Method for producing compound having bis(thiocarbonyl)disulfide skeleton

Abstract

To provide a new technical means that enables industrial production of compounds having a bis(thiocarbonyl)disulfide skeleton.SOLUTION: There is provided a method for producing a compound represented by Formula (I) (wherein R represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted cyclic alkyl group having 3 to 12 carbon atoms, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms, where an oxygen atom or a sulfur atom may be present between carbon bonds of the alkyl group, if possible), comprising the steps of: (A) reacting a compound represented by Formula (II) (wherein R is as defined in Formula (I)) or a salt thereof in the presence of sulfuric acid and hydrogen peroxide to obtain the compound represented by Formula (I); or (B) reacting a compound represented by Formula (II) (wherein R is as defined in Formula (I)) or a salt thereof in the presence of phosphoric acid and hydrogen peroxide to obtain the compound represented by Formula (I).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a compound having a bis(thiocarbonyl) disulfide skeleton. [Background technology]

[0002] Reversible addition-fragmentation chain transfer (RAFT) polymerization is a method of controlled living radical polymerization, in which trithiocarbonate compounds or dithiobenzoate esters are used as chain transfer agents (RAFT agents). RAFT polymerization is effective for synthesizing polymers with easy molecular weight control and narrow molecular weight distributions, and with the appropriate RAFT agent, it is possible to control the polymerization of a wide range of radically polymerizable monomers. Furthermore, since it does not contain halogens or heavy metals, it can achieve a polymerization system with low environmental impact.

[0003] Conventional free radical polymerization does not allow for control of polymerization, making it impossible to synthesize highly functional polymers. In contrast, RAFT polymerization makes it possible to synthesize polymers with narrow molecular weight distributions, making it easy to synthesize highly functional polymers. This makes it an important polymerization method for the production of highly functional polymeric materials.

[0004] To date, RAFT agents with various chemical structures have been developed and evaluated (Patent Documents 1, 2, and 3, and Non-Patent Document 1). Known useful precursors of RAFT agents include compounds having a bis(thiocarbonyl)disulfide skeleton (e.g., bis(dodecylsulfanylthiocarbonyl)disulfide, bis(phenylthiocarbonyl)disulfide, and 3,3'-(disulfane-1,2-dicarbonothioyl)bis(sulfanediyl)dipropionic acid) (Patent Documents 1, 4, and 5).

[0005] For example, Patent Document 6 proposes a method for synthesizing 3,3'-[dithiobis(carbonothioylthio)]bis[propionic acid] by reacting 3-mercaptopropionic acid with carbon disulfide in the presence of triethylamine and oxidizing the purified trithiocarbonate with iodine.

[0006] Furthermore, Patent Document 7 proposes a method for synthesizing bis(dodecylsulfanylthiocarbonyl)disulfide by reacting dodecyl mercaptan with carbon disulfide in the presence of a base and oxidizing the purified trithiocarbonate with p-toluenesulfonyl chloride. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2017-503066 [Patent Document 2] European Patent No. 0910587 [Patent Document 3] U.S. Patent No. 6,747,111 [Patent Document 4] Japanese Patent Application Laid-Open No. 2009-67840 [Patent Document 5] International Publication No. 2017 / 035570 [Patent Document 6] US Patent Application Publication No. 2015 / 0073109 [Patent Document 7] Chinese Patent Application Publication No. 114989375 [Non-patent literature]

[0008] [Non-Patent Document 1] Macro.,35,No.18,(2002)6754 Summary of the Invention

[0009] The methods described in the above-mentioned documents use raw materials such as iodine and p-toluenesulfonyl chloride, which have a large environmental impact and / or are expensive as general-purpose products, and therefore it is extremely difficult to industrially produce compounds having a bis(thiocarbonyl)disulfide skeleton.

[0010] Therefore, an object of the present disclosure is to provide a new technical means that enables industrial mass production of compounds having a bis(thiocarbonyl)disulfide skeleton.

[0011] The present inventors have found that the use of sulfuric acid and / or phosphoric acid and hydrogen peroxide enables the mass production of compounds having a bis(thiocarbonyl)disulfide skeleton. The present disclosure is based on this finding.

[0012] According to one embodiment of the present disclosure, a compound of formula (I): [ka] (In the formula, R represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted cyclic alkyl group having 3 to 12 carbon atoms, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms, where an oxygen atom or a sulfur atom may be present between the carbon bonds of the alkyl group, if possible. A method for producing a compound represented by the formula: (A) in the presence of sulfuric acid and hydrogen peroxide, a compound of formula (II): [ka] (wherein R is as defined in formula (I)). or a salt thereof to obtain a compound of formula (I); or (B) in the presence of phosphoric acid and hydrogen peroxide, a compound of formula (II): [ka] (wherein R is as defined in formula (I)). or a salt thereof to obtain a compound of formula (I).

[0013] According to the present disclosure, it is possible to industrially produce a compound having a bis(thiocarbonyl) disulfide skeleton. The present disclosure can be particularly advantageously used in producing a compound having a bis(thiocarbonyl) disulfide skeleton inexpensively and efficiently. Specific Description of the Invention

[0014] According to one embodiment of the present disclosure, a method for producing a compound represented by formula (I) comprises reacting a compound represented by formula (II) or a salt thereof in the presence of sulfuric acid and / or phosphoric acid and hydrogen peroxide. The use of sulfuric acid and / or phosphoric acid and hydrogen peroxide in the production of a compound represented by formula (I) is advantageous in that it eliminates the need for environmentally hazardous compounds (e.g., p-toluenesulfonyl chloride) that were required in conventional methods. Furthermore, since sulfuric acid and / or phosphoric acid and hydrogen peroxide can be used as solutions, it eliminates the need for solids (e.g., iodine) that were required in conventional methods, which is advantageous in that it can facilitate production control. Each reaction is described in detail below.

[0015] [ka]

[0016] [Step of preparing a compound represented by formula (II) or a salt thereof] According to one embodiment of the present disclosure, in the production of a compound represented by formula (I), a step of preparing a compound represented by formula (II) or a salt thereof (also referred to as "step (1)" in the present disclosure) may be carried out.

[0017] (Compound represented by formula (I)) In the present disclosure, the compound of formula (I) has the following structure: [ka] (In the formula, R represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted cyclic alkyl group having 3 to 12 carbon atoms, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms, where an oxygen atom or a sulfur atom may be present between the carbon bonds of the alkyl group, if possible. It is said to have the following.

[0018] In the present disclosure, the term "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring, and the aromatic ring may be monocyclic, polycyclic, or heterocyclic. The number of carbon atoms in the aromatic hydrocarbon group, not including the number of carbon atoms in substituents, is usually 6 to 60, preferably 6 to 40, and more preferably 6 to 20. Examples of aromatic hydrocarbon groups include monocyclic aromatic hydrocarbons (e.g., benzene) or polycyclic aromatic hydrocarbons (e.g., bicyclic aromatic hydrocarbons such as naphthalene, indene, naphthoquinone, indenone, and tetralone; tricyclic aromatic hydrocarbons such as anthracene, phenanthrene, dihydrophenanthrene, fluorene, anthraquinone, phenanthoquinone, and fluorenone; tetracyclic aromatic hydrocarbons such as benzanthracene, benzophenanthrene, benzofluorene, pyrene, and fluoranthene; pentacyclic aromatic hydrocarbons such as dibenzanthracene, dibenzophenanthrene, dibenzofluorene, indenofluorene, perylene, and benzofluoranthene; hexacyclic aromatic hydrocarbons such as spirobifluorene; and heptacyclic aromatic hydrocarbons such as benzospirobifluorene and acenaphthofluoranthene), from which one hydrogen atom directly bonded to a carbon atom constituting the ring has been removed. The aromatic hydrocarbon group may also be a group in which multiple such groups are bonded. Specific examples of aromatic hydrocarbon groups include, but are not limited to, phenyl, naphthyl, anthryl, phenanthryl, biphenylyl, and the like.

