JPS6024792B2 - Method for producing pyran derivatives - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a compound having a novel basic structure.For details, refer to the following formula (in the formula, R and R2 represent a lower alkyl group, and R3 represents an alkoxyalkyl group or an alkylthioalkyl group). This invention relates to a method for producing a compound represented by: Compounds produced according to the present invention are useful as herbicides. The object of the present invention is to obtain these compounds industrially advantageously and to provide a simple and highly effective herbicide. The present inventors are currently considering those suitable for the above purpose among many pyran derivatives, and found that the general formula (wherein R, , R2
has the same meaning as defined above. ) was reacted with a compound represented by the general formula R3-0-NQ [m] (wherein R3 has the same meaning as defined above), resulting in the reaction with the compound represented by the general formula [1] ] can be industrially advantageously obtained, and moreover, it is possible to obtain the compound represented by
It exhibits an extremely excellent selective herbicidal effect against weeds of the grass family, such as grasshopper and grasshopper, and is particularly effective against leguminous crops such as azuki beans and soybeans, which are susceptible to chemical damage caused by many other herbicides, as well as broad-leaved crops such as beets. They found that it was almost harmless, and after conducting further biological and physicochemical research, they completed the present invention. The present inventors have already reported that 4-hydroxy-6-methyl-
A herbicide containing an a-pyrone derivative as an active ingredient has already been known as Patent Application Publication No. 16916/1971, but in order to completely kill the rice weeds mentioned above, a fairly large amount of the herbicide must be used. This is one drawback of this herbicide. That is, according to the description in the above-mentioned publication and the follow-up tests conducted by the present inventors, in actual use, the expected effect can be obtained with a dose of 500 mg of active ingredient per 10 are;
If the dosage is less than 250 ta per 0 are, it will not be possible to kill all the weeds, and a complete effect will not be obtained. When the compound of the present invention is used as a herbicide, its herbicidal action is strong and complete weed control can be expected at doses of 250/10 are or less than 125 are by the same treatment method as known herbicides. The herbicide of the present invention is applied by foliar spraying, and even at a dose that completely kills the rice weed grasshopper, it has no effect on broad-leaved crops such as radish, soybeans, peas, spinach, and beets. In addition, in the pre-emergence soil treatment of weeds, even at a dose that completely inhibits the germination of crabgrass, there is no effect on the seeds of broad-leaved crops.The safety of herbicides against broad-leaved crops is extremely high, and their application is They can also be used in a wide range of application times, locations and concentrations. Furthermore, since the pest control agent of the present invention is used at a low concentration, there is no concern about residual toxicity in the soil or plants or acute toxicity to animals, animals, and fish, and the herbicide can be used safely. Among the compounds represented by the general formula [1], those in which R and R2 are ethyl groups and R3 is a methoxyethyl group exhibit particularly excellent effects. Next, the active ingredient compounds of the present invention are shown in Table 1. Table 1 (n
D: jlU fold) In the production of the compound of the present invention, the general formula of the raw material

