DESCRIPTION
PROCESS FOR PRODUCING 2-IMIDAZOLIDINONE COMPOUND AND 4,5-DIALKOXY-2-IMIDAZOLIDINONE COMPOUND
Technical Field [0001]
The present invention relates to a process for producing a 2-imidazolidinone compound and a 4,5-dialkoxy-2-imidazolidinone compound which is a synthetic raw material thereof. The 2-imidazolidinone compound and the 4,5-dialkoxy-2-imidazolidinone compound are compounds useful as raw materials or synthetic intermediates for medicines or agricultural chemicals, for example.
Background Art [0002]
Conventionally, as a process for producing a 2-imidazolidinone compound, there have been disclosed, for example, a process for producing 1,3-dimethyl-2-imidazolidinone comprising reacting phosgene with 1,3-dimethylethylenediamine at a low temperature (see Non-Patent Document 1, for example), a process for producing 1,3-dimethyl-2-imidazolidinone comprising reacting 2-imidazolidinone with dimethyl sulfate (see Non-Patent Document 2, for example) and a process for producing 1,3-dimethyl-2-imidazolidinone comprising reacting triphenylantimony, phosphorus pentasulfide and carbon dioxide under high pressure (see Non-Patent Document 3, for example). However, any of the processes are disadvantageous as an industrial process for producing a 2-imidazolidinone compound in that a highly toxic reagent or an expensive reagent has to be used and the reaction conditions are severe, for example. [0003]
Conventionally, as a process for producing a 4,5-

dialkoxy-2-imidazolidinone compound, there has been disclosed, for example, a process for producing 4,5-dibutoxy-1,3-dimethylimidazolidin-2-one comprising reacting an aqueous glyoxal solution, 1,3-dimethylurea, 1-butanol and concentrated sulfuric acid at room temperature (see Patent Document 1, for example). However, this process is disadvantageous in that it takes so much effort and energy to remove the acid catalyst used (sulfuric acid) from the reaction solution and discard the catalyst. Patent Document 1: International Publication WO 90/00407 Non-Patent Document 1: J. Chem. Soc, 1956, 5041. Non-Patent Document 2: Synth. Commun., 18(5), 487 (1988) Non-Patent Document 3: J. Org. Chem., 57(28), 7339 (1992)
Disclosure of the Invention Problem to be Solved by the Invention [0004]
Specifically, an object of the present invention is to solve the above problems and provide an industrially suitable process for producing a 2-imidazolidinone compound and a 4,5-dialkoxy-2-imidazolidinone compound, in which the 2-imidazolidinone compound and 4,5-dialkoxy-2-imidazolidinone compound are produced by a simple method in high yield.
Means for solving the problem [0005]
A first object of the present invention is achieved by a process for producing a 2-imidazolidinone compound represented by the general formula (2): [0008]

wherein R represents a hydrogen atom or a hydrocarbon group, R1 and R2 may be the same or different and each represent a hydrogen atom or a hydrocarbon group, and R3 represents an alkyl group,
which process comprises reacting a dicarbonyl compound represented by the general formula (3): [0011]

[0 012] wherein R is as defined above,
a urea compound represented by the general formula (4) : [0013]

[0014] wherein R1 and R2 are as defined above, and
an alcohol represented by the general formula (5): [0015]
R3OH (5)
[0016]
wherein R3 is as defined above, in the presence of a solid acid catalyst.
Effect of the Invention [0019]
The present invention can provide an industrially suitable process for producing a 2-imidazolidinone compound and a 4,5~dialkoxy-2-imidazolidinone compound, in which the 2-imidazolidinone compound and 4,5-dialkoxy-2-

