JPH0446170A - New benzofuran derivative and herbicide containing same derivative - Google Patents

Abstract

NEW MATERIAL:Compounds of formula I (R<1> and R<2> are H or lower alkyl; n is 0, 1 or 2; A is lower alkyl, lower alkenyl, lower alkynyl, etc.). EXAMPLE:5-(p-Toluenesulfonyl)-3,3-dimethyl-2,3-dihydrobenzofuran. USE:A herbicide having selectivity to cultured crops, having a high safety especially to rice and expectative as a herbicide for paddy fields. PREPARATION:A compound of formula II (X<1> is halogen) is reacted with a compound of formula III, etc., in the presence of a Lewis acid catalyst in a suitable solvent to obtain the objective compound represented by formula Ia. The reaction is carried out using the compound of formula III generally in an amount of 1.0-5.0 time mol based on the compound of formula II in a solvent such as dichloroethane or dichloromethane.

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 as an active ingredient.

(Prior art and invention or problem to be solved) Conventionally,
In JP-A No. 55-20788, 2゜3-dihydro-
The use of 5-cyanobenzo7lane compounds as active ingredients in herbicides has been described and is known.

However, these compounds are not necessarily satisfactory because their herbicidal efficacy is insufficient or their selectivity between crops and weeds is poor.

(Means for Solving the Problems) The present inventors provide a compound that has an excellent herbicidal effect against undesirable plants even at a small application amount, and shows a high degree of selectivity between crops and weeds. As a result of various studies, we discovered a benzofuran derivative represented by the following general formula (1) and arrived at the present invention.

That is, the present invention provides - formula (r) l [wherein R'% R'' may be the same or different and represents a hydrogen atom or a lower alkyl group, n represents 0.1 or 2, and A represents a lower Alkyl group, lower alkenyl group,
lower alkynyl group, alkoxyalkyl group, alkylcarbonylalkyl group, alkoxycarbonylalkyl group, cyanoalkyl group, optionally substituted aralkyl group,
1 represents an optionally substituted pyrimidine, an optionally substituted pyridazine, an optionally substituted quinoxaline, an optionally substituted benzoxazole, an optionally substituted benzothiazole, or an optionally substituted aryl group A new benzofuran derivative.

When R1 and R2 in formula (1) above are lower alkyl groups, preferred examples are lower alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, n
-Propyl group, inpropyl group, etc. can be mentioned.

Further, n represents O, 1 or 2, preferably 2.

The specific group of A in the above formula (1) will be explained below.

(1) Lower alkyl group: A lower alkyl group having 1 to 5 carbon atoms is preferable, and examples thereof include methyl group, ethyl group, 0-propyl group, isopropyl group, n-butyl group, t-butyl group, and neopentyl group.

(2) Lower alkenyl group and lower alkynyl group; preferably those having 1 to 5 carbon atoms, such as allyl group, metaallyl group, crotyl group, propargyl group, 2-butynyl group, etc.

(3) Alcokyne alkyl group: The alkoxy moiety in this group is preferably a lower alkoxy group having 1 to 5 carbon atoms, such as a methoxy group, an ethoxy group, an isobuCpoquine group, and the like. The alkylene part of the alkoxyalkyl group is preferably a straight chain or branched lower alkylene having 1 to 5 carbon atoms.

(4) Alkylcarbonylalkyl group: The alkyl moiety in this group is preferably a lower alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and the like. The alkylene part of the alkylcarbonylalkyl group has 1 to 5 carbon atoms.
Straight chain or branched lower alkylene is preferred.

(5) Alkoxycarbonylalkyl The alkoxy moiety in this group is preferably a lower alkoxy group having 1 to 5 carbon atoms, such as a methoxy group, an ethoxy group, an impropoxy group, and the like. The alkylene part of the alkoxycarbonylalkyl group is preferably a linear or branched lower alkylene having 1 to 5 carbon atoms.