[0019] The substituted aromatic hydrocarbon group refers to an aromatic hydrocarbon group substituted with one or more identical or different optional substituents (for example, but not limited to, a halogen group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an ester group, an amide group, etc.). Examples of the substituted aromatic hydrocarbon group include, but are not limited to, methylphenyl, ethylphenyl, propylphenyl, isopropylphenyl, butylphenyl, isobutylphenyl, t-butylphenyl, hexylphenyl, heptylphenyl, octylphenyl, dodecylphenyl, xylyl, trimethylphenyl, chlorophenyl, bromophenyl, fluorophenyl, cyanophenyl, methoxyphenyl, ethoxyphenyl, propoxyphenyl, butoxyphenyl, etc.

[0020] In the present disclosure, the "cyclic alkyl group having 3 to 12 carbon atoms" is not particularly limited as long as it is a cyclic alkyl group having 3 to 12 carbon atoms, and examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and decahydronaphthyl.

[0021] The substituted cyclic alkyl group having 3 to 12 carbon atoms means the above cyclic alkyl group having 3 to 12 carbon atoms substituted with one or more identical or different arbitrary substituents (including, but not limited to, for example, a halogen group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an ester group, an amide group, etc.).

[0022] In the present disclosure, examples of the "linear or branched alkyl group having 1 to 20 carbon atoms" include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl.

[0023] The substituted linear or branched alkyl group having 1 to 20 carbon atoms means the linear or branched alkyl group having 1 to 20 carbon atoms substituted with one or more identical or different arbitrary substituents (including, but not limited to, for example, a halogen group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an ester group, an amide group, etc.).

[0024] In the present disclosure, the substituted or unsubstituted, linear or branched alkyl group having 1 to 20 carbon atoms, in which "if possible, an oxygen atom or a sulfur atom may be present between carbon bonds of the alkyl group", may, if possible, have an oxygen atom or a sulfur atom between carbon bonds of the alkyl group, and even in this case, the alkyl group has 1 to 20 carbon atoms.

[0025] Examples of the substituted or unsubstituted, linear or branched alkyl group having 1 to 20 carbon atoms in which an oxygen atom or a sulfur atom may be present between the carbon bonds of the alkyl group include, but are not limited to, -CH2-O-CH3, -C2H4-O-C2H5, -C3H6-O-C3H7, -C4H8-O-C4H9, -C5H 10 -O-C5H 11 , -CH 12 -O-C6H 13 , -CH 14 -O-C7H 15 , -CH 16 -O-C8H 17 , -CH 18 -O-C9H 19 , -C 10 H 20 -OC 10 H 21 , -C2H4-O-CH3, -CH2-O-C2H5, etc., in which an oxygen atom is present between the carbon bonds; -CH2-S-CH3, -C2H4-S-C2H5, -C3H6-S-C3H7, -C4H8-S-C4H9, -C5H 10 -S-C5H 11 , -CH 12 -S-C6H 13 , -CH 14 -S-C7H15 , -CH 16 -S-C8H 17 , -CH 18 -S-C9H 19 , -C 10 H 20 -SC 10 H 21 , -C2H4-S-CH3, -CH2-S-C2H5, etc., in which a sulfur atom is present between the carbon bonds; Examples include:

[0026] An "alkylamino group" in the present disclosure includes an amino group substituted with one or more of the same or different straight-chain or branched-chain alkyl groups having 1 to 20 carbon atoms. Examples of alkylamino groups include, but are not limited to, methylamino, ethylamino, propylamino, isopropylamino, butylamino, pentylamino, neopentylamino, hexylamino, heptylamino, octylamino, nonylamino, decylamino, dimethylamino, diethylamino, dipropylamino, diisopropylamino, dibutylamino, dipentylamino, dineopentylamino, dihexylamino, diheptylamino, dioctylamino, dinonylamino, didecylamino, ethylmethylamino, methylpropylamino, ethylpropylamino, and the like.

[0027] In the present disclosure, the term "ester group" refers to a group represented by the group -COOR', where R' is an alkyl group having 1 to 20 carbon atoms.

[0028] In the present disclosure, an "amide group" refers to a group represented by the group -C(O)NR'R'', where R' and R'' are each independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 20 carbon atoms. Examples of the amide group include, but are not limited to, methylamide, ethylamide, propylamide, isopropylamide, butylamide, pentylamide, neopentylamide, hexylamide, heptylamide, octylamide, nonylamide, decylamide, dimethylamide, diethylamide, dipropylamide, diisopropylamide, dibutylamide, dipentylamide, dineopentylamide, dihexylamide, diheptylamide, dioctylamide, dinonylamide, didecylamide, ethylmethylamide, methylpropylamide, and ethylpropylamide.

[0029] The "heterocyclic group" in the present disclosure may be monocyclic, polycyclic, or heterocyclic, as long as it contains at least one heteroatom (e.g., oxygen atom, sulfur atom, nitrogen atom, etc.) in the ring structure. The number of carbon atoms in the heterocyclic group, not including the number of carbon atoms in the substituent, is usually 6 to 60, preferably 6 to 40, and more preferably 6 to 20. Specific examples of the aromatic hydrocarbon group and the heterocyclic group include, but are not limited to, pyridyl, pyrimidinyl, quinolyl, isoquinolyl, pyrazinyl, triazinyl, naphthyridinyl, acridinyl, phenanthrolinyl, carbolinyl, purinyl, indolizinyl, naphthyridinyl, phthalazinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, phenanthridinyl, perimidinyl, anthridinyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, dihydropyrrolopyrrolyl, indolyl, isoindolyl, indolizinyl, indazolyl, benzimidazolyl, benzotriazolyl, and carbazolyl. , azaindolyl, azaindazolyl, pyrazolopyrimidinyl, purinyl, adenyl, guanidinyl, acridinyl, phenazinyl, furanyl, thiophenyl, benzofuranyl, isobenzofuranyl, benzothienyl, isobenzothiophenyl, dibenzofuranyl, dibenzothienyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl, furopyrrolyl, thienopyrrolyl, benzoxazolyl, benzisoxazolyl, benzothiazolyl, benzisothiazolyl, benzothiadiazolyl, phenoxathiinyl, benzo[1,2-b:4,5-b']dithiophenyl, bipyridinyl, furyl, thienyl, and the like.

[0030] The substituted heterocyclic group means a heterocyclic group substituted with one or more identical or different arbitrary substituents (including, but not limited to, for example, a halogen group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an ester group, an amide group, etc.).

[0031] In the present disclosure, the term "halogen group" includes, but is not limited to, fluorine, chlorine, bromine, iodine, and the like.

[0032] The "alkoxy group having 1 to 20 carbon atoms" in the present disclosure may be linear or branched, and includes, but is not limited to, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, etc.

[0033] According to one embodiment of the present disclosure, R is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms, preferably an unsubstituted aromatic hydrocarbon group, an unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms, or a linear or branched alkyl group having 1 to 20 carbon atoms substituted with one carboxyl group, more preferably an unsubstituted phenyl group, an unsubstituted linear or branched alkyl group having 1 to 15 carbon atoms, or a linear alkyl group having 1 to 15 carbon atoms substituted with one carboxyl group.

[0034] According to a preferred embodiment of the present disclosure, R is of the formula: -(CH2) n -COOH, formula:-(CH2) n -CH3, or formula: -(CH2) n -Ph (wherein n is an integer from 1 to 15 and Ph is a phenyl group), preferably R is a group of the formula: -(CH 11 -COOH, formula:-(CH2) 11 -CH3 or of the formula: -CH2-Ph.

[0035] (Compound represented by formula (II)) According to one embodiment of the present disclosure, the compound of formula (II) has the following structure: [ka] wherein R is as defined in this disclosure. It is said to have the following.

[0036] The salt of the compound represented by formula (II) is not particularly limited, and may be any salt, as long as it is possible to produce the compound represented by formula (I). Examples of salts of the compound represented by formula (II) include, but are not limited to, metal salts such as alkali metal salts (e.g., lithium salt, sodium salt, potassium salt), alkaline earth metal salts (e.g., magnesium salt, calcium salt), transition metal salts (e.g., aluminum salt, zinc salt), and other salts (e.g., ammonium salt). The salt of the compound represented by formula (II) is preferably a metal salt, more preferably an alkali metal salt or alkaline earth metal salt, and even more preferably a sodium salt or potassium salt.

[0037] The compound represented by formula (II) or a salt thereof prepared in step (1) may be commercially available or may be synthesized by any method (for example, synthesized by the method described below).

[0038] According to one embodiment of the present disclosure, the preparation step (i.e., step (1)) comprises reacting a compound of formula (III): [ka] wherein R is as defined in this disclosure. to obtain a compound represented by formula (II) (also referred to as "step (1')" in the present disclosure).

[0039] [ka]

[0040] (Compound represented by formula (III)) According to one embodiment of the present disclosure, the compound of formula (III) has the following structure: [ka] wherein R is as defined in this disclosure. It is said to have the following.

[0041] (carbon disulfide) The amount of carbon disulfide used in step (1') is not particularly limited as long as the reaction can proceed. The amount of carbon disulfide may be, for example, 0.01 to 10 mol, preferably 0.1 to 10 mol, and more preferably 0.3 to 3 mol, based on 1 mol of the compound represented by formula (III).

[0042] Step (1') may be carried out in the presence of a compound represented by the formula: MOH (wherein M is a metal or -NH4, preferably an alkali metal, alkaline earth metal or -NH4, more preferably sodium or potassium).

[0043] [ka]

[0044] When step (1') is carried out in the presence of a compound represented by MOH, a compound represented by formula (II-1) (i.e., a salt of a compound represented by formula (II)): [ka] wherein R and M are as defined in this disclosure. can be obtained as an intermediate compound.

[0045] (Compounds represented by MOH) Examples of the compound represented by MOH include alkali metal hydroxides, alkaline earth metal hydroxides, and ammonium hydroxide, and are preferably alkali metal hydroxides or alkaline earth metal hydroxides, and more preferably sodium hydroxide or potassium hydroxide.

[0046] The amount of the compound represented by MOH used in step (1') is not particularly limited as long as the reaction can proceed. The amount of the compound represented by MOH may be, for example, 0.01 to 20 moles, preferably 0.1 to 10 moles, and more preferably 0.3 to 5 moles, based on 1 mole of the compound represented by formula (III). The amount of the compound represented by MOH may be, for example, 0.01 to 20 moles, preferably 0.1 to 10 moles, and more preferably 0.3 to 3 moles, based on 1 mole of carbon disulfide.

[0047] (solvent) Step (1') may be carried out in the presence of a solvent, if necessary. The solvent used in step (1') is not particularly limited as long as the reaction proceeds, and examples thereof include water; organic solvents such as methanol, ethanol, isopropanol, butanol, isobutanol, ethylene glycol, propylene glycol, THF, dioxane, dimethyl ether, diethyl ether, dimethoxyethane, dioxane, DMF, DMA, N-methylpyrrolidone, methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, dichloromethane, chloroform, 1,2-dichloroethane, toluene, hexane, and acetonitrile; and any mixed solvents thereof. These may be used alone or in any combination of two or more. The solvent used in step (1') preferably contains water. The amount of solvent used is not particularly limited as long as the reaction proceeds, and can be appropriately adjusted by a person skilled in the art.

[0048] The temperature in step (1') is not particularly limited as long as the reaction can proceed, and can be appropriately adjusted by a person skilled in the art. The temperature in step (1') may be, for example, -20 to 60°C, preferably 0 to 50°C, and more preferably 10 to 40°C.

[0049] The time for step (1') is not particularly limited as long as the reaction can proceed, and can be appropriately adjusted by a person skilled in the art. The time for step (1') may be, for example, 0.5 to 48 hours, preferably 1 to 24 hours, and more preferably 1 to 10 hours.

[0050] In step (1'), the compound represented by formula (III), carbon disulfide, and optionally the compound represented by MOH and solvent may all be charged into a reactor at the same time or in any order. Furthermore, for a given component (e.g., carbon disulfide), the entire amount may be charged at once, or may be charged in multiple portions.

[0051] [Step of reacting the compound represented by formula (II) or a salt thereof in the presence of sulfuric acid and hydrogen peroxide] According to one embodiment of the present disclosure, a method for producing a compound represented by formula (I) includes a step (also referred to as "step (2)" in the present disclosure) of reacting a compound represented by formula (II) or a salt thereof in the presence of sulfuric acid and hydrogen peroxide. Sulfuric acid and hydrogen peroxide are inexpensively available, which is advantageous in that it can reduce the cost of industrially mass-producing the compound represented by formula (I). [ka]

[0052] The compound represented by formula (II) or a salt thereof used in step (2) may be, for example, the compound prepared in the above preparation step.

[0053] (sulfuric acid) The amount of sulfuric acid used in step (2) is not particularly limited as long as the reaction can proceed. The amount of sulfuric acid in step (2) may be, for example, 0.1 to 10 mol, preferably 0.3 to 5 mol, and more preferably 0.8 to 1.1 mol, based on 1 mol of the compound represented by formula (II). The amount of sulfuric acid in step (2) may be, for example, 0.1 to 10 mol, preferably 0.3 to 5 mol, and more preferably 0.8 to 1.1 mol, based on 1 mol of the compound represented by formula (III). In particular, using an amount of sulfuric acid in step (2) of 0.8 to 1.1 mol, based on 1 mol of the compound represented by formula (II) or (III), is advantageous in terms of improving the yield and / or purity of the compound represented by formula (I) obtained.

[0054] (hydrogen peroxide) The amount of hydrogen peroxide used in step (2) is not particularly limited as long as the reaction can proceed. The amount of hydrogen peroxide in step (2) may be, for example, 0.1 to 10 mol, preferably 0.3 to 5 mol, and more preferably 0.8 to 1.1 mol, based on 1 mol of the compound represented by formula (II). The amount of hydrogen peroxide in step (2) may be, for example, 0.1 to 10 mol, preferably 0.3 to 5 mol, and more preferably 0.8 to 1.1 mol, based on 1 mol of the compound represented by formula (III). In particular, using an amount of hydrogen peroxide in step (2) of 0.8 to 1.1 mol, based on 1 mol of the compound represented by formula (II) or (III), is advantageous in terms of improving the yield and / or purity of the resulting compound represented by formula (I).

