SO3H; and xv) tetrafluoroboric acid HBF4.

[0186] Acceptable solvates of the compounds described in the specification include conventional solvates such as those formed during the preparation of said compounds due to the presence of solvents. Examples include solvates due to the presence of water or linear or branched alcohols, such as ethanol or isopropanol.

[0187] The optical isomers are in particular the enantiomers and the diastereoisomers.

[0188] The compound (!') is the tautomeric form of the compound (I) when a tautomeric equilibrium exists according to the following scheme:

[0189] According to one embodiment of the present invention, Ri represents a hydrogen atom.

[0190] According to another embodiment of the present invention, Ri represents a linear (C1-C10) alkyl group or a branched (C3-C10) alkyl group, in particular a linear (C1-C6) alkyl group or a branched (C3-C6) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably ethyl. In particular, said alkyl group of Ri is not substituted.

[0191] According to one embodiment of the present invention, R2 represents a hydrogen atom.

[0192] According to another embodiment of the present invention, R2 represents a linear alkyl group (C1-C10) or a branched alkyl group (C3-C10), in particular a linear alkyl group (C1-C6) or a branched alkyl group (C3-C6), such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably a methyl or ethyl group; said alkyl group of R2 not being substituted.

[0193] According to another embodiment of the present invention, R2 represents a linear alkyl group (C1-C10) or a branched alkyl group (C3-C10), in particular a linear alkyl group (C1-C6) or a branched alkyl group (C3-C6), such that methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl; said alkyl group being substituted by one or more groups selected from i), ii), iii) and iv) as defined above. Preferably, said alkyl group being substituted by one or two groups selected from i), ii) and iii), more preferably by one or two groups selected from i) and iii), better substituted by a group iii) such as carboxy.

[0194] Another variant for the radical R2 is that said alkyl group is substituted by a group iv) in particular substituted by a phenyl group.

[0195] According to another embodiment of the present invention, R2 represents a cycloalkyl group (C3-C8), preferably a cycloalkyl group (C5-C7) such as cyclohexyl.

[0196] According to another embodiment of the present invention, R2 represents a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals, preferably a phenyl group in particular unsubstituted.

[0197] According to one embodiment, R3 represents a hydrogen atom.

[0198] According to another embodiment, R3 represents a linear C1-C10 or branched C3-C10 saturated alkyl group; in particular a linear (C1-C6) alkyl group or a branched (C3-C6) alkyl group, preferably a (C1-C4) alkyl group such as a methyl group.

[0199] Preferably, the compounds of formula (I) and the tautomer (!) or their salts, their optical isomers, racemates, and / or solvates such as hydrates and their derivatives, alone or as a mixture

[0200] have the following meanings:

[0201] Ri denotes a radical chosen from

[0202] a) a hydrogen atom, and

[0203] b) a linear C1-C6 or branched C3-C6 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, chosen from

[0204] i) -O-R3, and

[0205] ii) -S-R3,

[0206] preferably optionally substituted with one or more groups i);

[0207] R2 denotes a radical chosen from

[0208] a) a hydrogen atom;

[0209] b) a linear C1-C10 or branched C3-C10 or cyclic C3-C8 such as C5-C6 saturated hydrocarbon group optionally substituted by one or more groups, which may be the same or different, chosen from:

[0210] i) -O-R3,

[0211] ii)-S-R3,

[0212] iii) -C(O)-O-R3, and

[0213] iv) a phenyl group optionally substituted by one or more hydroxyls and / or by one or more C1-C4 alkoxy radicals such as methoxy,

[0214] preferably substituted by one or more groups chosen from i) and iii), preferably iii) such as carboxy; and

[0215] R3 denotes a radical chosen from

[0216] a) a hydrogen atom, and

[0217] b) a linear C1-C6 or branched C3-C6 saturated alkyl group

[0218] Preferably, the compounds of formula (I) and the tautomer (!) or their salts, their optical isomers, racemates, and / or solvates such as hydrates and their derivatives, alone or as a mixture

[0219] have the following meanings:

[0220] Ri denotes a radical chosen from

[0221] a) a hydrogen atom, and

[0222] b) a linear C1-C4 or branched C3-C4 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, selected from i) -OR3 more preferably unsubstituted;

[0223] R2 denotes a radical chosen from

[0224] a) a hydrogen atom; and

[0225] b) a linear C1-C10 or branched C3-C10 or cyclic C3-C8 such as C5-C6 saturated hydrocarbon group, optionally substituted by one or more groups, which may be the same or different, chosen from

[0226] i) -O-R3,

[0227] iii) -C(O)-O-R3,

[0228] iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C4 alkoxy radicals; and

[0229] R3 denotes a radical chosen from

[0230] a) a hydrogen atom, and

[0231] b) a linear C1-C4 or branched C3-C4 saturated alkyl group such as methyl or ethyl.

[0232] Preferably, the compounds of formula (I) and the tautomer (!) or their salts, their optical isomers, racemates, and / or solvates such as hydrates and their derivatives, alone or as a mixture

[0233] have the following meanings:

[0234] Ri is a hydrogen atom; and

[0235] R2 denotes a radical chosen from

[0236] a) a hydrogen atom, and

[0237] b) a linear C1-C5 or branched C3-C5 or cyclic C3-C8 saturated hydrocarbon group such as C5-C6, substituted by one or more groups, which may be the same or different, chosen from v) -C(O)-O-R3, preferably substituted by a group iii) -C(O)-O-R3; R2 is even more preferably a linear C1-C4 or branched C3-C4 saturated hydrocarbon group substituted by a group iii) -C(O)-OR3; and

[0238] R3 denotes a radical chosen from

[0239] a) a hydrogen atom, and

[0240] b) a linear C1-C4 or branched C3-C4 saturated alkyl group such as methyl or ethyl.