(5) Cyanoalkyl group: A cyanoalkyl group having a lower alkylene moiety having 1 to 5 carbon atoms is preferable, and examples thereof include a cyanomethyl group and a cyanethyl group.

(6) Aralkyl group which may be substituted: As the aralkyl group, benzyl group and phenethyl group are preferred. These aryl moieties may be substituted with one or more groups, and the substituents include halogen atoms, carbon atoms from 1 to
Examples include a lower alkyl group having 3 carbon atoms, a lower haloalkyl group having 1 to 3 carbon atoms, a lower alkoxy group having 1 to 3 carbon atoms, a nitro group, and preferably a fluorine atom, a chlorine atom, a methyl group, an ethyl group, an isopropyl group. , trifluoromethyl group, metquine group, etquine group, isopropoquine group, and nitro group.

(7) Optionally substituted pyrimidine, pyridazine, quinoxaline, benzoxazole and benzothiazole; The heterocycle may be substituted with one or more atoms or groups, examples of which include halogen atom, carbon number Examples include a lower alkyl group having 1 to 3 carbon atoms, a lower haloalkyl group having 1 to 3 carbon atoms, a lower alkoxy group having 1 to 3 carbon atoms, a nitro group, and preferably a fluorine atom, a chlorine atom,
Methyl group, ethyl group, isopropyl group, trifluoromethyl group, methoxy group, ethoxy group, inpropoxy group,
It is a nitro group.

(8) Aryl group which may be substituted: The aryl part of this group is preferably a benzene ring, diphenyl ring or 7talene ring.

These aryl moieties may be substituted by one or more, preferably from 1 to 3 atoms or groups. Halogen atom, carbon number 1 as an atom or group that can be substituted
-3 lower alkyl group, lower haloalkyl LM having 1 to 3 carbon atoms, lower alkokene group having 1 to 3 carbon atoms, nitro group, etc., fluorine atom, chlorine atom, bromine atom, methyl group, ethyl group, n -Propyl group, isopropyl group, trifluoromethyl group, methoxy group, ethoxy group, impropyl group, and nitro group are preferred. The alkylene moiety of the aralkyl group is preferably a straight chain or branched lower alkylene having 1 to 5 carbon atoms.

The optionally substituted aryl group in (8) is preferably represented by the formula % [wherein R3 and R7 independently represent a hydrogen atom, a lower alkyl group, or a lower alkoxy group, and R4 and R6
each independently represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower haloalkyl group, a lower alkoxy group, a nitro group, an ano group, or an alkoxycarbonyl group, and R6 is a hydrogen atom, a lower alkyl group, or a lower alkoxy group. or represents a nitro group, provided that R3, R4, R5, R
6. All R2 do not represent hydrogen atoms at the same time,
In addition, when R5 represents a nitro group, R4 and R6 do not represent a hydrogen atom at the same time.] A phenyl group represented by Al.

The lower alkyl group and lower alkoxy group represented by R3, R5, R-T in the phenyl group of the above formula,
A group having 1 to 3 carbon atoms is preferable, and examples thereof include a methyl group, an ethyl group, an isopropyl group, a methoxy group, a nidoquin group, and an isopropoxy group.

The lower alkyl group, lower haloalkyl group, and lower alkoxy group represented by R' and R6 are preferably groups having 1 to 3 carbon atoms, such as methyl group, ethyl group, isopropyl group, trifluoromethyl group, and methoxy group. , ethoxy group, isopropoquine stem, etc.

The halogen atom represented by R4 and R6 is preferably a fluorine atom or a chlorine atom.

The alkoxycarbonyl group represented by R4 and R1 is preferably a group having 1 to 5 carbon atoms, such as a methoxycarbonyl group and an ethoxycarbonyl group.

Specific examples of the compound of the present invention represented by formula (1) are shown in Table 1.

Table 1 l The benzofuran derivative represented by the general formula (1) of the present invention can be produced, for example, by the method shown below, but is not limited to these methods.

