JPH0336833B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is based on the general formula (In the formula, R and R' are lower alkyl groups, and X is a hydrogen atom, a chlorine atom, or a bromine atom.) The present invention relates to a pyrazolylurea derivative, a method for producing the same, and a herbicide containing the compound as an active ingredient. Incidentally, although the compound of the general formula has tautomers as shown in the following formula, in the following explanation, both are represented by the same formula. The compound of the present invention is characterized by having a tertiarybutyl group at the 5-position of the pyrazole ring, as shown in the general formula, and has a very significant herbicidal activity. Further, it is preferable that the 4th position of the pyrazole ring is unsubstituted or a halogen atom such as a chlorine atom or a bromine atom is introduced. The compound of the general formula shows strong herbicidal activity against a wide range of weeds, and if this active ingredient is applied at 0.5 to 10 kg per hectare just before the weeds germinate or at the early stage of their growth, it will take about 2 to 3 weeks. Over time, it can kill a wide range of weeds as described below. In addition, by limiting the amount of this compound applied or applying an appropriate application method, it is possible to cultivate specific crops such as corn, potatoes, sugarcane, peanuts, soybeans, sunflowers, barley, wheat, sorghum, cotton, and fruit trees. Weeds can be selectively controlled in the field. Typical examples of the compounds of the present invention include those shown in Table 1. The compounds in the table are numbered, and the compound numbers are also indicated in the following explanations. The melting point values in the table are uncorrected, and the NMR values were measured at 60 MHz using tetramethylsilane as a reference material, and the symbols s, d, t,
The peak patterns of q and m are 1, 2, 3, and 3, respectively.
4. Multiplet or br indicates a wide peak pattern, and J indicates a spin coupling constant. Note that compounds 1 and 2 are used as solvents for NMR measurement.
Deuterium dimethyl sulfoxide for compound 3,
For No. 4, deuterated chloroform was used.

