Stabilization of thiopyridinone compound and composition comprising thiopyridinone compound

Abstract

To provide a composition including a thiopyridinone compound with increased stability of the thiopyridinone compound over time, in particular when the composition is maintained for a relatively long period of time at elevated temperature.SOLUTION: The present invention relates to a composition comprising: (1) at least one thiopyridinone compound; (2) at least one pH adjusting agent; and (3) water, wherein the pH of the composition is from 4.5 to 6.5. The present invention can provide a composition including the (1) thiopyridinone compound with increased stability of the (1) thiopyridinone compound over time, in particular even when the composition is maintained for a relatively long period of time at elevated temperature.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to the stabilization of thiopyridinone compounds in compositions that include the compounds. [Background technology]

[0002] At different times in life, some people notice darker and / or more colored spots on their skin, more particularly on the face and hands, giving the skin an inhomogeneous appearance. These spots are due to a high concentration of melanin, especially in the keratinocytes located on the surface of the skin.

[0003] For the purpose of treating pigmented blemishes, the use of effective, non-toxic topical depigmenting substances is most particularly desired.

[0004] For example, arbutin, niacinamide and kojic acid are known skin depigmenting agents.

[0005] On the other hand, WO2017 / 102349 discloses a novel bleaching or whitening agent, namely, a thiopyridinone compound, which can exhibit a strong bleaching or whitening effect by reducing the production of melanin. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO2017 / 102349 [Patent Document 2] EP-A-3390363 [Patent Document 3] WO2017 / 102349 Summary of the Invention [Problem to be solved by the invention]

[0007] However, it has been discovered that thiopyridinone compounds tend to become unstable over time in compositions, especially when the compositions containing the thiopyridinone compounds are maintained at elevated temperatures for relatively long periods of time.

[0008] It is therefore an object of the present invention to provide compositions comprising thiopyridinone compounds that have enhanced stability of the thiopyridinone compounds over time, particularly when the compositions are maintained at elevated temperatures for relatively long periods of time. [Means for solving the problem]

[0009] The above objectives are: (1) At least one compound selected from a compound of the following formula (I), a tautomer of the following formula (I'), a salt thereof, a solvate such as a hydrate thereof, an optical isomer thereof, a racemate thereof, and a mixture thereof:

[0010] [ka]

[0011] (In the formula, R1 is, a) hydrogen atoms, and b) Saturated linear C1-C 10 Or branched C3~C 10 are alkyl groups, which may be the same or different, i) -O-R3 and ii)-S-R3 Saturated linear C1-C optionally substituted with one or more groups selected from 10 Or branched C3~C 10 Alkyl group represents a group selected from R2 is a) a hydrogen atom; b) Saturated linear C1-C 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group, which may be the same or different, i) -O-R3, ii)-S-R3, iii) -C(O)-O-R3, and iv) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl Group Saturated linear C1-C optionally substituted with one or more groups selected from 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group; c) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl groups and Including, R3 is a) a hydrogen atom, and b) Saturated linear C1-C 10 Or C3~C 10 Alkyl group (representing a group selected from the group consisting of (2) at least one pH adjuster; (3)Water A composition comprising: This can be achieved by a composition having a pH of 4.5 to 6.5, preferably 5 to 6.

[0012] Preferably, R1 in formulae (I) and (I') represents a hydrogen atom or or R1 in formula (I) and (I') is a linear (C1-C 10 ) Alkyl group or branched (C3-C 10 ) 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 R1 being unsubstituted.

[0013] Preferably, R2 in formulae (I) and (I') represents a hydrogen atom or or R2 in formula (I) and (I') is a straight chain (C1-C 10 ) Alkyl group or branched (C3-C 10 ) 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 a methyl or ethyl group, said alkyl group of R2 being unsubstituted.

[0014] Preferably, R2 in formula (I) and (I') is a straight chain (C1-C 10 ) Alkyl group or branched (C3-C 10 ) may represent an 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 methyl or ethyl, said alkyl group being substituted with one or more groups selected from i), ii), iii) and iv) above, preferably said alkyl group being substituted with one or two groups selected from i), ii) and iii), more preferably being substituted with one or two groups selected from i) and iii), and better still being substituted with one group iii) as carboxy.

[0015] Preferably, R2 in formulae (I) and (I') represents a (C3-C8) cycloalkyl group, preferably a (C5-C7) cycloalkyl group, such as cyclohexyl; or R2 in formula (I) and (I') is a C5-C alkyl group optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 It may represent an aryl group, preferably in particular an unsubstituted phenyl group.

[0016] Preferably, R3 in formulae (I) and (I') represents a hydrogen atom or or R3 in formula (I) and (I') is a saturated linear C1-C 10 Or branched C3~C10 It may represent an alkyl group, in particular a straight-chain (C1-C6) alkyl group or a branched (C3-C6) alkyl group, preferably a (C1-C4) alkyl group, such as a methyl group.

[0017] More preferably, R1 in formula (I) and (I') is a) hydrogen atoms, and b) saturated linear C1-C6 or branched C3-C6 alkyl groups, which may be the same or different; i) -O-R3 and ii) -S-R3 a saturated linear C1-C6 or branched C3-C6 alkyl group, optionally substituted with one or more groups selected from, preferably one or more groups i) represents a group selected from R2 in formula (I) and (I') is a) a hydrogen atom; b) Saturated linear C1-C 10 Or branched C3~C 10 or a cyclic C3 to C8 hydrocarbon group, which may be the same or different, i) -O-R3, ii)-S-R3, iii) -C(O)-O-R3, and iv) a phenyl group optionally substituted with one or more hydroxyl and / or one or more C1-C4 alkoxy groups, e.g. methoxy; Optionally substituted with one or more groups selected from i) and iii), preferably substituted with one or more groups selected from iii), such as carboxy. 10 Or branched C3~C 10 or a cyclic C3 to C8 hydrocarbon group represents a group selected from R3 in formula (I) and (I') is a) a hydrogen atom, and b) Saturated linear C1-C6 or C3-C6 alkyl group represents a group selected from Preferentially, the compounds of formula (I) and the tautomers (I′), their salts, their solvates, such as their hydrates, their optical isomers, their racemates and their mixtures have the following meanings: R1 in formula (I) and (I') is a) a hydrogen atom, and b) saturated linear C1-C4 or branched C3-C4 alkyl groups, which may be the same or different, and which are optionally substituted, more preferably unsubstituted, with one or more groups selected from i) -OR3; represents a group selected from R2 in formula (I) and (I') is a) a hydrogen atom; b) Saturated linear C1-C 10 Or branched C3~C 10 or a cyclic C3 to C8, for example C5 to C6, hydrocarbon group, which may be the same or different, i) -O-R3, iii) -C(O)-O-R3, and iv) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C4 alkoxy groups. 12 Aryl Group Saturated linear C1-C optionally substituted with one or more groups selected from 10 Or branched C3~C 10 or a cyclic C3 to C8, e.g., C5 to C6, hydrocarbon group; represents a group selected from R3 in formula (I) and (I') is a) a hydrogen atom, b) saturated linear C1-C4 or branched C3-C4 alkyl groups, such as methyl or ethyl represents a group selected from