[0055] The molar ratio of sulfuric acid to hydrogen peroxide (hydrogen peroxide / sulfuric acid) used in step (2) may be, for example, 0.01 to 100, preferably 0.1 to 10, and more preferably 0.65 or more and less than 2.2. In particular, setting the molar ratio of sulfuric acid to hydrogen peroxide (hydrogen peroxide / sulfuric acid) in step (2) to 0.65 or more and less than 2.2 is advantageous from the viewpoint of improving the yield and / or purity of the compound represented by formula (I) obtained.

[0056] According to one embodiment of the present disclosure, a mixture containing sulfuric acid and hydrogen peroxide (ie, sulfuric acid-acidified hydrogen peroxide) is used.

[0057] The amount of sulfuric acid contained in the mixture may be, for example, 10 to 30 mass %, preferably 12 to 28 mass %, and more preferably 15 to 25 mass %, based on the total mass of the mixture.

[0058] The amount of hydrogen peroxide contained in the mixture may be, for example, 5 to 10 mass %, preferably 6 to 9 mass %, and more preferably 6.5 to 8.5 mass %, based on the total mass of the mixture.

[0059] The mixture may contain components other than sulfuric acid and hydrogen peroxide (e.g., a solvent such as water). According to one embodiment of the present disclosure, the mixture contains sulfuric acid, hydrogen peroxide, and water. According to one embodiment of the present disclosure, the mixture consists essentially of sulfuric acid, hydrogen peroxide, and water. Here, "substantially" means that the mixture may contain impurities (e.g., impurities derived from raw materials such as sulfuric acid and hydrogen peroxide) that are inevitably contained in the production of the mixture.

[0060] When the mixture or the sulfuric acid-acidic hydrogen peroxide is used in step (2), the amount of the mixture or the sulfuric acid-acidic hydrogen peroxide used may be, for example, 0.1 to 10 parts by mass, preferably 0.3 to 8 parts by mass, and more preferably 1 to 5 parts by mass, based on 1 part by mass of the compound represented by formula (II) or (III).

[0061] The mixture may be prepared by, for example, mixing (e.g., stirring) sulfuric acid with other components (e.g., water) as needed, and then mixing the resulting mixture with hydrogen peroxide. The mixing time, temperature, etc., can be adjusted as appropriate by a person skilled in the art.

[0062] (solvent) Step (2) may be carried out in the presence of a solvent, if necessary. The solvent used in step (2) is not particularly limited as long as the reaction proceeds, and examples thereof include water; organic solvents such as methanol, ethanol, isopropanol, butanol, isobutanol, ethylene glycol, propylene glycol, THF, dioxane, dimethyl ether, diethyl ether, dimethoxyethane, dioxane, DMF, DMA, N-methylpyrrolidone, methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, dichloromethane, chloroform, 1,2-dichloroethane, toluene, hexane, and acetonitrile; and any mixed solvents thereof. These may be used alone or in any combination of two or more. The solvent used in step (2) preferably contains water. The amount of solvent used is not particularly limited as long as the reaction proceeds, and can be appropriately adjusted by a person skilled in the art.

[0063] The temperature in step (2) is not particularly limited as long as the reaction can proceed, and can be appropriately adjusted by a person skilled in the art. The temperature in step (2) may be, for example, −20 to 60° C., preferably 0 to 50° C., and more preferably 10 to 40° C.

[0064] The time for step (2) is not particularly limited as long as the reaction can proceed, and can be appropriately adjusted by a person skilled in the art. The time for step (2) may be, for example, 0.5 to 48 hours, preferably 1 to 24 hours, and more preferably 1 to 10 hours.

[0065] In step (2), the compound represented by formula (II), sulfuric acid, hydrogen peroxide, and an optional solvent may all be charged into a reactor at the same time or in any order. Furthermore, for one component (e.g., sulfuric acid), the entire amount may be charged at once or may be charged in multiple portions.

[0066] In the above step (2), phosphoric acid may be used together with sulfuric acid. In this case, a person skilled in the art can appropriately adjust the amounts of sulfuric acid, phosphoric acid, and hydrogen peroxide used, taking into consideration the amounts of phosphoric acid and hydrogen peroxide used in the step (2') described below.

[0067] [Step of reacting the compound represented by formula (II) or a salt thereof in the presence of phosphoric acid and hydrogen peroxide] According to one embodiment of the present disclosure, a method for producing a compound represented by formula (I) includes a step of reacting a compound represented by formula (II) or a salt thereof with phosphoric acid and hydrogen peroxide in the presence of phosphoric acid (also referred to as "step (2')" in the present disclosure). Phosphoric acid and hydrogen peroxide are inexpensively available, which is advantageous in that it can reduce the cost of industrially mass-producing the compound represented by formula (I). [ka]

[0068] The compound represented by formula (II) or a salt thereof used in step (2') may be, for example, the compound prepared in the above preparation step.

[0069] (phosphoric acid) The amount of phosphoric acid used in step (2') is not particularly limited as long as the reaction can proceed. The amount of phosphoric acid in step (2') may be, for example, 0.1 to 10 moles, preferably 0.5 to 3 moles, more preferably 0.7 to 2.1 moles, and even more preferably 1 to 2.1 moles, based on 1 mole of the compound represented by formula (II). The amount of phosphoric acid in step (2') may be, for example, 0.1 to 10 moles, preferably 0.5 to 3 moles, more preferably 0.7 to 2.1 moles, and even more preferably 1 to 2.1 moles, based on 1 mole of the compound represented by formula (III). In particular, using an amount of phosphoric acid in step (2') of 0.7 to 2.1 moles, based on 1 mole of the compound represented by formula (II) or (III), is advantageous in terms of improving the yield and / or purity of the compound represented by formula (I) obtained.

[0070] (hydrogen peroxide) The amount of hydrogen peroxide used in step (2') is not particularly limited as long as the reaction can proceed. The amount of hydrogen peroxide in step (2') may be, for example, 0.1 to 10 mol, preferably 0.3 to 5 mol, and more preferably 0.6 to 1.1 mol, based on 1 mol of the compound represented by formula (II). The amount of hydrogen peroxide in step (2') may be, for example, 0.1 to 10 mol, preferably 0.3 to 5 mol, and more preferably 0.8 to 1.0 mol, based on 1 mol of the compound represented by formula (III). In particular, using an amount of hydrogen peroxide in step (2') of 0.8 to 1.0 mol, based on 1 mol of the compound represented by formula (II) or (III), is advantageous in terms of improving the yield and / or purity of the compound represented by formula (I) obtained.

[0071] The molar ratio of phosphoric acid to hydrogen peroxide (hydrogen peroxide / phosphoric acid) used in step (2') may be, for example, 0.01 to 100, preferably 0.1 to 10, more preferably 0.1 to 1.3, and even more preferably 0.4 or more and less than 0.9. In particular, setting the molar ratio of phosphoric acid to hydrogen peroxide (hydrogen peroxide / phosphoric acid) in step (2') to 0.4 or more and less than 0.9 is advantageous from the viewpoint of improving the yield and / or purity of the compound represented by formula (I) obtained.