[0241] According to another preferred embodiment, the compounds of formula (I) and the tautomer (!) are chosen from the compounds of formula (II) below and also the tautomers thereof of formula (II') below, the salts thereof, the solvates thereof and the optical isomers thereof, and the racemates thereof, alone or as a mixture: O Il X (if YTYH '"R3 O xn ô (II) (il')

[0242] In formula (II) and (II'), R1 and R3 have the same meaning as R1 and R3 for the compounds of formula (I) and (I'), and X denotes an alkylene radical -(CH2)n- with n being an integer ranging inclusively from 1 to 10, preferably from 1 to 6, more preferably from 1 to 4, such that 1, preferably R3 represents a hydrogen atom.

[0243] Among the compounds of formula (I), the following compounds are preferably used, and their tautomer (I') or their salts, their optical isomers, racemates, and / or solvates such as hydrates and their derivatives, alone or in mixture: No. Structure Chemical Name CAS No. 1 Xy Y' YZ '"i / or 1 i HA - 'Y, 'N'' '-SH N-ethyl-2-thioxo-1,2-dihydropyridine-3-carboxamide 91859-75-5 2 N-méthyl-2-thioxo-1,2-d ihy dropyridine- 3 -c arbox amide 91859-74-4 3 ••V. .-‘‘s •'■"'•K SZ v‘ t r N-octyl-2-thioxo-1,2-dih ydropyridine-3-carboxa mide 91859-77-7 4 H K 'V jx rit N-benzyl-2-thioxo-1,2-d ihy dropyridine- 3 -c arbox amide 91859-79-9 5 Z / Vx ,,------s Hs!--( z M / / \\ / X \ / \\ - X 0 N-phényl-2-thioxo-1,2-d ihy dropyridine- 3 -c arbox amide 104857-16-1 6 Q Z^ z'"’ "<v"' 'sir'" U H '’W' v H N-cyclohexyl-2-thioxo-1 ,2-dihydropyridine-3-car boxamide 91859-78-8 7 ,,.J N-[2-(4-méthoxyphényl) éthyl] -2-thioxo-1,2-dihy dropyridine-3-carboxam ide 923682-88-6 8 ..A.x N-(2-méthylpropyl)-2-th ioxo-1,2-dihydropyridin e-3-carboxamide 1100027-79-9 9 XX' X-"' $ H N-pentyl-2-thioxo-1,2-di hydropyridine-3-carboxa mide 330667-57-7 10 •fl______. Y î ~ ~ “ N-nonyl-2-thioxo-1,2-di hydropyridine-3-carboxa mide 1031149-44-6 11 / \ 'X >-4' X \ N-(2-hydroxyéthyl)-2-th ioxo-1,2-dihydropyridin e-3-carboxamide 12 h J i h । '^s "^ks ri: -S x-'' '.< N,N-diéthyl 2-mercaptonicotinamide 13 '^jrZ LX ( v^« P YM.;. N-éthyl-N-(2-hydroxyét hyl)-2-thioxo-1,2-dihydr opyridine-3-carboxamid e 14 S | N-(2,3-dihydroxypropyl )-2-thioxo-1,2-dihydrop yridine-3-carboxamide 15 U .J'x < •■■' x. ■ . ---H N-(1,3-dihydroxypropan-2-yl)-2-thioxo-1,2-dihydropyridine-3-carboxamide 16 V"' hsc N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]a ethyl laninate 17 ... •:>' N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]p henyl ethyl alaninate 18 X Xy>- N-methyl-N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycinate ethyl 19 <••'.■ ■'X: N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]g glycinate ethyl 20 s G N- [(2-thioxo-1,2-dihydr opyridin-3-yl)carbonyl]g lycine 21 .■Y. ^0 y ^y" 'yA' H N-methyl-N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycine 22 X Ax N,N-bis(2-hydroxyethyl )-2-thioxo-1,2-dihydrop yridine-3-carboxamide 23 AA TI N-(3-methoxypropyl)-2-thioxo-1,2-dihydropyridi ne-3-carboxamide 24 r îi Y .YY. N-butyl-2-thioxo-1,2-di hydropyridine-3-carboxa mide

[0244] Among these compounds, the following compounds are more particularly preferred: No. Structure Chemical Name CAS No. 1 Y Ay' ' ir ' NHH N-ethyl-2-thioxo-1,2-dihydropyridine-3-carboxamide 91859-75-5 2 5¾ N-methyl-2-thioxo-1,2-dihydropyridine-3-carboxamide 91859-74-4 4 N-benzyl-2-thioxo-1,2-dihydropyridine-3-carboxamide 91859-79-9 X'''^^x"' \{X' amide 6 0 f \ 'xrX'"' ^---^ H dropyridine-3-carboxam ide 923682-88-6 9 N-pentyl-2-thioxo-1,2-di hydropyridine-3-carboxa mide 330667-57-7 11 \z HPX^H f Z\ J ' '' r;H N-(2-hydroxyethyl)-2-th ioxo-1,2-dihydropyridin e-3-carboxamide 12'"XGX^;; 1 (N,N-diethyl 2-mercaptonicotinamide 14 ri. f N-(2,3-dihydroxypropyl)-2-thioxo-1,2-dihydrop yridine-3-carboxamide 5- c 15 „0H 0 N-(1,3-dihydroxypropan ns -2-yl)-2-thioxo-1,2-dihy Cï K .-¼ Hi' X..." H 5 dropyridine-3-carboxam ide 16 1. .--K -□ fy Y y K y HSC N- [(2-thioxo-1,2-dihydr opyridin-3-yl)carbonyl]a ethyl laninate 17 ( gy UH $ XY N- [(2-thioxo-1,2-dihydr opyridin-3-yl)carbonyl]p henyl ethyl alaninate 18 \ -■■* L'x '•■■ 4 J. ... .= yy G. '1 N-methyl-N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]ethyl glycinate 19 ..,..,1.......... i ;! ' î< N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]g ethyl lycinate 20 1 N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]g lycine 21 CK OH >r' H N-methyl-N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycine

[0245] More preferably, among these compounds, the following compounds are more particularly preferred: No. Structure Chemical Name CAS No. 1 .. .1 zs. HHH N-ethyl-2-thioxo-1,2-dihydropyridine-3-carboxamide 91859-75-5 9 ¢. ''■■vV'' ■ ;3 im N-pentyl-2-thioxo-1,2-dihydropyridine-3-carboxamide 330667-57-7 16 rT » r" N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]a ethyl laninate 18 H | tj ''n N-methyl-N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl] ethyl glycinate 19 hr H N- [(2-thioxo-1,2-dihydr opyridin-3-yl)carbonyl]g ethyl lycinate 20 N- [(2-thioxo-1,2-dihydr opyridin-3-yl)carbonyl]g lycine 21 CHS H N-methyl-N-[(2-thioxo-1,2-dihydropyridin-3-yl) carbonyl] wisteria

[0246] Even more preferably, among these compounds, the following compounds are more particularly preferred: No. Structure Chemical Name CAS No. 18 N-methyl-N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]ethyl glycinate 19 0 XS-y ( yvy H N- [(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]g ethyl lycinate

[0247] In the most preferred embodiment, the compound according to the present invention is as follows:

[0248] All of the above compounds can be obtained by a chemical process known to those skilled in the art, from commercially available reagents.

[0249] The thiopyridinone compound (1) may be prepared according to the method described, for example, in EP-A-3390363 or WO 2017 / 102349, which is incorporated herein by reference.

[0250] The thiopyridinone compound (1) may be an active ingredient or an active compound in cosmetic or dermatological products. The term "active" ingredient or compound as used herein means an ingredient or compound that has an active cosmetic or dermatological property, such as antioxidant, whitening, UV filtering, and antibacterial effects. The thiopyridinone compound (1) used in the present invention may function as a depigmenting, bleaching, or bleaching agent, and thus the composition according to the present invention may be used as a bleaching product or as a cosmetic composition for bleaching a keratinous material.

[0251] The thiopyridinone compound (1) can be used as an agent for depigmenting, bleaching or whitening the skin, body hair, eyelashes or hair, and also the lips and / or nails, and preferably the skin, in particular for removing pigmentation spots or aging spots, and / or as an anti-tanning agent.

[0252] The amount of the thiopyridinone compound(s) (1) in the composition according to the present invention may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more, relative to the total weight of the composition.

[0253] Furthermore, the amount of the thiopyridinone compound(s) (1) in the composition according to the present invention may be 10% by weight or less, preferably 5% by weight or less, and more preferably 3% by weight or less, relative to the total weight of the composition.

[0254] The amount of the thiopyridinone compound(s) (1) in the composition according to the present invention may range from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, more preferably from 0.1% to 3% by weight, relative to the total weight of the composition.

[0255] (Lipophilic antioxidant)

[0256] The composition according to the present invention comprises (2) at least one lipophilic antioxidant. Two or more lipophilic antioxidants may be used in combination. Thus, a single type of lipophilic antioxidant or a combination of different types of lipophilic antioxidant may be used.

[0257] According to the present invention, antioxidants are compounds that can suppress or reduce oxidation. Antioxidants can capture or remove active oxygen species such as singlet oxygen, hydroxyl radical, superoxide anion radical, hydrogen peroxide.

[0258] Antioxidants can deactivate the various free radical forms that may be present in the skin.

[0259] The lipophilic antioxidant (2) is different from the thiopyridinone compound (1).

[0260] A reducing agent can be used as a lipophilic antioxidant (2).

[0261] Lipophilic antioxidant (2) here means that the partition coefficient of the antioxidant between n-butanol and water is > 1, more preferably > 10 and even more preferably > 100.

[0262] The lipophilic antioxidant agent (2) is hydrophobic, and is not a hydrophilic antioxidant agent such as ascorbic acid or glutathione.

[0263] As a lipophilic antioxidant (2), phenolic antioxidants that have a hindered phenol structure or a semi-hindered phenol structure within the molecule may be mentioned. Specific examples of such compounds include

[0264] 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid) which has the INCI name pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2-tert-butyl-4-methoxyphenol, 3-tert-butyl-4-methoxyphenol, mono- or di- or tri-(a-methylbenzyl)phenol, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, the tris[N-(3,5-di-tert-butyl-4-hydroxybenzyl)]isocyanurate, the 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, butylidene-1,1bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionato]methane, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-l,l-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, l,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 2,2-thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], l,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-l,3,5-triazine-2,4,6-trione, 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-l,3,5-triazine, acrylate 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, 4,6-bis[(octylthio)methyl]-o-cresol, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate and 1,6-hexanediolbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0265] As lipophilic antioxidant (2), mention may also be made of BHA (butylated hydroxyl anisole = 2-tert-butyl-4-methoxyphenol and / or 3-tert-butyl-4-methoxyphenol) and BHT (butylated hydroxyl toluene = di-tert-butyl 4-hydroxytoluene).

[0266] As a lipophilic antioxidant (2), vitamin E (or tocopherols and tocotrienol) and derivatives thereof, such as tocopheryl acetate, may also be mentioned.

[0267] As lipophilic antioxidant (2), mention may also be made of diphenyl acrylates, preferably alpha-cyanodiphenylacrylates which can be represented by the following general formula:

[0268] in which

[0269] one or both of R1 and R2 is independently a straight or branched chain C1-C30 alkoxy radical and any non-alkoxy radical R1 or R2 is hydrogen; and

[0270] R3 is a straight or branched chain C|-C| alkyl.

[0271] Alternatively, one or both of R1 and R2 is independently a C1-C2 alkoxy radical i_8 and any non-alkoxy radical R1 or R2 is hydrogen; and R3 is straight or branched chain C2-20 alkyl.

[0272] Alternatively, one or both of R1 and R2 is independently methoxy, and any non-methoxy R1 or R2 is hydrogen; and R3 is straight or branched chain C2-20 alkyl.

[0273] A suitable alpha-cyanodiphenylacrylate is ethylhexyl methoxycrylene, or 2-ethylhexyl 2-cyano-3-(4-methoxyphenyl)-3-phenylpropenoate, wherein R 1 is methoxy, R 2 is hydrogen, and R 3 is 2-ethylhexyl.