[0018] (1) The compound may be selected from the following compounds 1 to 24, their tautomers, their salts, their solvates such as hydrates, their optical isomers, their racemates, and mixtures thereof, particularly 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, more preferably 20.

[0019] [Table 1A]

[0020] [Table 1B]

[0021] [Table 1C]

[0022] [Table 1D]

[0023] The amount of the (1) compound in the composition according to the present invention may be 0.01% by mass to 10% by mass, preferably 0.05% by mass to 5% by mass, and more preferably 0.1% by mass to 3% by mass, based on the total mass of the composition.

[0024] (2) The pH adjusting agent may be selected from an acidifying agent, a basifying agent, and mixtures thereof.

[0025] The amount of (2) pH adjuster in the composition according to the present invention may be 0.01% by mass to 15% by mass, preferably 0.05% by mass to 10% by mass, and more preferably 0.1% by mass to 5% by mass, relative to the total mass of the composition.

[0026] The amount of (3) water in the composition according to the present invention may be 20% by mass to 99% by mass, preferably 30% by mass to 95% by mass, and more preferably 40% by mass to 90% by mass, based on the total mass of the composition.

[0027] The composition according to the invention may be for the whitening of keratinous materials, preferably the skin.

[0028] The present invention also relates to a cosmetic method, preferably a whitening method, for keratinous materials, preferably skin, comprising the steps of: applying the composition according to the invention to keratinous materials; The present invention also relates to a method, comprising:

[0029] Another aspect of the present invention is (1) at least one compound selected from a compound of the following formula (I), a tautomer of the following formula (I'), a salt thereof, a solvate such as a hydrate thereof, an optical isomer thereof, a racemate thereof, and a mixture thereof:

[0030] [ka]

[0031] (In the formula, R1 is, a) hydrogen atoms, and b) Saturated linear C1-C 10 Or branched C3~C 10 are alkyl groups, which may be the same or different, i) -O-R3 and ii)-S-R3 Saturated linear C1-C optionally substituted with one or more groups selected from 10 Or branched C3~C 10 Alkyl group represents a group selected from R2 is a) a hydrogen atom; b) Saturated linear C1-C 12 Or branched C3~C 12or a cyclic C3 to C8 hydrocarbon group, which may be the same or different, i) -O-R3, ii)-S-R3, iii) -C(O)-O-R3, and iv) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl Group Saturated linear C1-C optionally substituted with one or more groups selected from 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group; c) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups 12 Aryl groups and represents a group selected from R3 is a) a hydrogen atom, and b) Saturated linear C1-C 10 Or C3~C 10 Alkyl group represents a group selected from (2) Use of at least one pH adjusting agent in a composition comprising The use of the composition to control the pH of the composition to between 4.5 and 6.5 to stabilize the compound (1). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] As a result of extensive investigation, the inventors have discovered that it is possible to provide a thiopyridinone compound, or a composition comprising a thiopyridinone compound, in which the stability of the thiopyridinone compound over time is enhanced, particularly when the composition is maintained at elevated temperatures for relatively long periods of time.

[0033] Therefore, the composition according to the invention (1) At least one compound selected from the group consisting of a compound of the following formula (I), a tautomer of the following formula (I'), a salt thereof, a solvate such as a hydrate thereof, an optical isomer thereof, a racemate thereof, and a mixture thereof (hereinafter referred to as a "thiopyridinone compound"):

[0034] [ka]

[0035] (In the formula, R1 is, a) hydrogen atoms, and b) Saturated linear C1-C 10 Or branched C3~C 10 are alkyl groups, which may be the same or different, i) -O-R3 and ii)-S-R3 Saturated linear C1-C optionally substituted with one or more groups selected from 10 Or branched C3~C 10 Alkyl group represents a group selected from R2 is a) a hydrogen atom; b) Saturated linear C1-C 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group, which may be the same or different, i) -O-R3, ii)-S-R3, iii) -C(O)-O-R3, and iv) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl Group Saturated linear C1-C optionally substituted with one or more groups selected from 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group; c) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups.12 Aryl groups and represents a group selected from R3 is a) a hydrogen atom, and b) Saturated linear C1-C 10 Or branched C3~C 10 Alkyl group (representing a group selected from the group consisting of (2) at least one pH adjuster; (3)Water Including, The pH of the composition is from 4.5 to 6.5, preferably from 5 to 6.

[0036] The composition according to the present invention can exhibit enhanced stability of the (1) thiopyridinone compound contained therein.

[0037] In other words, the composition according to the present invention can enhance the stability of the (1) thiopyridinone compound therein. The term "stability" of the (1) thiopyridinone compound can be determined by the change in the amount of the (1) thiopyridinone compound in the composition according to the present invention during a specific period of time. Enhanced "stability" means that the change in the amount of the (1) thiopyridinone compound over time is further limited.

[0038] The compositions according to the present invention can exhibit enhanced stability of the (1) thiopyridinone compound therein, even when the compositions are maintained at elevated temperatures, such as 55° C., for relatively long periods of time, such as two weeks.

[0039] Therefore, the composition according to the present invention can be stored under high temperature conditions for a long period of time.

[0040] In addition, the enhanced stability of the (1) thiopyridinone compound can result in improved or enhanced bioavailability of the (1) thiopyridinone compound, which can function as a bleaching or whitening agent. Thus, the composition according to the present invention can provide an enhanced or improved bleaching or whitening effect.

[0041] The composition, use, etc. according to the present invention will be described in detail below.