Method (II) (III) (1)
-a) [In the formula, R1, R''8 and A are Fuji general formula (?)
has the same meaning as in , and Xl represents a halogen atom. ] The compound of the present invention is a compound represented by the formula (I [) and a compound represented by the formula (I
It can be obtained by reacting a compound represented by [+] in an appropriate solvent in the presence of an L6wis acid catalyst. The sulfonyl halide of intermediate (II) can be obtained by a method known per se or a production method analogous thereto (for example, as described in Journal of the C
chemical 5ociety, 5eries C
, p. 1265; 1965).

The compound (III) used has the following properties with respect to the compound (If):
Usually, 1.0 to 5.0 mole times is appropriate.

The solvent used here may be any solvent as long as it is inert to the reaction components; for example, dichloroethane or dichloromethane is preferred. There is no particular restriction on the amount of solvent used, but it is usually 5 to 20 times the amount of compound (II) by weight.

Lewis acid catalysts include, for example, aluminum chloride,
Ferric chloride, tin tetrachloride, antimony pentachloride, titanium tetrachloride, etc. can be used. The amount of Lewisism catalyst used is
The appropriate amount is usually 1.0 to 5.0 times the amount of compound (II).

The reaction temperature can be arbitrarily set within the temperature range of water cooling to the boiling point of the solvent.

Although the reaction time varies depending on the setting conditions, it can usually be completed in 1 to 48 hours.

Product (I-a) can be isolated from the reaction mixture by conventional methods and easily purified by recrystallization, column chromatography, etc.

Method B (IV) (V) (1-a) [In the formula, R1, R2 and A have the same meanings as in the general formula (I), and X2 represents a halogen atom. j The compound of the present invention is a compound represented by formula (IV) and a compound represented by formula (V
) in the coexistence of a Lewis acid catalyst,
It can be obtained by reaction in a suitable solvent.

The amount of compound (V) used is usually 1.0 to 5.0 times the amount of compound (IV) by mole.

The solvent used here may be any solvent as long as it is inert to the reaction components; for example, dichloroethane or dichloromethane is preferred. There is no particular limit to the amount of solvent used, but it is usually 5 to 20 times the amount of compound (■). It is appropriate to double the amount.

As the Levi acid catalyst, for example, aluminum chloride,
Ferric chloride, tin tetrachloride, antimony pentachloride, titanium tetrachloride, etc. can be used. The amount of Lewis acid catalyst used is
Usually, 1.0 to 5.0 times the mole of compound (TV) is appropriate.

The reaction temperature can be arbitrarily set within the range of water cooling to the exhaustion point of the solvent.

Although the reaction time varies depending on the setting conditions, it can usually be completed in 1 to 48 hours.

Product (Ia) can be isolated from the reaction mixture by conventional methods and easily purified by recrystallization, column chromatography, etc.

C method (■) (■) (
I-b) [where R1, R2 and A are represented by the general formula (r
), x3 represents a halogen atom. ] The compound of the present invention is a compound represented by the formula (Vr) and a compound represented by the formula (■
) in a suitable solvent in the presence of a base.

The amount of compound (Vl) used is usually 0.5 to 5.0 times the amount of compound (■) by mole.

Examples of solvents include ketones such as acetone; ethers such as tetrahydrofuran, dioxane, and ether; esters such as ethyl acetate; halogenated hydrocarbons such as dichloromethane; aromatic hydrocarbons such as benzene and chlorobenzene; Polar solvents such as formamide can be used alone or in combination. Furthermore, a mixed system of water and the above-mentioned solvents can also be implemented.

There are no particular restrictions on the amount of solvent used, but it is usually
A suitable amount is 5 to 20 times the amount of (2) by weight.

Examples of bases used include inorganic substances such as alkali carbonates and caustic alkalis, and metal hydrides such as sodium hydride and potassium hydride.
(2) is usually 1.0 to 5.0 times by mole.

The reaction temperature can be arbitrarily set within the temperature range of water cooling to the boiling point of the solvent.