[0072] According to one embodiment of the present disclosure, a mixture containing phosphoric acid and hydrogen peroxide (ie, phosphoric acid-acidic hydrogen peroxide) is used.

[0073] The amount of phosphoric acid contained in the mixture may be, for example, 10 to 50 mass %, preferably 20 to 45 mass %, and more preferably 25 to 40 mass %, based on the total mass of the mixture.

[0074] The amount of hydrogen peroxide contained in the mixture may be, for example, 1 to 10 mass %, preferably 2 to 8 mass %, and more preferably 3 to 7 mass %, based on the total mass of the mixture.

[0075] The mixture may contain components other than phosphoric acid and hydrogen peroxide (e.g., a solvent such as water). According to one embodiment of the present disclosure, the mixture contains phosphoric acid, hydrogen peroxide, and water. According to one embodiment of the present disclosure, the mixture consists essentially of phosphoric acid, hydrogen peroxide, and water. Here, "substantially" means that the mixture may contain impurities that are unavoidably contained in the production of the mixture (e.g., impurities derived from raw materials such as phosphoric acid and hydrogen peroxide).

[0076] When the mixture or the phosphoric acidic hydrogen peroxide is used in step (2'), the amount of the mixture or the phosphoric acidic hydrogen peroxide used may be, for example, 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 1 to 8 parts by mass, based on 1 part by mass of the compound represented by formula (II) or (III).

[0077] The mixture may be prepared by, for example, mixing (e.g., stirring) phosphoric acid with other components (e.g., water) as needed, and then mixing the resulting mixture with hydrogen peroxide. The mixing time, temperature, etc., can be adjusted as appropriate by a person skilled in the art.

[0078] (solvent) Step (2') may be carried out in the presence of a solvent, if necessary. The solvent used in step (2') is not particularly limited as long as the reaction proceeds, and examples thereof include water; organic solvents such as methanol, ethanol, isopropanol, butanol, isobutanol, ethylene glycol, propylene glycol, THF, dioxane, dimethyl ether, diethyl ether, dimethoxyethane, dioxane, DMF, DMA, N-methylpyrrolidone, methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, dichloromethane, chloroform, 1,2-dichloroethane, toluene, hexane, and acetonitrile; and any mixed solvents thereof. These may be used alone or in any combination of two or more. The solvent used in step (2') preferably contains water. The amount of solvent used is not particularly limited as long as the reaction proceeds, and can be appropriately adjusted by a person skilled in the art.

[0079] The temperature in step (2') is not particularly limited as long as the reaction can proceed, and can be appropriately adjusted by a person skilled in the art. The temperature in step (2') may be, for example, -20 to 60°C, preferably 0 to 50°C, and more preferably 10 to 40°C.

[0080] The time for step (2') is not particularly limited as long as the reaction can proceed, and can be appropriately adjusted by a person skilled in the art. The time for step (2') may be, for example, 0.5 to 48 hours, preferably 1 to 24 hours, and more preferably 1 to 10 hours.

[0081] In step (2'), the compound represented by formula (II), phosphoric acid, hydrogen peroxide, and an optional solvent may all be added to a reactor at the same time or in any order. Furthermore, for one component (e.g., sulfuric acid), the entire amount may be added at once or may be added in multiple portions.

[0082] In the above step (2'), phosphoric acid may be used together with sulfuric acid. In this case, a person skilled in the art can appropriately adjust the amounts of sulfuric acid, phosphoric acid, and hydrogen peroxide used, taking into consideration the amounts of sulfuric acid and hydrogen peroxide used in the above step (2).

[0083] [Step of purifying the compound represented by formula (I)] According to one embodiment of the present disclosure, the method for producing the compound represented by formula (I) may include a step of purifying the compound represented by formula (I) obtained in the above step (also referred to as "step (3)" in the present disclosure).

[0084] Any purification method can be used in step (3), and may be, for example, distillation, recrystallization, column chromatography, etc. When the purification in step (3) is carried out by recrystallization, the solvent to be used includes, but is not limited to, aprotic polar solvents such as diethyl ether, dioxane, tetrahydrofuran, dimethoxyethane, methyl ethyl ketone, acetonitrile, propionitrile, ethyl acetate, butyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, and dimethyl sulfoxide; protic polar solvents such as methanol, ethanol, and isopropyl alcohol; and nonpolar solvents such as benzene and toluene. These may be used alone or in any combination of two or more.

[0085] In addition to the above-mentioned steps, other steps (e.g., a filtration step, a concentration step, a drying step, etc.) may be carried out as necessary. Such other steps may be carried out at any position before or after the above-mentioned steps.

[0086] [Uses of the compound represented by formula (I)] Compounds of formula (I) can be used as precursors to reagents (eg, RAFT agents) that can be used in RAFT polymerization processes.

[0087] For example, a reagent usable in RAFT polymerization may be obtained by reacting a compound represented by formula (I) with a radical initiator (e.g., 4,4'-azobis(4-cyanovaleric acid)). The reaction may be carried out in the presence of a desired solvent. The reaction product obtained by the reaction may be purified (e.g., concentrated under reduced pressure, washed) as needed. The conditions (temperature, time, etc.) for the reaction and purification may be appropriately adjusted by a person skilled in the art.

[0088] For example, the desired polymer can be obtained by reacting the RAFT agent obtained above with a desired radical polymerizable monomer (e.g., methyl methacrylate) in the presence of a desired radical initiator (e.g., azobisisobutyronitrile).

[0089] [Use of mixtures containing sulfuric acid and hydrogen peroxide] According to another embodiment of the present disclosure, there is provided use of a mixture comprising sulfuric acid and hydrogen peroxide for oxidizing a compound represented by formula (II) or a salt thereof in the production of a compound represented by formula (I). According to another embodiment of the present disclosure, there is provided use of a reagent comprising sulfuric acid and hydrogen peroxide for oxidizing a compound represented by formula (II) or a salt thereof in the production of a compound represented by formula (I).

[0090] The definitions of each term and preferred embodiments in the above embodiments are as described above in the method for producing the compound represented by formula (I) of the present disclosure.

[0091] The present disclosure encompasses the following: [1] Formula (I): [ka] (In the formula, R represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted cyclic alkyl group having 3 to 12 carbon atoms, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms, where an oxygen atom or a sulfur atom may be present between the carbon bonds of the alkyl group, if possible. A method for producing a compound represented by the formula: (A) in the presence of sulfuric acid and hydrogen peroxide, a compound of formula (II): [ka] (wherein R is as defined in formula (I)). or a salt thereof to obtain a compound of formula (I); or (B) in the presence of phosphoric acid and hydrogen peroxide, a compound of formula (II): [ka] (wherein R is as defined in formula (I)). or a salt thereof to obtain a compound of formula (I). [2] The method according to [1], which comprises the step of preparing a compound represented by formula (II) or a salt thereof. [3] The preparation step is carried out by reacting a compound of formula (III): [ka] (wherein R is as defined in claim 1). to obtain a compound represented by formula (II) or a salt thereof. [4] The method according to any one of [1] to [3], wherein the salt of the compound represented by formula (II) is a metal salt. [5] The method according to any one of [1] to [4], wherein the salt of the compound represented by formula (II) is an alkali metal salt or an alkaline earth metal salt. [6] The method according to any one of [1] to [5], wherein the salt of the compound represented by formula (II) is a sodium salt or a potassium salt. [7] The method according to any one of [1] to [6], wherein R is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms. [8] R is a compound of the formula: -(CH2) n -COOH or formula: -(CH2) n The method according to any one of [1] to [7], wherein n is an integer of 1 to 15. [9] The method according to any one of [3] to [8], wherein the amount of sulfuric acid in (A) is 0.8 to 1.1 moles based on 1 mole of the compound represented by formula (III).