[0042] [Composition] The composition according to the invention comprises (1) at least one thiopyridinone compound; (2) at least one pH adjuster, and (3)Water Including, The composition has a pH of 4.5 to 6.5.

[0043] The (1) thiopyridinone compound, (2) pH adjuster, and (3) water, as well as other features of the composition according to the present invention, are described below.

[0044] (Thiopyridinone compounds) The composition according to the present invention comprises at least one (1) thiopyridinone compound. Two or more (1) thiopyridinone compounds may be used in combination. Thus, a single type of (1) thiopyridinone compound or a combination of different types of (1) thiopyridinone compounds may be used.

[0045] (1) The thiopyridinone compound is selected from a compound of the following formula (I), a tautomer of the following formula (I′), a salt thereof, a solvate such as a hydrate thereof, an optical isomer thereof, a racemate thereof, and a mixture thereof:

[0046] [ka]

[0047] (In the formula, R1 is, a) hydrogen atoms, and b) Saturated linear C1-C 10 Or branched C3~C 10 are alkyl groups, which may be the same or different, i) -O-R3 and ii)-S-R3 Saturated linear C1-C optionally substituted with one or more groups selected from 10 Or branched C3~C 10 Alkyl group represents a group selected from R2 is a) a hydrogen atom; b) Saturated linear C1-C 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group, which may be the same or different, i) -O-R3, ii)-SR 3、 iii) -C(O)-O-R3, and iv) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl Group Saturated linear C1-C optionally substituted with one or more groups selected from 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group; c) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl groups and represents a group selected from R3 is a) a hydrogen atom, and b) Saturated linear C1-C 10 Or branched C3~C 10 Alkyl group (representing a group selected from the group consisting of

[0048] For purposes of this invention, unless otherwise specified: - Saturated linear C1-C 12 Or branched C3~C 12 The hydrocarbon group is a saturated linear C1-C 12 Or C3~C 12 Hydrocarbon group, preferably linear C1-C 10 Or branched C3~C 10A hydrocarbon group, more preferably a "linear (C1-C6)" corresponding to a linear C1-C6 or branched C3-C6 hydrocarbon group. 12 ) Alkyl or branched (C3-C 12 ) alkyl group". Preferentially, the linear or branched radicals may be selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl, hexyl, heptyl, octyl, nonyl and decyl. More preferentially, the saturated linear or branched alkyl radicals may be selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl and tert-butyl, pentyl, hexyl, heptyl and octyl, e.g. methyl, ethyl, n-pentyl, n-nonyl, isobutyl. - A saturated "cyclic C3-C8" hydrocarbon group is a monocyclic or bicyclic cycloalkyl group containing 3 to 8 carbon atoms, in particular a monocyclic cycloalkyl group in the range C5 to C7, such as a cyclohexyl group. - "Alkoxy group" refers to a group in which the alkyl group is linear or branched C1-C 16 , preferentially an alkyl-oxy group which is a C1-C8 hydrocarbon-based group. - when an alkoxy group is optionally substituted, this implies that the alkyl group is optionally substituted as described above. - an "aryl" group denotes a fused or non-fused monocyclic or bicyclic carbocyclic group containing 5 to 12 carbon atoms, preferably 6 to 10 carbon atoms, in which at least one ring is aromatic, preferentially the aryl group is a phenyl, biphenyl, naphthyl, more preferably a phenyl group; - The term "at least one" is synonymous with the term "one or more." - The term "inclusive" with respect to a concentration range means that the limits of the range are included within the stated range.

[0049] Salts of the compounds of formula (I), (I'), (II) or (II') below include the conventional non-toxic salts of said compounds formed, for example, from organic or inorganic acids or from organic or inorganic bases.

[0050] As a salt of a compound of formula (I), (I'), (II) or (II'): Compounds of formula (I) or (II) inorganic bases, such as, for example, sodium, potassium, calcium, ammonium, magnesium, lithium hydroxide, and sodium, potassium or calcium carbonate or hydrogen carbonate, or - organic bases such as primary, secondary or tertiary alkylamines, e.g. triethylamine or butylamine Mention may be made in particular of salts obtained by adding the primary, secondary or tertiary alkylamine to the alkylamine. The primary, secondary or tertiary alkylamine may contain one or more nitrogen and / or oxygen atoms and thus, 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.

[0051] Mention may also be made of the salts of amino acids, such as lysine, arginine, guanidine, glutamic acid and aspartic acid.Advantageously, the salts of the compounds of formula (I) or (II) (when they contain a carboxy group) may be chosen from the alkali metal or alkaline earth metal salts, for example the sodium, potassium, calcium or magnesium salts, and the ammonium salts.

[0052] The "organic or inorganic acid salt" is more particularly selected from the salts derived from i) hydrochloric acid HCl, ii) hydrobromic acid HBr, iii) sulfuric acid HSO, iv) alkylsulfonic acids: Alk-S(O)OH, such as methanesulfonic acid and ethanesulfonic acid, v) arylsulfonic acids: Ar-S(O)OH, such as benzenesulfonic acid and toluenesulfonic 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 HPO, xiii) acetic acid CHC(O)OH, xiv) trifluoromethanesulfonic acid CFSOH, and xv) tetrafluoroboric acid HBF.

[0053] Acceptable solvates of the compounds described herein include conventional solvates, such as those formed during the preparation of the compounds as a result of the presence of a solvent, for example, solvates resulting from the presence of water or from the presence of linear or branched alcohols, such as ethanol or isopropanol.

[0054] Optical isomers are in particular enantiomers and diastereoisomers.

[0055] Compound (I') is a tautomeric form of compound (I) when a tautomeric equilibrium exists according to the following scheme:

[0056] [ka]

[0057] According to one embodiment of the present invention, R1 represents a hydrogen atom.

[0058] According to another embodiment of the present invention, R1 is a linear (C1-C 10 ) Alkyl group or branched (C3-C 10) 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 R1 is unsubstituted.

[0059] According to one embodiment of the present invention, R2 represents a hydrogen atom.

[0060] According to another embodiment of the present invention, R2 is a linear (C1-C 10 ) Alkyl group or branched (C3-C 10 ) an alkyl group, particularly a linear (C1-C6) alkyl group or a branched (C3-C6) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably a methyl or ethyl group, wherein the alkyl group of R2 is unsubstituted.