Although the reaction time varies depending on the setting conditions, the reaction can usually be completed in 1 to 48 hours.

Product (1-b) can be isolated from the reaction mixture by conventional methods and easily purified by recrystallization, column chromatography, etc.

D method (■) (II)
(1-b) [wherein R1, R2 and A are the general formula (
It has the same meaning as in I). ] The compound of the present invention can be prepared by dissolving compound A-NH, in concentrated hydrochloric acid,
Add sodium nitrite to make a diazonium salt (represented by (■) in the above reaction formula) solution, and convert this to compound (ff).
can be obtained in addition to.

The compound (■) used is usually 0 for compound (II)
．． 5 to 5.0 mole times is appropriate.

The solvent used here may be any solvent as long as it is inert to the reaction process, and for example, those described in the above Method C, such as dimethylformamide, can be used. There are no particular restrictions on the amount of solvent used, but usually the compound (ff
) is suitably 5 to 20 times the amount by weight.

The reaction temperature can be arbitrarily set within the temperature range of water cooling to the boiling point of the solvent.

The reaction time varies depending on the setting conditions, but usually the reaction can be completed in 1 to 48 hours.

Product (I-b) can be isolated from the reaction mixture by conventional methods and easily purified by recrystallization, column chromatography, etc.

E method ([-b) (r-c) [In the formula, R1, R2 and A are the above general formula (I) The meaning is the same as in , and m represents ■ or 2.

1 The compound of the present invention in which n is 1 or 2 in formula (1) above can be produced by oxidizing the compound of the present invention represented by formula (1-b) using an oxidizing agent.

Compound (1-b) can be obtained by the above method C and method D.

Examples of the oxidizing agent include hydrogen peroxide, aromatic peracids such as metachloroperbenzoic acid, and aliphatic peracids such as peracetic acid and pertrifluoroacetic acid. The amount of oxidizing agent used in the reaction is
A suitable amount is I to 3 moles relative to compound (r-b).

A solvent does not necessarily need to be used, but if it is used, it depends on the type of oxidizing agent. For example, for hydrogen peroxide, water, glacial acetic acid, acetone, etc. are used, and for aromatic peracids, oxidizing agents such as hachloroform, dichloromethane, etc. Hydrogens or ethers such as ether and dioxane are preferred. In the case of aliphatic peracids, it is preferred to use an excess of the oxidizing agent itself.

There are no particular restrictions on the amount of solvent used, but it is usually
5 to 20 times the weight of 1-b) is suitable.

The reaction temperature can be arbitrarily set within the temperature range of water cooling to the boiling point of the solvent.

Although the reaction time varies depending on the setting conditions, it can usually be completed in 10 minutes to 24 hours.

Product (1-c) can be isolated from the reaction mixture by conventional methods and easily purified by recrystallization, column chromatography, etc.

Next, the present invention will be explained in more detail by giving specific examples.

Example 1 1.5 g of aluminum chloride and 8 mQ of dichloromethane were stirred, and (3,3-dimethyl 2,3-dihydrobenzofuran-5-yl)sulfonyl chloride 2 was added thereto at room temperature.
．． Add 0g;. Stirring was continued for an additional 30 minutes, and this reaction solution was added dropwise to a solution of 0.8 g of toluene and 8 mC of dichloromethane at room temperature with stirring, and the mixture was allowed to stand overnight. The reaction solution was poured into ice-cooled IN hydrochloric acid, the organic layer was washed with water, dried, the solvent was distilled off, and the mixture was purified by silica gel column chromatography. 1.6 g (yield: 65%) of the desired 5-(p-toluenesulfonyl)-3,3-dimethyl-2,3-dihydrobenzofuran was obtained.

