JPS625432B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a carbamate derivative, a method for producing the same, and a herbicide characterized by containing the compound as an active ingredient. It is well known that arylthiocarbamate compounds have antibacterial properties as medicines. It is also known that certain aryl N-aryl carbamate compounds can be used as herbicides. The present inventors previously discovered that certain N-pyridyl carbamate derivatives have herbicidal activity. The present inventors further completed the present invention as a result of intensive research to develop a compound having sufficient herbicidal activity and a high degree of selectivity among N-pyridyl carbamate derivatives. That is, the present invention is based on the general formula (): (In the formula, X represents an oxygen atom or a sulfur atom,
R represents a halogen atom or a lower alkyl group,
n represents 1 or 2. The present invention provides a method for producing a carbamate derivative represented by (hereinafter referred to as the compound of the present invention), and a herbicide characterized by containing the compound as an active ingredient. The herbicide containing the compound of the present invention as an active ingredient exhibits extremely excellent herbicidal activity against many weeds including field weed, especially in flooded rice fields, and is virtually harmless to transplanted paddy rice. , suitable as a herbicide for paddy fields. The carbamate derivative represented by the general formula () of the present invention can be produced according to the following reaction formula. (In the formula, X represents an oxygen atom or a sulfur atom,
R represents a halogen atom or a lower alkyl group,
n represents 1 or 2, and Hal represents a halogen atom. ) The above reaction is carried out in the presence of a dehydrohalogenating agent,
Further, the reaction usually proceeds in the presence or absence of a reaction solvent at a reaction temperature of 0°C to 150°C, and the reaction time is about several minutes to 48 hours. Examples of dehydrohalogenation agents include alkali hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth hydroxides such as calcium hydroxide, and alkali carbonates such as sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate. , metal hydrides such as sodium hydroxide, and tertiary amines such as triethylamine, dimethylaniline, and pyridine. In reaction formula (2), 2 of the raw materials
-Methylaminopyridine derivatives can be used as dehydrohalogenating agents. Reaction solvents include water, alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone and methyl ethyl ketone, aromatic hydrocarbons such as benzene, toluene, and xylene, ethers such as ethyl ether, tetrahydrofuran, and dioxane, and chlorine. Halogenated hydrocarbons such as benzene, chloroform, carbon tetrachloride and dichloroethane, polar solvents such as dimethylformamide and dimethyl sulfoxide, etc. are used. Substituted pyridine derivatives, carbamoyl halide derivatives and thiocarbamoyl halide derivatives, which are raw materials for the compounds of the present invention, can be obtained, for example, by the following method. (In the formula, R, n, X and Hal have the same meanings as above.) Next, the method for producing the compound of the present invention will be explained in more detail with reference to Reference Examples and Examples. [Reference example] 2,6-
25 g of dichloropyridine and 600 ml of a 40% methylamine aqueous solution were taken and reacted at 120°C for 5 hours. After the reaction was completed, the autoclave was cooled, the contents were taken out, and the solids were collected by filtration. Next, this solid was recrystallized from n-hexane to give a melting point of 63.5 to 64.5.
2-chloro-6-methylaminopyridine at °C
Obtained 22.7g. Elemental analysis value (%) Actual value C: 50.41 H: 4.99 N: 19.73 Calculated value C: 50.54 H: 4.95 N: 19.64 15 g of trichloromethyl chloroformate was added to 200
ml of benzene and add 2-chloro-6-
A solution prepared by dissolving 14.25 g of methylaminopyridine in 100 ml of benzene was added dropwise at 10° C. while stirring. After the reaction mixture was heated under reflux with stirring all day and night, benzene was distilled off under reduced pressure. The resulting residue was purified by column chromatography (silica gel, developed with benzene) and further recrystallized from hexane to give N-(6-chloro-2-pyridyl)-N-methylcarbamoyl with a melting point of 41-42°C. Chloride 19.5g
I got it. Elemental analysis value (%) Actual value C: 40.79 H: 3.11 N: 13.29 Calculated value C: 41.00 H: 2.94 N: 13.66 [Example 1] 2-naphthyl N-(6-methyl-2-pyridyl)-N- Method for producing methyl carbamate (Compound No. 1 of the present invention) N-(6-methyl-2-pyridyl)-N-methylcarbamoyl chloride 1.85 g, 2-naphthol
1.44 g and 1.38 g of anhydrous potassium carbonate were added to 50 ml of methyl ethyl ketone and heated under reflux for 48 hours. After the reaction mixture was cooled to room temperature, it was poured into cold water and the product was extracted with benzene. The benzene solution was washed successively with water and a saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and then benzene was distilled off under reduced pressure. The residue was subjected to column chromatography (silica gel, ethyl acetate/benzene = 1/9
(V/V) development) to produce 2-naphthyl N-
2.63 g (yield 90%) of (6-methyl-2-pyridyl)-N-methylcarbamate was obtained. A part of this product was recrystallized from ethanol to obtain colorless crystals with a melting point of 91-92.5°C. [Example 2] 0-2-naphthyl N-(5,6-dimethyl-
2-Pyridyl)-N-methylthiocarbamate production method (invention compound No. 8) 2,3-dimethyl-6-methylaminopyridine
1.36g and 1.38g of anhydrous potassium carbonate in acetone 20
ml of acetone and 2.23 g of 0-2-naphthyl chlorothioformate with stirring at room temperature.
ml and added. After stirring as it was for 30 minutes, the mixture was heated under reflux for 2 hours. After the reaction mixture was cooled to room temperature, it was poured into cold water and the product was extracted with benzene. The benzene solution was washed successively with water and a saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and then benzene was distilled off under reduced pressure. The residue was purified by column chromatography (silica gel, developed with ethyl acetate/benzene = 1/9 (V/V)) to give 0-2-naphthyl N-(5,6-dimethyl-2-pyridyl)-N- Methylthiocarbamate
2.74g (85% yield) was obtained. A part of this product was recrystallized from ethanol to obtain colorless crystals with a melting point of 108-109°C. Table 1 shows representative examples and physical constants of the compounds represented by the above general formula ().