[0061] According to another embodiment of the present invention, R2 is a linear (C1-C 10 ) Alkyl group or branched (C3-C 10 ) an 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 methyl or ethyl, said alkyl group being substituted by one or more groups selected from i), ii), iii) and iv) above. Preferably, said alkyl group is substituted by one or two groups selected from i), ii) and iii), more preferably by one or two groups selected from i) and iii), and better still by one group iii) as carboxy.

[0062] Another variation of the group R2 is where the alkyl group is substituted with one group iv), in particular with one phenyl group.

[0063] According to another embodiment of the invention, R2 represents a (C3-C8) cycloalkyl group, preferably a (C5-C7) cycloalkyl group, such as cyclohexyl.

[0064] According to another embodiment of the present invention, R2 is a C5-C alkyl group optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 It represents an aryl group, preferably an unsubstituted phenyl group.

[0065] According to one embodiment, R3 represents a hydrogen atom.

[0066] According to another embodiment, R3 is a saturated linear C1-C 10 Or branched C3~C 10 It represents an alkyl group, particularly a linear (C1-C6) alkyl group or a branched (C3-C6) alkyl group, preferably a (C1-C4) alkyl group, for example a methyl group.

[0067] Preferably, the compounds of formula (I) and tautomers (I') or their salts, their optical isomers, their racemates, and / or their solvates, such as hydrates, either alone or in admixture, are Has the following meaning: R1 is, a) hydrogen atoms, and b) saturated linear C1-C6 or branched C3-C6 alkyl groups, which may be the same or different; i) -O-R3 and ii)-S-R3 A saturated linear C1-C6 or branched C3-C6 alkyl group optionally substituted with one or more groups selected from represents a group selected from R2 is a) a hydrogen atom, b) Saturated linear C1-C 10 Or branched C3~C 10 or a cyclic C3 to C8 hydrocarbon group, which may be the same or different, i) -O-R3, ii)-SR 3、 iii) -C(O)-O-R3, and iv) a phenyl group optionally substituted with one or more hydroxyl and / or one or more C1-C4 alkoxy groups, e.g., methoxy. Optionally substituted with one or more groups selected from i) and iii), preferably substituted with one or more groups selected from iii) and carboxy, etc. 10 Or branched C3~C 10 Or a cyclic C3-C8 hydrocarbon group represents a group selected from R3 is a) a hydrogen atom, and b) Saturated linear C1-C6 or C3-C6 alkyl group represents a group selected from

[0068] Preferentially, the compounds of formula (I) and the tautomers (I') or their salts, their optical isomers, their racemates and / or their solvates, such as hydrates, either alone or in mixture, Has the following meaning: R1 is, a) a hydrogen atom, and b) saturated linear C1-C4 or branched C3-C4 alkyl groups, which may be the same or different, and which are optionally substituted, more preferably unsubstituted, with one or more groups selected from i) -OR3; represents a group selected from R2 is a) hydrogen atoms, and b) Saturated linear C1-C 10 Or branched C3~C 10 or a cyclic C3 to C8, for example C5 to C6, hydrocarbon group, which may be the same or different, i) -O-R3, iii) -C(O)-O-R3; iv) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C4 alkoxy groups. 12 Aryl Group Saturated linear C1-C optionally substituted with one or more groups selected from 10 Or branched C3~C 10 or a cyclic C3 to C8, e.g., C5 to C6, hydrocarbon group represents a group selected from R3 is a) a hydrogen atom, and b) saturated linear C1-C4 or branched C3-C4 alkyl groups, such as methyl or ethyl represents a group selected from

[0069] Preferentially, the compounds of formula (I) and the tautomers (I') or their salts, their optical isomers, their racemates and / or their solvates, such as hydrates, either alone or in mixture, Has the following meaning: R1 is a hydrogen atom, R2 is a) a hydrogen atom, and b) a saturated linear C1-C5 or branched C3-C5 or cyclic C3-C8, e.g. C5-C6, hydrocarbon group, which may be the same or different; v) substituted with one or more groups selected from -C(O)-O-R3, preferably one group iii) a saturated linear C1-C5 or branched C3-C5 or cyclic C3-C8, e.g. C5-C6, hydrocarbon group, R2 is even more preferably a saturated linear C1-C4 or branched C3-C4 hydrocarbon group substituted with one group iii) -C(O)-O-R3; R3 is a) a hydrogen atom, and b) saturated linear C1-C4 or branched C3-C4 alkyl groups, such as methyl or ethyl represents a group selected from

[0070] According to another preferred embodiment, the compounds of formula (I) and the tautomers (I') are selected from among the compounds of formula (II) below and their tautomers of formula (II') below, their salts, their solvates and their optical isomers, and their racemates, either alone or in mixtures.

[0071] [ka]

[0072] In the formulae (II) and (II'), R1 and R3 have the same meaning as R1 and R3 in the compounds of the formulae (I) and (I'), and X is an alkylene group -(CH2) n -, n is an integer ranging from 1 to 10 inclusive, preferably ranging from 1 to 6, more preferably ranging from 1 to 4, for example, 1, and preferably, R3 represents a hydrogen atom.

[0073] Among the compounds of formula (I), the following compounds are preferably used, alone or in mixtures, and their tautomers or their salts, their optical isomers, their racemates and / or their solvates, such as hydrates:

[0074] [Table 2A]

[0075] [Table 2B]

[0076] [Table 2C]

[0077] [Table 2D]

[0078] Of these compounds, the following are more particularly preferred:

[0079] [Table 3A]

[0080] [Table 3B]

[0081] [Table 3C]

[0082] More preferably, among these compounds, the following compounds are more particularly preferred:

[0083] [Table 4A]

[0084] [Table 4B]

[0085] Even more preferably, among these compounds, the following compounds are more particularly preferred:

[0086] [Table 5]

[0087] In the most preferred embodiment, the compound according to the invention is:

[0088] [Table 6]

[0089] All of the above compounds can be obtained from commercially available reagents by chemical methods known to those skilled in the art.

[0090] (1) Thiopyridinone compounds can be prepared, for example, according to the methods described in EP-A-3390363 or WO2017 / 102349, which are incorporated herein by reference.

[0091] (1) Thiopyridinone compound may be an active ingredient or active compound in cosmetic or dermatological products. The term "active" ingredient or compound as used herein means an ingredient or compound having cosmetic or dermatological active properties, such as antioxidant effect, whitening effect, UV shielding effect and antibacterial effect. (1) Thiopyridinone compound used in the present invention can function as a decolorizing agent, bleaching agent or whitening agent, and therefore the composition according to the present invention can be used as a whitening product or as a cosmetic composition for whitening keratinous materials.

