JPS5834470B2 - New diphenyl ether compounds and selective herbicides - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on the general formula (wherein, X represents a halogen atom or a trifluoromethyl group).

) and herbicides containing these compounds as active ingredients.

It is known that certain types of diphenyl ether compounds have excellent herbicidal properties, such as 2,4-
Dichlorophenyl-3-methoxy-4-nitrophenyl ether (hereinafter abbreviated as chlormethoxynil).

) etc. are widely used as herbicides for initial use in paddy fields,
The development of herbicides with even higher selectivity and herbicidal activity is desired.

For this purpose, the practical application of a large number of diphenyl ether compounds has been studied, but these compounds differ in their herbicidal activity, degree, etc. due to slight differences in their chemical structure, such as the type, number, or position of substituents. It is extremely difficult to predict the herbicidal activity of these compounds based on their chemical structure similarities with known diphenyl ether compounds, since they differ significantly in expression, selectivity, and persistence of efficacy.

The present inventors synthesized various new diphenyl ether compounds and examined their herbicidal activity. As a result, the compound represented by the general formula [■] showed superior herbicidal activity and high selectivity compared to chromethoxynil. The present invention was completed based on this fact.

In other words, the group of compounds represented by the general formula [I], which are the active ingredients of the present invention, are more active than chromethoxynil against many weeds, including Japanese millet, which is a harmful weed of rice fields, even at low concentrations, and cause no chemical damage to paddy rice. It has various excellent herbicidal properties such as extremely small size.

Also, in field crops, 2,4-dichlorophenyl-4
-nitrophenyl ether (hereinafter abbreviated as NIP)
Compared to soybeans, which are highly active against many weeds, including the harmful weeds such as crabgrass and hackberry, even at low concentrations, soybeans,
It has various excellent herbicidal properties, including extremely low phytotoxicity to other useful plants.

Next, a synthetic example and its physical property data will be illustrated as a representative example of the compound represented by the general formula CI).

The active ingredient compounds of Examples and Test Examples are shown below by the numbers of Synthesis Examples.

Synthesis Example 1 2-Kururo 4-)'J fluoromethylphenyl 3
-(N-methylsulfamoyloxyethoxy)-4-
Synthesis of nitrophenyl ether (compound 1) (a) In a 100 m7 flask equipped with a stirrer, thermometer, dropping device and condenser, 2-chlor 4-1! J
Fluoromethylphenyl-3-hydroxy-4-nitrophenyl ether 34'y and anhydrous potassium carbonate 1.4
1 and 50 rrLl of dimethylformamide.

Heat this mixture to 80-85℃ and stir for 2 hours.
~Bromethanol 3,7? was added dropwise.

After reacting at the same temperature for 1 hour, it was cooled to room temperature, the reaction solution was discharged into water, the precipitated crystals were collected by filtration, and air-dried. Phenyl ether 3.32 (yield 85
．． 9%).

(b) 2-chloro-4-)'J fluoromethylphenyl-3-hydroxyethoxy-4-nitrophenyl ether synthesized in the above (a) in a flask of the same type 3.21
and 1 gram of triethylamine were dissolved in 50 liters of benzene and charged.

While keeping this solution at 30-35°C and stirring, N-
1.3 l of methylsulfamoyl chloride was slowly added dropwise.

After reacting at the same temperature for 1 hour, the reaction solution was washed three times with water.
The mixture was then dehydrated with anhydrous sulfuric acid (IJ), and benzene was distilled off under reduced pressure to obtain 362 oil.

This was carried out using silica gel column chromatography (development, elution:
The product was purified with benzene/ethyl acetate (25/1, 2/v) to obtain the desired product 2f (yield 51.3%).

Melting point 111-112°C COCl3° NMR (δ - ppm) MS 2.80 (3H, d, NCH3) 440 (4H, m, -0CH2CH20-) 4.85
(IH, m, -NH-) Elemental analysis value (calculated value) %, C40,57 (40,81)
, H2,86 (3,00) N6.15 (5,95) as C16H14CIF3N207S, CI 7.48 (7,53
) F12.00 (12,11), 37.03 (6,8
1) Synthesis Example 2 Synthesis of 2,4-dichlorophenyl-3-(N-methylsulfamoyloxyethoxy)-4-nitrophenyl ether (Compound 2) Synthesis was performed in the same manner as in Synthesis Example 1.

Purification was performed by a recrystallization method using benzene.

Yield 68.6% Melting point 134-135°C Elemental analysis value (calculated value) %, C41,13 (41,20)
, H3,28 (3,23) CI5H14CI2N20□S N6.36 (6,41), CI 16.59 (16,
21) 87.22(7,23), When the compound of the present invention is used as a herbicide, one or more other herbicides, insecticides, fungicides, plant growth regulators, etc. Not only can it be used in combination with agricultural chemicals, soil conditioners, or fertilizing substances, but also mixed formulations with these are also possible.

For example, herbicides used in combination with the herbicide of the present invention include:
Urea herbicides, thiol carbamate herbicides, organophosphorus herbicides, acid amide herbicides, triazine herbicides,
There are allyloxy fatty acid herbicides, etc.

The content of the herbicide of the present invention is preferably 2 to 10% in granules, 20 to 80% in wettable powders, and 10 to 50% in emulsions (all percentages by weight).

Next, the herbicide according to the present invention will be explained in more detail with reference to formulation examples and herbicidal activity test examples, but the present invention is of course not intended to be developed at these times.

Example 1 16 parts of a granule compound, 70 parts of bentonite, 21 parts of talc, 2 parts of sodium dodecylbenzenesulfonate and 1 part of sodium ligninsulfonate were mixed, and an appropriate amount of water was added and kneaded, followed by an extrusion granulator. The mixture was granulated using a conventional method and dried to obtain 100 parts of granules.

Example 2 250 parts of a hydrating agent compound, 40 parts of hydroxide, and 10 parts of sodium dodecylbenzenesulfonate were mixed and ground to give 100 parts of a hydrating agent.
I got the department.

Example 3 Emulsion compound 1 10 parts Tsurupol (emulsifier manufactured by Toho Chemical Co., Ltd.) 1
0 parts and 80 parts of benzene were mixed and dissolved to obtain 100 parts of an emulsion.

Next, the excellent herbicidal effect and selectivity ★ of the compound of the present invention will be specifically disclosed through test examples.

Test Example 1 Paddy field weed control test R 15,000 Wagner pots were filled with soil, and seeds of Japanese grasshopper, firefly, Helaomodaka, and Cyperus spp. One plant was used, and the two plants were transplanted and grown in a greenhouse.

Three days after transplanting paddy rice, 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 1 above.

One month after the treatment, weed growth and chemical damage to paddy rice were investigated, and the results shown in Table 1 were obtained.

In this table, the degree of chemical damage to the action and the herbicidal effect on weeds are expressed by comparing the state of emergence or growth of crops or weeds with that of the air-dried type in the untreated area, according to the following evaluation criteria.

The test compounds were indicated by the compound number of the synthesis example.

Evaluation criteria .

Air dry gravity ratio vs. untreated area, □～□. . Survival rate in %1 61-90%2
31-60%3
11-30%4 6-10
%5 0 to 5% Test Example 2 Field Crop Weed Control Test Earl 15,000 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 an amount of water equivalent to 101 parts per ar* using a wettable powder prepared according to the method of Example 2, and sprayed with a micro-pressure sprayer. Spread.

This was grown in a greenhouse.

Thirty days after the chemical spraying, the appearance and growth of crops and weeds was investigated, and the results shown in Table 2 were obtained.

In this table, the classification of growth states of crops and weeds and the test compound numbers are the same as in Table 1.

Claims (1)

[Scope of Claims] A diphenyl ether compound represented by the general formula 1 (wherein X represents a halogen atom or a trifluoromethyl group). A selective herbicide characterized by containing a diphenyl ether compound represented by the general formula 2 (wherein X represents a halogen atom or a trifluoromethyl group) as an active ingredient.