A 3-acylpyrone derivative represented by [0] and an amine represented by general formula [m] are reacted in an inert solvent. The reaction temperature is from room temperature to the boiling point of the solvent used, preferably at a temperature higher than room temperature. After a reaction period of 3 minutes to several hours, the solvent is replaced if necessary for alkaline extraction, the alkaline layer is made acidic with hydrochloric acid, and the precipitated oil or crystals are separated by solvent extraction or sieving to obtain the desired product. After purification by recrystallization or column chromatography, the structure was confirmed from elemental analysis, NMR spectrum, and melon spectrum. Next, the method for producing the compound of the present invention will be explained in detail with reference to Examples. Example 1 3-[1-(N-methoxyethoxyami/)propyritene-6-ethyl-3,4-dihydro 2 days-pyran-2
・Dissolve 2.0 mol of 4-dione 6-ethyl-4-hydroxy-3-propionyl-Q-pyrone (0.01 mol) in 20 cc of ethanol, and dissolve 0.9 methoxyethoxyamine.
0.0 mol (0.011 mole) was added and continued at room temperature for 2 hours, then at about 70-8 pi for 30 minutes. After cooling, ethanol was removed under reduced pressure, and the residue was dissolved in chloroform and extracted twice with 15 cc of 5% caustic soda. The alkaline layer was acidified with hydrochloric acid, and the separated oil was extracted with 15 cc of chloroform.The chloroform layer was washed with water and dried over magnesium sulfate. Thereafter, the chloroform layer was distilled off under reduced pressure to obtain a colorless oily 3-[1
-(N-methoxyshethoxyamino)propylidene]-6
-Ethyl-3,4-dihydro yielded -pyran-2,4-dione for 2.2 hours. Yield Total % Refractive index: n answer 1.5
309 Next, regarding herbicides characterized by containing one or more compounds represented by the general formula [1] of the present invention as an active ingredient, generally an appropriate amount is mixed with a carrier and mixed with water. Solid carriers used in the form of Japanese preparations, emulsions, powders, granules, etc. include talc, bentonite, clay, diatomite, vermiculite, etc., and liquid carriers include water, alcohol, benzene, xylene, Kerosene, mineral oil, cyclohexane, cyclohexanone dimethylformamide, etc. are used. If necessary, a surfactant may be added to these preparations in order to obtain a uniform and stable form. The wettable powders and emulsions thus obtained are diluted with water to a predetermined concentration, and as a suspension or emulsion, the powders and granules are directly treated with soil or sprayed on hollyhock. In addition, the pest control agent of the present invention may be a known fungicide, insecticide, acaricide or herbicide, such as a urea herbicide such as Linuron or DCMU, a triazine herbicide such as atrazine or simazine, or an amide herbicide such as Aranup. It can also be used in combination with herbicides. Next, some reference examples regarding the preparations of the present invention will be shown, but the active ingredient compounds, additives, and addition ratios are not limited to these reference examples and can be varied within a wide range. Reference example 1 Wettable powder compound 1 5 Sogan Keisouji 21 parts talc
2 parts alkyl sulfate soda 9 parts or more are mixed uniformly,
Finely pulverize to obtain a wettable powder containing 50% of the active ingredient. Reference Example 2 Emulsion Compound 2 25 parts xylene 5 Ikarito dimethylformamide 13 parts Polyoxyethylene phenyl ether 12 parts or more are mixed and dissolved to obtain an emulsion containing 25% of the active ingredient. Reference Example 3 Granule Compound 3 1 Base: Talc 38 parts Clay 30,000 parts Pentonite 1 Loose Part: Sodium alkyl sulfate 5 parts or more are mixed uniformly and pulverized finely, and then processed into a granulator with a diameter of 0.5-1. Granules containing 10% of the active ingredient are obtained by making granules from the side. Next, test examples regarding the effect of the herbicide of the present invention will be shown. Test Example 1 Flooded Soil Treatment Test A pot with a surface area of 60 m was filled with soil, and after sowing about 6 sows of soybean seeds and lightly covering the pot, the pot was flooded with water to the extent that the soil surface was moistened. 10 cc of a chemical solution of a predetermined concentration prepared by diluting an emulsion of each test compound with water was poured into a pot and placed in a greenhouse. Two weeks later, the growth status of the barnyard grass was investigated. The growth status was expressed in 6 stages from 0 to 5, with 0 indicating the same level of growth as untreated and 5 indicating death or non-germination, and the results shown in Table 2 were obtained. Table 2 Test Example 2 Single-leaf stage treatment test A pot with a surface area of 6 ratio was filled with soil, and about 5 soybeans of Aspera were sown thereon, lightly covered with soil, and grown in a greenhouse. When the T. japonica grew to the single-leaf stage, the pots were flooded with water to a depth of about three stripes, and a chemical solution of a predetermined concentration prepared by diluting an emulsion of each compound with water was poured into each pot. Two weeks later, the growth status of the Tainubie was investigated. Expressing the growth state according to the same criteria as Test Example 1,
The results shown in Table 3 were obtained. Table 3 Test Example 3 Soil surface treatment test Soil mixed with crabgrass and pigweed seeds was packed into pots with a surface area ratio of 10 and grown in a greenhouse. Before the germination of crabgrass and pigweed, 5 cc of a chemical solution of a predetermined concentration prepared by diluting an emulsion of each test compound with water was sprayed onto the soil surface, and 21 days later, the growth status of crabgrass and pigweed was investigated. The growth status was expressed according to the same criteria as Test Example 1, and the results shown in Table 4 were obtained. Table 4 Test Example 4 Hollyhock Treatment Test A pot with a surface area of 100 cm was filled with soil, covered with soil lightly with seeds of crabgrass and pigweed, and grown in a greenhouse. When the crabgrass grows at the 2- to 4-leaf stage, a prescribed concentration of chemical solution prepared by diluting each test compound emulsion with water is applied 100 times per day.
The foliar and foliage spraying treatment was carried out at the proportion of the mountain. Two weeks later, the growth status of the crabgrass and pigweed was investigated, and the growth status was expressed according to the same criteria as in Test Example 1, and the results shown in Table 5 were obtained. Table 5

Claims (1)

[Claims] 1 A compound represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 and R_2 represent lower alkyl groups. R_3 represents an alkoxyalkyl group or an alkylthioalkyl group.) General formulas ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 and R_2 represent lower alkyl groups, R_
3 represents an alkoxyalkyl group or an alkylthioalkyl group. ) A method for producing a compound represented by