[0092] (1) The thiopyridinone compounds can be used as agents for depigmenting, bleaching or whitening the skin, body hair, eyelashes or hair, as well as the lips and / or nails, preferably the skin, in particular for removing pigmentation or senescence spots and / or as sun protection agents.

[0093] The amount of (1) the thiopyridinone compound in the composition according to the present invention may be 0.01% by mass or more, preferably 0.05% by mass or more, and more preferably 0.1% by mass or more, based on the total mass of the composition.

[0094] On the other hand, the amount of (1) the thiopyridinone compound in the composition according to the present invention may be 10% by mass or less, preferably 5% by mass or less, and more preferably 3% by mass or less, based on the total mass of the composition.

[0095] The amount of (1) thiopyridinone compound in the composition according to the present invention may be in the range of 0.01% by mass to 10% by mass, preferably 0.05% by mass to 5% by mass, and more preferably 0.1% by mass to 3% by mass, relative to the total mass of the composition.

[0096] (pH adjuster) The composition of the present invention includes (2) at least one pH adjusting agent (pH adjuster). Two or more pH adjusting agents may be used in combination. Thus, a single type of pH adjusting agent or a combination of different types of pH adjusting agents may be used.

[0097] (2) The pH adjuster is different from (1) a thiopyridinone compound.

[0098] (2) At least one acidifier and / or at least one basifier (alkaline agent) may be used as a pH adjuster.

[0099] The acidifying agent may be monobasic or polybasic, such as a dibasic acid.

[0100] The acidifying agent can be, for example, a mineral (inorganic) acid, such as hydrochloric acid, sulfuric acid, phosphoric acid, or a carboxylic acid, for example tartaric acid, citric acid, and lactic acid, as well as an organic acid, such as a sulfonic acid.

[0101] The basifying agent may be monovalent or polyvalent, such as a divalent base.

[0102] The basifying agents may be mineral (inorganic) or organic or hybrid.

[0103] The inorganic basifying agent may be selected from ammonia, alkali metal carbonates or bicarbonates, such as sodium or potassium carbonate and bicarbonate, alkali metal hydroxides, such as sodium and potassium hydroxide, and mixtures thereof.

[0104] The organic basifying agent can be selected from organic amines having a pKb at 25° C. of less than 12, preferably less than 10, and even more advantageously less than 6. It should be noted that it is the pKb that corresponds to the highest basicity function. In addition, the organic amine does not include any alkyl or alkenyl fatty chain containing more than 10 carbon atoms.

[0105] The organic basifying agents may be chosen, for example, from alkanolamines, oxyethylenated and / or oxypropylenated ethylenediamines, amino acids, and amine compounds of formula (III):

[0106] [ka]

[0107] (In the formula, W represents a C1-C6 divalent alkylene group optionally substituted with one or more hydroxyl groups or C1-C6 alkyl groups and optionally interrupted by one or more heteroatoms such as O and N; R x , R y , R z , and R t may be the same or different and represent a hydrogen atom, a C1-C6 alkyl group, a C1-C6 hydroxyalkyl group, or a C1-C6 aminoalkyl group).

[0108] Examples of amine compounds of formula (III) that may be mentioned include 1,3-diaminopropane, 1,3-diamino-2-propanol, spermine and spermidine.

[0109] The term "alkanolamine" refers to an organic amine containing a primary, secondary or tertiary amine functional group and one or more linear or branched C1-C8 alkyl groups bearing one or more hydroxyl groups.

[0110] Alkanolamines such as monoalkanolamines, dialkanolamines or trialkanolamines containing one to three identical or different C1-C4 hydroxyalkyl groups may be suitable for the present invention. Among compounds of this type, mention may be made of monoethanolamine (MEA), diethanolamine, triethanolamine, monoisopropanolamine, 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.

[0111] The amino acids that may be used are of natural or synthetic origin, in their L-, D- or racemic form, and more particularly contain at least one acid function chosen from carboxylic, sulfonic, phosphonic or phosphoric functions. The amino acids may be in neutral or ionic form.

[0112] Among the amino acids that may be used in the present invention, mention may in particular be made of aspartic acid, glutamic acid, alanine, arginine, ornithine, citrulline, asparagine, carnitine, cysteine, glutamine, glycine, histidine, lysine, isoleucine, leucine, methionine, N-phenylalanine, proline, serine, taurine, threonine, tryptophan, tyrosine and valine.

[0113] It may be preferred that the amino acid is a basic amino acid that optionally contains an additional amine functionality contained in the ring or a ureido functionality.

[0114] Such basic amino acids may preferably be chosen from those corresponding to the following formula (IV):

[0115] [ka]

[0116] (In the formula, R is

[0117] [ka]

[0118] -(CH2)3-NH2, -(CH2)2-NH2, -(CH2)2-NH-CO-NH2, and

[0119] [ka]

[0120] represents a group selected from

[0121] Compounds corresponding to formula (IV) include histidine, lysine, arginine, ornithine and citrulline.

[0122] The organic basifying agent can be chosen from organic amines of the heterocyclic type, in addition to histidine, already mentioned among the amino acids, mention may in particular be made of pyridine, piperidine, imidazole, triazole, tetrazole and benzimidazole.

[0123] The organic basifying agent may also be selected from amino acid dipeptides, such as carnosine, anserine and balenine, among others, that may be used in the present invention.

[0124] The organic basifying agent can also be selected from compounds containing a guanidine function.Amines of this type that can be used in the present invention, in addition to arginine already mentioned as an amino acid, can in particular be 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.

[0125] In a preferred embodiment of the present invention, the organic basifying agent may be selected from amino acids, preferably basic amino acids, more preferably arginine, lysine, histidine or mixtures thereof. Even more preferentially, the organic basifying agent may be arginine.

[0126] Hybrid compounds that may be mentioned include the salts of acids such as carbonic or hydrochloric acid with the aforementioned amines. In particular, guanidine carbonate or monoethanolamine hydrochloride may be used.

[0127] (2) The pH adjuster 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, based on the total weight of the composition.

[0128] (2) The pH adjuster may be present in an amount of less than or equal to 15%, preferably less than or equal to 10%, and more preferably less than or equal to 5% by weight, based on the total weight of the composition.

[0129] (2) The pH adjuster 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, relative to the total weight of the composition.

[0130] Compositions according to the invention preferably have a pH of 4.5 or greater, more preferably 5 or greater.

[0131] Compositions according to the invention preferably have a pH of 6.5 or less, more preferably 6 or less.

[0132] The composition according to the present invention preferably has a pH of 4.5-6.5, more preferably 5-6.

[0133] 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 according to JIS Z 8802 (2011).

[0134] In order to stabilize the pH of the composition according to the invention, it may be preferable to also use at least one buffer or buffering agent (2) as a pH adjusting agent in combination with the acidifying agent and / or basifying agent.

[0135] The buffer may be any commonly known buffer. For example, a salt of an acid or base, preferably a salt of a weak acid or base, may be used. For example, when citric acid or lactic acid is used as the acidifying agent, sodium citrate or sodium lactate may be used as the buffer.

[0136] (water) The composition according to the present invention comprises (3) water.

[0137] The amount of (3) water in the composition according to the present invention may be 20% by mass or more, preferably 30% by mass or more, and more preferably 40% by mass or more, based on the total mass of the composition.

[0138] On the other hand, the amount of (3) water in the composition according to the present invention may be 99% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less, based on the total mass of the composition.

[0139] The amount of (3) water in the composition according to the present invention may be 20% by mass to 99% by mass, preferably 30% by mass to 95% by mass, and more preferably 40% by mass to 90% by mass, based on the total mass of the composition.

[0140] (Optional Additives) The composition according to the invention may also comprise any optional additives commonly used in the cosmetic field, for example selected from solvents, antioxidants, chelating agents, cosmetic active agents other than component (1), such as oils, preservatives, and mixtures thereof.

[0141] It is routine for a person skilled in the art to adjust the nature and amounts of the above-mentioned optional additives which may be present in the composition according to the invention so that the desired cosmetic properties are not affected by said additives.

[0142] The solvent may include one or several cosmetically acceptable organic solvents, which may be alcohols, especially monohydric 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, sugars and sugar alcohols; and ethers such as ethylene glycol monomethyl, monoethyl and monobutyl ether, propylene glycol monomethyl, monoethyl and monobutyl ether, and butylene glycol monomethyl, monoethyl and monobutyl ether.

[0143] The organic solvent may be present in a concentration of from 0.01% to 30% by weight, preferably from 0.1% to 20% by weight, and more preferably from 1% to 10% by weight, relative to the total weight of the composition.

[0144] [Preparation] The composition according to the present invention can be prepared by mixing the above essential and optional ingredients in a conventional manner.

[0145] For example, the composition according to the present invention comprises: (1) at least one thiopyridinone compound; (2) at least one pH adjuster, and (3)Water The composition can be prepared by a method comprising the step of mixing

[0146] Any of the optional ingredients can be further mixed.

[0147] The mixing can be carried out at any temperature, such as room temperature (e.g., 20 to 25° C., preferably 25° C.), preferably at a temperature of 30° C. or higher, preferably at 40° C. or higher, more preferably at 50° C. or higher, etc. It is preferable to further mix with any of the above-mentioned optional components, such as a pH adjuster.

[0148] 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, etc. It is preferred that the composition according to the present invention is in the form of an emulsion, preferably an O / W emulsion, more preferably an O / W gel emulsion.

[0149] [Beauty method] The composition according to the invention can be used as a cosmetic or dermatological composition, preferably a cosmetic composition, more preferably a cosmetic composition for keratinous materials, such as the skin, scalp, hair, mucous membranes such as the lips, and nails.

[0150] The composition according to the invention can be used as a bleaching, whitening or whitening product for keratinous materials such as the skin. In particular, the composition according to the invention can be used as a whitening product.

[0151] The composition according to the invention may preferably be intended for application to keratinous materials, such as the skin, the scalp and / or the lips, preferably the skin.

[0152] The composition according to the invention can therefore be used in a cosmetic method for keratinous materials, preferably skin. In one embodiment, the invention relates to a cosmetic method, preferably a whitening method, for keratinous materials, preferably skin, comprising the step of applying a composition according to the invention to the keratinous materials.

[0153] The composition according to the invention can be used as a topical cosmetic composition in the form of a lotion, milk, cream, gel, paste, serum, foam or spray.

[0154] [use] The present invention also relates to (1) at least one compound selected from a compound of the following formula (I), a tautomer of the following formula (I′), a salt thereof, a solvate such as a hydrate thereof, an optical isomer thereof, a racemate thereof, and a mixture thereof:

[0155] [ka]

[0156] (In the formula, R1 is, a) hydrogen atoms, and b) Saturated linear C1-C 10 Or branched C3~C 10 are alkyl groups, which may be the same or different, i) -O-R3 and ii)-S-R3 Saturated linear C1-C optionally substituted with one or more groups selected from 10 Or branched C3~C 10 Alkyl group represents a group selected from R2 is a) a hydrogen atom; b) Saturated linear C1-C 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group, which may be the same or different, i) -O-R3, ii)-SR 3、 iii) -C(O)-O-R3, and iv) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl Group Saturated linear C1-C optionally substituted with one or more groups selected from 12 Or branched C3~C 12 or a cyclic C3 to C8 hydrocarbon group; c) C5-C optionally substituted with one or more hydroxyl and / or one or more C1-C8 alkoxy groups. 12 Aryl groups and represents a group selected from R3 is a) a hydrogen atom, and b) Saturated linear C1-C 10 Or C3~C 10 Alkyl group represents a group selected from (2) Use of at least one pH adjusting agent in a composition comprising The present invention also relates to the use of the composition to stabilize the compound (1) by controlling the pH of the composition to between 4.5 and 6.5.

[0157] The term "stabilize" has the same meaning as enhancing stability.

[0158] The use according to the present invention can enhance the stability of (1) a thiopyridinone compound in a composition containing the (1) thiopyridinone compound.

[0159] Therefore, the use according to the present invention can make it possible to store a composition containing (1) a thiopyridinone compound for a long period of time, especially under high temperature conditions.

[0160] The above explanations regarding (1) thiopyridinone compound and (2) pH adjuster for the composition according to the present invention may also apply to those used in the use according to the present invention.

[0161] The composition in use according to the invention may comprise any of the optional ingredients described above in relation to the composition according to the invention. EXAMPLES

[0162] The present invention will now be described in more detail by means of examples. However, these examples should not be construed as limiting the scope of the present invention.

[0163] (Examples 1 to 3 and Comparative Example 1) [Preparation] Each of the compositions according to Examples 1 to 3 and Comparative Example 1 was prepared by mixing the components shown in Table 1. All figures for the amounts of components are based on "mass %" as the active material.

[0164] [Table 7]

[0165] N-[(2-thioxo-1,2-dihydropyridin-3-yl)carbonyl]glycine (2-mercaptonicotinoylglycine): Compound 20 [evaluation] (pH) The pH at 25° C. of each of the compositions according to Examples 1 to 3 and Comparative Example 1 was measured as follows.

[0166] device: 1. pH meter; Laqua F-71 (Horiba) 2.pH electrode; 9615S-10D (Horiba) 3. pH standard solution (Horiba) 4. pH probe internal solution (Horiba)

[0167] procedure: 1. The internal liquid supply port of the pH meter was opened and the internal liquid was supplied around the electrode. 2. Calibration was performed using standard solutions at pH 9, 7 and 4. 3. The electrodes were washed with deionized water. 4. The protective cover of one of the electrodes (glass electrode) was removed, and the electrode was immersed in each of the compositions of Examples 1 to 3 and Comparative Example 1. 5. The pH was recorded after it had stabilized.

[0168] The results are shown in the "pH" row of Table 1.

[0169] (Residual rate of thiopyridinone compounds) The amount of the thiopyridinone compound in each of the compositions according to Examples 1 to 3 and Comparative Example 1 was measured by the following timing HPLC-UV assay.

[0170] Timing (1) Immediately after the composition was prepared (T0) Timing (2): 2 weeks after preparation (the composition was kept at 55° C. in a sealed, light-proof container)

[0171] The details of the HPLC-UV assay are as follows.

[0172] Equipment / Reagents

[0173] [Table 8]

[0174] HPLC conditions

[0175] [Table 9]

[0176] The residual percentage of thiopyridinone compounds was determined by the following formula: Residual rate of thiopyridinone compounds (%) = Amount of thiopyridinone compound at timing (2) / Amount of thiopyridinone compound at timing (1) The results are shown in Table 1 in the row "Residual rate (%) of thiopyridinone compound."

[0177] The residual rate of thiopyridinone compounds was classified according to the following criteria. Very good: 90% or more Good: 50% or more and less than 90% Defective: Less than 50% The results are shown in the "Stability" row of Table 1.

[0178] (result) The compositions according to Examples 1 to 3, which contained a thiopyridinone compound and a pH adjuster for controlling the pH of the composition to 4.5 to 6.5, were more stable, even under high temperature conditions, and therefore most of the thiopyridinone compound remained, compared to the composition according to Comparative Example 1, which had a pH of more than 6.5.

Claims

1. (1) At least one compound selected from the compounds of the following formula (I), the tautomers of the following formula (I'), salts thereof, solvates such as hydrates thereof, optical isomers thereof, racemates thereof, and mixtures thereof: 【Chemical 1】 (In the formula, R 1 is a) represents a hydrogen atom, and b) Saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 is an alkyl group, which may be the same or different, i)-O-R 3 and ii)-S-R 3 optionally substituted by one or more groups selected from, saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 alkyl group a group selected from, R 2 is a) a hydrogen atom and b) Saturated straight-chain C 1 ~C 12 or branched C 3 ~C 12 or cyclic C 3 ~C 8 which is a hydrocarbon group and may be the same or different i)-O-R 3 、 ii)-S-R 3 、 iii)-C(O)-O-R 3 and iv) one or more hydroxyl and / or one or more C 1 to C 8 aryl group optionally substituted with an alkoxy group having C 5 to C 12 aryl group optionally substituted by one or more groups selected from, saturated linear C 1 ~C 12 or branched C 3 ~C 12 or cyclic C 3 ~C 8 hydrocarbon group, and c) one or more hydroxyls and / or one or more C 1 -C 8 aryl group optionally substituted with an alkoxy group having C 5 -C 12 and an aryl group a group selected from, R 3 is a) a hydrogen atom, and b) Saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 alkyl group a group selected from) (2) At least one pH adjuster, and (3) water comprising, a composition, preferably a cosmetic composition, having a pH of 4.5 to 6.5, preferably 5 to 6.

2. R of formula (I) and (I') 1 represents a hydrogen atom, or or R of formula (I) and (I') 1 is a linear (C 1 -C 10 ) alkyl group or a branched (C 3 -C 10 ) alkyl group, particularly a linear (C 1 -C 6 ) alkyl group or a branched (C 3 -C 6 ) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably ethyl, and particularly where the alkyl group of R 1 is unsubstituted, the composition according to claim 1.

3. R of formula (I) and (I') 2 represents a hydrogen atom, or or R of formulas (I) and (I') 2 is a linear (C 1 ~C 10 ) alkyl group or a branched (C 3 ~C 10 ) alkyl group, particularly a linear (C 1 ~C 6 ) alkyl group or a branched (C 3 ~C 6 ) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably a methyl or ethyl group, and the alkyl group of R 2 is unsubstituted, the composition according to claim 1.

4. R of formula (I) and (I') 2 is a linear (C 1 ~C 10 ) alkyl group or a branched (C 3 ~C 10 ) alkyl group, particularly a linear (C 1 ~C 6 ) alkyl group or a branched (C 3 ~C 6 ) alkyl group, such as methyl, ethyl, n-pentyl, n-nonyl, isobutyl, more preferably methyl or ethyl, and the alkyl group is substituted with one or more groups selected from the above i), ii), iii) and iv), preferably the alkyl group is substituted with one or two groups selected from i), ii) and iii), more preferably one or two groups selected from i) and iii), and even better is substituted with one group iii) as carboxy. The composition according to claim 1.

5. R of formulas (I) and (I') 2 is a (C 3 -C 8 ) cycloalkyl group, preferably a (C 5 -C 7 ) cycloalkyl group, for example, represents cyclohexyl, or or R of formula (I) and (I') 2 is a C optionally substituted by one or more hydroxyls and / or one or more C 1 -C 8 aryl group, preferably an unsubstituted phenyl group, the composition according to claim 1 5 -C 12 ​

6. R of formula (I) and (I') 3 represents a hydrogen atom, or or R of formula (I) and (I') 3 is a saturated straight-chain C 1 to C 10 or branched C 3 to C 10 alkyl group, particularly a straight-chain (C 1 to C 6 ) alkyl group or a branched (C 3 to C 6 ) alkyl group, preferably a (C 1 to C 4 ) alkyl group, for example, a methyl group, the composition according to claim 1.

