JPS60172965A - Production of thiocarbamate derivative - Google Patents

Abstract

PURPOSE:To obtain the titled substance useful as a herbicide, in high yield and purity, by reacting an alkylphenyl chlorothioformate with an aminopyridine derivative in the presence of sodium carbonate in methanol, and adding water to the reaction product. CONSTITUTION:The compound of formula I (R1 is 2-5C alkyl) is made to react with the compound of formula II (R2 is H, halogen, lower alkyl or lower alkoxy) in methanol in the presence of sodium carbonate at normal temperature for 10hr, and water is added to the reaction product to obtain the objective compound of formula III. The methanol used as the solvent may contain <=25% water, and the amount of methanol is 5-30pts.wt. per 1pt.wt. of the compound of formula II. The amount of water to be added after the reaction is selected to give an aqueous solution of methanol containing 3-30% water.

Description

[Detailed Description of the Invention] Related. 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 of this compound and the production method.

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.

In addition, as a production method, we proposed a method in which an alkylphenylchlorotheoformate and an aminopyridine derivative are reacted in an organic solvent in the presence of a dehydrohalogenation reagent.

The present inventors further determined how to obtain the compound of the present invention industrially and as a result of various tests and intensive studies, the inventors determined that an alkylphenyl chlorothioformate and an aminopyridine derivative were prepared 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 relates to an alkylphenylchlorothioformate represented by the general formula (1) (wherein R represents an alkyl group having 2 to 5 carbon atoms) and an alkylphenylchlorothioformate represented by the general formula (It) (wherein the formula represents a hydrogen atom, halogen atom, lower alkyl group,
Indicates a lower alkoxy group. ) is reacted in methanol in the presence of sodium carbonate, and then water is added. A method for producing a derivative is provided.

Next, the method of implementing the present invention will be described in detail.

The aminopyridine derivative and sodium carbonate were mixed with methanol (
(may contain water).

Then the alkylphenylchlorothioformate is added dropwise. After dropping the entire amount of alkylphenylchlorothiopormate, 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 complete, 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 with the alkylphenylchlorothioformate, and the sodium carbonate is used in an equivalent or more amount.

Methanol used as a solvent may contain 25% or less of water, and is used in an amount of 5 to 60 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. Since the purity of the thiocarbamate derivative decreases if it exceeds 30%, it is preferable to use an amount such that the concentration in the methanol aqueous solution is 3 to 30%.

The reaction can be completed within 10 hours at room temperature.

By applying this pressure, 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 (5'-tert-butylphenylchlorothioformate) 5-tert-butylphenol 649 and thiophosgene 509 in t-chloroform 600d while maintaining at 5 to 10°C 20ml of 20ml aqueous sodium hydroxide solution 200+ml
! After adding i and stirring for 13 hours, separate the chloroform layer,
Distilled after drying with calcium chloride, boiling point 125-124°C
71 g of 5-tert-butylphenylchlorothioformate with a concentration of 1/4 amHg was obtained.

Elemental analysis value ((!, 1B,, as czos) OHa
t s Actual value (ch) 57.62 5.77 15.601596 calculated value (%) 57-76 5.75 15.50
14.02 Raw material preparation example 2 (4-tert-phthylphenylchlorothioformate) Boiling point 103°C/8 by the same method as raw material preparation example 1
1 uHgO4-tert-fluorophenyl chlorothioformate was obtained.

Raw material preparation example 3 (2-chloro-6-methylaminopyridine)'2.6-
25 g of dichloropyridine and 40% methylamine aqueous solution 6
The mixture was kept at 120°C in a 0dk autoclave and stirred for 5 hours. After the reaction was completed, the contents were taken out and the solids were collected by filtration. This solid was then recrystallized from n-hexane,
22.7 g of 2-chloro-6-methylaminopyridine with a melting point of 65.5-64.5°C was obtained.

Elemental analysis value (L: 4H, C6N) OHN at actual measurement value (2)) 5α634.89 19.71 24
．． 77 calculated value @) 5α54 4.95 19.64
24.86 Raw material preparation example 4 (2-methoxy-6-methylaminopyridine) 20 g of 2-chloro-6-methylaminopyridine.