Example 2 1.08 g of m-triple olomethylaniline was added to 1 part of concentrated hydrochloric acid.
．． Dissolved in 0 mQ and crushed ice 4.59, cooled to 0 °C, 1.1 m of sodium nitrite 0.509 (2 aqueous solution at 4 °C
was added gradually at a rate not exceeding . This solution was mixed with 1.13 g of 5-mercapto-3,3-dimethyl-2<3-dihydrobenzofuran and 0.48 g of potassium hydroxide in 11.
The mixture was added to a solution dissolved in 3n+Q aqueous solution at 40 to 50°C, extracted in the same manner for another 30 minutes, washed with water, and dried. The solution was evaporated and the residue was purified by column chromatography on Silicage J. 1.309 (yield: 51%) of the desired 5-(3-1-lifluoromethylphenylthio)33-dimethyl-2,3-dihydrobenzofuran was obtained.

Example 3 5-(3-1lifluoromethylphenylthio)3, 3
-dimethyl-2,3-dihydrobenzofuran 0.55g
was dissolved in dichloromethane lOmQ, 0.32 g of metachloroperbenzoic acid was gradually added at 0°C, and the mixture was further stirred for 2 hours at O''C.The reaction solution was dissolved in an aqueous solution of sodium hydrogen carbonate,
After successively washing with water and drying, the solvent was distilled off and the product was purified by silica gel column chromatography. Objective 5-
(3-trifluoromethylphenylsulfinyl)-3
゜3-Dimethyl-2,3-dihydropenzofuran Example 4 5-(3-trifluoromethylphenylthio)3.3-
0.50 g of dimethyl-2,3-dihydrobenzofuran was dissolved in 1Omf2 of chloroform, 0.669 g of metachloroperbenzoic acid was gradually added at 0°C, and the mixture was further stirred at room temperature overnight. The reaction solution was washed successively with an aqueous sodium hydrogen carbonate solution and water, dried, the solvent was distilled off, and the residue was purified by silica gel column chromatography. Objective 5-(3
-trifluoromethylphenylsulfonyl)-3,3-
Dimethyl-2,3-dihydrobenzofuran 0°41g
(yield 75%).

Example 5 2.0 g of 5-mercapto-3,3-dimethyl-2,3-dihydrobenzofuran was dissolved in 10 mQ of dimethylformamide.
, 1.53 g of anhydrous potassium carbonate was added thereto, 2.08 g of ethyl iodide was gradually added at room temperature while stirring, and the mixture was further stirred at room temperature overnight. The reaction mixture was poured into water, extracted with ether, washed with water, dried, the solvent was distilled off, and the mixture was purified by silica gel column chromatography. Objective 5-
2.0 g (yield: 87%) of ethylthio-3,3-dimethyl-2,3-dihydrobenzofuran was obtained.

Synthesis of Example 6: 0.50 g of 5-methylthio-3,3-dimethyl-2,3-dihydrobenzofuran was dissolved in 5 m of dichloromethane (2), and 0.58 g of metachloroperbenzoic acid was gradually added at 0°C. The reaction solution was further stirred at 0°C for 2 hours and allowed to float.The reaction solution was washed with an aqueous sodium bicarbonate solution and water in turn, dried, the solvent was distilled off, and the target 5-methylsulfinyl was purified by silica gel column chromatography. 0.20 g of -3,3-dimethyl 2.3 dihydrobenzofuran (yield 37%) was obtained.

Example 7 1.80 g of 5-mercapto-3,3-dimethyl-2,3-dihydrobenzofuran was dissolved in 5 mQ of dimethylformamide.
1.66 g of anhydrous potassium carbonate was added thereto, and 1.57 g of p-methoxybenzyl chloride was gradually added at room temperature while stirring. After further stirring at room temperature for 2 hours, the reaction solution was
It was poured into an aqueous sodium hydroxide solution, extracted with ether, and washed with water.

After drying, the solvent was distilled off and the residue was purified by silica gel column chromatography. 2.43 g (yield: 81%) of the desired 5-(4-methoxybenzylthio)-3,3-dimethyl-2,3 dihydrobenzofuran was obtained.

Compounds listed in Table 2 below were synthesized by a similar method.

