JPH0220635B2 - - Google Patents

Description

[Detailed description of the invention]

This invention is based on the general formula [In the formula, R ₁ , R ₂ and X represent a lower alkyl group, and R ₃ represents a hydrogen atom, a lower alkyl group, or a group
R ₄ CO- (in the formula, R ₄ represents an unsubstituted phenyl group), and n represents 0 or 1. ]
The present invention relates to a novel pyrazole derivative and a salt thereof. In the above formula (1), examples of lower alkyl groups for R ₁ , R ₂ , R ₃ and X include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. Examples include straight-chain or branched alkyl groups having 1 to 4 carbon atoms. Examples of salts of the compound of general formula (1) include salts with monovalent to trivalent metal ions such as sodium, potassium, calcium, magnesium, aluminum, iron, manganese, zinc, nickel, cobalt, or copper: N ⁺ H ₄ , N ⁺ H(CH ₃ ) ₃ , N ⁺ H ₂
(C ₂ H ₅ ) ₂ , N ⁺ H ₃ CH (CH ₃ ) ₂ , N ⁺ H ₃ CH ₂ CH ₂ OH
or salts with ammonium ions such as N ⁺ H ₃ CH ₂ CH ₂ OC ₂ H ₅ . Examples of the novel pyrazole derivatives of the present invention include the following. 1 1,3-dimethyl-4-(2-methylaminobenzoyl)-5-hydroxypyrazole2 1,3-dimethyl-4-(2-n-propylaminobenzoyl)-5-hydroxypyrazole3 1,3-dimethyl -4-(2-benzamidobenzoyl)-5-hydroxypyrazole 4 3-n-butyl-1-methyl-4-(2-ethylaminobenzoyl)-5-hydroxypyrazole 5 4-(2-benzamido-5-methyl benzoyl)-1,3-dimethyl-5-hydroxypyrazole 6 4-(4-aminobenzoyl)-1,3-dimethyl-5-hydroxypyrazole The number attached to the name of each compound above, that is, the compound number is , hereinafter referred to in its entirety. The novel compound () according to the present invention is produced by heating and stirring a pyrazole derivative () in the presence of equimolar or more of a basic alkali metal salt or a basic alkaline earth metal salt, as shown in the following formula. be done. (In the formula, R ₁ , R ₂ , R ₃ , X and n have the same meanings as described above.) Basic salts used include carbonates such as potassium carbonate and sodium carbonate; calcium hydroxide; , hydroxides such as magnesium hydroxide:
Cyanamides such as calcium cyanamide: alkoxides such as sodium methoxide, potassium ethoxide, sodium isopropoxide, potassium tert-butoxide are preferably used. Furthermore, a system in which these basic salts are formed in the reaction solvent may be used. The reaction is carried out in the presence or absence of a solvent, but it is preferable to use a solvent in order to carry out the reaction smoothly. Examples of solvents used include lower alcohols such as isopropanol or tert-butanol; dioxane; Ethers such as diisopropyl ether, tetrahydrofuran or dioxane-tetrohydrofuran, or mixed solvents thereof; ketones such as methyl ethyl ketone or diethyl ketone are used. The reaction temperature is not particularly limited, and the reaction is usually carried out at about 80 to 200°C. The time required for the reaction is usually 0.5 to 5
It's time. After the reaction is completed, the target compound is collected from the reaction mixture by a conventional method. For example, by distilling off the solvent from the reaction mixture after completion of the reaction, the target compound can be obtained as a salt of the alkali metal or alkaline earth metal used. The target compound of the obtained salt can be isolated in a free state by adjusting the pH of the salt to 3 or less, usually by adding an acid. This product can be further purified by conventional methods such as recrystallization to obtain a pure product. The starting compound of formula () is produced according to a known method, for example, the method described in JP-A-50-37776. Among the compounds having the general formula () of the present invention,
The compound represented by the formula () is as shown in the following formula,
It is also produced by reducing a compound having the general formula (). [In the formula, R ₁ , R ₂ , X and n have the same meanings as described above, and R ₅ is a group R ₆ CO- (wherein, R ₆ represents an unsubstituted phenyl group.) shows. In carrying out the above reaction, the reaction is easily carried out by contacting the compound having the general formula () with a reducing agent in a suitable inert solvent.
