JPH0477487A - Benzofuran derivative and herbicide containing the same - Google Patents

Abstract

NEW MATERIAL:A compound of formula I [R<1> is H, lower alkylcarbonyl, lower alkoxycarbonyl, (halogen-substituted) lover alkyl sulfonyl, hydroxylcarbonyl, aminocarbonyl, (substituted) arylcarbonyl ; R<2> is lover alkoxy, lower alkylcarbonyl, (substituted) pyrimidinyloxy, OH]. EXAMPLE:4-(4,6-Dimethoxypyrinuidinyl-2-oxy)-3-hydroxybenzofuran. USE:A herbicide. PREPARATION:A compound of formula II is made to react with a substituted halide of formula: R<1>-X (X is halogen) in the presence of a base (e.g. sodium carbonate) for 1-24 hr.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel benzofuran derivative and a herbicide containing the same.

[Conventional technology]

Physiolochesky Akchivnye to Shestova (
Φsi a M OJI Oq e CK u n
A K T 5inHb+$1 Be+necraa
) Volume 18, page 75 (1986) contains the following general formula (■
) 2-phenyl-2-(pyrimidinyl-2-
1,000) Acetic acid and related compounds are listed as insecticidal and nematicidal active substances.

OW (wherein Y' and Y' represent a group selected from a methyl group, a trifluoromethyl group, a diethylaminoxy group, a phenyl group, and a methoxy group, Z is hydrogen or a phenyl group, and W is a hydroxyl group or its sodium [Problems to be Solved by the Invention] The present invention relates to a benzofuran ring having a substituent at a specific position, and a PIJ compound having a benzofuran ring having a substituent at the 4th and 6th positions. The present invention provides a novel benzofuran derivative having a structure in which FjKn is condensed via an oxygen atom, and a herbicide containing the same. This compound exhibits excellent herbicidal effects against annual and perennial weeds, and has high safety against certain types of crops.

[Means to solve the problem]

The benzofuran derivative of the present invention has the following general formula (% formula). roxycarbonyl group, aminocarbonyl group,
It is a cyano group, an arylcarbonyl group or a substituted arylcarbonyl group. Among these, hydrogen or lower alkoxycarbonyl groups are particularly preferred.

Examples of lower alkylcarbonyl groups include arylcarbonyl groups in which the alkyl moiety has 1 to 4 carbon atoms, such as methylsulfonyl group, ethylcarbonyl group, n-propylcarbonyl group, isobutylcarbonyl group, n-butylcarbonyl group, and isobutyl group. Examples include carbonyl group, 2-butylcarbonyl group, tert-butylcarbonyl group, and the like.

Examples of lower alkoxycarbonyl groups include alkoxycarbonyl groups whose alkyl moiety has 1 to 4 carbon atoms, such as mesocarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-propoxycarbonyl group,
-butoxycarbonyl group, isobutoxycarbonyl group,
Examples include sec-butoxycarbonyl group and tertiary-butoxycarbonyl group.

Examples of lower alkylsulfonyl groups include those having 1 to 4 carbon atoms;
Alkylsulfonyl groups such as methylsulfonyl group, ethylsulfonyl group, n-propylsulfonyl group, isopropylsulfonyl group, n-butylsulfonyl group, isobutylsulfonyl group, 2-butylsulfonyl group, tertiary-butylsulfonyl group, etc.

Examples of halo-substituted lower alkylsulfonyl groups include alkylsulfonyl groups obtained by substituting the above-mentioned lower alkylsulfonyl groups with fluorine, chlorine, etc., such as trifluoromethylsulfonyl groups, trifluoroethylsulfonyl groups,
There are trichloromethylsulfonyl groups, etc.

Examples of substituted arylcarbonyl groups include arylcarbonyl groups having two or less substituents, such as 2-methylphenylcarbonyl group, 3-methylphenylcarbonyl group,
4-methylphenylcarbonyl group, 2-chlorophenylcarbonyl group, 3-chlorophenylcarbonyl group, 4-chlorophenylcarbonyl group, 2-nitrophenylcarbonyl group, 3-nitrophenylcarbonyl group, 4-nitrophenylcarbonyl group, 2 .4-dinitrophenylcarbonyl group, 3.5-dinitrophenylcarbonyl group, etc.

