JPS6126991B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel pyridyl-2-oxybenzene derivative, a method for producing the same, and uses thereof. For details, see the general formula [] The present invention relates to a compound represented by the formula (in which R represents hydrogen, a methyl group, or an ethyl group), a method for producing the same, and a herbicide characterized by containing at least one of these compounds as an active ingredient. An object of the present invention is to provide an industrially advantageous production of a practically extremely useful herbicide. The present inventors have endeavored to search for herbicides that are less harmful to rice among pyridyl-2-oxybenzene compounds, and have found that the compound of the present invention has many excellent characteristics as a herbicide. This discovery led to the completion of the present invention. The pyridyl-2-oxy-benzene derivatives of the present invention and their physical properties are shown in Table 1 below, and they can be produced by the following method.

[Table] First, 4-(3,5-dichloropyridyl-2-oxy)-1,2-dinitrobenzene (compound 2)
is manufactured as follows. That is, m-nitrophenol and 3,5-dichloro-2-bromo-pyridyl are mixed in the presence of a deoxidizing agent such as sodium hydroxide or potassium carbonate without a solvent or in a polar solvent, for example,
100-180℃ in dimethylformamide, preferably
React at 140-150 for 2-4 hours to form 3-(3・5
-Dichloropyridyl-2-oxy)-nitrobenzene (Compound 1) is produced. In addition to the above, dimethyl sulfoxide side and sulfolane may be used as polar solvents. Next, Compound 2 can be produced with high selectivity by nitrating Compound 1 with a mixed acid at 10 to 70°C, preferably at 50 to 60°C for 1 to 3 hours. Compound 2 has good crystallinity and can be easily purified by recrystallization, but even a crude product can be used satisfactorily.
General formula [] using compound 2 (In the formula, R ₃ represents hydrogen, a methyl group, or an ethyl group.) The compound represented by the following formula can be easily produced by reacting Compound 2 with an excess (more than twice the mole) of various types of hydrazine. The various hydrazines mentioned here include hydrazine, methylhydrazine,
Refers to alkylhydrazine such as ethylhydrazine. Inert solvents are used as reaction solvents, but generally dioxane, tetrahydrofuran,
It is desirable to use benzene and toluene. The reaction time and reaction temperature vary depending on the solvent used, but the reaction time is 30 minutes to 3 hours, preferably 1 to 2 hours, and the reaction temperature is 10°C to 100°C, preferably room temperature to 70°C.
°C is appropriate. The method for producing the compound represented by the general formula [] will be specifically explained below with reference to Examples. Example 1 Synthesis of 4-(3,5-dichloropyridyl-2-oxy-1,2-dinitrobenzene (compound 2)) m-nitrophenol 78 g (0.56 mol), potassium carbonate 13.8 g (1 mol) and dimethyl 3.5-
127 g (0.56 mol) of dichloro-2-bromopyridine was added, the temperature was gradually raised, and the mixture was reacted at 140 to 145°C for 2 hours. After the reaction solution was cooled, it was filtered under suction, and the filtrate was concentrated under reduced pressure to obtain 154 g of a crude product. This crude product was recrystallized from ethanol to obtain 120 g of 3-(3,5-dichloro-pyridyl-2-oxy)-nitrobenzene (Compound 1) (yield: 75%). Next, 59 g (0.2 mol) of the above 3-(3,5-dichloro-pyridyl-2-oxy)-nitrobenzene (compound-1) was added to 500 ml of 95% sulfuric acid.
A mixed acid [a mixed solution of 20 ml of fuming nitric acid (specific gravity 1.5) and 50 ml of 95% sulfuric acid] prepared separately at room temperature was added dropwise over about 1 hour. 50 more after addition
After stirring at ~60°C for 1 hour to react, the reaction solution was discharged into ice-cold water and the precipitated crystalline 4-
(3,5-dichloro-pyridyl-2-oxy)-
65.5 g of 1,2-dinitrobenzene (compound 2) was obtained. This was recrystallized from a mixture of ethanol and ethyl acetate to obtain 60 g of highly pure compound 2 (yield: 90.9
%). Example 2 Synthesis of 4-(3,5-dichloro-pyridyl-2-oxy)-2-hydrazino-nitrobenzene (compound 3) 4-(3,5-dichloro-pyridyl-2-oxy)-1,2- Dinitrobenzene (compound 2) 33
g (0.1 mol) in 50 ml of dioxane and stirred at room temperature to add 15 g of hydrazine hydrate.
(0.3 mol) was gradually added dropwise. Thereafter, the mixture was stirred at the same temperature for 2 hours to complete the reaction. This reaction solution was discharged into ice-cold water, the precipitated crystals were collected, and recrystallized using ethanol to obtain 4-(3.
26.5 g of 5-dichloropyridyl-2-oxy)-2-hydrazino-nitrobenzene (compound 3) was obtained (yield: 84%). Note that Compounds 4 and 5 can also be synthesized by the same method as in Example 2. Next, the herbicide according to the present invention will be explained with reference to Examples, but the present invention is not limited thereto. The content of the compound of the present invention in the herbicide of the present invention is preferably 2 to 10% in granules, 20 to 30% in wettable powders, and 10 to 50% in emulsions (all percentages are by weight). Example 3 Granule Compound 1: 6 parts, bentonite 70 parts, talc 21
1 part, 2 parts of sodium dodecylbenzenesulfonate and 1 part of sodium ligninsulfonate, and after adding an appropriate amount of water and kneading, the mixture is granulated using an extrusion granulator in a conventional manner and dried to obtain 100% of granules. I got the department. Example 4 Wettable powder 50 parts of Compound 2, 40 parts of diatomaceous earth, and 10 parts of sodium dodecylbenzenesulfonate were mixed and ground to obtain 100 parts of a wettable powder. Example 5 Emulsion 10 parts of Compound 3, 10 parts of Sorbol (emulsifier manufactured by Toho Chemical Co., Ltd.) and 80 parts of benzene were mixed and dissolved to form an emulsion.
Got 100 copies. Next, the excellent herbicidal effects and selectivity of the compounds of the present invention will be specifically disclosed using test examples. Test Example 1 Paddy field weed control test R/5000 Wagner pots were filled with soil, and seeds of Japanese millet, firefly, Helaomodaka, and Cyperus spp. One plant was used as a book, and the two plants were transplanted and grown in a greenhouse. Three days after rice transplantation, at the beginning of weed emergence, a predetermined amount of the test compound was submerged in water using a granule according to the method described in Example 3 above. One month after the treatment, weed growth and chemical damage to paddy rice were investigated, and the results shown in Table 2 were obtained. In this table, the degree of chemical damage to crops and the herbicidal effect on weeds are expressed by comparing the state of emergence or growth of crops or weeds with the air dry weight of untreated plots, according to the evaluation criteria below. The test compounds were indicated by compound numbers in Table 1 above.

【table】

【table】

[Table] Test Example 2 Paddy field weed control test Earl/5000 Wagner pots were filled with soil and seeds of Japanese millet, firefly, Helaomodaka, and Cyperus japonica were sown and submerged in water. 2) Two plants were used as one plant, and the two plants were transplanted and grown in a greenhouse. During the weed growth period 10 days after transplanting paddy rice, a predetermined amount of the test compound was submerged using a granule according to the method described in Example 3 above. One month after the treatment, weed growth and chemical damage to paddy rice were investigated, and the results shown in Table 3 were obtained. In this table, the degree of chemical damage to crops and the herbicidal effect on weeds are expressed according to the classification shown in Test Example 1 by comparing the state of emergence or growth of crops or weeds with the air dry weight of untreated plots.

【table】

[Table] Test Example 3 Field Crop Weed Control Test Earl/5000 Wagner pots were filled with soil, and seeds of soybean, crabgrass, foxtail grass, blueberry, and whiteweed were sown. Three days after seeding, a predetermined amount of the test compound was diluted to 10 equivalent amounts of water per are using a wettable powder prepared according to the method of Example 4, and sprayed using a micro-pressure sprayer. This was grown in a greenhouse. 30 days after spraying the chemical,
The occurrence and growth conditions of crops and weeds were investigated and the results shown in Table 4 were obtained.

【table】

【table】

Claims (1)

[Claims] 1. General formula [] (In the formula, R represents hydrogen, a methyl group, or an ethyl group.) A pyridyl-2-oxybenzene derivative represented by the following formula. 2 4-(3,5-dichloropyridyl-2-oxy)-1,2-dinitrobenzene and general formula R-
A method for producing a pyridyl-2-oxy-benzene derivative represented by the general formula [], which comprises reacting various hydrazine represented by NHNH ₂ (wherein R represents hydrogen, methyl group or ethyl group). General formula [] (In the formula, R represents hydrogen, a methyl group, or an ethyl group.) 3 4-( Obtained by reacting 3,5-dichloro-2-brombridine with metanitrophenol and nitrating the resulting compound) 3.5
The method according to claim 2, characterized in that -dichloropyridyl-2-oxy)-1,2-dinitrobenzene is used. 4 General formula [] A herbicide containing a pyridyl-2-oxy-benzene derivative represented by the formula (wherein R represents hydrogen, methyl group or ethyl group).