The reducing agent used in the reaction is not particularly limited as long as it is a reducing agent normally used in reduction reactions, and examples include combinations of metals such as tin, iron, zinc, and zinc amalgam, and hydrochloric acid, sulfuric acid, and acetic acid: or combinations of the above metals with alkali metal hydroxides such as sodium hydroxide, or alkali sulfides such as ammonium sulfide; combinations of metals such as sodium, sodium amalgam, magnesium, magnesium amalgam, zinc, iron, etc. with water; etc. can be mentioned. Further, metal hydride compounds such as sodium boron hydroxide and lithium boron hydroxide; low-valent metal compounds such as stannous chloride, stannous sulfide, and ferrous hydroxide may also be used. The solvent used in the reaction is not particularly limited as long as it is not involved in this reaction, and includes, for example, water: lower alcohols such as methanol, ethanol, or isopropanol: ethers such as ethyl ether, tetrahydrofuran, or dioxane, and methylene. Examples include halogenated carbons such as chloride or trichloroethane; organic acids such as acetic acid or propionic acid; and mixed solvents of these solvents. Although the reaction is carried out using a stoichiometric amount of reducing agent, it is usually preferable to use an excess amount (approximately 1.1 to 1.5 times the mole) of the reducing agent in order to carry out the reaction quickly. There is no particular limitation on the reaction temperature, and the reaction is usually carried out at room temperature, but the reaction may proceed at higher or lower temperatures. The time required for the reaction is usually 1 to 10 hours. After the reaction is completed, the target compound is collected from the reaction mixture by a conventional method. For example, it can be obtained by separating insoluble matter from the reaction mixture and distilling off the solvent from the liquid under reduced pressure. If necessary, it can also be purified by conventional methods such as recrystallization. The raw material compound of the formula () is produced according to a known method, for example, the method described in JP-A-55-33454. The method for producing the novel pyrazole derivative () of the present invention will be explained in more detail with reference to Examples. Example 1 1,3-dimethyl-4-(2-methylaminobenzoyl)-5-hydroxypyrazole 1,3-dimethyl-5-(2-methylaminobenzoyloxy)pyrazole 0.3g, potassium carbonate (anhydrous) 0.338g A mixture of 1.5 ml of tert-butanol and 1.5 ml of tert-butanol was heated under reflux for 3 hours with vigorous stirring.
After cooling, benzene and water were added to the reaction mixture, and after shaking, the organic layer was separated, and the solvent was distilled off under reduced pressure to recover 0.19 g of raw material. Next, the aqueous layer was made acidic (PH = 4) with dilute hydrochloric acid, extracted with chloroform, and the extract was dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and the residue was washed with ethanol. 93 mg of the target compound was obtained. (yield 31
%) Melting point: 170-171℃ (resolidification solvent: ethanol) Elemental analysis value (%) As C ₁₃ H ₁₅ N ₃ O ₂ Calculated value C, 63.66: H, 6.16: N, 17.13 Experimental value C, 63.63: H, 6.20:N, 17.08 Example 2 4-(2-benzamido-5-methylbenzoyl)-1,3-dimethyl-5-hydroxypyrazole 5-benzoyloxy-1,3-dimethyl-4
After dissolving 1.895 g of -(5-methyl-2-nitrobenzoyl)pyrazole in 20 ml of glacial acetic acid, 0.84 g of iron powder was added little by little while stirring while keeping the internal temperature at 45°C. After the addition was completed, the mixture was stirred at 40-45°C for 1 hour, the insoluble matter was separated, and the liquid was distilled off under reduced pressure to obtain an oily substance, which was then subjected to silica gel column chromatography. -Collect the part eluted with acetone mixture (6:1) to recover 1.2 g of raw material, then collect the part eluted with ethanol,
The solvent was distilled off from the eluate to obtain 0.58 g of a residue. This product was dissolved in ethanol, acidified with hydrochloric acid, the solvent was distilled off under reduced pressure, chloroform was added to perform extraction, and the solvent was distilled off from the extract to obtain 0.4 g of the target compound. Melting point 233°C (Re-solidification solvent: ethanol) Elemental analysis value (%) As C ₂₀ H ₁₉ N ₃ O ₃ Calculated value C, 68.75: H, 5.48: N, 12.03 Experimental value C, 68.32: H, 5.46: N, 11.96 Using 4-(4-nitrobenzoyl)-1,3-dimethyl-5-hydroxypyrazole as a raw material, the reaction was carried out according to the method of Example 2 above,
The following compounds were prepared. 4-(4-aminobenzoyl)-1,3-dimethyl-5-hydroxypyrazole, mp191℃ The compound having the above general formula () and its salts are used as herbicides, causing weeds to turn white and die. Has characteristics. The compound of the present invention can be mixed with a carrier and, if necessary, other adjuvants, to form a formulation commonly used as a herbicide, such as powder, coarse powder, fine granules, etc.
It is used after being prepared into granules, wettable powders, emulsions, aqueous solutions, aqueous solutions, oil suspensions, etc. The carrier here refers to a synthetic or natural carrier that is mixed into the herbicide to aid in the reach of the active ingredient to the area to be treated, and to facilitate the storage, transportation, or handling of the active ingredient. means an inorganic or organic substance. Emulsification, dispersion, wetting, spreading, binding, disintegration control,