Further, R2 in the general formula (1) is a lower alkoxy group, a lower alkylcarbonyloxy group, a pyrimidinyloxy group, a substituted pyrimidinyloxy group, a hydroxy group, or an agriculturally acceptable salt thereof. Among these, a hydroxy group, a pyrimidinyloxy group, or a substituted pyrimidinyloxy group is particularly preferred.

Examples of lower alkoxy groups include alkoxy groups having 1 to 4 carbon atoms, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, and tertiary-butoxy groups. etc.

Examples of the lower alkylcarbonyloxy group include an alkylcarbonyloxy group whose alkyl moiety has 1 to 4 carbon atoms, such as a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, and an isopropylcarbonyloxy group. , n-butylcarbonyloxy group, isobutylcarbonyloxy group, 2-butylcarbonyloxy group, tert-butylcarbonyloxy group, and the like.

Examples of substituted pyrimidinyltoxy groups include 4゜6-dimethylpyrimidinyl-2-oxy group, 4chloro-6-medonitocypyrimidinyl-2-oxy group, 4.6-dicyclopyrimidinyl-2-oxy group, 4.6-dimethylpyrimidinyl-2-oxy group, -cymethoxypyrimidinyl-2-oxy group, etc.

Examples of agriculturally acceptable salts of hydroxy groups include sodium salts, potassium salts, ammonium salts, isopropylammonium salts, triethylammonium salts, and the like.

Specific examples of the compound of the present invention represented by the general formula (1) are shown in Table 1. However, the present invention is not limited thereto.

Production method The compound of the present invention can be produced, for example, by the method shown in the following formula.

(Manufacturing method l) In general formula (1), when R2 is a hydroxy group.

(In the formula, R1 has the same meaning as above, and X represents a halogen atom.) In the above reaction formula, the compound represented by formula (3) is prepared by adding the compound represented by formula (1) without a solvent or in an appropriate manner. in solvent,
After generating an anion with a suitable base at a temperature of -78°C to less than the boiling point of the solvent, a substituted halide represented by formula (2) is added, and 1 to 2
It is produced by reacting for 4 hours.

Examples of solvents used in this reaction include alcohols such as methanol, ethanol, and isopropanol;
Aromatic hydrocarbons such as benzene, toluene, xylene,
halogenated hydrocarbons such as dichloromethane and chloroform; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, and 1,4-dioxane;
Examples include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aprotic polar solvents such as dimethyl formamide, dimethyl sulfoxide, and dimethyl acetamide, acetonitrile, and water.

Bases used in this reaction include carbonates such as sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate, metal hydroxides such as sodium hydroxide and potassium hydroxide, sodium methylate, and sodium ethylate. Examples include metal alcoholades such as, alkyl metal hydrides such as sodium hydride and potassium hydride, and lithium amides such as lithium diethylamide and lithium bistrimethylsilylamide.

The compound represented by formula (1) can be prepared, for example, by a method known in the literature (Journal of the American
chemical 5ociety1,61.2328
(1939)) was reacted with a substituted pyrimidine in the presence of a suitable base at room temperature to below the boiling point of the solvent in the absence of a solvent or in the presence of a suitable solvent. It is produced by reacting for ~24 hours.

(Manufacturing method 2) In general formula (I), when R2 is a lower alkoxy group or a lower alkylcarbonyloxy group.

(In the formula, R3 represents a lower alkyl group or a lower alkylcarbonyl group, R' and R' have the same meanings as above. X represents a halogen atom.) R3 in the substituted halide of formula (4) is , a lower alkyl group or a lower alkylcarbonyl group.

Examples of lower alkyl groups include alkyl groups having 1 to 4 carbon atoms, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, nibutyl group, tertiary butyl group, etc. There is.

Examples of lower alkylcarbonyl groups include alkylcarbonyl groups in which the alkyl moiety has 1 to 4 carbon atoms, such as methylcarbonyl group, ethylcarbonyl group, n-propylcarbonyl group, isopropylcarbonyl group, n-butylcarbonyl group, and isobutyl group. Examples include carbonyl group, 2-butylcarbonyl group, tert-butylcarbonyl group, and the like.

In the above reaction formula, the compound represented by formula (5) is prepared by combining the compound represented by formula (3) in the presence of a suitable base, without a solvent or in a suitable solvent, at a temperature of -78°C to below the boiling point of the solvent. temperature, a substituted halide represented by formula (4) and 1 to 24
Manufactured by a time reaction.

