JPS5938222B2 - substituted phenyl urea - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides novel 3-(4-crotyloxyph'enyl)
-1,1-dimethylurea (hereinafter abbreviated as "the compound of the present invention").

Therefore, the object of the present invention is to provide a novel compound that can selectively weed even barnyard grasses such as Japanese millet at the 4- to 5-leaf stage, which were conventionally considered difficult to weed in paddy fields. 3- according to the present invention
(4-crotyloxyphenyl)-1,1-dimethylurea has a substituent having a double bond, and there are isomers of trans type and cis type shown by the following chemical structural formula,
Each has different physical properties.

Transformer type: 〉C:C</CH3 HCH2O〇NHenN< Melting point 1150-116℃ Cis type: 〉C-C〈CH.

CH3CH2O〇NHWN Melting point: 1330-134°C The present invention may include trans-type, cis-type, and mixtures thereof in arbitrary proportions, and unless otherwise specified in the following description, these are collectively referred to as the present invention. It is called an invention compound.

The Japanese millet, which is the main weed target of the present invention, is the most typical of the rice millet species, and is a type of wild millet that is adapted to breed in areas ranging from shallow to deep water.

The grass shape of the plants and animals is very similar to that of rice, but it grows faster than rice. When it becomes an adult plant, it becomes taller than rice,
The ears will emerge above the rice and become more visible. When Japanese millet grows, the paddy rice is shaded and the amount of light it receives is limited.
The photosynthesis or nutrient absorption function of paddy rice decreases. As a result, the growth of paddy rice is inhibited and the yield is adversely affected. In addition, with the recent spread of agricultural machinery such as combines,
If Japanese millet remains during harvest, its seeds will be mixed into the harvested rice, leading to a decline in the quality of the rice. Therefore, how to effectively weed weeds such as Japanese shrimp has been one of the important issues in paddy rice culture technology. In order to solve these technical problems, new herbicides have been developed and put into practical use one after another.

For example, as an active ingredient, 2,4-dichlorophenyl-4
/-nitrophenyl ether (NIP), 2,4,6-
Trichlorophenyl-4' nitrophenyl ether (C
NP), 2,4-dichlorophenyl-31-methoxy-
4'-nitrophninyl ether (chromethoxynil),
5-tertiary-1-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2-one (oxadiazone), 2-chloro-2',
6'-diethyl-N-(butoxymethyl)acetanilide (butachlor), 2,4-bis(ethylamino)-
6-Methylthio-1,3,5 triazine (simetrine)
, s-ethylhexahythro 1H-azepine-1-carbothioate (molinate), 4-chlorobenzyl N,
N-diethylthiol overmade (benthiocarb)
, N-(0,0-di-n-propyldithiophosphorylacetyl)-2-methylpiperidine (piperophos), and the like. These herbicides have a herbicidal effect on Japanese millet from before emergence to around the two-leaf stage.

In transplanted paddy fields, the early stage of growth of Japanese millet occurs before and after the rice is transplanted, and in direct-seeded paddy fields, the paddy rice itself is a young plant in its early stages of development, and its drug resistance is extremely weak. If a herbicide is applied at such a time, it is not possible to apply a large amount of the herbicide to the paddy rice field because all of the herbicides have relatively low selectivity. Therefore, currently, chemicals are applied within a range that does not cause harm to rice, and as a result, it is said that it is not possible to completely control Japanese millet, and a certain amount of Japanese millet remains. In addition, the outbreak period of Japanese millet is long, and it is not possible to control the later outbreaks of Japanese millet with a single application of chemicals. For these reasons, in transplanted paddy fields, so-called systematic control, in which chemical treatment is performed twice before and after rice transplantation and again 20 days after rice transplantation, has become commonplace.

However, if the remaining Japanese millet that could not be controlled by the first application is at the 3rd to 5th leaf stage at the time of the second chemical treatment, the second application will not be able to control it, causing a problem. Therefore, there is a strong demand for the development of a herbicide that has a strong herbicidal effect on barnyard grasses such as Japanese millet, which have advanced leaf stages. In addition, in direct-seeded rice fields, there is a strong desire to develop herbicides that have even higher selectivity between rice and barnyard grass and are safe for young rice seedlings that have just emerged.

In order to meet these demands, the present inventors synthesized a wide variety of compounds and conducted repeated herbicidal tests.

Among them, substituted phenyl urea-based 3-[4-(2
-Chlor-2-putenyloxy)phenyl]1,1-dimethylurea (CBPDU) was found to be useful, and based on this knowledge, we are conducting further studies with the aim of developing a better herbicide for rice fields. As a result, the present invention was completed. The compound of the present invention is CBPDU
The herbicidal power against Japanese millet at the 5-leaf stage is enhanced and the chemical damage to rice is further reduced compared to the above, and it is extremely promising and highly practical in achieving the above objectives. A series of substituted phenyl urea compounds were published in Japanese Patent Publication in 1973 according to the general formula.
It is described in the publication No.-2329. However, the compound of the present invention is not specifically described in this publication and is a completely new compound. According to the same publication, the herbicidal properties of a series of compounds similar to the compounds of the present invention against oats, wheat, beads, chrysanthemums, soybeans, corn, mustard, clover, and sparrow vines exceeded test examples. It is also described. This description merely shows that a series of substituted phenyl urea compounds can be used as field herbicides. Therefore, the novel compound of the present invention, which is not described in the same publication, has intergeneric selectivity between rice and barnyard grass, and is effective against barnyard grass at the 4- to 5-leaf stage, which was considered impossible to weed with conventional herbicides. No one can predict whether it will be able to specifically kill weeds. In addition, as substituted phenyl urea herbicides as described in the same publication, 3-(3,4-diclophenyl)-1,1-dimethylurea (DCMU), 3-(3,
4-dichlorophenyl)-1-methoxy-1-methylurea (linyuron) and the like are known and are used as field herbicides. These herbicides exhibit strong herbicidal activity against various weeds because they inhibit the Bill reaction, but they also have poor selectivity and cause strong chemical damage to paddy rice. Therefore, with the exception of some such as DCMU, which is used as a field herbicide in limited cultivation of crops, there are no substituted phenyl urea compounds that have been put to practical use as herbicides for paddy rice. The substituted phenyl urea compound of the present invention is
Unlike the conventional substituted phenyl urea herbicides mentioned above, this is a novel compound that has a high degree of intergeneric selectivity between rice and barnyard grass, and provides a new type of herbicide for paddy fields.

Its characteristics are as clarified in the test examples below. That is, as shown in Test Example 1, the trans-type, the cis-type, and mixtures thereof in arbitrary proportions have similar levels of milleticidal activity and selectivity for paddy rice. The compound of the present invention is superior to 3-[4-(3-chloro-2butenyloxy)phenyl]-1,1-dimethylurea in terms of herbicidal activity against Japanese millet at the 5-leaf stage and phytotoxicity against paddy rice. Showed selectivity. It also exhibited far superior herbicidal activity against Japanese millet as compared to the compound described in Japanese Patent Publication No. 48-2329. Furthermore, DCMU
Conventional substituted phenyl urea compounds such as Yarinyuron kill not only Japanese millet but also rice and have non-selective activity, whereas the compound of the present invention is a completely different drug from these compounds. be. Also, test example 2
As shown in , the compound of the present invention has 1
It exhibits high herbicidal activity against Japanese millet at the leaf stage, and can also completely kill millet at the 5-leaf stage, which is difficult to weed with known herbicides.