NMR data of those compounds are shown in Table 2 below.

Table 2 (S 6H), 1.33 (S.

38X2) The herbicide of the present invention contains the novel benzofuran derivative represented by formula (1) above as an active ingredient.

When the compound of the present invention is used as a herbicide, it is mixed with carriers, diluents, additives, auxiliaries, etc. commonly used in the preparation of agricultural chemicals by a method known per se. It is used in the form of preparations such as powders, granules, wettable powders, emulsions, aqueous solutions, and tablets. It can also be mixed or used in combination with other agricultural chemicals, such as fungicides, insecticides, acaricides, other herbicides, plant growth regulators, fertilizers, soil conditioners, and the like. In particular, when used in combination with other herbicides, it not only reduces the amount of chemicals used and saves labor, but also expands the herbicidal spectrum due to the synergistic action of both herbicides and further increases the herbicidal spectrum due to the synergistic action. You can also expect good results.

As the carrier or diluent used in formulation, solid or liquid carriers commonly used in agriculture are used. Solid carriers include clays represented by the kaolinite group, montmorillonite group, or abatalgite group, talc, mica, waxite, pumice, vermiculite, gypsum, carbonate, dolomite, diatomaceous earth, magnesium coal, and phosphorus. Ashite, zeolite, silicic anhydride,
Inorganic substances such as synthetic silicate - vegetable organic substances such as soybean flour, tanoko flour, walnut flour, wheat flour, wood flour, starch, crystalline cellulose; coumaron resin, petroleum resin, alkyd resin, polyvinyl chloride, Synthetic gums such as polyalkylene glycol, ketone pulp, ester gum, copal gum, and dammar gum are natural polymer compounds; other examples include waxes such as carnauba wax and beeswax, and waxes.

Suitable liquid carriers include, for example, paraffinic or naphthenic hydrocarbons such as kerosene, mineral oil, spindle oil, white oil; aromatic hydrocarbons such as toluene, quinolene, ethylbenzene, cumene, methylnaphthalene;
Ethers such as dioxane and tetrahydrofuran: Ketones such as acetone, methyl ethyl ketone, diisobutyl ketone, cyclohexanone, acetophenone, and isophorone; Esters such as ethyl acetate, amyl acetate, ethylene glycol acetate, diethylene glycol acedate, dibutyl maleate, diethyl succinate, etc. Alcohols such as methanol, n-hexanol, ethylene glycol, diethylene glycol, nclohexanol, benzyl alcohol; Ether alcohols such as ethylene glycol ethyl ether, ethylene glycol phenyl ether, diethylene glycol ethyl ether, diethylene glycol butiether; dimethyl formamide , polar solvents such as dimethylsulfokind, water, and the like.

In addition, surfactants and other auxiliary agents may be used for the purpose of emulsifying, dispersing, wetting, spreading, binding, adjusting disintegrability, stabilizing active ingredients, improving fluidity, preventing rust, etc. of the compound of the present invention. . Examples of surfactants used include nonionic, anionic, cationic, and zwitterionic compounds, but typically nonionic and/or
Anionic compounds are 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, and compounds in which ethylene oxide is polymerized and added to alkyl phenols such as isooctylphenol and nonylphenol. ,
Compounds obtained by polymerizing and adding ethylene oxide to alkylnaphthols such as butylnaphthol and octylnaphthol, compounds obtained by polymerizing and adding ethylene oxide to higher fatty acids such as balmitic acid, stearic acid, and oleic acid, higher fatty acid esters of polyhydric alcohols such as sorbitan, and Examples thereof include a compound obtained by polymerizing and adding ethylene oxide, and a compound obtained by polymerizing and adding ethylene oxide and propylene oxide.

Suitable anionic surfactants include, for example, sodium lauryl sulfate, alkyl sulfate salts such as oleyl alcohol sulfate amine salts, alkyl sulfonates such as sodium sulfosuccinate dioctyl ester, and sodium 2-ethylhexene sulfonate. : Aryl sulfonates such as sodium isopropylnaphthalene sulfonate, sodium methylene hisnaphthalene sulfonate, sodium lignin sulfonate, and sodium dodenlebenzene sulfonate.