imidazolidinone compound are produced by a simple method in high yield.
Best Mode for Carrying Out the Invention [0020]
[Process for producing 2-imidazolidinone compound from 4,5-dialkoxy-2-imidazolidinone compound by hydrogenation reaction]
The present invention relates to a process for producing a 2-imidazolidinone represented by the general formula (2), comprising reacting a 4,5-dialkoxy-2-imidazolidinone compound represented by the general formula (1) with hydrogen in the presence of a metal catalyst. [0021]
The 4,5-dialkoxy-2-imidazolidinone compound used in the hydrogenation reaction of the present invention is represented by the above general formula (1). In the general formula (1), R1, R2 and R may be the same or different and each represent a hydrogen atom or a hydrocarbon group. Examples of the hydrocarbon group include alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group; cycloalkyl groups having 3 to 6 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group; aralkyl groups having 7 to 12 carbon atoms such as a benzyl group, a phenethyl group and a phenylpropyl group; and aryl groups having 6 to 2 0 carbon atoms such as a phenyl group, a tolyl group, a biphenylyl group and a naphthyl group. These groups include various isomers. [0022]
R3 is an alkyl group. Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group. These groups

include various isomers. [0023]
The metal catalyst used in the hydrogenation reaction of the present invention comprises at least one metal atom selected from the group consisting of palladium, platinum and nickel. Specific examples of the metal catalyst include palladium/carbon, palladium/barium sulfate, palladium hydroxide/platinum, platinum/carbon, platinum sulfide/carbon, palladium-platinum/carbon, platinum oxide and Raney nickel. These metal catalysts may be used singly or in a mixture of two or more. [0024]
The amount of the metal catalyst used is, in terms of a metal atom, preferably 0.00 001 to 0.5 mole, and more preferably 0.00002 to 0.1 mole per mole of the 4,5-dialkoxy-2 -imidazolidinone compound. [0025]
The amount of hydrogen used in the hydrogenation reaction of the present invention is preferably 0.1 to 20 moles, and more preferably 0.2 to 10 moles per mole of the 4,5-dialkoxy-2-imidazolidinone compound. [0026]
The hydrogenation reaction of the present invention is carried out in the presence or absence of a solvent. The solvent that may be used is not particularly limited so long as it does not inhibit the reaction. Examples of the solvent include water; alcohols such as methanol, ethanol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol, ethylene glycol and triethylene glycol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; amides such as N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; ureas such as N,N'-dimethylimidazolidinone; sulfoxides such as dimethyl sulfoxide; nitriles such as acetonitrile, propionitrile and benzonitrile,- ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; and

aromatic hydrocarbons such as benzene, toluene and xylene. Alcohols are preferably used. These organic solvents may be used singly or in a mixture of two or more. [0027]
The amount of the solvent used is appropriately adjusted according to the homogeneity and the condition of stirring of the reaction solution and is preferably 0 to 50 g based on 1 g of the 4,5-dialkoxy-2-imidazolidinone compound. [0028]
The hydrogenation reaction of the present invention is carried out by a method of mixing the 4,5-dialkoxy-2-imidazolidinone compound, the metal catalyst and the solvent and reacting the mixture with stirring in a hydrogen atmosphere, for example. In this case, the reaction temperature is preferably 0 to 2 0 0°C, and more preferably 10 to 15 0°C, and the reaction pressure is preferably 0.1 to 10 MPa, and more preferably 0.1 to 1 MPa. [0029]
The 2-imidazolidinone compound obtained in the hydrogenation reaction of the present invention can be isolated and purified by a general method such as neutralization, extraction, filtration, concentration, distillation, recrystallization, crystallization or column chromatography, after completion of the reaction. [0030]
[Process for producing 4,5-dialkoxy-2-imidazolidinone compound from dicarbonyl compound, urea compound and alcohol (raw material synthesis 1)]
The present invention relates to a process for producing a 4,5-dialkoxy-2-imidazolidinone compound represented by the general formula (1), comprising reacting a dicarbonyl compound represented by the general formula (3), a urea compound represented by the general formula (4) and an alcohol represented by the general formula (5) (raw material synthesis 1) .

