JPS63431B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing thiocarbamate derivatives. More specifically, the present invention relates to a novel method for producing thiocarbamate derivatives, which is characterized by reacting an alkylphenyl chlorothioformate with an aminopyridine derivative in methanol in the presence of sodium carbonate. Although the thiocarbamate derivative obtained by the production method of the present invention is a new compound that has not been described in any literature,
The present inventors have already proposed the usefulness and manufacturing method of this compound. A herbicide containing the compound of the present invention as an active ingredient exhibits excellent herbicidal activity against many weeds including field weeds, and is suitable as a herbicide for paddy fields. It also has applicability as a herbicide for upland fields. Furthermore, as a manufacturing method, we proposed a method in which an alkylphenyl chlorothioformate and an aminopyridine derivative are reacted in an organic solvent in the presence of a dehydrohalogenation reagent. The present inventors further conducted various tests and intensively studied methods for obtaining the compounds of the present invention industrially advantageously. As a result, the present inventors prepared an alkyl phenyl chlorothioformate and an aminopyridine derivative in methanol in the presence of sodium carbonate. The present invention was completed by discovering that a highly pure thiocarbamate derivative can be produced by reacting and then adding water without purification by operations such as column chromatography and recrystallization. That is, the present invention is based on the general formula () (In the formula, R ₁ represents an alkyl group having 2 to 5 carbon atoms.) Alkylphenyl chlorothioformate represented by the general formula () (In the formula, R ₂ represents a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group.) The aminopyridine derivative represented by the following formula is reacted in methanol in the presence of sodium carbonate, and then water is added. General formula () (In the formula, R ₁ and R ₂ are the same as above.) A method for producing a thiocarbamate derivative represented by the following is provided. Next, the method of implementing the present invention will be described in detail. Add the aminopyridine derivative and sodium carbonate to methanol (which may contain water). Then the alkyl phenyl chlorothioformate is added dropwise. After dropping the entire amount of alkyl phenyl chlorothioformate, a predetermined amount of water is added to precipitate a thiocarbamate derivative, which is a reaction product.
In addition, hydrogen chloride produced by reacting an alkylphenyl chlorothioformate with an aminopyridine derivative is reacted with sodium carbonate to precipitate a salt (hereinafter referred to as salt). After the reaction is completed, the reaction solution is filtered to collect the thiocarbamate derivative and salt. Next, the collected thiocarbamate derivative and salt are washed with water to remove the salt and obtain a highly pure thiocarbamate derivative. The aminopyridine derivative is used in an equimolar amount as the alkyl phenyl chlorothioformate, and the sodium carbonate is used in an equivalent or more amount. Methanol used as a solvent may contain up to 25% water, and is used in an amount 5 to 30 times the weight of the aminopyridine derivative. The amount of water added after the reaction is closely related to the concentration of water in the methanol used for the reaction, but if the concentration of water in the methanol aqueous solution after addition is less than 3%, the recovery rate of high purity thiocarbamate derivatives will decrease. When the concentration is low and exceeds 30%, the purity of the thiocarbamate derivative decreases, so the concentration in the methanol aqueous solution is
An amount of ~30% is preferred. The reaction can be completed within 10 hours at room temperature. In this manner, the target thiocarbamate derivative of the present production method can be obtained with high purity and high yield. Next, the present invention will be explained in detail with reference to raw material preparation examples and examples, but the present invention is not limited only to these examples. Raw material preparation example 1 (3-tert-butylphenyl chlorothioformate) 64 g of 3-tert-butylphenol and 50 g of thiophosgene were added to 200 ml of a 20% aqueous sodium hydroxide solution in 600 ml of chloroform while maintaining the temperature at 5 to 10°C.13 After stirring for an hour, separate the chloroform layer, dry it with calcium chloride, and distill it to boiling point 123-124℃/4
71 g of 3-tert-butylphenyl chlorothioformate was obtained at mmHg. Elemental analysis value (as C ₁₁ H ₁₃ ClOS) C H Cl S Actual value (%) 57.62 5.77 15.60 13.96 Calculated value (%) 57.76 5.73 15.50 14.02 Raw material preparation example 2 (4-tert-butylphenyl chlorothioformate) Boiling point 103℃/
4-tert-butylphenyl chlorothioformate was obtained at 8 mmHg. Raw material preparation example 3 (2-chloro-6-methylaminopyridine) 25 g of 2,6-dichloropyridine and 60 ml of a 40% methylamine aqueous solution were kept at 120° C. and stirred for 5 hours in an autoclave. After the reaction was completed, the contents were taken out and the solids were collected by filtration. This solid is then
- Recrystallized from hexane, melting point 63.5-64.5℃
22.7 g of -chloro-6-methylaminopyridine was obtained. Elemental analysis value (as C ₆ H ₇ ClN ₂ ) C H N Cl Actual value (%) 50.63 4.89 19.71 24.77 Calculated value (%) 50.54 4.95 19.64 24.86 Raw material preparation example 4 (2-methoxy-6-methylaminopyridine) 2 -20 g of chloro-6-methylaminopyridine,
11.5 g of sodium hydroxide and 80 ml of methanol were kept at 170° C. and stirred for 5 hours in an autoclave. After the reaction was completed, methanol was distilled off, and the ether extract of the residue was dried over magnesium sulfate, and then the ether was distilled off. Distill the residue under reduced pressure to a boiling point of 83-92℃/5
15.6 g of 2-methoxy-6-methylaminopyridine of mmHg was obtained. Elemental analysis value (as C ₇ H ₁₀ N ₂ O) C H N O Measured value (%) 60.97 7.41 20.13 11.49 Calculated value (%) 60.85 7.30 20.27 11.58 Example 1 2-Methyl-6 in a 300 ml three-necked flask - 6.3 g of methylaminopyridine, 2.8 g of sodium carbonate
11.8 g of 3-tert-butylphenylchlorothioformate was added dropwise to the mixture over 30 minutes while stirring with a magnetic stirrer at room temperature. After the dropwise addition, the mixture was further stirred for 2 hours to complete the reaction. After the reaction was completed, 9 ml of water was added, the contents were taken out from the flask, and the solid was collected by filtration. Then water
Wash the solid with 150ml of O having a melting point of 116-117.5℃.
-3-tert-butylphenyl N-methyl-N-
14.9 g of (6-methyl-2-pyridyl)thiocarbamate (compound No. 1) was obtained. Analysis by high performance liquid chromatography showed that the purity was 99.5%. Elemental analysis value (as C ₁₈ H ₂₂ N ₂ OS) C H N Actual value (%) 68.87 6.96 8.84 Calculated value (%) 68.75 7.05 8.91