[0274] As a lipophilic antioxidant (2), mention may also be made of ferulic acid and derivatives thereof (esters, salts, etc.). In particular, mention may be made of esters of ferulic acid and C1-C30 alcohols, in particular methyl ferulate, ethyl ferulate, isopropyl ferulate and octyl ferulate, as well as oryzanol, in particular gamma-oryzanol, such as oryzanol-A, oryzanol-C and campesteryl ferulate.

[0275] As a lipophilic antioxidant (2), non-phenolic antioxidants may be mentioned. For example, a non-phenolic compound including sulfur including at least one sulfur atom may be mentioned, in particular thiodipropionic acid and derivatives thereof (esters, salts, etc.), such as dilauryl thiodipropionate, dimyristyl thiodipropionate and distearyl thiodipropionate.

[0276] It is preferable that the lipophilic antioxidant (2) is selected from the group consisting of dibutylhydroxytoluene (BHT), ethylhexyl methoxycrylene, tocopheryl acetate, oryzanol, pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, dilauryl thiopropionate, and mixtures thereof.

[0277] The amount of the lipophilic antioxidant(s) (2) in the composition according to the present invention may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more, relative to the total weight of the composition.

[0278] Furthermore, the amount of the lipophilic antioxidant(s) (2) in the composition according to the present invention may be 10% by weight or less, preferably 5% by weight or less, and more preferably 3% by weight or less, relative to the total weight of the composition.

[0279] The amount of the lipophilic antioxidant(s) (2) in the composition according to the present invention may range from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, more preferably from 0.1% to 3% by weight, relative to the weight total composition.

[0280] The weight ratio of the amount of the thiopyridinone compound(s) (1) to the amount of the lipophilic antioxidant(s) (2), in the composition according to the present invention, may be 0.1 or more, preferably 0.4 or more, and more preferably 0.6 or more.

[0281] Furthermore, the weight ratio of the amount of the thiopyridinone compound(s) (1) to the amount of the lipophilic antioxidant(s), in the composition according to the present invention, may be 4 or less, preferably 3 or less, and more preferably 2 or less.

[0282] The weight ratio of the amount of the thiopyridinone compound(s) (1) to the amount of the lipophilic antioxidant(s), in the composition according to the present invention, may range from 0.1 to 4, preferably from 0.4 to 3, and more preferably from 0.6 to 2.

[0283] (pH correction agent)

[0284] The composition according to the present invention may comprise (3) at least one pH correcting agent (pH corrector). Two or more pH correcting agents may be used in combination. Thus, a single type of pH correcting agent or a combination of different types of pH correcting agents may be used.

[0285] As pH correction agent (3), at least one agent may be used acidifying agent and / or at least one basifying agent (alkaline agent).

[0286] The acidifying agent may be a monovalent or polyvalent acid, such as divalent.

[0287] The acidifying agents may be, for example, mineral (inorganic) acids such as hydrochloric acid, sulfuric acid, phosphoric acid, or organic acids such as carboxylic acids, for example tartaric acid, citric acid and lactic acid, as well as sulfonic acids.

[0288] The basifying agent may be a monovalent or polyvalent base, such as divalent.

[0289] Basifying agents can be mineral (inorganic) or organic, or hybrid.

[0290] The mineral basifying agents may be chosen from aqueous ammonia; alkali metal carbonates or bicarbonates such as sodium or potassium carbonates and sodium or potassium bicarbonates; alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and mixtures thereof.

[0291] The organic basifying agents may be chosen from organic amines whose pKb at 25°C is less than 12, preferably less than 10, and even more advantageously less than 6. It should be noted that this is the pKb corresponding to the function of greatest basicity. In addition, the organic amines do not comprise any alkyl or alkenyl fatty chain comprising more than ten carbon atoms.

[0292] The organic basifying agent may be chosen, for example, from alkanolamines, oxyethylenated and / or oxypropylenated ethylenediamines, amino acids and amine compounds of formula (III) below:

[0293] in which

[0294] W represents a divalent C1-C6 alkylene radical optionally substituted by one or more hydroxyl groups or a C1-C6 alkyl radical, and optionally interrupted by one or more heteroatoms such as O and N, and

[0295] Rx, Ry, Rz and Rt, which may be identical or different, represent a hydrogen atom or a C1-C6 alkyl, C1-C6 hydroxyalkyl, or C1-C6 aminoalkyl radical.

[0296] Examples of amine compounds of formula (III) which may be mentioned include 1,3-diaminopropane, 1,3-diamino-2-propanol, spermine and spermidine.

[0297] The term “alkanolamine” designates an organic amine comprising a primary, secondary or tertiary amine function, and one or more linear or branched CrC8 alkyl groups carrying one or more hydroxyl radicals.

[0298] Alkanolamines such as monoalkanolamines, dialkanolamines or trialkanolamines comprising one to three identical or different C1-C4 hydroxyalkyl radicals may be suitable for the present invention. Among the compounds of this type, mention may be made of monoethanolamine (MEA), diethanolamine, triethanolamine, monoisopropa-nolamine, diisopropanolamine, N-dimethylaminoethanolamine, 2-amino-2-methyl-1-propanol, triisopropanolamine, 2-amino-2-methyl-1,3-propanediol, 3-amino-1,2-propanediol, 3-dimethylamino-1,2-propanediol and tris(hydroxymethylamino)methane.

[0299] The amino acids which can be used are of natural or synthetic origin, in their L, D or racemic form, and comprise at least one acid function chosen more particularly from the carboxylic acid, sulfonic acid, phosphonic acid or phosphoric acid functions. The amino acids can be in neutral or ionic form.