Examples of solvents used in this reaction include alcohols such as methanol, ethanol, and isopropanol;
Aromatic hydrocarbons such as benzene, toluene, xylene,
halogenated hydrocarbons such as dichloromethane and chloroform; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, and 1.4-fluorine;
Examples include ketones such as acetone and methyl ethyl getone, esters such as methyl acetate and ethyl acetate, non-polar polar solvents such as dimethyl formamide, dimethyl sulfoxide, and dimethyl ayatamide, acetonate, water, etc. It will be done.

Bases used in this reaction include carbonates such as sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, metal hydroxides such as sodium hydroxide and potassium hydroxide, sodium methylate, sodium methyl Metal alcoholas such as lat, J'alkyl metal hydrides such as sodium hydride and potassium hydride,
Examples include lithium diethylamide, lithium bistrimethylsilylamide, and other lithium γλ stones, and organic bases such as pyridine and triethylamine.

Next, the method for producing the compound of the present invention will be explained with reference to Examples.

<Example 1> 11(/1.(i-nmethoxypyriminyl-2t+shi)-3-hydroxybenzofuran (compound number 1) and 3,4-bis(4,6-cymethoxypyrimidinyl-2-oxy) ) Synthesis of benzofuran (Compound No. 18) Method known in the literature (Journal of the Ame
rican chemical 5ociety,,6
1,2328 (1939))
Dihydroxy-α-bromoacetophenone2. 3g
(10 mmol) was dissolved in 50 ml of dimethylformamide, 1.38 g (10 mmol) of potassium carbonate and 2.6-cymethoxy-2-methylsulfonylpyrimidine. Add 18g (1.0mmol) and stir at room temperature for 24 hours.
Stir for hours. The reaction solution was poured into 200 g of water, extracted three times with 50 g of ethyl acetate, the organic layer was dried over anhydrous magnesium sulfate, and the solvent was distilled off to obtain 3.8 g of a crude product. This was purified by silica gel column chromatography (developing solvent: cohexane/ethyl acetate - 10/1) to obtain the desired 4-(4,6-simethoxypyrimidinyl 2-t-
t-C) -:3-Hydroxybenzofuran (Compound No. 1) 0. 6g (yield 21%) and 3゜4-
Bis(4,6dimethoxypyrimidinyl-2oxy)benzofuran (Compound No. 18) 0°6g (Yield 17%
) was obtained.

Compound number 1 mp: l 41i, (1~l 49. [I
'CNMR: (δ, (]I) CI3) (
ppm)3,78(611,s),'4.53(211,s)
, s), 5.73 (ltl, s).

6.75-6.93 (21t, t), 7.50
~7.67 (III, t) Compound No. 18 NMR: (δ, CD CIp) ()'I'm)3
, 63 (611,s), 3.68 (611,s),
5.65 (211, s).

6, 92-7.40 (311, m), 7.73
(ill, s><Example 2> 4-(4,(i-dimethoxypyrimidinyl-2oxy)-3-hydroxy-2-propionylbenzofuran(
Synthesis of Compound No. 10) Diisopropylamine 0. 2
A solution of 3 g (2.3 mmol) in tetrahydrofuran was cooled to -78°C, and 0.97 rd (2.3 mmol) of a 1.6N butyllithium solution was added to -78°C. The solution was stirred for 5 minutes, returned to room temperature, stirred for 10 minutes, and cooled again to -78°C.To this solution was added 4-(4°6-cymethoxypyrimidinyl-2).
-oxy)-3hydroxybenzofuran0. 5g (
A 3me solution of 1.7 mmo+) in tetrahydrofuran was added dropwise and stirred for 15 minutes at -78°C, followed by 0.0 mm of propionyl chloride. 26 g (2.1 mmol) of Tetrahydro7ran 1-solution was added and stirred at -78°C for 1 hour.

The reaction solution was returned to room temperature, poured into 30 me water, and
Extracted three times with ethyl acetate, the organic layer was dried with anhydrous magnesium sulfate-C', and the solvent was distilled off to obtain the crude product 1.2.
I got g. This was purified by silica gel column chromatography (developing solvent: hexane/ethyl acetate = 10/I) to obtain the desired 4-(4゜6-cymethoxypyrimidinyl-2-oxy)-3-hydroxy-2-propionyl. Benzofuran (compound number 10) fl, 39g (yield 65
%) was obtained.

mp+56.5~58.5℃ NMR: (δ, CDCL) (ppm) 0.90~
1.27 (3H, t), 1.97-2.60 (2H
,Q).

3.71 (6H,S), 5.70 (IH,S),
6.87~? , 33° (3H, m), 7.83 (
IH,s) <Example 3> Synthesis of 3-acetoxy-4-(4,6-simethoxypyrimidinyl-2-oxy)-2-methoxycarbonylbenzofuran (Compound No. 4) Synthesized in the same manner as in Example 2 4-(4,6-Simethoxypyrimidinyl-2-oxy)-3-hydroxy-2-methoxycarbonylhensifuran (Compound No. 2) 0. 23g (0.7mm
triethylamine 0 in the tetrahydrofuran solution of
゜1 g (1 mmol) and 80 m of acetyl chloride
g (1 mmol) was added thereto, and the mixture was stirred at room temperature for 1 hour. The solvent was distilled off, and the resulting crude product was subjected to silica gel column chromatography (developing solvent: hexane/ethyl acetate = 5
/l) to obtain the desired 3-acetoxy-4-(4,
6-Simethoxypyrimidinyl-2-oxy)-2-methoxycarbonylhensyfuran (Compound No. 4) 0.24
g (yield 91%) was obtained.

mp: 132.5-135.0°CNMR: (δ,
CDCl1) (ppm)2,10(3H,s
), 3.73 (6H, s), 3.90 (3H, s)
.

5, 75 (IH, s), e, 73-7.75 (3
H, m) Various compounds shown in Table 1 above were synthesized in the same manner as in Examples 1.2 and 3 above.

Formulation When the compound of the invention is used as a herbicide, a carrier,
Mix with diluents, additives, auxiliaries, etc. using known methods to prepare formulations commonly used as agricultural chemicals, such as powders, granules, wettable powders, emulsions, water-solvents, flowables, etc. be done. It can also be mixed or used in combination with other agricultural chemicals, such as fungicides, insecticides, acaricides, other herbicides, plant growth regulators, etc.; fertilizers; soil conditioners, etc.

In particular, when used in combination with other herbicides, it is expected that the amount of chemicals used will not only be reduced and labor saved, but that the herbicidal spectrum will be expanded due to the synergistic action of both herbicides, and even higher effects will be achieved through synergistic action. can.

As the carrier or diluent used in formulation, solid or liquid carriers commonly used in agriculture are used. Examples of solid carriers include clays represented by kaolinite group, montmorillonite group, or abatalgite group, talc, mica, waxite, pumice, vermiculite,
Inorganic substances such as gypsum, calcium carbonate, dolomite, diatomaceous earth, magnesium lime, apatite, theolite, anhydrous silicic acid, synthetic calcium silicate; soybean flour, tobacco flour,
Plant organic substances such as walnut flour, wheat flour, wood flour, starch, crystalline cellulose; coumaron resin, petroleum resin, alkyd resin, polyvinyl chloride, polyalkylene glycol,
Synthetic or natural polymer compounds such as ketone resin, ester gum, copal gum, and Danzl gum; other examples include waxes such as carnauba wax and beeswax, and urea.

Examples of liquid carriers include paraffinic or naphthenic hydrocarbons such as kerosene, mineral oil, spindle oil, and white oil; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, cumene, and methylnaphthalene; and ethers such as dioxane and tetrahydrofuran. Ketones such as acetone, methyl ethyl ketone, diisobutyl ketone, cyclohexanone, acetophenone, isophorone: ethyl acetate, amyl acetate, ethylene glycol acetate,
Esters such as diethylene glycol acetate, butyl maleate, diethyl succinate; methanol, n-
Alcohols such as hexanol, ethylene glycol, diethylene glycol, cyclohexanol, benzyl alcohol; ether alcohols such as ethylene glycol ethyl ether, ethylene glycol phenyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether; dimethyl formamide,
Examples include polar solvents such as dimethyl sulfoxide, water, and the like.

Surfactants and other auxiliary agents may also be used for the purpose of improving fluidity, preventing rust, etc. Examples of surfactants used include nonionic, anionic, cationic and zwitterionic surfactants, but typically nonionic and/or anionic surfactants are used. compound is used.

Suitable nonionic surfactants include, for example, compounds in which ethylene oxide is polymerized and added to higher alcohols such as lauryl alcohol, stearyl alcohol, and oleyl alcohol; compounds in which ethylene oxide is polymerized and added to alkylphenols such as isooctylphenol and nonylphenol; Compounds in which ethylene oxide is polymerized and added to alkylnaphthols such as butylnaphthol and octylnaphthol; compounds in which ethylene oxide is polymerized and added to higher fatty acids such as palmitic acid, stearic acid, and oleic acid; higher fatty acid esters of polyhydric alcohols such as sorbitan; Compounds obtained by polymerizing and adding ethylene oxide to it; compounds obtained by polymerizing and adding ethylene oxide and propylene oxide; and the like.

Suitable anionic surfactants include, for example, alkyl sulfate salts such as sodium lauryl sulfate and oleyl alcohol sulfate amine salt; alkyl sulfonic acids such as sodium sulfosuccinate octyl ester and sodium 2-ethylhexene sulfonate. Salts: Aryl sulfonates such as sodium isopropylnaphthalene sulfonate, sodium methylene bisnaphthalene sulfonate, sodium likunin sulfonate, and sodium dodecylbenzene sulfonate. Furthermore, the herbicide of the present invention may contain polymeric compounds such as casein, gelatin, albumin, glue, sodium alginate, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, etc., in order to improve the properties of the preparation and increase the herbicidal effect. Other adjuvants may also be used in combination.

The above-mentioned carriers and various auxiliary agents are used individually or in combination as appropriate depending on the purpose, taking into account the dosage form of the preparation, the place of application, etc.

The (active ingredient) content of the compound (I) of the present invention in the various formulations thus obtained varies depending on the formulation, but is usually 0.01 to 99% by weight, preferably 0.01 to 99% by weight. It is 1 to 80% by weight.

In the case of powder, for example, the active ingredient compound is usually 0.1 to 2
It contains 5% by weight, and the remainder is solid carrier.

In the case of hydrating agents, for example, the active ingredient compound is usually 5 to 80%
% by weight, the remainder being a solid carrier, a dispersion wetting agent,
A protective colloid, an antifoaming agent, etc. are added as necessary.

In the case of granules, for example, the active ingredient compound is usually 0.1 to 2
It contains 0% by weight, and the remainder consists mostly of solid carriers, surfactants, etc. The active ingredient compound is uniformly mixed with the solid carrier, or is uniformly fixed or adsorbed on the surface of the solid carrier, and the particle size is about 0.2 to 1.5 mm.
It is.

In the case of an emulsion, for example, it usually contains 5 to 30% by weight of the active ingredient compound, this includes about 5 to 20% by weight of an emulsifier, and the remainder is a liquid carrier, with a rust preventive added if necessary. .

The benzofuran derivative of the present invention can be applied as a compound of general formula (I) or in any preparation form as described above.

The herbicide of the present invention can be applied to exterminate or control various weeds growing in rice fields and fields from before emergence to the growing season.

The application amount is about 0.001 to 5 kg per lha as the amount of the compound represented by general formula (I) (active ingredient amount),
The amount is preferably about 0.01-1, and can be changed as appropriate depending on the type of target weed, growth stage, application location, application time, weather, etc.

Next, examples of herbicides using the compounds of the present invention will be given. 1 part in the formulation below is based on weight.

<Example 4 (granules)> Compound No. 18 1 part bentonite 54 parts talc
40 parts sodium dodecylbenzene sulfonate 2 parts sodium lignin sulfonate 2 parts polyoxyethylene alkylaryl ether After thoroughly mixing 1 part or more, add an appropriate amount of water, knead, and granulate using a granulator. 100 parts of granules were obtained.

<Example 5 (hydrating agent)> Compound number 3 20 parts diatomaceous earth
60 parts white carbon
15 parts sodium ligninsulfonate 3 parts sodium dodecylbenzenesulfonate 2 or more parts were mixed and uniformly mixed and ground in a kneader to obtain 100 parts of a wettable powder.

<Example 6 (emulsion)> Compound number 4 30 parts xylene
55 parts cyclohexanone
10 parts calcium dodecylhensensulfonate 3 parts polyoxyethylene alkylaryl ether Two or more parts were uniformly mixed and dissolved to obtain 100 parts of an emulsion.

Drugs using the compounds of the present invention were prepared according to the above-mentioned formulation examples.

〔Effect of the invention〕

The benzofuran derivative represented by the general formula (1) of the present invention is a novel compound that has not been described in any literature.