[Table] The compound of the present invention can be produced, for example, according to the following reaction formula (wherein R is as described above). This reaction usually involves benzene, toluene, xylene, carbon tetrachloride, chloroform, methylene chloride,
A dehydrochlorination agent such as pyridine or triethylamine is present in an organic solvent such as dioxane, and the process is carried out at a temperature of about 20 to 120°C. The reaction may be carried out by suspending a base such as potassium carbonate or sodium carbonate in a solvent such as acetone or dioxane, and heating the suspension to reflux. Alternatively, the reaction may be carried out by heating in pyridine. It is easy to chlorinate or bromine the 4-position of the pyrazole ring, and chloroform, dichloromethane,
A 5-tert-butyl-3-pyrazolylurea compound in which the 4-position is unsubstituted is chlorinated or brominated using acetic acid, water, etc. as a solvent and an appropriate chlorinating agent or brominating agent such as chlorine, bromine, or sulfuryl chloride. Manufactured by The compound produced by the above reaction is generally sparingly soluble in water, but soluble in common organic solvents, and particularly well soluble in alcohols, acetone, and the like. However, it is difficult to dissolve in petroleum solvents such as hexane and pentane. Incidentally, the raw material compound used in the above reaction can be produced from cyanopinacholine and hydrazine, for example, according to the following reaction formula. Next, synthesis examples will be shown for reference, and the method for producing the active compound of the present invention will be specifically described. Example 1 Production of 3-amino-5-tertiarybutylpyrazole () 125 g of cyanopinacholine was dissolved in 200 ml of ethanol, 55 g of hydrazine hydrate was added, and the mixture was heated under reflux for 2 hours. After the reaction, ethanol is distilled off, alkaline water is added to the residue, extracted with 500 ml of benzene, dried over anhydrous sodium sulfate, and benzene is distilled off. The residue solidified upon standing, yielding 131 g of 3-amino-5-tertiarybutylpyrazole (). Example 2 Preparation of N,N-dimethyl N'-(5-tertiarybutyl-3-pyrazolyl)urea (1) 4.2 g of aminopyrazole and 3.2 g of triethylamine were dissolved in 50 ml of methylene chloride, and 32 g of dimethylcarbamoyl Add chloride. After heating under reflux for 5 hours, the mixture is cooled and washed with water. The organic layer was removed, the solvent was distilled off, a mixed solvent of hexane and benzene was added to crystallize it, and the mixture was filter-dried to give 2.0 g of N,N-dimethyl-N'-(5-tertiarybutyl-3-pyrazolyl)urea. I got (1). The melting point after recrystallization from aqueous methanol was 220-222°C. Example 3 N,N-dimethyl-N'-(5-tertiarybutyl-4-chloro-3-pyrazolyl)urea (2)
Production of Compound 1, 2.1 g, was suspended in 30 ml of carbon tetrachloride, and 1.4 g of sulfuryl chloride was added dropwise at 10-15°C. After further reaction at that temperature for 2 hours, an aqueous potassium carbonate solution is added to precipitate crystals. This was filtered and washed with water to obtain 1.4 g of Compound 2.
Parent peaks were found at 244 and 246 by mass spectrometry. Example 4 N,N-dimethyl-N'-(5-tertiarybutyl-4-bromo-3-pyrazolyl)urea (3)
Production of Compound 1 10g was dissolved in 50ml of acetic acid, bromine 7.6
Drop g. After reacting at room temperature for 3 hours, the reaction product was poured into ice water to crystallize. After filtering and washing with water, 11.7 g of compound 3 was obtained. Parent peak is 288 by mass spectrometry
and 300 recognized. Example 5 Production of N,N-diethyl-N'-(5-tertiarybutyl-3-pyrazolyl)urea (4) Dissolve 4.2 g of pyrazoleamine () in 50 ml of methylene chloride, and dissolve N,N-diethylcarbamoyl chloride. Add 4.1g. After heating under reflux for 5 hours, it is cooled and washed with water. The organic layer was taken, the solvent was distilled off, hexane was added to crystallize it, and it was dried by filtration to give 3.2 g.
Compound 4 was obtained. The active compounds according to the invention can be formulated into dosage forms such as emulsions, wettable powders, pastes, flowable powders, granules, etc. by applying conventional formulation methods. Furthermore, the compounds of the present invention can be mixed with other herbicides. Furthermore, in order to expand the range of action, it can be used in combination with agricultural chemicals other than herbicides, such as insecticides, nematicides, and fungicides. Next, examples of typical dosage forms will be given. "Parts" in the description indicate parts by weight. Example 1 Wettable powder Compound 50 shown in Table 1 as an active ingredient
10 parts of diatomaceous earth, 35 parts of clay, 3 parts of sodium polyoxyethylene alkyl acrylic ether sulfonate, and 2 parts of sodium alkylnaphthalene sulfonate are mixed and ground to obtain a wettable powder containing 50% of the active ingredient compound. When using, dilute with water to the specified concentration and spray. Example 2 Granules 5 parts of the compound in Table 1, 20 parts of bentonite, clay
Mix 73 parts and 2 parts of sodium dodecylbenzenesulfonate, add about 20 parts of water, knead with a mixer, granulate with a granulator, and then dry and granulate to contain 5% of the active ingredient. Obtain granules. Example 3 Emulsion Compound 15 shown in Table 1 as active ingredient
parts, 40 parts of dimethylacetamide, 40 parts of xylene, and 5 parts of polyoxyethylene alkyl allyl ether.
A homogeneous solution is obtained by mixing the two parts to obtain an emulsion containing 15% of the active ingredient. When using, dilute with water to the specified concentration and spray. The novel urea derivative of the general formula has excellent herbicidal activity and is therefore suitable for controlling weeds growing in fields, orchards, non-agricultural lands, etc. When this active compound is sprayed on the soil surface or mixed into the soil, it can significantly inhibit the growth of weeds and cause them to die. Weeds can also be controlled by spraying this agent on the stems and leaves of growing weeds. If the dosage of this compound is controlled and the application rate is selected to be 0.5 to 5 kg per hectare, corn,
It can be used as a selective herbicide in cultivated fields of wheat, barley, sugarcane, soybeans, peanuts, sunflowers, potatoes, cotton, fruit trees, etc. It can also be applied as a non-selective herbicide by increasing the application rate. The compounds of the present invention can be used, for example, to control the following weeds: That is, dicotyledonous plants such as Stellaria media, Chenopodium album, and Sagima
japo-nica), Chonopodium
ficifolium), Polygonum
nodosum), Purslane (Po-rtulaca)
oleracea), shepherd's purse (Capsella bursapastoris),
Lepidium virginicum, Porippa indica, Cardamine hexuosa, Abutilon
avicennae), American golden deer (Sida
spinosa), Malva morning glory (Ipomoea
purpurea), Senecio vulgaris, Sonchus asper, Bidens frondosa, Ambrosia
artemisiaefolia), Aster
subulatus), Hotokenoza (Lamium am
plexicavle), oxalis (Oxalis cornicolate),
Amaranthus retroflexus, Vicia sativa, Galium
spurium), Solanum nigrum,
Datura stramonium, etc.
Poaceae plants, such as Poa
annua), Sparrowglove (Alopeculus)
aequalis), crabgrass (Digitaria adsen−dens),
Eleusine indica, Setaris viridis, Echinochloa crus
-galii), Agropyron
tsukushiensis), Lolium perenne,
Bromus catharticos, oat (Avena tatua), polypogon
Higegaweri), Panicum
dichotomiflorom), Cyperaceae weeds such as Cyperus microiria, Chperus lria, Carex
rugata) etc. The compounds of the present invention have excellent herbicidal efficacy against a wide range of weeds as described above, and are particularly effective when applied to the surface of fields or the foliage of plants just before or after weeds germinate. High pest control effect can be obtained. Also, when the compound of the present invention is mixed into the soil, an extremely excellent weed control effect can be obtained. In order to demonstrate the herbicidal effect of the herbicide according to the present invention,
A more detailed explanation will be provided by giving some representative test examples. Test example 1 Pre-emergence soil treatment
Herbicidal effect on plants when treated with volcanic ash soil in pots with an area of ¹⁰⁰ cm Zea mays), wheat (Triticum aestivum),
Sow the seeds of Phaseolus radiatus,
Immediately after covering with soil to a thickness of approximately 5 mm, prepare a wettable powder using the compounds listed in Table 1 according to Example 1, dilute this with water, and obtain the amount of active ingredients per hectare.
A dose equivalent to 10 kg was administered onto the soil surface of each pot. Two weeks after treatment, the herbicidal effect on plants was investigated. The weeding effect was visually observed: 0: No effect ~
5: Displayed in Table 2 as an index of 6 levels of complete death.