11.5 g of sodium hydroxide and 80 Wt 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. The residue was distilled under reduced pressure to a boiling point of 86-92℃/511! lllH
g of 2-methoxy-6-methylaminopyridine 15.6
I got g.

Elemental analysis value (as 0, H, oN, O) C! H'N
O Actual value (%) 6G, 97 7.41 2G, 13 1
1.49 Calculated value (chi) 6 (L85 7.50 20.
27 11.58 Example 1 In a third 300 ml flask, add 63 g of 2-methyl-6-methylaminopyridine and 2.89.5 g of sodium carbonate.
60 ml of water-containing methanol was taken, and while stirring with a magnetic stirrer at room temperature, 11.8 g of 3-tert-butylphenylchlorothioformate was added dropwise over 30 minutes.

After the dropwise addition, the mixture was 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. Next, the solid was washed with water at 150 dK and O-3-tart-butylphenyl N-methyl-N-
(6-Methyl-2-pyridyl)thiocarbamate (compound genus 1) 14.99 was obtained.

Analysis by high performance liquid chromatography showed that the purity was 9.
It was 95chi.

Elemental analysis value (as 0,, H,, N, 'O8) q HN Actual value (chi) 6a87 6.96 a84 calculated value (%
) 6 a 75 7.05 8.91 Example 2' 2-Methoxy-6-methylaminopyridine &? 9. Sodium carbonate 2.7g, 10
% water-containing methanol solution was taken, and while stirring with a magnetic stirrer at room temperature, 11.4 g of 4-tert-butylphenylchlorothioformate 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 carried out to obtain a melting point of 87-88.
15.19 of Q-4-tert-butylphenyl N-methyl-N-(6-medoxy 2-pyridyl) thiocarbamate (compound A2) at 15°C were obtained.

When analyzed by high performance liquid chromatography, the purity was 9.
It was 9.0chi.

Elemental analysis value (as C18Htt N, o, s) OHN actual value (@ 65.58 12 a41 calculated value (t4)
65,436.71 8.48 Examples 3 to 8 An aminopyridine derivative, a dehydrohalogenation reagent, and water-containing methanol were placed in the same reactor as in Example 1, and all of the alkyl phenyl chlorothioformate was added dropwise. The reaction was carried out under the following conditions.

After the reaction was completed, a dithiocarbamate derivative was obtained by the same reaction procedure as in Example 1. The results are shown in Table 1.

Further, the physical constants of the obtained compound are shown in Table 2.

Next, application examples of the compounds obtained by the production method of the present invention will be shown.

Application example: Weeding effect test under flooded conditions Paddy soil was placed in a porcelain pot with a diameter of 9 cIn, water was added, and after plowing, weed seeds were sown on the surface layer of the soil, and one paddy rice seedling (variety, Nipponbare) at the two-leaf stage was grown. Two plants were planted at a depth of -. The next day, two wounds were flooded, and a hydrating powder containing 10 grams of each compound was diluted to 10 grams of water per pot and dropped onto the water surface. (Test chemical amount: 1259/10 a) Thereafter, the sample was 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 rules are as follows. The results are shown in Table 3.

Display Paddy rice chemical damage Weeding effect 5 Death 100% control (remaining amount of weeds 0 inches) 4 Severe damage 80 inches control (residual amount of plants 20 inches) 3゛ Medium Harm 60
% control (residual grass amount 40 cm) 2 Slight damage 40 cm control (remaining grass amount 60 cm) 1 Slight damage 20 g) control (remaining grass leaves 8
0chi) 0 harmless 0chi control (residual grass amount 100%) -Table 3

Claims (1)

[Claims] (1) General formula (1) (In the formula, R represents an alkyl group having 2 to 5 carbon atoms.) The represented alkylphenylchlorothioformate and the general formula (n) (In the formula, R2 is a hydrogen atom. , a halogen atom, a lower alkyl group, or a lower alkoxy group) is reacted in methanol in the presence of total sodium carbonate, and then water is added. RI+R1 is the same as above.) A method for producing a thiocarbamate derivative represented by: