JPS5910322B2 - herbicide - Google Patents

Description

Detailed Description of the Invention The present invention is based on the general formula (wherein R1 represents a hydrogen atom or a methyl group, and R2
is characterized by containing as an active ingredient a compound represented by a hydroxyl group when R1 is a hydrogen atom, and a hydroxyl group, a lower alkylamino group, a hydrogen atom, or a lower alkyl group when R1 is a methyl group. The present invention relates to a new herbicide.

An object of the present invention is to provide an excellent herbicide that selectively controls paddy field weeds without causing harm to paddy rice.

Conventionally, 2,4-D and MCPA, which are phenoxy herbicides, have been widely used to control weeds other than those belonging to the Poaceae family in rice fields.

However, depending on the time of use, soil, or weather conditions, these herbicides can often cause chemical damage to paddy rice, and there is a strong demand for the development of herbicides that can be safely used without chemical damage. There is.

The present inventors have conducted extensive research on herbicides that are not affected by the time of use, soil, or weather conditions, and are extremely harmless, and as a result, the above general formula [■], which is the active ingredient of the herbicide of the present invention, has been found. Although the compound shown in the following shows an extremely excellent herbicidal effect against annual and perennial broad-leaved weeds other than the Poaceae family and weeds of the Cyperaceae family,
The inventors have found that, at dosages sufficient to control these weeds, no malformed leaves or other phytotoxicity are observed in paddy rice, and based on this finding, the present invention has been completed.

The compound of the present invention is usually used by blending it into a carrier commonly used for agricultural chemicals, but it can also be used in combination with other herbicides and other agricultural chemicals or fertilizing substances, and it can also be used in mixed formulations. You can also do that.

Table 1 shows the physical properties of the representative compound represented by the general formula CI), which is the active ingredient of the herbicide of the present invention.

Next, a typical synthesis example of the compound of the present invention will be shown.

Synthesis Example 1 Synthesis of α-(β-naphthoxy)propionic hydroxamic acid (Compound 2) α-(β-naphthoxy)propionic acid 21.6F (0.
1 mol) and 43.2f (0.4 mol) of thionyl chloride were reacted in 200 rIL of benzene with stirring for 30 minutes under reflux.

After the reaction is complete, the reaction solution is distilled under reduced pressure to remove benzene, excess thionyl chloride, and hydrochloric acid gas, and the resulting oily α
Mono(β-naphthoxy)propionic acid chloride was dissolved in 20 ml of benzene.

Hydroxylamine hydrochloride 2 8. Of (0.4
mole), 80 grams of water, 16.7 grams of granular sodium hydroxide (
0.4 mol) (purity 96%), and ethanol 200
The solution was added dropwise to the rILl mixture at room temperature while stirring.

After the dropwise addition was completed, the mixture was stirred at 50° C. for 2 hours to complete the reaction.

The reaction solution was cooled to room temperature, the precipitated sodium chloride was separated, and the mixed solvent of ethanol, benzene, and water was distilled off under reduced pressure from the solution, and the crystalline residue obtained was further recrystallized with benzene. 16.55' of compound 2 (mp, 126-1
(decomposed at 27°C).

Synthesis Example 2 α-(β-naphthoxy)propionmethylhydrazide (
Synthesis of Compound 3) 23.5f (0.1 mol) of α-(β-naphthoxy)propionic acid chloride obtained by the method of Synthesis Example 1 was added to benzene 5
0771 l.

This solution was then diluted with 13.8f (0.3f) of methylhydrazine.
mol) and 200 rlLl of benzene.
Dropwise while stirring at 0℃, and then stirred at room temperature for 30 minutes.
The reaction was completed by stirring for a minute.

The reaction mixture was discharged into 500 rrLl of cold water and stirred to yield 16.11 white crystals of high purity compound 3 (mp,
168.5-170°C).

Synthesis Example 3 Synthesis of 0-(N-ethylcarbamoyl)-[α-(β-naphthoxy)-propion]hydroxamate (Compound 4) α-(β-naphthoxy)propion hydroxamic acid obtained in Synthesis Example 1 6.9 f (0.03 mol), triethylamine 1rrLl1 and acetone 200rrL
While stirring the mixture, add 2.9 f? of ethyl isocyanate to it at 10°C. (0.04 mol) was added dropwise.

After the dropwise addition was completed, the mixture was stirred under reflux for 1 hour to react.

Ethanol and excess ethyl isocyanate were distilled off from this reaction solution under reduced pressure, and the residue was recrystallized from benzene to give 4.5 tons of white crystals of Compound 4 (mp, 96-9
(decomposed at 7°C).

Note that Compound 1 and Compound 5 can be synthesized in the same manner as in Synthesis Example 1 and Synthesis Example 3, respectively.

Next, examples of the herbicide of the present invention will be given, but the additives and the blending ratio can be varied within a wide range and are not limited to these.

In the examples, "parts" represent "parts by weight."

Example 1 20 parts of emulsion compound 1, 70 parts of solvent naphtha, and 10 parts of emulsifier Solpol 800 (registered trademark) are mixed and dissolved to obtain 100 parts of emulsion.

Add water to this and emulsify it to make a spray liquid.

Example 2 Wettable powder 50 parts of Compound 2, ±40 parts of diatomaceous powder, and 10 parts of sodium totecylbenzenesulfonate are mixed and ground to obtain 100 parts of a wettable powder.

This is suspended in water to make a spray solution.

Example 3 Wettable powder compound 4 40 parts, bentonite 30 parts, diatomite ±2
0 parts and 10 parts of sodium ligninsulfonate are mixed and ground to obtain 100 parts of a wettable powder.

This is suspended in water to make a spray solution.

Example 4 10 parts of granule compound 3, 65 parts of bentonite, 20 parts of talc, 2 parts of polyoxyethylene glycol monolaurate,
and 3 parts of sodium naphthalene sulfonate,
An appropriate amount of water is added and kneaded, followed by granulation using an extrusion granulator in a conventional manner to obtain 100 parts of granules.

Spread this directly by hand or with a granulator.

Example 5 Granule compound 5 7 parts, bentonite 50 parts, talc 40 parts,
After mixing 2 parts of sodium dodecylbenzenesulfonate and 1 part of dioctyl sulfosuccinate, an appropriate amount of water was added and kneaded, and the mixture was granulated in a conventional manner using an extrusion granulator to obtain 100% granules. get the part.

Spread this directly by hand or with a granulator.

Next, the effects of the herbicide of the present invention will be specifically explained using test examples.

Test Example 1 Herbicidal effect test on field weeds A clay pot with an inner diameter of 18 cIIL was filled with clay soil, and weed seeds, rice, corn, and wheat seeds were sown and covered with soil, and grown in a greenhouse. .

When weeds and crops grow to the 3- to 4-leaf stage, a predetermined amount of the test compound is made into an emulsion or wettable powder, diluted in an appropriate amount of water, and sprayed over the entire surface of the plant's foliage with a microsprayer. Spread.

One month after spraying, the herbicidal effect on various weeds and the chemical damage to crops were investigated, and the results shown in Table 2 were obtained.

In this table, the herbicidal effect of the test compound is classified into 6 levels, with "0" indicating no effect on the growth of crops or weeds and "5" indicating completely killing them. displayed.

Test Example 2 Herbicidal effect test on paddy field weeds A/5000 Wagner pot was filled with paddy soil, kept hydrated, and paddy rice seedlings (variety: Nipponbare) at the 2.5 leaf stage were transplanted into the pot. Then, an appropriate amount of paddy weeds were sown into this.

Five days after transplanting paddy rice, a predetermined amount of the test compound was applied in the form of an emulsion or a wettable powder to water the inside of the pot.

During the test period, the water depth in the pot was maintained at 3 cIIL, and leakage treatment was carried out at ICrfL per day.

One month after the chemical treatment, the effects on weeds and the chemical damage to paddy rice were investigated, and the results shown in Table 3 were obtained.

The display classification of efficacy and degree of drug damage is in accordance with Test Example 1.

As is clear from the above test results, the herbicide of the present invention exhibits an extremely remarkable selective herbicidal effect, and is effective against various weeds that are harmful to field crops and paddy rice cultivation, without causing any chemical damage to cultivated crops. It has excellent pest control effects over a wide range.

Claims (1)

[Claims] 1 General formula (wherein R1 represents a hydrogen atom or a methyl group, R
No. 2 is characterized in that it contains as an active ingredient a compound represented by a hydroxyl group when R1 is a hydrogen atom, and a hydroxyl group, a lower alkylamino group, a hydrogen atom, or a lower alkyl group when R1 is a methyl group. and herbicides.