[0031]
The dicarbonyl compound used in the raw material synthesis 1 of the present invention is represented by the above general formula (3). In the general formula (3), R represents a hydrogen atom or a hydrocarbon group. Examples of the hydrocarbon group include alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group; cycloalkyl groups having 3 to 6 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group; aralkyl groups having 7 to 12 carbon atoms such as a benzyl group, a phenethyl group and a phenylpropyl group; and aryl groups having 6 to 2 0 carbon atoms such as a phenyl group, a tolyl group, a biphenylyl group and a naphthyl group. These groups include various isomers.
[0032]
The dicarbonyl compound used may also be a solution in water or an organic solvent inert to the reaction, or may also be a multimer or the like (obtained by intermolecular condensation).
[0033]
The urea compound used in the raw material synthesis 1 of the present invention is represented by the above general formula (4). In the general formula (4), R1 and R2 may be the same or different and each represent a hydrogen atom or a hydrocarbon group. Examples of the hydrocarbon group include alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group; cycloalkyl groups having 3 to 6 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group; aralkyl groups having 7 to 12 carbon atoms such as a benzyl group, a phenethyl group and a phenylpropyl group; and aryl groups having 6 to 2 0 carbon atoms such as a phenyl group, a tolyl group, a

biphenylyl group and a naphthyl group. These groups
include various isomers.
[0034]
The amount of the urea used in the raw material synthesis 1 of the present invention is preferably 0.8 to 1.2 moles, and more preferably 0.9 to 1.1 moles per mole of the dicarbonyl compound. [0035]
The alcohol used in the raw material synthesis 1 of the present invention is represented by the above general formula (5) . In the general formula (5), R3 is an alkyl group. Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group. These groups include various isomers. [0036]
The amount of the alcohol used in the raw material synthesis 1 of the present invention is preferably 0.5 to 200 moles, and more preferably 2.0 to 150 moles per mole of the dicarbonyl compound. [0037]
The solid acid catalyst used in the raw material synthesis 1 of the present invention is not particularly limited so long as it is a solid having a Bronsted acid site. Examples of the solid acid catalyst include clay minerals such as acid clay; sulfonic acid based cation exchange resins such as Amberlite (trade name), Dowex (trade name), Diaion (trade name), Deniolite (trade name), Lewatit (trade name) and Sumikaion (trade name); fluorinated sulfonic acid resins such as Nafion,- and inorganic oxides such as silica-alumina, zeolite and vanadium oxide. Sulfonic acid based cation exchange resins are preferably used. These solid acid catalysts may be used singly or in a mixture of two or more. [0038]
The amount of the solid acid catalyst used is

preferably 0.001 to 1.0 g, and more preferably 0.02 to 0.9 g based on 1 g of the dicarbonyl compound. [0039]
The raw material synthesis 1 of the present invention may be carried out in the presence of a solvent other than an alcohol. The solvent used is not particularly limited so long as it does not inhibit the reaction. Examples of the solvent include water; amides such as N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; ureas such as 1,3-dimethylimidazolidinone; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons such as benzene, toluene and xylene; esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile and propionitrile; and sulfoxides such as dimethyl sulfoxide. Nitriles, ureas, carboxylates and aromatic hydrocarbons are preferably used. These solvents may be used singly or in a mixture of two or more. [0040]
The amount of the solvent used is appropriately adjusted according to the homogeneity and the condition of stirring of the reaction solution and is preferably 0 to 100 g, and more preferably 0 to 50 g based on 1 g of the urea compound. [0041]
The raw material synthesis 1 of the present invention is carried out by a method of mixing the solid acid catalyst, the dicarbonyl compound, the urea compound and the alcohol and then reacting the mixture with stirring, for example. In this case, the reaction temperature is preferably 0 to 3 0 0°C, and more preferably 20 to 200°C, and the reaction pressure is not particularly limited. [0042]
The 4,5-dialkoxy-2-imidazolidinone compound obtained in the raw material synthesis 1 reaction of the

present invention can be isolated and purified by a general method such as neutralization, extraction, filtration, concentration, distillation, recrystallization, crystallization or column chromatography, after completion of the reaction. [0043]
[Process for producing 4,5-dialkoxy-2-imidazolidinone compound by etherification of 4,5-dihydroxy-2-imidazolidinone compound (raw material synthesis 2)]
The 4,5-dialkoxy-2-imidazolidinone compound represented by the general formula (1) in the present invention can also be synthesized by reacting a 4,5-dihydroxy-2-imidazolidinone compound represented by the general formula (6): [0044]