The compound represented by the general formula (I) of the present invention has a benzofuran ring having a substituent at a specific position, and a pyrimidine ring having specific substituents bonded to the 4th and 6th positions with oxygen. It is characterized by a structure in which the benzofuran derivatives are bonded through atoms, and it is thought that this structural feature allows this benzofuran derivative to exhibit excellent herbicidal activity.

The compounds and herbicides of the present invention can control various weeds growing in agricultural land from pre-emergence to the growing season.

For example, paddy field weeds such as field weeds, scallops, water holly, Japanese holly, azalea, water chickweed, yellow chickweed, pine snail, and snail grass, as well as snail grass, foxtail grass, staghorn grass, sycamore, sparrow gnome, chickweed, polygonum, moths, crocodile, stagweed, and American golden deer. It can control various weeds in upland areas such as morning glories, Japanese fir, pigweed, shepherd's purse, ashweed, meadowweed, japonica, and buckwheat.

Furthermore, it can be used not only in rice fields and fields, but also in orchards, mulberry gardens, lawns, and non-agricultural lands.

Moreover, the compounds of the present invention have selectivity for certain cultivated crops, and are particularly excellent in selectivity for crops such as rice, wheat, barley, turgid, corn, sugarcane, and cotton.

Next, the effects of the herbicide of the present invention will be explained by giving test examples.

<Test Example 1 (Field soil stem and leaf treatment)> A square pot (30 x 30 x 12 cm) was filled with field soil, and certain amounts of various crops and various weed seeds shown in Table 2 were sown, and each plant was grown at the 1.5 to 3 leaf stage. It was grown in a greenhouse until The compounds of the present invention or comparative compounds shown in Table 2 were prepared into wettable powders according to Example 5, and the water diluted solution was adjusted to have the amount of active ingredients shown in Table 2 by 5004! /h
The foliage of each plant was evenly sprayed at an amount equivalent to that of a. Twenty-one days after the chemical spraying, the herbicidal effects on various weeds and the degree of chemical damage to various crops were determined according to the criteria in Table 2. The results are shown in Table 3.

Test Example 2 (Pre-germination soil treatment in upland field)〉Square pot (
30 x 30 x 12 cm) was filled with field soil, and after sowing fixed amounts of various crops and various weed seeds shown in Table 3, the soil was covered with 1 cm of soil.

The compound of the present invention or the comparative compound shown in Table 4 was prepared into a wettable powder according to Example 5, and the water diluted solution was adjusted to the amount of active ingredient shown in Table 3, equivalent to a spraying amount of 5001/ha. Spread evenly over the soil surface.

Twenty-one days after the chemical spraying, the herbicidal effects on various weeds and the degree of chemical damage to various crops were determined according to the criteria in Table 2. The results are shown in Table 4.

<Test Example 3 (Paddy field weed pre-emergence treatment)> Square pot (
14 x 14 x 9 cm) was filled with paddy soil, and an appropriate amount of water and chemical fertilizer were added and kneaded to form a paddy field. Two rice seedlings grown so that the reserved number of leaves was two were transplanted into each pot. Further, seeds and tubers of various weeds shown in Table 4 were sown in fixed amounts, and each compound shown in Table 5 was prepared into granules according to Example 4 and treated. Twenty-seven days after the chemical treatment, the herbicidal effects on various weeds and the degree of chemical damage to paddy rice were determined according to the criteria in Table 2. The results are shown in Table 5.

<Test Example 4 (Paddy field weed growing season treatment)> The same procedure as Test Example 3 was carried out except that the chemical treatment, paddy rice transplantation, and weed sowing were carried out 10 days later. The results are shown in Table 6.

Table 2 Evaluation criteria (11 steps) Paddy field weed pre-germination treatment Comparative example

Claims (2)

[Claims] (1) A benzofuran derivative represented by the general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R^1 is a hydrogen atom, a lower alkylcarbonyl group, a lower alkoxycarbonyl group, a lower alkylsulfonyl group, a halo-substituted lower alkylsulfonyl group, a hydroxycarbonyl group, An aminocarbonyl group, a cyano group, an arylcarbonyl group, or a substituted arylcarbonyl group, and R^2 is a lower alkoxy group, a lower alkylcarbonyloxy group, a pyrimidinyloxy group, a substituted pyrimidinyloxy group, a hydroxy group, or an agriculturally acceptable group thereof. salt) (2) A herbicide containing the benzofuran derivative according to claim 1.