[0300] As amino acids which may be used in the present invention, mention may in particular be made of aspartic acid, glutamic acid, alanine, arginine, omithine, citrulline, asparagine, carnitine, cysteine, glutamine, glycine, histidine, lysine, isoleucine, leucine, methionine, N-phenylalanine, proline, serine, taurine, threonine, tryptophan,

[0301]

[0302] tyrosine and valine. It may be preferable that the amino acids are basic amino acids comprising an additional amine function optionally included in a ring or in a ureido function. Such basic amino acids may preferably be chosen from those corresponding to formula (IV) below:

[0303]

[0304] in which R represents a group chosen from:

[0305]

[0306]

[0307]

[0308]

[0309]

[0310]

[0311] -(CH2)3-NH2, -(CH2)2-NH2, -(CH2)2-NH-CO-NH2, and Compounds corresponding to formula (IV) include histidine, lysine, arginine, ornithine and citrulline. The organic basifying agent may be chosen from heterocyclic organic amines. In addition to histidine, which has already been mentioned among the amino acids, pyridine, piperidine, imidazole, triazole, tetrazole and benzimidazole may be mentioned in particular. The organic basifying agent may also be chosen from amino acid dipeptides. Amino acid dipeptides that may be used in the present invention include, in particular, carnosine, anserine and balein. The organic basifying agent may also be chosen from compounds comprising a guanidine function. As amines of this type which may be used in the present invention, in addition to arginine, which has already been mentioned as an amino acid, mention may be made in particular of creatine, creatinine, 1,1-dimethylguanidine, 1,1-diethylguanidine, glycocyamine, metformin, agmatine, N-amidinoalanine, 3-guanidinopropionic acid, 4-guanidinobutyric acid and 2-([amino(imino)methyl]amino)ethane-1-sulfonic acid.

[0312] In a preferred embodiment of the present invention, the organic basifying agent may be selected from amino acids, preferably basic amino acids, and more preferably arginine, lysine, histidine or mixtures thereof. Even more preferably, the organic basifying agent may be arginine.

[0313] Hybrid compounds that may be mentioned include salts of the aforementioned amines with acids such as carbonic acid or hydrochloric acid. Guanidine carbonate or monoethanolamine hydrochloride may in particular be used.

[0314] The pH correcting agent (3) may be present in an amount of 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more, relative to the total weight of the composition.

[0315] The pH correcting agent (3) may be present in an amount of 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less, relative to the total weight of the composition.

[0316] The pH correcting agent (3) may be present in an amount ranging from 0.01% to 15% by weight, preferably from 0.05% to 10% by weight, and more preferably from 0.1% to 5% by weight or less, relative to the total weight of the composition.

[0317] It is preferable that the composition according to the present invention has a pH of 4.5 or higher, and more preferably 5 or higher.

[0318] It is preferable that the composition according to the present invention has a pH of 6.5 or less, and more preferably 6 or less.

[0319] It is preferable that the composition according to the present invention has a pH of 4.5 to 6.5, and more preferably of 5 to 6.

[0320] The pH of the composition means the pH of the aqueous phase of the composition according to the present invention. The pH can be measured in accordance with JIS Z 8802 (2011).

[0321] It may be preferable that at least one buffer or buffering agent is also used, as pH correcting agent (3), in combination with the acidifying agent and / or the basifying agent, in order to stabilize the pH of the composition according to the present invention.

[0322] As the buffer, any of the commonly known buffers may be used. For example, salts of acids or bases, preferably salts of weak acids or weak bases, may be used. For example, sodium citrate or sodium lactate may be used as the buffer, if citric acid or lactic acid is used as the acidifying agent.

[0323] (Water)

[0324] The composition according to the present invention may comprise (4) water.

[0325] The amount of water (4) in the composition according to the present invention may be 30% by weight or more, preferably 35% by weight or more, and more preferably 40% by weight or more, relative to the total weight of the composition.

[0326] Furthermore, the amount of water (4) in the composition according to the present invention may be 99% by weight or less, preferably 95% by weight or less, and more preferably 90% by weight or less, relative to the total weight of the composition.

[0327] The amount of water (4) in the composition according to the present invention may be from 30% to 99% by weight, preferably from 35% to 95% by weight, and more preferably from 40% to 90% by weight, relative to the total weight of the composition.

[0328] (Other optional additives)

[0329] The composition according to the present invention may also comprise any other optional additive(s) usually used in the field of cosmetics, chosen, for example, from solvents, chelating agents, cosmetic active agents other than ingredient (1), such as oils, preservatives, and mixtures thereof.

[0330] It is part of the ordinary operations for a person skilled in the art to adjust the nature and quantity of the above optional additives which may be present in the composition according to the present invention in such a way that the desired cosmetic properties are not affected thereby.

[0331] As for the solvents, one or more cosmetically acceptable organic solvents may be mentioned, which may be alcohols: in particular monovalent alcohols such as ethyl alcohol, isopropyl alcohol, benzyl alcohol and phenylethyl alcohol; diols such as ethylene glycol, propylene glycol and butylene glycol; other polyols such as glycerol, a sugar and carbohydrate alcohols; and ethers such as monomethyl, monoethyl and monobutyl ethers of ethylene glycol, monomethyl, monoethyl and monobutyl ether of propylene glycol, and monomethyl, monoethyl and monobutyl ethers of butylene glycol.

[0332] The organic solvent(s) may be present in a concentration of 0.01% to 30% by weight, preferably 0.1% to 20% by weight, and more preferably 1% to 10% by weight, relative to the total weight of the composition.

[0333] [Preparation]

[0334] The composition according to the present invention can be prepared by mixing the essential and optional ingredients described above in a conventional manner.

[0335] For example, the composition according to the present invention can be prepared by a process comprising the steps of

[0336] mixture of

[0337] (1) at least one thiopyridinone compound; and

[0338] (2) at least one lipophilic antioxidant.

[0339] It is possible to further mix any of the optional ingredients.

[0340] The mixing may be carried out at any temperature such as room temperature (e.g., 20-25°C, preferably 25°C), preferably at a temperature of 30°C or higher, preferably 40°C or higher, and more preferably 50°C or higher. It is preferable to further mix with any of the optional ingredients described above such as a pH correcting agent.