[0045] where R, R1 and R2 are as defined above, with
an alcohol represented by the general formula (5): [0046]
R3OH (5)
[0047]
where R3 is as defined above,
in the presence of a solid acid catalyst (raw material synthesis 2).
The 4,5-dihydroxy-2-imidazolidinone compound of the present invention is represented by the general formula
(6) . In the general formula (6) , R, R1 and R2 are as defined above. The 4,5-dihydroxy-2-imidazolidinone compound can be synthesized by a known method or a method

analogous to the known method. [0048]
The alcohol used in the raw material synthesis 2 of the present invention is represented by the above general formula (5). In the general formula (5), R3 is as defined above. [0049]
The amount of the alcohol is preferably 0.5 to 200 moles, and more preferably 2.0 to 150 moles per mole of the 4,5-dihydroxy-2-imidazolidinone compound. [0050]
The solid acid catalyst used in the raw material synthesis 2 of the present invention is not particularly limited so long as it is a solid having a Bronsted acid site. Examples of the solid acid catalyst include clay minerals such as acid clay; sulfonic acid based cation exchange resins such as Amberlite (trade name), Dowex (trade name), Diaion (trade name), Deniolite (trade name), Lewatit (trade name) and Sumikaion (trade name); fluorinated sulfonic acid resins such as Nafion; and inorganic oxides such as silica-alumina, zeolite and vanadium oxide. Sulfonic acid based cation exchange resins are preferably used. These solid acid catalysts may be used singly or in a mixture of two or more. [0051]
The amount of the solid acid catalyst used is preferably 0.001 to 1.0 g, and more preferably 0.002 to 0.9 g based on 1 g of the 4,5-dihydroxy-2-imidazolidinone compound. [0052]
The raw material synthesis 2 of the present invention may be carried out in the presence of a solvent other than an alcohol. The solvent used is not particularly limited so long as it does not inhibit the reaction. Examples of the solvent include water; amides such as N,N-dimethylformamide, N,N-dimethylacetamide and

N-methylpyrrolidone; ureas such as 1,3-dimethylimidazolidinone; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons such as benzene, toluene and xylene; carboxylates such as ethyl acetate and butyl acetate; nitriles such as acetonitrile and propionitrile; and sulfoxides such as dimethyl sulfoxide. Nitriles, ureas, carboxylates and aromatic hydrocarbons are preferably used. These solvents may be used singly or in a mixture of two or more. [0053]
The amount of the solvent used is appropriately adjusted according to the homogeneity and the condition of stirring of the reaction solution and is preferably 0 to 100 g, and more preferably 0 to 50 g based on 1 g of the 4,5-dihydroxy-2-imidazolidinone compound. [0054]
The raw material synthesis 2 of the present invention is carried out by a method of mixing the solid acid catalyst, the 4,5-dihydroxy-2-imidazolidinone compound and the alcohol and then reacting the mixture with stirring, for example. In this case, the reaction temperature is preferably 0 to 2 0 0°C, and more preferably 10 to 100°C, and the reaction pressure is not particularly limited. [0055]
The 4,5-dialkoxy-2-imidazolidinone compound obtained in the raw material synthesis 2 of the present invention can be isolated and purified by a general method such as neutralization, extraction, collection by filtration, concentration, distillation, recrystallization, crystallization or column chromatography, after completion of the reaction. The 4,5-dialkoxy-2-imidazolidinone compound can be continuously used for the next reaction (the reaction of the 4,5-dialkoxy-2-imidazolidinone compound with hydrogen) without isolation and purification

in particular.
Examples
[0056]
Next, the present invention will be specifically-described by way of Examples,- however, the scope of the present invention is not limited thereto.
[0057]
Example 1 (Synthesis of 4,5-dimethoxy-l,3-dimethyl-2-
imidazolidinone: raw material synthesis 1)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer and a thermometer were added 1.0 0 g of 1,3-dimethylurea (11.3 mmol), 1.65 g of an aqueous 40 wt% glyoxal solution (11.3 mmol), 0.2 g of a sulfonic acid based cation exchange resin (trade name: Dowex 50WX2) and 10 ml of methanol (247 mmol), and the
mixture was reacted with stirring at 60°C for 4.5 hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 1.5 0 g of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 76%). [0058]
Example 2 (Synthesis of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 1)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer and a thermometer were added 1.0 0 g of 1,3-dimethylurea (11.3 mmol), 1.65 g of an aqueous 40 wt% glyoxal solution (11.3 mmol), 0.2 g of a sulfonic acid based cation exchange resin (trade name: Dowex M31) and 10 ml of methanol (247 mmol), and the
mixture was reacted with stirring at 60°C for 4.5 hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 1.46 g of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 74%). [0059]