Moreover, in either case, it does not cause any chemical damage to paddy rice.
Furthermore, in field tests in transplanted paddy fields, weeding of Japanese millet, which could not be completely weeded even with conventional systematic treatments, can be completely weeded by applying the compound of the present invention. In addition, the Compound 1 of the present invention can selectively weed Japanese millet in the flooded direct seeding cultivation method, which is considered to be a labor-saving rice cultivation method compared to the transplant cultivation method. It is believed that this will contribute to the advancement of technology. Furthermore, the acute oral toxicity LD5O value of the compound of the present invention in SD rats is 2,000 mg/K9 or higher for all of the trans type, cis type, and an equal amount mixture of trans type and cis type, and the acute fish toxicity TLm value for carp fry. (according to the official method of the Ministry of Agriculture and Forestry) are all 20P or higher.

This confirms that the compound of the present invention is a photosynthesis-inhibiting type and is highly toxic to barnyard grasses such as Japanese shrimp, but is completely safe for humans and useful animals and plants such as fish. This indicates that the compound is an excellent compound that can be safely used as a commercial herbicide. As explained above, the compound of the present invention was completely unexpected from the prior art, and the present invention was made based on completely new findings.

The compound of the present invention can be produced by the method of the following reaction formula (4).

(Wherein,
It can be easily produced by a general reaction in which -ol is reacted with phosphorus halide, thionyl halide, etc. accompanied by allyl rearrangement.

The compound of the formula [] can be prepared by, for example, a method in which para-aminophenol and dimethylcarbamoyl chloride are reacted in the presence of an acid binder (South Africa Patent No. 6803283), a method in which para-aminophenol is reacted with phosgene, and dimethylamine (British Patent No. 1153261). ), or by a method of reacting para-aminophenol, diphosgene (trichloromethyl chloroformate), and dimethylamine as shown in the following reference production example. When compound [1] and compound [] are reacted in the method of reaction formula [A], compound [1] may be used as a solvent, but it is usually preferable to use an organic solvent.

As the organic solvent, most organic solvents such as hydrocarbons, halogen-substituted hydrocarbons, ethers, alcohols, acid amides, and dimethyl sulfoxides can be used. Further, as the acid binder, organic amines such as triethylamine and pyridine, or inorganic bases such as potassium carbonate can be used. Depending on the type of halogen in compound [1], the reaction time can be shortened by adding a catalytic amount of a salt such as potassium iodide. Although the reaction proceeds at room temperature, it is usually carried out with heating.

In this case, any temperature from room temperature to the boiling point of the solvent can be selected, but it is preferable to carry out the reaction at a temperature below the boiling point of the compound [1] used. The reaction time depends on the compound used [1
], the reaction is completed in a very short time when a polar solvent is used, although it varies depending on the solvent, reaction temperature, etc. After the reaction is complete, the salts of the acid binder are removed and the solvent is distilled off to obtain the compound of the present invention. It can also be obtained by fractionation.

Examples 1 and 2 show the production method according to reaction formula [A].

The compound of the present invention can also be produced by the method of the following formula [B].

Compounds of formula [] can be obtained by a conventional method by reaction of p-crotyloxyaniline with phosgene or diphosgene.

Dimethylamine [ ] can be used in either gaseous or aqueous form. [B] To carry out the reaction, organic solvents such as hydrocarbons, halogen-substituted hydrocarbons, and ethers are usually used, but when using an aqueous solution of dimethylamine, it is best to use a solvent that is immiscible with water. The reaction can be carried out advantageously.

Although the reaction usually completes in a short time, the reaction time can be further shortened by adding a basic substance such as trimethylamine or dibutyltin diacetate, or in some cases by heating.

After the reaction is completed, the solvent is usually distilled off to obtain the compound of the present invention, but in some cases, a solvent such as benzene and water may be added to separate the compound. In addition, if the reaction is not completed when obtaining the compound [], part or most of the []
A carbamoyl chloride of the formula is present as a precursor. However, in the case of reaction [B], the compound [] gives the compound of the present invention [] according to the following reaction formula [C], and there is no problem in production.

Therefore, it can also be used in place of the compound of formula [ ].
Example 3 shows a manufacturing method according to reaction formula [C].

Furthermore, the compound of the present invention can also be produced by the method of reaction formula [D] below. The compound [] can be produced by a method of reducing p-crotyloxynitrobenzene obtained by a condensation reaction of crotyl halide and p-nitrophenol.

Further, the compound [] is produced by a general method of reacting dimethylamine with phosgene or diphosgene. [D
] In order to carry out the reaction of the formula, hydrocarbons,
This is carried out using halogen-substituted hydrocarbons, ether type 2, etc., and an organic basic substance such as triethylamine or pyridine or an inorganic base such as potassium carbonate as an acid binding agent.

Does the reaction proceed at room temperature? However, the reaction time can often be shortened by heating. After the reaction is complete, the salts of the acid binding agent are removed by a furnace and the solvent is distilled off to obtain the compound of the present invention. It can also be obtained by fractionation.
Example 4 shows a manufacturing method according to reaction formula [D].

Note that the manufacturing method is not limited to the following examples. Reference production example 3 - Production method of (4-hydroxyphenyl)-1,1-dimethylurea Put diphosgene (trichloromethyl chloroformate) 1009 and ethyl acetate 11 into the flask of 21, and add para-aminophenol while stirring under ice-water cooling. 109
f! Add little by little.

After the addition was completed, the mixture was heated and refluxed for 1 hour. After cooling, a 50% aqueous solution of dimethylamine 1809 was added dropwise under water cooling, and after the dropwise addition was completed, the mixture was stirred at room temperature for 20 minutes. The generated crystals are suction filtered, washed with water, and dried to obtain the target compound as white crystals.
89 (yield 82.1%) was obtained. When recrystallized from a mixed solvent of acetone and methanol, it showed a melting point of 205-6°C.
The resulting compound was used in Examples 1 and 2. Example 1 3-(4-trans-crotyloxyphenyl)-1,
Method for producing 1-dimethylurea 3-(
4-Hydroxyphenyl)-1,1-dimethylurea 18
．． 09, 13.89 ml of anhydrous potassium carbonate, 9.19 ml of trans-crotyl chloride, and 100 ml of acetone were added, and the mixture was refluxed for 5 hours with stirring.

After cooling, water and benzene were added, and the benzene layer was separated, washed with water, and dried over anhydrous sodium sulfate. When benzene was distilled off under reduced pressure, the target product was obtained as white crystals (22.69% yield: 96.4%).
%). When recrystallized from a mixed solvent of cyclohexane and acetone, it showed a melting point of 115-116°C.
The chemical shifts of the nuclear magnetic resonance spectrum (in deuterated chloroform) were as follows. Example 2 Method for producing 3-(4-ciscrotyloxyphenyl)-1,1-dimethylurea 18.09 g of 3-(4-hydroxyphenyl)-1,1-dimethylurea in a 300 ml flask
, 13.89 g of anhydrous potassium carbonate, 9.1 g of cis-crotyl chloride, and 100 ml of acetone were added, and the mixture was refluxed for 3 hours with stirring.

When processed in the same manner as in Production Example 1, the target product becomes 2 as white crystals.
2.89 (yield 9Z3%) was obtained. When recrystallized from a mixed solvent of cyclohexane and acetone, the melting point is 133-13.
It showed 4°C. What is the chemical shift of the nuclear magnetic resonance spectrum (in deuterium chloroform)? It was hot. Example 3 3-(4-transcrotyloxyphenyl)1,1-
Method for producing dimethyl urea 18.99% of 4-trans crotyloxyphenyl isocyanate is mixed with 100Tn1 of benzene
10.0% of a 50% aqueous solution of dimethylamine was added dropwise with stirring while cooling with water, and after the dropwise addition, the mixture was stirred at room temperature for 1 hour.

The benzene layer was separated, washed with water and dried over anhydrous sodium sulfate, and the benzene was distilled off under reduced pressure to obtain the desired product 23.09 (yield 98.2%) as white crystals. When recrystallized from a mixed solvent of citalohexane and acetone, the melting point is 115.
~116°C was shown. Example 4 Method for producing 3-(4-transcrotyloxyphenyl)-1,1-dimethylurea 12.99 g of dimethylcarbamoyl chloride is placed in a 500 ml flask, and 9.59 g of pyridine is added dropwise under ice-water cooling.

Subsequently, 4-transcrotyloxyanili]no16,3
A solution of 9 dissolved in 50 d of chloroform is added dropwise. After the dropwise addition, the mixture was heated and stirred and refluxed for 1 hour. After cooling, water was added to separate the chloroform layer, which was washed with diluted hydrochloric acid, followed by diluted caustic soda, and then water. After drying over anhydrous sodium sulfate, chloroform was distilled off under reduced pressure to obtain the desired product as white crystals (20.49I (yield: 87.10I)). When recrystallized from a mixed solvent of cyclohexane and acetone, it showed a melting point of 115-116°C. When using the compound of the present invention as a herbicide for paddy fields, the compound of the present invention may be used as it is or dissolved in an appropriate solvent, but it is preferable to use various carrier auxiliaries as in the case of ordinary herbicides. It is preferable to formulate them into granules, wettable powders, emulsions, etc., and use them.

Further, it can be mixed with known herbicides, insecticides, fungicides, plant growth regulators, etc. to expand its application. Some pharmaceutical examples of the present invention are shown below, but the content of active ingredients, carriers, auxiliary ingredients, amounts added thereof, etc. are not limited to the formulation examples.

Note that parts in the formulation examples indicate parts by weight. Formulation example 1 (granules) 10 parts of the compound of the present invention (trans type), 15 parts of bentonite
1 part, 2 parts of sodium dodecylbenzenesulfonate, and 73 parts of tare were thoroughly mixed, further added with 20 parts of water, mixed in a kneader, granulated through a pulverizer, and then dried in a fluidized bed dryer to obtain 10% active ingredient. A herbicide for paddy fields containing the following was obtained.

Formulation Example 2 By using the cis type instead of the trans type in Formulation Example 1, a herbicide for rice fields containing 10% of the active ingredient was obtained.

Formulation Example 3 A herbicide for rice fields containing 10% of the active ingredient was obtained by using 5 parts of the trans type and 5 parts of the cis type in Formulation Example 1.

Formulation Example 4 (Emulsion) When 20 parts of the compound of the present invention (trans type), 65 parts of Diglole, and 15 parts of Solpol (manufactured by Toho Chemical Co., Ltd., trade name of emulsifier) are mixed and dissolved, a product for rice fields containing 20% of the active ingredient is prepared. Herbicide was obtained.

Formulation Example 5 (Emulsion) By using the cis type instead of the trans type in Formulation Example 4, a herbicide for rice fields containing 20% of the active ingredient was obtained.

Formulation Example 6 (Wettable powder) When 20 parts of the compound of the present invention (trans type), 3 parts of calcium lignin sulfonate, 2 parts of polyoxyethylene nonyl phenyl ether, and 75 parts of clay are uniformly mixed and pulverized, the active ingredient A paddy herbicide containing 20% was obtained.

Next, the fact that the compound of the present invention is an excellent herbicide with high usability as a herbicide for paddy fields will be explained using test examples.

Test example 1 (selectivity test between Japanese millet and paddy rice) 500
Paddy soil (alluvial soil) was filled in a Wagner pot with a size of 1/0 are, and 50 Japanese rice seeds and 30 rice seeds were sown on the surface of the pot, and the water depth was maintained at about 1 cTn.

When the Japanese millet reached the 1-leaf and 5-leaf stages, Formulation Example 4
A chemical solution of a predetermined concentration of an emulsion prepared according to the method was added dropwise.
Thirty days after the chemical treatment, the dry weights of Japanese millet and paddy rice were measured, and the inhibition rate was calculated in comparison with the untreated plot. However, the comparison drugs DCMU and Linuron were commercially available products, and the comparison drugs A to N were prepared and used according to the compounds of the present invention (the same applies to the following test examples).

The results are shown in Table 1. However, in this test example and the following test examples, comparative drugs A to N are
It is a compound described in Publication No. 2329 and has the following chemical structure.

Comparative drug A: (CBPDU) Test example 2 (herbicidal effect test) Paddy soil (alluvial loam) was filled in a concrete pot of 1/400 are (50 (177! x 50c1n)).
200 seeds of Japanese millet were sown on the surface layer, and about 3C
TfL was flooded.

Paddy rice at the 2.5 leaf stage before the appearance of Japanese millet (variety: Asahi)
Three plants were planted, and eight plants were transplanted per pot. The granules prepared according to Formulation Example 1 were applied to Japanese millet at the 1-leaf stage (3.5-leaf stage in paddy rice) and at the 5-leaf stage (7-leaf stage in rice rice).
Thirty days after the drug treatment, an investigation was conducted using the same method as in Test Example 1. The results are shown in Table 2. However, the comparative drugs CPN, bentiocarb, molinate, and cymetrine were commercially available products. Test example 3 (Field test in transplanted paddy fields) Using a 10 square meter paddy field, 3 paddy fields were used after puddling.
Transplant 1 seedling paddy rice (variety: Asahi) at 2.5 leaf stage on day 0
, 3 to 5 (?Ml7'藜★!5) When the catfish stem reached the four-leaf stage, a predetermined dose of the granules prepared according to Formulation Example 1 was applied.

The test results were investigated in the same manner as in Test Example 1 on the 60th day after transplanting paddy rice. However, for I7, all commercially available products were used for comparative drugs, and for comparative drug 2, CNP was applied on the 3rd day after rice transplantation, and a mixture of bentiocarb and simetrine was applied on the 25th day.The results are shown in Table 3. Table Test Example 4 (Field test of flooded direct-seeded paddy fields) A 10 square meter paddy field was used, and 309 Japanese millet seeds were sown during puddling, and the flooding depth was maintained at 3 to 5 CTIL.

On the third day of puddling, 509 paddy rice (variety: Asahi) was sown at the time of germination. When the Japanese millet and paddy rice reached the 2-3 leaf stage, a predetermined amount of the emulsion prepared according to Formulation Example 4 was uniformly sprayed using a manual sprayer. Test results are after drug treatment 2
On the first day, an investigation was conducted in the same manner as in Test Example 1. However, Comparative Drug 1 was a commercially available product, and Comparative Drug 2 was prepared and used according to Formulation Example 4.

Test Example 5 As a test method, paddy soil (alluvial loam) was sieved and filled into a 1/7500 are Wagner pot.

Thereafter, two paddy rice plants (variety: Asahi) at the 2nd and 3rd leaf stage were transplanted into the center of the pot, and 20 seeds of firefly were sown per pot on the soil surface, and the pot was flooded to a depth of approximately 2 cTn. Other aphids and cypresses were assumed to be naturally occurring. After sowing, when each weed reached each leaf age listed in the following table, a chemical solution of a predetermined concentration of an emulsion prepared according to Formulation Example 4 was dropped onto the surface of the pot. The test was conducted in 3 consecutive sessions in 1 section, and the results were determined by drug treatment 2.
After 0 days, the herbicidal effect and the degree of chemical damage to paddy rice were evaluated according to the evaluation criteria shown below. In addition, the comparative drug molinate,
Benthiocarb and DCMU were commercially available herbicides used as test chemicals.

Claims (1)

[Claims] 3-(4-crotyloxyphenyl)-1,1-dimethylurea.