[Table] Test Example 2 Herbicidal effect on plants when subjected to foliar spray treatment Pots with a surface area of 100 cm ² were filled with volcanic ash soil. gonum nodosum), blueberry (Amaranthus retro-flexus), corn (Zea mays), wheat (Triticum aestivum),
Sow the seeds of Phaseolus radiatus,
Cover with soil to a depth of about 1cm and place it in the greenhouse until there are 1 to 2 weeds.
When the leaves formed, a hydrating powder of the compound of the present invention was diluted in an amount equivalent to 10 kg/ha with water equivalent to 1000/ha and sprayed using a sprayer. Ten days after the chemical spraying, the results were investigated using the same criteria as in Test Example 1, and the results were expressed using a 6-level index. The test results are shown in Table 3.

[Table] Test Example 3 Herbicidal effect on paddy field weeds and phytotoxicity test on paddy rice A pot with a surface area of 120 cm ² was filled with paddy soil.
Seeds of Echinoehloa crus-galli and Monochoria vaginalis were mixed into a soil pot with a surface layer of about 2 cm.
acicularis) and two-leaf stage rice weeds.
Transplant to a new location and keep the water depth at about 3 cm. Three days later, a hydrating powder containing the compound of the present invention prepared according to Example 1 was administered into water at a dosage equivalent to 10 kg per hectare. Three weeks after chemical treatment, the herbicidal effect and chemical damage to paddy rice were investigated. The herbicidal effect and the chemical damage to crops were investigated using the same criteria as in Test Example 1, and expressed using a 6-level index. The test results are shown in Table 4. From Table 4, it can be seen that the compounds of the present invention are effective in killing weeds, which are important weeds in paddy fields, such as grasshoppers, Japanese grasshoppers, and Japanese grasshoppers. However, this group of compounds also affects paddy rice.

【table】

Claims (1)

[Claims] 1. General formula (In the formula, R and R' are lower alkyl groups, and X is a hydrogen atom, a chlorine atom, or a bromine atom.) A 5-tertiarybutyl-3-pyrazolylurea derivative represented by the formula: 2 A general formula characterized by reacting 5-tertiarybutyl-3-aminopyrazole with a compound represented by the general formula [Formula] (wherein R and R' represent a lower alkyl group) A method for producing a 5-tertiarybutyl-3-pyrazolylurea derivative represented by the formula (in which R and R' are as described above). 3 General formula (In the formula, R and R' represent a lower alkyl group.)
A general formula characterized by chlorinating or brominating a 5-tertiarybutyl-3-pyrazolylurea derivative represented by (In the formula, X′ represents a chlorine atom or a bromine atom,
R and R' are as above. ) A method for producing a 5-tertiarybutyl-3-virazolyl urea derivative. 4 General formula (In the formula, R and R' are lower alkyl groups, and X is a hydrogen atom, a chlorine atom, or a bromine atom.) A herbicide containing a 5-tertiarybutyl-3-pyrazolylurea derivative represented by the following as an active ingredient: agent.