Example 3 (Synthesis of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 1)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer and a thermometer were added 1.0 0 g of 1,3-dimethylurea (11.3 mmol), 0.95 g of glyoxal trimer dihydrate (4.5 mmol), 0.2 g of a sulfonic acid based cation exchange resin (trade name: Dowex M31) and 10 ml of methanol (247 mmol), and the mixture was reacted
with stirring at 60°C for 4.5 hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 1.65 g of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 84%). [0060]
Example 4 (Synthesis of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 1)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer and a thermometer were added 1.00 g of 1,3-dimethylurea (11.3 mmol), 1.65 g of an aqueous 40 wt% glyoxal solution (11.3 mmol), 0.2 g of a sulfonic acid based cation exchange resin (trade name: Dowex 50WX2) and 10 ml of n-butanol (109 mmol), and the
mixture was reacted with stirring at 60°C for 4.5 hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 1.02 g of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 35%). [0061]
Reference Example 1 (Synthesis of 4,5-dihydroxy-l,3-dimethyl-2-imidazolidinone)
To a glass container having an internal volume of 10 0 0 ml equipped with a stirrer, a thermometer and a dropping funnel were added 290 g of an aqueous 4 0 wt% glyoxal solution (2.0 mol) and triethylamine (the pH of the reaction solution being 9). Next, a solution of 176 g of 1,3-dimethylurea (2.0 mol) in 176 ml of water was

slowly added while maintaining the liquid temperature at
25 to 35°C. Then, the mixture was reacted with stirring at the same temperature for 15 hours to obtain 666.6 g of an aqueous solution containing 4,5-dihydroxy-2-imidazolidinone. [0062]
To 333.3 g of the solution was added 700 ml of diethyl carbonate, and water was azeotropically distilled (40 to 60°C, 2 to 13 kPa) . The resulting white solid was filtered and dried under reduced pressure at 50°C to obtain 137 g of 4,5-dihydroxy-l,3-dimethyl-2-imidazolidinone having a purity of 94.1% (absolute quantitative value by high performance liquid chromatography) (isolation yield based on 1,3-dimethylurea: 8 8.3%). [0063]
Example 5 (Synthesis of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 2)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dihydroxy-l,3-dimethylimidazolidinone (3.4 mmol), 100 mg of a sulfonic acid based cation exchange resin (trade name: Nafion) and 5 ml of methanol, and the mixture was reacted at room temperature for five hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (determined by the internal standard method) to find that 540 mg of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 91%). [0064]
Example 6 (Synthesis of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 2)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 50 0 mg of 4,5-dihydroxy-l,3-dimethylimidazolidinone (3.4 mmol), 100 mg of a sulfonic

acid based cation exchange resin (trade name: Dowex 5 0WX2) and 5 ml of methanol, and the mixture was reacted at room temperature for 16 hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (determined by the internal standard method) to find that 571 mg of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 96%).
[0065]
Example 7 (Synthesis of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 2)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 5 00 mg of 4,5-dihydroxy-l,3-dimethylimidazolidinone (3.4 mmol), 100 mg of a sulfonic acid based cation exchange resin (trade name: Dowex 5 0WX2), 1 ml of methanol and 0.5 ml of water, and the mixture was reacted at room temperature for five hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (determined by the internal standard method) to find that 571 mg of 4,5-dimethoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 96%) .
[0066] Example 8 (Synthesis of 1,3-dimethyl-2-imidazolidinone)
To a stainless steel pressure-resistant vessel having an internal volume of 10 0 ml equipped with a stirrer and a thermometer were added 1.00 g of 4,5-dimethoxy-1,3-dimethyl-2-imidazolidinone (5.7 mmol), 0.1 g of platinum-palladium/carbon and 10 ml of ethylene glycol, and the mixture was stirred in a hydrogen atmosphere (2.4
MPa) at 150°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 598 mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 91%). [0067]