Furthermore, the herbicide of the present invention may contain polymeric compounds such as casein, gelatin, albumin, glue, sodium alginate, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, polyvinyl alcohol, etc., in order to improve the properties of the preparation and increase the herbicidal effect. It is also possible to use adjuvants.

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 application situation, etc.

The content of the compound (active ingredient) of the present invention in the various formulations thus obtained varies depending on the formulation, but it is usually appropriate to range from 0.1 to 99%, particularly from 1 to 80%. Weight percent is most preferred.

In the case of powders, for example, the active ingredient compound is usually 1 to 25
% by weight, the remainder being solid carrier.

In the case of hydrating agents, for example, the active ingredient compound is usually
The content is 90% by weight, and the remainder is a solid carrier, a dispersion wetting agent, and if necessary, a protective colloid agent, an antifoaming agent, etc. are added.

In the case of granules, for example, the active ingredient compound is usually 1 to 35
% by weight, and the remainder is mostly solid carrier, surfactant, 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 emulsions, for example, the active ingredient compound is usually 5.-3
This includes about 5 to 20% by weight of an emulsifier, and the remainder is a liquid carrier, with a rust preventive added as needed.

In the case of flowable agents, for example, the active ingredient compound is usually
In addition to this, 3 to 10% by weight of a dispersion wetting agent is included, and the remainder is water, with protective colloids, preservatives, antifoaming agents, etc. being added as necessary.

The novel benzofuran derivatives of the present invention can be applied either as compounds of formula (1) or in any of the preparation forms 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 approximately 0.01 to 5 kg per lha as the amount of the compound represented by the general formula (1) (active ingredient amount), preferably 0.0. The amount is about 1 to 2 kg, and the selection can be changed as appropriate depending on the type of target weed, growth stage, application location, application time, weather, etc.

Next, several embodiments of formulation examples using the compounds of the present invention will be shown.

"Parts" in the following formulation examples are based on weight.

Formulation example 1 (granules) Compound amount 11 5 parts bentonite 50 parts talc
40 parts dode/rubenzene sulfonate soda 2 parts lignin sulfonate sodium 2 parts polyoxyethylene styrylphenyl ether After thoroughly mixing 1 part or more, add an appropriate amount of water, mix, and use a granulator. Formulation example 2 (wettable powder) obtained by granulation to obtain 100 parts of granules Compound: 5 20 parts diatomaceous material ± 60 parts white carbon
15 M Sodium ligninsulfonate 3 parts Sodium dodecylbenzenesulfonate
Two or more parts were mixed and pulverized uniformly using a kneader to obtain 100 parts of an irrigation agent.

Formulation Example 3 (Emulsion) Compound 173 30 parts xylene
55 parts cyclohexanone
10 parts calcium dodecylbenzenesulfonate 3 parts polyoxyethylene styrylphenyl ether At least 2 parts were homogeneously 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.

(Effects of the Invention) The benzofuran derivative represented by the above general formula (1) of the present invention is a novel compound described at the end of the literature.

The compound represented by the above general formula (1) is characterized by having a structure in which sulfide, sulfokind, or sulfone is bonded at the 5-position of the benzofuran skeleton,
It is thought that its structural characteristics provide excellent herbicidal effects.

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, Nobie,
It can control paddy field weeds such as bulrush, Japanese cypress, Japanese cypress, black-capped tit, black-capped chickadee, and grass weed, as well as upland weeds such as black-and-white grass, black-and-white fern, black-and-white grass, black-and-white grasshopper, Japanese grasshopper, Japanese barnyard grass, and barnyard grass. Furthermore, it can be used not only in paddy fields and fields, but also in orchards, mulberry fields, lawns, and non-agricultural lands.