[Table] Example 2 2-methoxy-6- in a 300ml three-necked flask
Methylaminopyridine 6.9g, sodium carbonate 2.7
Take 80 ml of 10% water-containing methanol solution and stir with a magnetic stirrer at room temperature.
tert-butylphenyl chlorothioformate 11.4
g was added dropwise over 20 minutes. After the dropwise addition, the mixture was further stirred for 2 hours to complete the reaction. After the reaction was completed, 8 ml of water was added, the contents were taken out from the flask, and the same operation as in Example 1 was performed to determine the melting point.
O-4-tert-butylphenyl N- at 87-88℃
15.1 g of methyl-N-(6-methoxy-2-pyridyl)thiocarbamate (compound No. 2) was obtained. Analysis by high performance liquid chromatography showed that the purity was 99.0%. Elemental analysis value (as C ₁₈ H ₂₂ N ₂ O ₂ S) C H N Actual value (%) 65.38 6.82 8.41 Calculated value (%) 65.43 6.71 8.48

[Table] Examples 3 to 8 An aminopyridine derivative, a dehydrohalogenation reagent, and water-containing methanol were placed in the same reaction apparatus as in Example 1, and an alkylphenyl chlorothioformate was added dropwise to react under the conditions shown in Table 1. I let it happen. After the reaction was completed, a thiocarbamate derivative was obtained by the same reaction procedure as in Example 1. The result is the first
Shown in the table. Further, the physical constants of the obtained compound are shown in Table 2.

【table】

[Table] Application examples of the compounds obtained by the production method of the present invention are shown below. Application example: Weeding effect test under flooded conditions Paddy soil was placed in a porcelain pot with a diameter of 9 cm, water was added, and after plowing, weed seeds were sown on the soil surface.
Paddy rice seedlings (variety, Nipponbare) in the leaf stage are planted at a depth of 1 cm.
Two plants were planted. The next day, the pots were flooded with 2 cm of water, and a hydrating powder containing 10% of each compound was diluted in 10 ml of water per pot and dropped onto the water surface. (Amount of test drug 125g/
10a) Thereafter, the plants were left in a greenhouse, and three weeks after the chemical solution treatment, the herbicidal effect and the effect on paddy rice were investigated. The evaluation was displayed on a 6-level scale, and the specific details are as follows. The results are shown in Table 3. Indication Paddy rice chemical damage weeding effect 5 Death 100% control (residual weed amount 0%) 4 Severe damage 80% control (remaining weed amount 20%) 3 Medium damage 60% control (remaining weed amount 40%) 2 Minor damage 40 % control (60% amount of remaining grass) 1 Slight damage 20% control (80% amount of remaining grass) 0 No harm 0% control (100% amount of remaining grass)

【table】

Claims (1)

[Claims] 1 General formula () (In the formula, R ₁ represents an alkyl group having 2 to 5 carbon atoms.) Alkylphenyl chlorothioformate represented by the general formula () (In the formula, R ₂ represents a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group.) The aminopyridine derivative represented by the following formula is reacted in methanol in the presence of sodium carbonate, and then water is added. General formula () (In the formula, R ₁ and R ₂ are the same as above.) A method for producing a thiocarbamate derivative represented by the following.