Example 9 (Synthesis of 1,3-dimethyl-2-imidazolidinone)
To a stainless steel pressure-resistant vessel having an internal volume of 10 0 ml equipped with a stirrer and a thermometer were added 1.00 g of 4,5-dimethoxy-1,3-dimethyl-2-imidazolidinone (5.7 mmol), 0.1 g of platinum-palladium/carbon and 10 ml of ethylene glycol, and the mixture was stirred in a hydrogen atmosphere (2.4
MPa) at 50°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 605 mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 92%). [0068] Example 10 (Synthesis of 1,3-dimethyl-2-imidazolidinone)
To a stainless steel pressure-resistant vessel having an internal volume of 100 ml equipped with a stirrer and a thermometer were added 4.00 g of 4,5-dimethoxy-1,3-dimethyl-2-imidazolidinone (22.8 mmol), 0.4 g of platinum-palladium/carbon and 40 ml of water, and the mixture was stirred in a hydrogen atmosphere (2.4 MPa) at
150°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 2.39 g of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 92%) . [0069]
Example 11 (Synthesis of 1,3-dimethyl-2-imidazolidinone) To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dimethoxy-1,3-dimethylimidazolidinone (2.9 mmol), 0.05 g of platinum-palladium/ carbon and 5 ml of n-butyl alcohol, and the mixture was stirred in a hydrogen atmosphere (normal
pressure) at 100°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 2 91

mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 89%). [0070]
Example 12 (Synthesis of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 2)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 5 00 mg of 4,5-dihydroxy-l,3-dimethylimidazolidinone (3.4 mmol), 50 mg of a sulfonic acid based cation exchange resin (trade name: Dowex 5 0WX4) and 5 ml of n-butyl alcohol (55 mmol), and the mixture was reacted at room temperature for 16 hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (determined by the internal standard method) to find that 813 mg of 4,5-dibutoxy-l,3-dimethylimidazolidinone was formed (reaction yield: 92%). [0071]
Example 13 (Synthesis of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 2)
To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dihydroxy-l,3-dimethyl-2-imidazolidinone (3.4 mmol), 100 mg of a sulfonic acid based cation exchange resin (trade name: Dowex 50WX4) and 5 ml of n-butyl alcohol (55 mmol), and the mixture was
reacted at 50°C for five hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (determined by the internal standard method) to find that 613 mg of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone was formed (reaction yield: 70%). [0072]
Example 14 (Synthesis of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone: raw material synthesis 2)
To a glass container having an internal volume of 300 ml equipped with a stirrer, a thermometer and a reflux condenser were added 20 g of 4,5-dihydroxy-l,3-

dimethylimidazolidinone (137 mmol), 2 g of a sulfonic acid based cation exchange resin (trade name: Dowex 50WX4) and 200 ml of n-butyl alcohol (2.2 mol), and the mixture was reacted at room temperature for five hours. After completion of the reaction, the reaction solution was filtered and the filtrate was concentrated under reduced pressure. The resulting concentrate was purified by-silica gel column chromatography (eluent: hexane/ethyl acetate = 10/1) to obtain 27 g of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone as a colorless liquid (isolation yield: 76%). [0073]
The physical properties of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone were as follows.
XH-NMR (DMSO-d6, 5 (ppm) ) ; 0.93 (6H, t, J = 7.3 Hz), 1.32-1.45 (4H, m), 1.53-1.63 (4H, m), 2.87 (6H, s), 3.39-3.51
(4H, m), 4.55 (2H, s) CI-MS (m/e); 259 (M + 1)
[0074]
Example 15 (Synthesis of 1,3-dimethyl-2-imidazolidinone) To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone (1.9 mmol), 0.05 g of platinum-palladium/carbon and 5 ml of n-butyl alcohol, and the mixture was stirred in a hydrogen atmosphere (normal
pressure) at 100°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 216 mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 98%). [0075]
Example 16 (Synthesis of 1,3-dimethyl-2-imidazolidinone) To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dibutoxy-l,3-dimethyl-

2-imidazolidinone (1.9 mmol), 0.05 g of palladium/carbon and 5 ml of n-butyl alcohol, and the mixture was stirred
in a hydrogen atmosphere (normal pressure) at 100°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 15 8 mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 72%). [0076]
Example 17 (Synthesis of 1,3-dimethyl-2-imidazolidinone) To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone (1.9 mmol), 0.05 g of platinum-palladium/ carbon and 5 ml of n-butyl alcohol, and the mixture was stirred in a hydrogen atmosphere (normal
pressure) at 50°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 216 mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 98%). [0077]
Example 18 (Synthesis of 1,3-dimethyl-2-imidazolidinone) To a glass container having an internal volume of 3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone (1.9 mmol), 0.05 g of platinum-palladium/ carbon and 5 ml of ethyl alcohol, and the mixture was stirred in a hydrogen atmosphere (normal
pressure) at 100°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 212 mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 96%). [0078]
Example 19 (Synthesis of 1,3-dimethyl-2-imidazolidinone) To a glass container having an internal volume of

3 0 ml equipped with a stirrer, a thermometer and a reflux condenser were added 500 mg of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone (1.9 mmol), 0.05 g of platinum-palladium/carbon and 5 ml of isopropyl alcohol, and the mixture was stirred in a hydrogen atmosphere (normal
pressure) at 100°C for six hours. After completion of the reaction, the reaction solution was analyzed by gas chromatography (internal standard method) to find that 210 mg of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 95%). [0079]
Example 20 (Synthesis of 1,3-dimethyl-2-imidazolidinone) To a glass container having an internal volume of 1000 ml equipped with a stirrer, a thermometer and a reflux condenser were added 100 g of 4,5-dibutoxy-l,3-dimethyl-2-imidazolidinone (387 mmol), 10 g of platinum-palladium/carbon (trade name: ASCA2 (manufactured by N.E. Chemcat Corporation)) and 700 ml of n-butyl alcohol, and the mixture was stirred in a hydrogen atmosphere (normal
pressure) at 55 to 65°C for 12 hours. After completion of the reaction, the reaction solution was filtered and the filtrate was concentrated under reduced pressure. The resulting concentrate was distilled under reduced pressure
(90°C, 0.2 kPa) to obtain 33.7 g of 1,3-dimethyl-2-imidazolidinone as a colorless liquid (isolation yield: 76%) . [0080]
Example 21 (Synthesis of 1,3-dimethyl-2-imidazolidinone) (Reaction A: raw material synthesis 2)
To a glass container having an internal volume of 2000 ml equipped with a stirrer, a thermometer and a reflux condenser were added 13 0 g of 4,5-dihydroxy-l,3-dimethylimidazolidinone synthesized in Reference Example 1 (0.84 mol), 13 g of a sulfonic acid based cation exchange resin (trade name: Dowex 50WX2) and 13 0 0 ml of n-butyl alcohol. The mixture was reacted at room temperature for

17 hours to obtain a reaction solution containing 4,5-dibutoxy-1,3-dimethyl-2-imidazolidinone as a main component. (Reaction B)
The reaction solution was filtered and then 13 g of platinum-palladium/carbon (ASCA: 5 0% wet) was added to the resulting filtrate. The mixture was reacted with stirring
in a hydrogen atmosphere (normal pressure) at 60 to 80°C for eight hours. After completion of the reaction, the reaction solution was filtered and analyzed by gas chromatography (internal standard method) to find that 83.11 g of 1,3-dimethyl-2-imidazolidinone was formed (reaction yield: 87%). Then, the reaction solution was
distilled under reduced pressure (100 to 110°C, 1.2 kPa) to obtain 70.55 g of 1,3-dimethyl-2-imidazolidinone having a purity of 96% as a colorless transparent liquid
(isolation yield based on 4 , 5-dihydroxy-l,3-dimethyl-2-imidazolidinone: 71%).
[0081]
Reference Example 2 (Synthesis of 4,5-dihydroxy-l,3-dimethyl-2-imidazolidinone)
The reaction was carried out under the same conditions as in Reference Example 1, except that diethyl carbonate was changed to butyl acetate in Reference Example 1. As a result, 133.18 g of 4,5-dihydroxy-l,3 -dimethyl-2-imidazolidinone having a purity of 89.6%
(absolute quantitative value by high performance liquid chromatography) was obtained (isolation yield based on 1,3-dimethylurea: 81.7%).
Industrial Applicability [0082]
The present invention relates to a process for producing a 2-imidazolidinone compound and a 4,5-dialkoxy-2-imidazolidinone compound. The 2-imidazolidinone compound and the 4,5-alkoxy-2-imidazolidinone compound are