Furthermore, the compound of the present invention has selectivity for cultivated crops, is extremely safe for rice, and effectively controls various weeds that occur in rice fields, so it is expected to be effective as an excellent herbicide for rice fields. can.

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

Test Example 1 (Paddy soil treatment) A plastic pot with an area of 200 cm was filled with paddy soil mixed with an appropriate amount of chemical fertilizer, and three plants of two-leaf rice (variety: Koshihikari) grown at room temperature were placed in the pot. (2
This plant (1 plant) was transplanted, and seeds of Japanese wildflower, Japanese cypress, Japanese azalea, and Japanese firefly, and tubers of Japanese apricot, Japanese cypress, and Japanese cypress were sown.

Three days after transplanting paddy rice and sowing weeds, each compound shown in Table 3 was prepared into a wettable powder according to Formulation Example 2, and diluted with an appropriate amount of water so that the active ingredient was 0.2 kg or 0.5 kg per lha. and added dropwise with a pipette. The herbicidal effect and the degree of chemical damage were investigated 90 days after the chemical treatment according to the next leaf standard.

The results are shown in Table 3.

Weeding effect remaining rate (residual rate relative to untreated area) 0% 1% 11% 21% 31-41% 51% 61% 71% 81% 91% or more ~ 1% ~ 10% ~ 20% ~ 30% ~ 40% ~ 50% ~ 60% ~ 70% ~ 80% ~ 90% ~ Less than 100% Phytotoxicity complete death 90% ~ 99% suppression 80% ~ 89% 〃 70% ~ 79% 60% ~ 69% 50% ~ 59% 40 % ~ 49% 30% ~ 39% 〃 20% ~ 29% 〃 10%-19%++ 0% ~ 9X Table Comparison Compound A represents the following compound (the same applies hereinafter) Test Example 2 (Paddy growing season treatment) Area 200 A cm2 plastic pot was filled with paddy soil mixed with an appropriate amount of chemical fertilizer, and three plants (2
This plant (1 plant) was transplanted, and seeds of Japanese wildflower, Japanese cypress, Japanese azalea, and Japanese firefly, and tubers of Japanese apricot, Japanese cypress, and Japanese cypress were sown.

Ten days after transplanting paddy rice and sowing weeds, each compound shown in Table 4 was adjusted to a hydrating powder according to Formulation Example 2, and lha
It was diluted with an appropriate amount of water so that each sample weighed 0.5 kg or 1.0 kg, and was added dropwise with a pipette.

The herbicidal effect and the degree of chemical damage were investigated 30 days after the chemical treatment according to the same criteria as Test Example 1.

The results are shown in Table 4.

table

Claims (2)

[Claims] (1) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) [In the formula, R^1 and R^2 may be the same or different and represent a hydrogen atom or a lower alkyl group, and n is 0, 1 or 2, A is a lower alkyl group, a lower alkenyl group, a lower alkynyl group, an alkoxyalkyl group, an alkylcarbonylalkyl group, an alkoxycarbonylalkyl group, a cyanoalkyl group, an optionally substituted aralkyl group, a substituted represents an optionally substituted pyrimidine, an optionally substituted pyridazine, an optionally substituted quinoxaline, an optionally substituted benzoxazole, an optionally substituted benzothiazole, or an optionally substituted aryl group] Benzofuran derivative. (2) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) [In the formula, R^1 and R^2 may be the same or different and represent a hydrogen atom or a lower alkyl group, and n is 0, 1 or 2, A is a lower alkyl group, a lower alkenyl group, a lower alkynyl group, an alkoxyalkyl group, an alkylcarbonylalkyl group, an alkoxycarbonylalkyl group, a cyanoalkyl group, an optionally substituted aralkyl group, a substituted represents an optionally substituted pyrimidine, an optionally substituted pyridazine, an optionally substituted quinoxaline, an optionally substituted benzoxazole, an optionally substituted benzothiazole, or an optionally substituted aryl group] A herbicide characterized by containing a derivative as an active ingredient.