[10] The method according to any one of [3] to [9], wherein the amount of hydrogen peroxide in (A) is 0.8 to 1.1 moles based on 1 mole of the compound represented by formula (III).

[11] The method according to any one of [1] to

[10] , wherein the molar ratio of sulfuric acid to hydrogen peroxide (hydrogen peroxide / sulfuric acid) in (A) is 0.65 or more and less than 2.2.

[12] The method according to any one of [1] to

[11] , wherein the sulfuric acid and hydrogen peroxide in (A) are sulfuric acid-acidic hydrogen peroxide.

[13] The method according to

[12] , wherein the amount of sulfuric acid contained in the sulfuric acid-acidified hydrogen peroxide is 10 to 30 mass % based on the total mass of the sulfuric acid-acidified hydrogen peroxide.

[14] The method according to

[12] or

[13] , wherein the amount of hydrogen peroxide contained in the sulfuric acid-acidic hydrogen peroxide is 5 to 10 mass % based on the total mass of the sulfuric acid-acidic hydrogen peroxide.

[15] The method according to any one of

[12] to

[14] , wherein the amount of the sulfuric acid-acidic hydrogen peroxide is 0.1 to 10 parts by mass based on 1 part by mass of the compound represented by formula (III).

[16] The method according to any one of [3] to [8], wherein the amount of phosphoric acid in (B) is 0.7 to 2.1 moles based on 1 mole of the compound represented by formula (III).

[17] The method according to any one of [3] to [8] and

[16] , wherein the amount of hydrogen peroxide in (B) is 0.8 to 1.0 moles based on 1 mole of the compound represented by formula (III).

[18] The method according to any one of [3] to [8],

[16] and

[17] , wherein the molar ratio of phosphoric acid to hydrogen peroxide (hydrogen peroxide / phosphoric acid) in (B) is 0.4 or more and less than 0.9.

[19] The method according to any one of [1] to [8] and

[16] to

[18] , wherein the phosphoric acid and hydrogen peroxide in (B) are phosphoric acid-acidic hydrogen peroxide.

[20] The method according to

[19] , wherein the amount of the phosphoric acidic hydrogen peroxide is 0.1 to 20 parts by mass based on 1 part by mass of the compound represented by formula (III). [Example]

[0092] The method of the present disclosure will be described in more detail below using examples. However, the following examples are not intended to limit the method of the present disclosure in any way. Unless otherwise specified, percentages and ratios described herein are by mass. Furthermore, unless otherwise specified, units and measurement methods described herein are in accordance with the provisions of the Japanese Industrial Standards (JIS).

[0093] [Preparation example of sulfuric acid acidified hydrogen peroxide] To a 5 L beaker containing 3,319 g of water, 1,051 g of 96% sulfuric acid was added dropwise at 15° C., followed by stirring for 30 minutes at 15° C. To the resulting mixture, 624 g of 60% hydrogen peroxide was added dropwise, followed by stirring for 30 minutes at 15° C., yielding 4,994 g of sulfuric acid-acidic hydrogen peroxide.

[0094] [Preparation example of phosphoric acid-acidic hydrogen peroxide] 973 g of 85% phosphoric acid was added dropwise to a 3 L beaker containing 1,050 g of water at 15° C., followed by stirring for 30 minutes at 15° C. 198 g of 60% hydrogen peroxide was added dropwise to the resulting mixture, followed by stirring for 30 minutes at 15° C., yielding 2,221 g of phosphoric acid-acidic hydrogen peroxide.

[0095] [Example 1: Synthesis of bis(dodecylsulfanylthiocarbonyl) disulfide (Compound 1)] [ka]

[0096] A 1-L four-neck flask was charged with 80 g of 1-dodecanethiol and 400 g of water, and 52.7 g of 30% aqueous caustic soda solution was added dropwise at 10°C. The mixture was then stirred at 10°C for 1 hour, and 31.6 g of carbon disulfide was added dropwise. After the addition, the mixture was warmed to room temperature and stirred for 1 hour. Then, 148.2 g of sulfuric acid-acidic hydrogen peroxide (a mixture of 31.8 g of 96% sulfuric acid (0.78 times the moles of 1-dodecanethiol), 19.2 g of 60% hydrogen peroxide (0.86 times the moles of 1-dodecanethiol), and 97.2 g of water) was added dropwise at 10°C. The mixture was then stirred at 10°C for 2 hours. The resulting precipitate was filtered, washed with water, and dried to obtain Compound 1 (109.7 g, HPLC purity: 95.7%, yield: 100%) as yellow crystals. The results are shown in Table 1.

[0097] mp.30℃ 1 H NMR(400MHz,CDCl3)δ=0.88(3H,t,J=6.8Hz),1.25-1.40(20H,m),1.69(2H,q,J=7.4Hz),3.29(2H,t,J=7.4Hz) 13 C NMR(100MHz,CDCl3)δ=14.2,22.8,27.4,29.0,29.1,29.4,29.5,29.6,29.7,32.0,38.4,221.4

[0098] [Reference Example 1: Synthesis of bis(dodecylsulfanylthiocarbonyl) disulfide (Compound 1)] The same method as in Example 1 was carried out, except that 119.6 g of hydrogen peroxide (a mixture of 22.4 g of 60% hydrogen peroxide (1.00 times the moles of 1-dodecanethiol) and 97.2 g of water) was used instead of sulfuric acid-acidic hydrogen peroxide. As a result, the target compound 1 was not obtained. The results are shown in Table 1.

[0099] [Table 1]

[0100] [Example 2: Synthesis of bis(benzylsulfanylthiocarbonyl) disulfide (compound 2) 1] [ka]

[0101] A 500 mL four-neck flask was charged with 25 g of benzyl mercaptan and 125 g of water, and 26.9 g of 30% aqueous caustic soda solution was added dropwise at 10°C. The mixture was then stirred at 10°C for 1 hour, followed by the dropwise addition of 15.8 g of carbon disulfide. After the dropwise addition, the mixture was warmed to room temperature and stirred for 1 hour. Then, 72.9 g of sulfuric acid-acidic hydrogen peroxide (a mixture of 16.0 g of 96% sulfuric acid (0.80 times the moles of benzyl mercaptan), 9.6 g of 60% hydrogen peroxide (0.86 times the moles of benzyl mercaptan), and 47.3 g of water) was added dropwise at 10°C. The mixture was then stirred at 10°C for 2 hours. The resulting precipitate was filtered, washed with water, and dried to obtain Compound 2 (34.7 g, HPLC purity: 90.6%, yield: 87%) as yellow crystals. The results are shown in Table 2.