[0341] The form of the composition according to the present invention is not particularly limited, and may take various forms such as a W / O emulsion, an O / W emulsion, a gel, a solution, or the like. It is preferable that the composition according to the present invention is in the form of an emulsion, preferably an O / W emulsion, and more preferably an O / W gel emulsion.

[0342] [Cosmetic process]

[0343] The composition according to the present invention can be used as a cosmetic or dermatological composition, preferably as a cosmetic composition, and more preferably as a cosmetic composition for a keratinous material. As keratinous material, mention may be made of the skin, the scalp, the hair, the mucous membranes such as the lips and the nails.

[0344] The composition according to the present invention can be used as a depigmentation, bleaching or whitening product for a keratinous material such as the skin. In particular, the composition according to the present invention can be used as a whitening product.

[0345] The composition according to the present invention may preferably be intended for application to a keratinous material such as the skin, the scalp and / or the lips, preferably the skin.

[0346] Thus, the composition according to the present invention can be used for a cosmetic process for a keratinous material, preferably the skin. In one embodiment, the present invention relates to a cosmetic process, preferably a whitening process, for a keratinous material, preferably the skin, comprising the step of applying to the keratinous material the composition according to the present invention.

[0347] The composition according to the present invention can be used as a topical cosmetic composition in the form of a lotion, a milk, a cream, a gel, a paste, a serum, a mousse or an aerosol.

[0348] [Use]

[0349] The present invention also relates to a use of (2) at least one an- lipophilic antioxidant in a composition comprising (1) at least one compound selected from the compounds of formula (I) below, the tautomers of formula (I) below, the salts thereof, the solvates, such as hydrates, of these, the optical isomers thereof, the racemates thereof, and the mixtures thereof:

[0350] (I) (!')

[0351] in which

[0352] Ri denotes a radical chosen from

[0353] a) a hydrogen atom, and

[0354] b) a linear C1-C10 or branched C3-C10 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, chosen from

[0355] i) -O-R3, and

[0356] ii) -S-R3,

[0357] and

[0358] R2 denotes a radical chosen from

[0359] a) a hydrogen atom,

[0360] b) a linear C1-C12 or branched C3-C12 or cyclic C3-C8 saturated hydrocarbon group optionally substituted by one or more groups, which may be the same or different, chosen from

[0361] i) -O-R3,

[0362] ii) -S-R3,

[0363] iii) -C(O)-O-R3, and

[0364] iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more CrC8 alkoxy radicals, and

[0365] c) a C5-C12 aryl group, optionally substituted by one or more hydroxyls and / or by one or more CrC8 alkoxy radicals

[0366] in which

[0367] R3 denotes a radical chosen from

[0368] a) a hydrogen atom, and

[0369] b) a linear C1-C10 or branched C3-C10 saturated alkyl group

[0370] in order to stabilize the compound(s) (1).

[0371] The term “stabilize” has the same meaning as increase stability.

[0372] The use according to the present invention can increase the stability of the thiopyridinone compound (1) in the composition comprising it.

[0373] Therefore, the use according to the present invention can enable a composition comprising the thiopyridinone compound (1) to be stored for a long period of time, and in particular even under hot conditions.

[0374] The above explanations relating to the thiopyridinone compound (1) and the lipophilic antioxidant (2) for the compositions according to the present invention can also be applied to those used in the use according to the present invention.

[0375] The composition in the use according to the present invention may include any of the optional ingredients as explained above for the compositions according to the present invention.

[0376] EXAMPLES

[0377] The present invention will be described in more detail with the aid of examples. However, these examples should not be construed as limiting the scope of the present invention. [Examples 1-6 and Comparative Example 1]

[0378] [Preparation]

[0379] Each of the compositions according to Examples 1 to 6 and Comparative Example 1 was prepared by mixing the ingredients listed in Table 1. The numerical values ​​for the amounts of the ingredients are all based on "% by weight" as active materials.

[0380] [Tableauxl] Ingredients Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. Comp. 1 Water qsplOO qsplOO qsplOO qsplOO qsplOO qsplOO qsplOO Glycerin 3 3 3 3 3 3 3 Butylene glycol 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Preservatives 0.7 0.7 0.7 0.7 0.7 0.7 0.7 N-[(2-thioxo-l,2-dihy dropyridin-3-yl)carbo nyl]glycine 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Potassium hydroxide 0.34 0.34 0.34 0.34 0.34 0.34 0.34 C13-16 isoparaffin 2 2 2 2 2 2 2 Thickeners 0.75 0.75 0.75 0.75 0.75 0.75 0.75 Dilauramidoglutamid e lysine sodium 0.4 0.4 0.4 0.4 0.4 0.4 0.4 3,5-Di-tert-butyl-4-h ydroxytoluene 0.5 - - - - - - Ethylhexyl methoxycrylene - 0.5 - - - - - Tocopheryl acetate - - 0.5 - - - - Oryzanol - - - 0.5 - - - Pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnam ate - - - - 0.5 - - Dilauryl thiodipropionate - - - - - 0.5 - UV filters 25 25 25 25 25 25 25 Parkii buty-rospermum butter 1 1 1 1 1 1 1 (shea) Sorbitan oleate 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Poly (C10-30 alkyl acrylate) 0.5 0.5 0.5 0.5 0.5 0.5 0.5

[0381] N-[(2-thioxo-l,2-dihydropyridin-3-yl)carbonyl]glycine (2-MERCAPTONICOTINOYL GLYCINE): Compound 20

[0382] [Evaluations]

[0383] (Remaining level of thiopyridinone compound)

[0384] The amount of the thiopyridinone compound in each of the compositions according to Examples 1 to 6 and Comparative Example 1 was measured by HPLC-UV assay at the following times.

[0385] Instant (1) Just after the preparation of the composition (T0)

[0386] Instant (2) 2 weeks after preparation, where the composition was kept in a hermetically sealed container and protected from light at 55°C

[0387] The details of the HPLC-UV assay were as follows.