compounds useful as raw materials or synthetic intermediates for medicines or agricultural chemicals, for example.

CLAIMS
1. A process for producing a 2-imidazolidinone
compound represented by the general formula (2):

wherein R1, R2 and R may be the same or different and each represent a hydrogen atom or a hydrocarbon group,
which process comprises reacting a 4,5-dialkoxy-2-imidazolidinone compound represented by the general formula (1) :

wherein R1, R2 and R are as defined above, and R3
represents an alkyl group,
with hydrogen in the presence of a metal catalyst.
2. The process for producing a 2-imidazolidinone compound according to claim 1, wherein the metal catalyst comprises at least one metal element selected from the group consisting of palladium, platinum and nickel.
3. The process for producing a 2-imidazolidinone compound according to claim 1 or 2, further comprising reacting
a dicarbonyl compound represented by the general formula (3):


wherein R represents a hydrogen atom or a hydrocarbon group,
a urea compound represented by the general formula

wherein R1 and R2 may be the same or different and each represent a hydrogen atom or a hydrocarbon group, and
an alcohol represented by the general formula (5):
R3OH (5)
wherein R3 represents an alkyl group,
in the presence of a solid acid catalyst to produce a 4,5-dialkoxy-2-imidazolidinone compound represented by the general formula (1).
4. The process for producing a 2-imidazolidinone compound according to claim 1 or 2, further comprising reacting
a 4,5-dihydroxy-2-imidazolidinone compound represented by the general formula (6):

wherein R1, R2 and R may be the same or different and each represent a hydrogen atom or a hydrocarbon group, with
an alcohol represented by the general formula (5):

R3OH (5)
wherein R3 represents an alkyl group,
in the presence of a solid acid catalyst to produce a 4,5-dialkoxy-2-imidazolidinone compound represented by the general formula (1).
5. The process for producing a 2-imidazolidinone
compound according to claim 4, wherein after the 4,5-
dialkoxy-2-imidazolidinone compound represented by the
general formula (1) is produced, the compound is reacted
with hydrogen in the presence of a metal catalyst without
isolating the compound.
6. A process for producing a 4,5-dialkoxy-2-
imidazolidinone compound represented by the general
formula (1):

wherein R1 and R2 may be the same or different and each represent a hydrogen atom or a hydrocarbon group, R3 represents an alkyl group, and R represents a hydrogen atom or a hydrocarbon group,
which process comprises reacting a dicarbonyl compound represented by the general formula (3):

wherein R is as defined above,
a urea compound represented by the general formula (4) :


wherein R1 and R2 are as defined above, and
an alcohol represented by the general formula (5):
R3OH (5)
wherein R3 is as defined above,
in the presence of a solid acid catalyst.
7. A process for producing a 4,5-dialkoxy-2-imidazolidinone compound represented by the general formula (1):

wherein R1, R2 and R may be the same or different and each represent a hydrogen atom or a hydrocarbon group, and R3 represents an alkyl group,
which process comprises reacting a 4,5-dihydroxy-2-imidazolidinone compound represented by the general formula (6):

wherein R1, R2 and R are as defined above, with
an alcohol represented by the general formula (5):
R3OH (5)

wherein R3 is as defined above,
in the presence of a solid acid catalyst.
8. The process for producing a 4,5-dialkoxy-2-imidazolidinone compound according to claim 6 or 7, wherein the solid acid catalyst is a sulfonic acid based cation exchange resin.