[0102] mp.79~85℃ 1 H NMR(400MHz,CDCl3)δ=4.50(4H,s),7.27-7.34(10H,m) 13 C NMR(100MHz,CDCl3)δ=43.1,128.1,128.8,129.3,133.8,220.3

[0103] [Reference Example 2: Synthesis of bis(benzylsulfanylthiocarbonyl) disulfide (compound 2)] The same procedure as in Example 2 was carried out, except that 58.7 g of hydrogen peroxide (a mixture of 11.4 g of 60% hydrogen peroxide (1.00 times the moles of benzyl mercaptan) and 47.3 g of water) was used instead of sulfuric acid-acidic hydrogen peroxide. As a result, the target compound 2 was not obtained. The results are shown in Table 2.

[0104] [Table 2]

[0105] [Example 3: Synthesis of 3,3'-(disulfane-1,2-dicarbonothioyl)bis(sulfanediyl)dipropionic acid (Compound 3) 1] [ka]

[0106] A 500 mL four-neck flask was charged with 252.2 g of 48% aqueous potassium hydroxide solution and 22.7 g of water, and 113.0 g of 3-mercaptopropionic acid was added dropwise at 20°C. The mixture was stirred at 10°C for 1.5 hours, and then 85.0 g of carbon disulfide was added. The mixture was then stirred at 10°C for 2 hours and then at 20°C for 17 hours, yielding 472.9 g of an aqueous potassium trithiocarbonate solution. A 1-L four-neck flask was charged with 412.5 g of sulfuric acid-acidified hydrogen peroxide (a mixture of 84.8 g of 96% sulfuric acid (0.78 times the moles of 3-mercaptopropionic acid), 51.9 g of 60% hydrogen peroxide (0.86 times the moles of 3-mercaptopropionic acid), and 275.8 g of water) and 38.3 g of methanol, and 472.9 g of an aqueous solution of potassium trithiocarbonate was added dropwise at 10°C. The mixture was then stirred at 10°C for 1 hour, and 87.6 g of 25% sulfuric acid was added dropwise. The mixture was stirred at 20°C for 15.5 hours. The resulting precipitate was filtered, washed with water, and dried to obtain compound 3 (163.8 g, NMR purity: 93.0%, yield: 85%) as a yellow powder. The results are shown in Table 3.

[0107] mp.126~130℃ 1 H NMR(400MHz,CDCl3)δ=2.69(4H,t,J=7.0Hz),3.52(4H,t,J=7.0Hz),12.56(2H,s) 13 C NMR(100MHz,CDCl3)δ=31.5,33.1,172.4,221.2

[0108] [Examples 4 to 8: Synthesis of 3,3'-(disulfane-1,2-dicarbonothioyl)bis(sulfanediyl)dipropionic acid (Compound 3) 2] The same method as in Example 3 was carried out, except that the ratio of sulfuric acid to hydrogen peroxide in the sulfuric acid-acidic hydrogen peroxide was changed to the ratio shown in Table 3, to obtain the target compound 3. The results are shown in Table 3.

[0109] [Reference Example 3: Synthesis of 3,3'-(disulfane-1,2-dicarbonothioyl)bis(sulfanediyl)dipropionic acid (Compound 3)] The same procedure as in Example 3 was carried out, except that 336.2 g of hydrogen peroxide (a mixture of 60.4 g of 60% hydrogen peroxide (1.00 times the moles of 3-mercaptopropionic acid) and 275.8 g of water) was used instead of sulfuric acid-acidic hydrogen peroxide. As a result, the target compound 3 was not obtained. The results are shown in Table 3.

[0110] [Table 3]

[0111] [Example 9: Synthesis of 3,3'-(disulfane-1,2-dicarbonothioyl)bis(sulfanediyl)dipropionic acid (compound 3) 4] [ka]

[0112] A 500 mL four-neck flask was charged with 95.7 g of 48% aqueous potassium hydroxide solution and 8.6 g of water, and 42.9 g of 3-mercaptopropionic acid was added dropwise at 20°C. The mixture was stirred at 10°C for 1.5 hours, and then 32.2 g of carbon disulfide was added. The mixture was then stirred at 10°C for 2 hours and then at 20°C for 17 hours, yielding 179.4 g of an aqueous potassium trithiocarbonate solution. A 500 mL four-neck flask was charged with 222.1 g of phosphoric acid-acidic hydrogen peroxide [97.3 g of 85% phosphoric acid (2.10 times the moles of 3-mercaptopropionic acid), 19.8 g of 60% hydrogen peroxide (0.87 times the moles of 3-mercaptopropionic acid), and 105.0 g of water] and 22.2 g of methanol, and 179.4 g of potassium trithiocarbonate solution was added dropwise at 10°C. The mixture was stirred at 10°C for 1 hour and then at 20°C for 15.5 hours. The resulting precipitate was filtered, washed with water, and dried to obtain compound 3 (64.1 g, NMR purity 93.3%, yield 89%) as a yellow powder. The results are shown in Table 4. mp.126-130℃ 1 H NMR(400MHz,CDCl3)δ=2.69(4H,t,J=7.0Hz),3.52(4H,t,J=7.0Hz),12.56(2H,s). 13 C NMR(100MHz,CDCl3)δ=31.5,33.1,172.4,221.2.

[0113] [Examples 10-11: Synthesis of 3,3'-(disulfane-1,2-dicarbonothioyl)bis(sulfanediyl)dipropionic acid (compound 3)] The same method as in Example 9 was carried out, except that the ratio of phosphoric acid to hydrogen peroxide in the phosphoric acid-acidic hydrogen peroxide solution was changed to the ratio shown in Table 4, to obtain the target compound 3. The results are shown in Table 4.

[0114] [Reference Example 4: Synthesis of 3,3'-(disulfane-1,2-dicarbonothioyl)bis(sulfanediyl)dipropionic acid (Compound 3)] The same procedure as in Example 9 was carried out, except that 336.2 g of hydrogen peroxide (a mixture of 60.4 g of 60% hydrogen peroxide (1.00 times the moles of 3-mercaptopropionic acid) and 275.8 g of water) was used instead of phosphoric acid hydrogen peroxide. As a result, the target compound 3 was not obtained. The results are shown in Table 4.

[0115] [Table 4]

[0116] From the results of Examples 1 to 8, when sulfuric acid acidified hydrogen peroxide solution was used, a compound having a bis(thiocarbonyl)disulfide skeleton could be produced from a trithiocarbonate compound or its salt. On the other hand, when hydrogen peroxide alone was used, a compound having a bis(thiocarbonyl)disulfide skeleton could not be produced (Reference Examples 1 to 3). Furthermore, the present inventors' investigations have revealed that when sulfuric acid alone was used, a compound having a bis(thiocarbonyl)disulfide skeleton could not be produced either. Furthermore, from the results of Examples 3 to 8, it is believed that the yield and / or purity of the compound having a bis(thiocarbonyl)disulfide skeleton is superior when sulfuric acid-acidic hydrogen peroxide is used in an amount of 0.8 to 1.1 molar times sulfuric acid and 0.8 to 1.1 molar times hydrogen peroxide per mole of the starting material (3-mercaptopropionic acid). Alternatively, it is believed that the yield and / or purity of the compound having a bis(thiocarbonyl)disulfide skeleton is superior when sulfuric acid-acidic hydrogen peroxide is used in an amount of 0.65 molar times or more and less than 2.2 molar times (preferably 0.65 to 2 molar times, more preferably 0.8 to 1.5 molar times, and even more preferably 0.8 to 1.3 molar times) hydrogen peroxide per mole of sulfuric acid.