[0388] Apparatus / Reagents Ultra Performance LC (UPLC) HPLC System RP18 HPLC Column, 1.7 pm, 2.1 mm x 100 mm Eluent A 0.1% phosphoric acid in water Eluent B Methanol

[0389] HPLC conditions UV Detector 296 nm Column Temp. 30 °C Flow Rate 0.4 ml / min Injection Volume 1 pl Mobile Phase Gradient Mode A: 0.1% Phosphoric Acid in Water B: Methanol

[0390] The remaining level of thiopyridinone compound was determined by the following equation:

[0391] Remaining rate of thiopyridinone compound (%) =

[0392] Amount of thiopyridinone compound at Time (2) / Amount of thio- compound Instant pyridinone (1)

[0393] The results are shown in the row “Remaining level of thiopyridinone compound (%)” in Table 2 below.

[0394] The remaining level of thiopyridinone compound was also classified according to the following criteria:

[0395] Very good: 90% or more

[0396] Good: more than 85% to less than 90%

[0397] Bad: 85% or less

[0398] The results are shown in the “Stability” row in Table 2 below.

[0399] [Tables2] Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. Comp. 1 Remaining rate (%) of thiopyridinone compound 87 89 89 92 92 89 85 Stability Good Good Good Very good Very good Good Bad

[0400] (Results)

[0401] The compositions according to Examples 1 to 6, each of which included a thiopyridinone compound and a variety of lipophilic antioxidants, were more stable, even at elevated temperature, such that a greater amount of the thiopyridinone compound remained, than with the composition according to Comparative Example 1 which did not include a lipophilic antioxidant.

Claims

Claims

1. A composition, preferably a cosmetic composition, comprising (1) at least one compound selected from the compounds of formula (I) below, the tautomers of formula (!') below, the salts thereof, the solvates, such as hydrates, of these, the optical isomers thereof, the racemates thereof, and the mixtures thereof: (i) (D in which Ri denotes a radical chosen from a) a hydrogen atom, and (b) a linear C1-C10 or branched C3-C10 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, selected from i) -O-R3, and ii) -S-R3, And R2 denotes a radical chosen from a) a hydrogen atom, (b) a linear C1-C12 or branched C3-C12 or cyclic C3-C8 saturated hydrocarbon group optionally substituted by one or more groups, which may be the same or different, chosen from i) -O-R3, ii) -S-R3, iii) -C(O)-O-R3, and iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals, and (c) a C5-C12 aryl group, optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals in which R3 denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C10-C10 or branched C3-C10 alkyl group; and (2) at least one lipophilic antioxidant selected from the group consisting of dibutylhydroxytoluene (BHT), ethylhexyl methoxycrylene, oryzanol, pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, dilauryl thiopropionate, and mixtures thereof.

2. Composition according to claim 1, wherein: Ri of formula (I) and (!') represents a hydrogen atom; or Ri of formula (I) and (!') represents a linear (C1-C10) alkyl group or a branched (C3-C10) alkyl group, in particular a linear (C1-C6) alkyl group or a branched (C3-C6) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably ethyl, in particular said alkyl group of Ri'is not substituted.

3. Composition according to claim 1 or 2, wherein: R2 of formula (I) and (!') represents a hydrogen atom; or R2 of formula (I) and (!') represents a linear alkyl group (C1-C10) or a branched alkyl group (C3-C10), in particular a linear alkyl group (C1-C6) or a branched alkyl group (C3-C6), such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably a methyl or ethyl group; said alkyl group of R2 being unsubstituted.

4. Composition according to claim 1 or 2, wherein: R2 of formula (I) and (!') represents a linear alkyl group (C1-C10) or a branched alkyl group (C3-C10), in particular a linear alkyl group (C1-C6) or a branched alkyl group (C3-C6), such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl; said alkyl group being substituted by one or more groups chosen from i), ii), iii) and iv) as defined above, preferably said alkyl group being substituted by one or two groups chosen from i), ii) and iii), more preferably by one or two groups chosen from i) and iii), better substituted by a group iii) such as carboxy.

5. Composition according to claim 1 or 2, in which: R2 of formula (I) and (!') represents a cycloalkyl group (C3-C8), preferably a cycloalkyl group (C5-C7) such as cyclohexyl; or R2 of formula (I) and (!') represents a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals, preferably a phenyl group in particular unsubstituted.

6. A composition according to any one of claims 1 to 5, wherein: R3 of formula (I) and (!') represents a hydrogen atom; or R3 of formula (I) and (!') represents a linear C1-C10 or branched C3-C10 saturated alkyl group; in particular a linear (C1-C6) alkyl group or a branched (C3-C6) alkyl group, preferably a (C1-C4) alkyl group such as a methyl group.

7. Composition according to any one of claims 1 to 6, in which: R 1 of formula (I) and (!') represents a radical chosen from a) a hydrogen atom, and b) a linear C 1 -C 6 or C 3 -C 6 branched saturated alkyl group optionally substituted by one or more groups, which may be the same or different, chosen from i) -O-R 3, and ii) -S-R 3, preferably optionally substituted by one or more groups i);R2 of formula (I) and (!') represents a radical chosen from a) a hydrogen atom, and b) a linear C1-C10 or branched C3-C10 or cyclic C3-C8 such as C5-C6 saturated hydrocarbon group, optionally substituted by one or more groups, which may be the same or different, chosen from i) -O-R3, ü) -S-R3, iii) -C(O)-O-R3, and iv) a phenyl group optionally substituted by one or more hydroxyls and / or by one or more C1-C4 alkoxy radicals such as methoxy, preferably substituted by one or more groups chosen from i) and iii), preferably iii) such as carboxy; and R3 of formula (I) and (!') represents a radical chosen from;