Surfactants used for the purpose of stabilizing active ingredients, improving fluidity, preventing rust, etc. can be nonionic, anionic, cationic, or amphoteric, but usually used are nonionic and/or anionic. The carrier and various auxiliary agents are used individually or in combination as appropriate depending on the purpose, taking into account the dosage form of the preparation, the application situation, etc. Powders, for example, usually contain 1 to 10% of the active ingredient compound.
It contains 25 parts by weight, and the remainder is solid carrier. Wettable powders usually contain, for example, 25 to 90 parts by weight of the active ingredient compound, with the remainder being a solid carrier and a dispersing wetting agent, with protective colloid agents, thixotropic agents, antifoaming agents, etc. being added as necessary. Granules, for example, usually contain 1 to 1 active ingredient compound.
It contains 35 parts by weight, and the remainder is mostly solid carrier. The active ingredient compound is uniformly mixed with the solid carrier, or is uniformly fixed or adsorbed on the surface of the solid carrier, and the particle size is about 0.2 to
It is about 1.5mm. Emulsions, for example, usually contain 5 to 5 active ingredients.
This includes approximately 5 to 20 parts by weight of an emulsifier, and the remainder is a liquid carrier, with a rust preventive added as required. When the herbicide of the present invention prepared in various dosage forms in this way is used to treat soil before or after the germination of weeds in rice fields or fields, the amount of active ingredient per 10 acres is preferably 10 to 2000 g, preferably 100 to 2000 g. Weeds can be effectively exterminated by throwing 500g. In addition, when trying to non-selectively exterminate weeds in non-agricultural lands, such as roads, grounds, house grounds, railroad tracks, etc.,
Weeds can be effectively exterminated by applying 200 to 4000g of the active ingredient per 10 acres. Test examples of the herbicide of the present invention prepared in this way are given below. The test drug used was a hydrating powder containing 50% of the active ingredient compound of the present invention. Test example 1 Paddy weed flooded soil treatment test ^Three polyethylene pots (A,
Fill pots B and C) with paddy soil, transplant one (two) seedlings of paddy rice (variety: Kinnanfu) at the 2.5-leaf stage into pot A, and add two tubers of Urikawa to represent perennial weeds. Plant a flower. In pot B, the seeds of Japanese azalea, azalea, and sycamore, representative of broad-leaved weeds, are mixed well with the soil. In addition, I transplanted one growing stock of Pinus vulgare, and planted two tubers of the perennial weed Cyperus japonica per pot. For Pot C, seeds of Japanese grasshopper and firefly, which are representative of narrow-leaved weeds, are mixed well with the soil. In addition, two tubers of the perennial weed Omodaka are planted per pot.
Pots A, B, and C were cultivated in a greenhouse for 3 days as a paddy field, and after the plants took root, the soil was treated with 10 c.c. of a suspension of the test chemical per pot in a flooded state. After 20 days of treatment, the herbicidal effect on each weed and the chemical damage to paddy rice were observed and determined. The results are shown in Table 1. However, the effective dose (g/a) in the table indicates the lowest dose at which the degree of growth inhibition of each plant (whitening area on the surface of the plant) is 70% or more.

[Table] Test Example 2 Pre-emergence soil treatment test for field weeds A polyethylene pot with a surface area of 150 cm ² was filled with field soil, and seeds of typical narrow-leaved weeds such as cane millet, mejishiba, hackberry, cypera, and cyperus were sown and covered with soil. did. Separately, a polyethylene pot with a surface area of 150 cm ² was filled with field soil, and seeds of broad-leaved weeds such as chickweed, dayflower, Japanese clover, golden millet, purslane, white foliage, and shepherd's purse were sown and covered with soil. Immediately after covering both pots with soil, a suspension of the test chemical was applied to the soil surface in an amount of 10 c.c. per pot. process
After 20 days, the herbicidal effect on each weed was observed. The results are shown in Table 2. However, the judgment criteria are the same as in Test Example 1, and are expressed in effective dose (g/a).

【table】

Claims (1)

[Claims] 1 formula [In the formula, R ₁ , R ₂ and X represent a lower alkyl group, and R ₃ is a hydrogen atom, a lower alkyl group or a group R ₄ CO
- (in the formula, R ₄ represents an unsubstituted phenyl group), and n represents 0 or 1. ] and its salts.