7. R of formulas (I) and (I') 1 is a) represents a hydrogen atom, and b) Saturated straight-chain C 1 ~C 6 or branched C 3 ~C 6 is an alkyl group, which may be the same or different i)-O-R 3 and ii)-S-R 3 Optionally substituted with one or more groups selected from, preferably optionally substituted with one or more groups i), saturated straight-chain C 1 ~C 6 or branched C 3 ~C 6 alkyl group a group selected from, R of formula (I) and (I') 2 is a) a hydrogen atom and b) Saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 or cyclic C 3 ~C 8 , for example C 5 ~C 6 is a hydrocarbon group, which may be the same or different, i)-O-R 3 、 ii)-S-R 3 、 iii)-C(O)-O-R 3 and iv) one or more hydroxyls and / or one or more C 1 -C 4 alkoxy group, for example a phenyl group optionally substituted with methoxy Optionally substituted with one or more groups selected from , preferably one or more groups selected from i) and iii), preferably substituted with iii) such as carboxy, etc., saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 or cyclic C 3 ~C 8 , for example C 5 ~C 6 hydrocarbon group and a group selected from, R of formula (I) and (I') 3 is a) a hydrogen atom, and b) Saturated straight-chain C 1 ~C 6 or C 3 ~C 6 alkyl group a group selected from, Preferentially, in the compounds of formula (I) and tautomers (I'), salts thereof, solvates such as hydrates thereof, optical isomers thereof, racemates thereof, and mixtures thereof, they have the following meanings: R of formula (I) and (I') 1 is a) a hydrogen atom, and b) saturated linear C 1 -C 4 or branched C 3 -C 4 alkyl group, which may be the same or different, and is optionally substituted with one or more groups selected from i)-OR 3 , more preferably unsubstituted, saturated linear C 1 -C 4 or branched C 3 -C 4 alkyl group a group selected from, R of formula (I) and (I') 2 is a) a hydrogen atom and b) Saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 or cyclic C 3 ~C 8 , for example C 5 ~C 6 is a hydrocarbon group, which may be the same or different, i)-O-R 3 、 iii)-C(O)-O-R 3 and iv) one or more hydroxyl and / or one or more C 1 to C 4 aryl group optionally substituted with a C 5 to C 12 aryl group optionally substituted with one or more groups selected from, saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 or cyclic C 3 ~C 8 , for example C 5 ~C 6 hydrocarbon group and a group selected from, R of formula (I) and (I') 3 is a) a hydrogen atom, b) Saturated straight-chain C 1 ~C 4 or branched C 3 ~C 4 alkyl group, such as methyl or ethyl a group selected from, the composition according to claim 1.

8. (1) The compound is selected from the following Compounds 1 to 24, tautomers thereof, salts thereof, solvates such as hydrates thereof, optical isomers thereof, racemates thereof, and mixtures thereof, particularly from Compounds 1, 2, 4, 6, 7, 9, 11, 12, 14, 15, 16, 17, 18, 19, 20, or 21, more specifically from Compounds 1, 9, 16, 18, 19, 20, or 21, preferably from Compounds 18, 19, 20, or 21, more preferably Compound 20, the composition according to claim 1. 【Table 1A】 【Table 1B】 【Table 1C】 【Table 1D】

9. The amount of the compound (1) in the composition is 0.01% to 10% by mass, preferably 0.05% to 5% by mass, more preferably 0.1% to 3% by mass based on the total mass of the composition, the composition according to claim 1.

10. (2) The pH adjuster is selected from acidifying agents, basifying agents, and mixtures thereof, the composition according to claim 1.

11. The composition according to claim 1, wherein the amount of the (2) pH regulator in the composition is 0.01% by mass to 15% by mass, preferably 0.05% by mass to 10% by mass, more preferably 0.1% by mass to 5% by mass, based on the total mass of the composition.

12. The composition according to claim 1, wherein the amount of the (3) water in the composition is 20% by mass to 99% by mass, preferably 30% by mass to 95% by mass, more preferably 40% by mass to 90% by mass, based on the total mass of the composition.

13. The composition according to claim 1, which is a keratin substance, preferably for whitening the skin.

14. A keratin substance, preferably a beauty method for the skin, preferably a whitening method, comprising: a step of applying the composition according to any one of claims 1 to 13 to the keratin substance The method comprising.

15. (1) At least one compound selected from the group consisting of a compound of the following formula (I), a tautomer of the following formula (I'), a salt thereof, a solvate such as a hydrate thereof, an optical isomer thereof, a racemate thereof, and a mixture thereof: 【Chemical 2】 (In the formula, R 1 is a) represents a hydrogen atom, and b) Saturated straight-chain C 1 ~C 10 or branched C 3 ~C 10 is a hydrocarbon group, which may be the same or different i)-O-R 3 and ii)-S-R 3 optionally substituted with one or more groups selected from, saturated straight-chain C 1 ~C 12 or branched C 3 ~C 12 hydrocarbon group a group selected from R 2 is a) represents a hydrogen atom and b) Saturated straight-chain C 1 ~C 12 or branched C 3 ~C 12 or cyclic C 3 ~C 8 which is a hydrocarbon group and may be the same or different i)-O-R 3 , ii)-S-R 3、 iii)-C(O)-O-R 3 and iv) one or more hydroxyl and / or one or more C 1 -C 8 aryl group optionally substituted with an alkoxy group of C 5 -C 12 aryl group optionally substituted with one or more groups selected from, saturated linear C 1 ~C 12 or branched C 3 ~C 12 or cyclic C 3 ~C 8 hydrocarbon group, and c) one or more hydroxyl and / or one or more C 1 to C 8 aryl group optionally substituted with an alkoxy group of C 5 to C 12 and an aryl group a group selected from R 3 is a) represents a hydrogen atom and b) Saturated straight-chain C 1 ~C 10 or C 3 ~C 10 alkyl group a group selected from The use of at least one pH regulator in a composition comprising: The use for stabilizing the (1) compound by controlling the pH of the composition to be from 4.5 to 6.5.

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