8. a) hydrogen atony, and b) a linear C1-C6 or branched C3-C6 saturated alkyl group, preferably, the compounds of formula (I) and the tautomer (!), the salts thereof, the solvates, such as hydrates, thereof, the optical isomers thereof, the racemates thereof, and the mixtures thereof, have the following meanings: Ri of formula (I) and (!') represents a radical chosen from: a) a hydrogen atom, and b) a linear C1-C4 or branched C3-C4 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, selected from i) -OR3more preferably unsubstituted; R2 of formula (I) and (!') represents a radical chosen from a) a hydrogen atom, and (b) a linear C1-C10 or branched C3-C10 or cyclic C3-C8 such as C5-C6 saturated hydrocarbon group, optionally substituted by one or more groups, which may be the same or different, chosen from i) -O-R3, iii) -C(O)-O-R3, and iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C4 alkoxy radicals; and R3 of formula (I) and (!') represents a radical chosen from: a) a hydrogen atom; b) a linear C1-C4 or branched C3-C4 saturated alkyl group such as methyl or ethyl. Composition according to any one of claims 1 to 7, in which: compound (1) is selected from compounds 1 to 24 below, tautomers thereof, salts thereof, solvates, such as hydrates, thereof, optical isomers thereof, racemates thereof, and mixtures thereof, in particular compounds 1, 2, 4, 6, 7, 9, 11, 12, 14, 15, 16, 17, 18, 19, 20 or 21, more particularly 1, 9, 16, 18, 19, 20 or 21, preferably 18, 19, 20 or 21, and more preferably 20: No. Structure Chemical name 1 F '1 H H N-éthyl-2-thioxo-1,2-dihydro pyridine-3-carboxamide 2 zÿ \x / x / s\ s, / s \ N-méthyl-2-thioxo-1,2-dihyd ropyridine-3-carboxamide 3 / X' VX- '"S ,..•■''* ■■•. ;,X'X .X'X X’"'' N-octyl-2-thioxo-1,2-dihydro pyridine-3-carboxamide 4 'X- N-benzyl-2-thioxo-1,2-dihydr opyridine-3-carboxamide 5 x> 7“t......} \ / «S p SA N-phényl-2-thioxo-1,2-dihyd ropyridine-3-carboxamide 6 H k A -4 H 5 N-cyclohexyl-2-thioxo-1,2-di hydropyridine-3-carboxamid e 7 N-[2-(4-méthoxyphényl)éthyl ] -2-thioxo-1,2-dihydropyridin e-3-carboxamide 8 ï h h j N-(2-méthylpropyl)-2-thioxo -1,2-dihydropyridine-3-carbo xamide 9 if'' “r^y' ’■■•--■"■■ 'Vs--'* N-pentyl-2-thioxo-1,2-dihydr opyridine-3-carboxamide 10 ri =. ... r r " N-nonyl-2-thioxo-1,2-dihydr opyridine-3-carboxamide 11 0 1, .. '■ X v. n XY x'x. § ’ GH ' ?|Z '''''l H N-(2-hydroxyéthyl)-2-thioxo-1,2-dihydropyridine-3-carbox amide 12 1 \ ... J "'\ / / / Z ' % I- / ■ N,N-diéthyl 2-mercaptonicotinamide 13 ü X -xy q......... V N-éthyl-N-(2-hydroxyéthyl)-2-thioxo-1,2-dihydropyridine -3-carboxamide 14 .L.. N-(2,3-dihydroxypropyl)-2-th ioxo-1,2-dihydropyridine-3-c arboxamide 15 N-(1,3-dihydroxypropan-2-yl)-2-thioxo-1,2-dihydropyridin e-3-carboxamide | b' : 16 ev, .b'V x—x .A ^!sx' ''"N" \ H / £ Ethyl N-[(2-thioxo-1,2-dihydropyri din- 3 - yl)carbony 1] alaninate 17 I Ethyl N-[(2-thioxo-1,2-dihydropyri din-3-yl)carbonyl]phenyl alaninate 18 •f ^vy''' 1 Ethyl N-methyl-N-[(2-thioxo-1,2-di hydropyridin-3-yl)carbonyl]glycinate 19 ,.,A, x'^'x X^x .x^:; Ethyl N-[(2-thioxo-1,2-dihydropyri din-3-yl)carbonyl]glycinate 20 N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycine 21 ■..2 / x / xr" hisr H N-methyl-N-[(2-thioxo-l,2-dihydropyridin-3-yl)carbonyl]g lycine 22 HN, ik. ioxo-1,2-dihydropyridine-3-c arboxamide 23 su N-(3-methoxypropyl)-2-thiox o-1,2-dihydropyridine-3-carb oxamide 24 SX N-butyl-2-thioxo-1,2-dihydro pyridine-3-carboxamide

9.

10. Cosmetic process, preferably a bleaching process, for a keratinous material, preferably the skin, comprising the step of: applying to the keratinous material the composition according to any one of claims 1 to 8. Use of (2) at least one lipophilic antioxidant selected from the group consisting of dibutylhydroxytoluene (BHT), ethylhexyl methoxycrylene, oryzanol, pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, dilauryl thiopropionate, and mixtures thereof these, in a composition comprising (1) at least one compound chosen from the compounds of formula (I) below, the tautomers of formula (!') below, the salts thereof, the solvates, such as hydrates, of these, the optical isomers of these, the racemates of these, and the mixtures of these: (i) (D in which Ri denotes a radical chosen from a) a hydrogen atom, and (b) a linear, branched, C1-C10 or C3-C10 saturated alkyl group optionally substituted by one or more groups, which may be the same or different, selected from i) -O-R3, and ii) -S-R3, And R2 denotes a radical chosen from a) a hydrogen atom, (b) a linear C1-C12 or branched C3-C12 or cyclic C3-C8 saturated hydrocarbon group optionally substituted by one or more groups, which may be the same or different, chosen from i) -O-R3, ü) -S-R3, iii) -C(O)-O-R3, and iv) a C5-C12 aryl group optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals, and (c) a C5-C12 aryl group, optionally substituted by one or more hydroxyls and / or by one or more C1-C8 alkoxy radicals in which R3 denotes a radical chosen from a) a hydrogen atom, and b) a saturated linear C1-C10 or branched C3-C10 alkyl group in order to stabilize the compound(s) (1).