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[Example 6]

Paddy soil was poured into a porcelain pot with a diameter of 9 cm, water was added, and weed seeds were sown on the surface layer of the soil.
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 pot was filled with water to a depth of 2 cm, and 10 ml of the prescribed dose of the hydrating agent of each compound of the present invention was added to each pot.
It was diluted with water and dropped onto the water surface. 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 2. Display Paddy rice chemical damage weeding effect 5 Death 100% control (residual weed amount 0%) 4 Severe damage 80% control (residual weed amount 20%) 3 Moderate 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 Harmless 0% control (100% amount of remaining grass)

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Claims (1)

[Claims] 1 General formula (): (In the formula, X represents an oxygen atom or a sulfur atom,
R represents a halogen atom or a lower alkyl group,
n represents 1 or 2. ) Carbamate derivatives represented by 2 General formula (): (In the formula, Y is a hydrogen atom, a halocarbonyl group, or a halothiocarbonyl group.) A naphthol derivative represented by the general formula (): (In the formula, Z is a halocarbonyl group or halotiocarbonyl group when Y in the formula () is a hydrogen atom, and is a hydrogen atom when Y in the formula () is a halocarbonyl group or a halothiocarbonyl group, and R is is a halogen atom or a lower alkyl group, and n is 1
or 2. ) is characterized by reacting with an aminopyridine derivative represented by General formula (): (In the formula, X represents an oxygen atom or a sulfur atom,
R represents a halogen atom or a lower alkyl group,
n represents 1 or 2. ) A method for producing a carbamate derivative represented by 3 General formula (): (In the formula, X represents an oxygen atom or a sulfur atom,
R represents a halogen atom or a lower alkyl group,
n represents 1 or 2. A herbicide characterized by containing a carbamate derivative represented by ) as an active ingredient.