[0117] The results of Examples 9 to 11 show that even when phosphoric acid-acidic hydrogen peroxide solution was used, a compound having a bis(thiocarbonyl)disulfide skeleton could be produced from a trithiocarbonate compound or its salt. On the other hand, when hydrogen peroxide alone was used, a compound having a bis(thiocarbonyl)disulfide skeleton could not be produced (Reference Example 4). Furthermore, the present inventors' investigations have revealed that even when phosphoric acid alone was used, a compound having a bis(thiocarbonyl)disulfide skeleton could not be produced. Furthermore, from the results of Examples 9 to 11, it is considered that the yield and / or purity of the compound having a bis(thiocarbonyl)disulfide skeleton obtained is superior when phosphoric acid-acidic hydrogen peroxide having 0.7 molar or more (preferably 1 molar or more) phosphoric acid relative to 1 mole of the starting material (3-mercaptopropionic acid), or preferably sulfuric acid-acidic hydrogen peroxide having 0.7 molar or more (preferably 1 molar or more) phosphoric acid and 0.8 molar or more hydrogen peroxide, is used. Alternatively, when phosphoric hydrogen peroxide containing 1.3 molar or less (preferably 1 molar or less, more preferably 0.8 molar or less, and even more preferably 0.5 molar or less) hydrogen peroxide per mole of phosphoric acid is used, the yield and / or purity of the resulting compound having a bis(thiocarbonyl)disulfide skeleton is considered to be superior.

[0118] Example 12: Synthesis of 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid (Compound 4) [ka]

[0119] A 2 L four-neck flask was charged with 100.9 g of compound 1 obtained in Example 1, 900 mL of ethyl acetate, and 108.2 g of 4,4'-azobis(4-cyanovaleric acid) (ACVA), and the mixture was stirred at 70°C for 8 hours. After stirring, the mixture was cooled to room temperature and concentrated under reduced pressure to remove the ethyl acetate. Heptane was added to the resulting reaction mixture to cause crystallization. The resulting precipitate was filtered and washed with water to obtain crude crystals (159 g). The crude crystals obtained were recrystallized twice using a mixed solvent of ethyl acetate and hexane to obtain compound 4 (58.6 g, yield: 40%) as a yellowish-white powder.

[0120] mp.60℃ 1H NMR(400MHz,CDCl3),δ=0.88(3H,t,J=6.6Hz),1.26-1.40(18H,m),1.68-1.71(2H,m),1.89(3H,s),2.41-2.71(4H,m),3.33(2H,t,J=7.6Hz) 13 C NMR(100MHz,CDCl3)δ=14.1,22.7,24.8,27.6,28.9,29.0,29.3,29.4,29.5,29.6,31.9,33.4,37.1,46.1,118.9,177.2,216.8

[0121] Example 13: Polymerization of methyl methacrylate using 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid (Compound 4) A 100 mL four-neck flask was charged with 15.0 g of methyl methacrylate, 605.5 mg of Compound 4 obtained in Example 12, 98.5 mg of azobisisobutyronitrile (AIBN), and 34.1 mL of toluene, and argon was bubbled through for 5 minutes. The mixture was then stirred at 60°C for 27 hours. After the reaction was completed, the mixture was cooled to room temperature and analyzed. The conversion of methyl methacrylate determined by H nuclear magnetic resonance spectroscopy was 89%, and the Mn, Mw, and Mw / Mn values ​​determined by gel permeation chromatography were 8,200, 9,900, and 1.20, respectively.

[0122] These results suggest that the use of sulfuric acid-acidified hydrogen peroxide in the synthesis of compounds with a bis(thiocarbonyl)disulfide skeleton, which are useful as RAFT agents, makes it possible to industrially and inexpensively produce compounds with a bis(thiocarbonyl)disulfide skeleton.

Claims

1. Formula (I): 【Chemical 1】 (In the formula, R represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted cyclic alkyl group having 3 to 12 carbon atoms, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms, where an oxygen atom or a sulfur atom may be present between the carbon bonds of the alkyl group, if possible. A method for producing a compound represented by the formula: (A) reacting a compound of formula (II): in the presence of sulfuric acid and hydrogen peroxide: 【Chemistry 2】 (wherein R is as defined in formula (I)). or a salt thereof to obtain a compound of formula (I); or (B) reacting a compound of formula (II) in the presence of phosphoric acid and hydrogen peroxide: 【Chemistry 3】 (wherein R is as defined in formula (I)). or a salt thereof to obtain a compound of formula (I).

2. 10. The method of claim 1, comprising providing a compound of formula (II) or a salt thereof:

3. The preparing step comprises reacting a compound of formula (III): 【Chemistry 4】 (wherein R is as defined in claim 1). to obtain a compound represented by formula (II) or a salt thereof.

4. 3. The method according to claim 1 or 2, wherein the salt of the compound of formula (II) is a metal salt.

5. 3. The method according to claim 1 or 2, wherein the salt of the compound of formula (II) is an alkali metal salt or an alkaline earth metal salt.

6. 3. The method according to claim 1 or 2, wherein the salt of the compound of formula (II) is a sodium salt or a potassium salt.

7. 3. The method according to claim 1, wherein R is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms.

8. R is a group of the formula: -(CH ２ ) ｎ -COOH or the formula: -(CH ２ ) ｎ -CH ３ (wherein n is an integer from 1 to 15).

9. The method according to claim 3, wherein the amount of sulfuric acid in (A) is 0.8 to 1.1 moles based on 1 mole of the compound represented by formula (III).

10. The method according to claim 3, wherein the amount of hydrogen peroxide in (A) is 0.8 to 1.1 moles based on 1 mole of the compound represented by formula (III).

11. 3. The method according to claim 1, wherein the molar ratio of sulfuric acid to hydrogen peroxide (hydrogen peroxide / sulfuric acid) in (A) is 0.65 or more and less than 2.

2.

12. 3. The method according to claim 1, wherein the sulfuric acid and hydrogen peroxide in (A) are sulfuric acid-acidic hydrogen peroxide.

13. The method according to claim 12, wherein the amount of sulfuric acid contained in the sulfuric acid-acidified hydrogen peroxide is 10 to 30% by mass based on the total mass of the sulfuric acid-acidified hydrogen peroxide.

14. The method according to claim 12, wherein the amount of hydrogen peroxide contained in the sulfuric acid-acidic hydrogen peroxide is 5 to 10% by mass based on the total mass of the sulfuric acid-acidic hydrogen peroxide.

15. The method according to claim 12, wherein the amount of the sulfuric acid-acidic hydrogen peroxide is 0.1 to 10 parts by mass based on 1 part by mass of the compound represented by formula (III).

16. The method according to claim 3, wherein the amount of phosphoric acid in (B) is 0.7 to 2.1 moles based on 1 mole of the compound represented by formula (III).

17. The method according to claim 3, wherein the amount of hydrogen peroxide in (B) is 0.8 to 1.0 moles based on 1 mole of the compound represented by formula (III).

18. 3. The method according to claim 1, wherein the molar ratio of phosphoric acid to hydrogen peroxide (hydrogen peroxide / phosphoric acid) in (B) is 0.4 or more and less than 0.

9.

19. 3. The method according to claim 1, wherein the phosphoric acid and hydrogen peroxide in (B) are phosphoric acid-acidic hydrogen peroxide.

20. The method according to claim 19, wherein the amount of the phosphoric acidic hydrogen peroxide is 0.1 to 20 parts by mass based on 1 part by mass of the compound represented by formula (III).

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