JP3014167B2 - 2,3-dihydrobenzofuran derivatives and herbicides containing these as active ingredients - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to novel 2,3-dihydrobenzofuran derivatives and herbicides containing these as active ingredients.

[0002]

2. Description of the Related Art It has been reported that alkylsulfonate derivatives of 2,3-dihydrobenzofuran-5-ols have herbicidal activity, as disclosed in JP-B-55-45523 and JP-A-53-455.
98936 and the like. However,
The use of the compounds described in these publications is a field-acting herbicide, and there is no description of a test example as a rice herbicide.

[0003] The inventors of the present invention have tested and evaluated the compounds described in these publications in paddy fields. As a result, the herbicidal activity against nobies, which is one of the most important weeds in paddy fields, was insufficient, and the crops were not used. It had a fatal disadvantage of causing serious phytotoxicity to a certain rice plant.

[0004]

SUMMARY OF THE INVENTION
-As a result of various studies on the herbicidal activity of dihydrobenzofuran-based compounds, the compounds of the prior art showed insufficient herbicidal activity against nobies, one of the most important weeds in paddy fields, and also showed that It had the fatal drawback of causing serious phytotoxicity.

[0005] Accordingly, an object of the present invention is to find a compound which can be applied not only to a field but also to a paddy field having excellent herbicidal activity without causing phytotoxicity to paddy rice.

That is, while the present invention is safe against paddy rice, it shows strong herbicidal activity against annual weeds such as nobies, tamayatsuri, konagi and kikasigusa as well as perennial weeds such as fireflies, mizuyatsuri, kuroguwai, matsubai and urikawa. Another object of the present invention is to find a compound having excellent performance as a herbicide for paddy rice.

[0007] Further, by soil treatment or foliage treatment, it is also effective for Meishiba, Chickweed, Polygonum, Inubiyu, Komegayatsuri, Purslane, Novorogiku, Shiroza, Hamasuge, Hirugao, Tsumexa, Yaegura, Sparrowleaf, Spodoptera velutipes, Nazuna, Enokorogusa, etc. An object of the present invention is to find a compound that is effective not only as a herbicide for paddy rice but also as a herbicide for field action and other non-agricultural lands.

[0008]

The present inventors have conducted various studies on the herbicidal activity of 2,3-dihydrobenzofuran compounds in order to solve the above-mentioned problems. The present inventors have found a group of compounds that are also effective as field-acting herbicides and other herbicides for non-agricultural lands, and have completed the present invention.

That is, the present invention relates to a compound represented by the general formula (I):
0)

[0010]

Embedded image [In the formula, R ¹ represents a hydrogen atom, a methyl group or a halogen atom, and R ² represents a hydrogen atom or a methyl group. R ³ is a lower alkyl group, a lower alkyl group substituted with a halogen atom, a phenyl group substituted with a methyl group or a methoxy group or a halogen atom, a benzyl group, a benzyl group substituted with a halogen atom, or a compound represented by the general formula (II) ( Chemical formula 11)

[0011]

Embedded image (Wherein R ⁴ and R ⁵ represent a hydrogen atom, a lower alkyl group, a phenyl group, a benzyl group, a benzyl group substituted with a halogen atom or a pentamethylene group). And a herbicide containing the derivative as an active ingredient.

The term "lower alkyl group" used herein means a methyl group, an ethyl group, an n-propyl group, an iso-propyl group,
The term "n-butyl group, iso-butyl group, tert-butyl group, etc." refers to a lower alkyl group substituted with a halogen atom, for example, a chloromethyl group, a trifluoromethyl group, a pentafluoroethyl group or the like.

Next, a method for producing the compound of the present invention will be described.

Some of the compounds of the present invention of the general formula (I) are described in Journal of Organic Chemistry (J. Org.
Chem.) 33, 3346 (1968);
In some cases, it can be produced by a known method described in US Pat. No. 4,555,523, U.S. Pat. No. 3,184,457, or a method analogous thereto, but as described below, it has been generally quite difficult. That is, it can be produced by a production method (i) (Chem. 12) shown below using a compound of the general formula (VI) obtained by reacting an enamine obtained from isobutyraldehyde and morpholine with benzoquinone or a derivative thereof as a starting material.

[0015]

Embedded image

That is, the compound represented by the general formula (VI) is obtained from benzoquinone or a derivative thereof and an enamine compound in the step (a). When tolquinone is used, it is generally obtained as a mixture of those having a methyl group at the 6-position and those having a methyl group at the 7-position.

The compound represented by the general formula (VII) is prepared in an organic solvent by the step (b), and the compound represented by the general formula (VI) is converted into benzene, toluene, xylene, chlorobenzene, diethyl ether, dioxane, Dissolved in an inert solvent such as tetrahydrofuran, methylene chloride, chloroform, methyl ethyl ketone, acetone, etc., and equimolar or slightly excess trifluoromethanesulfonyl halide or trifluoromethanesulfonic anhydride and an organic base such as triethylamine, pyridine, N, N-dimethylaniline Alternatively, the reaction is performed by adding a powdered inorganic carbonate or bicarbonate such as potassium carbonate, sodium carbonate, or potassium bicarbonate. Further, the reaction can be carried out using sodium metal, sodium hydride or the like, or pyridine can be used also as a reaction solvent. The reaction temperature can be from −50 ° C. to the boiling point of the solvent, but it is preferable to carry out the reaction in a relatively low temperature range. After completion of the reaction, the target compound can be purified by performing ordinary post-treatment.

The compound represented by the general formula (VIII) is obtained by the step (c), usually by hydrolysis in a water solvent using hydrochloric acid or sulfuric acid as a catalyst.

One part of the compound represented by the general formula (XI) is
After chlorinating the compound represented by the general formula (VIII) to obtain a compound represented by the general formula (IX), the step (e) is continued.
The reaction can be carried out by performing a substitution reaction with ammonia or a primary amine to obtain a compound represented by the general formula (X), and further reacting the compound with sulfonyl chloride or sulfonic anhydride in step (f). , As described below, generally involves considerable difficulty. That is, in the step (d), the compound represented by the general formula (VIII) is prepared by using an inert solvent such as benzene, toluene, xylene, diethyl ether, dioxane, tetrahydrofuran, methylene chloride, chloroform, and acetonitrile or no solvent. ,
The reaction is carried out using at least an equivalent of thionyl chloride in the presence of a catalytic amount of pyridine or N, N-dimethylformamide at room temperature or, if necessary, with heating. Although (IX) can be obtained, (IX) is generally not stable for a long time. In the step (e), the compound represented by the general formula (IX) is converted into an aqueous ammonia solution or a methanol solution in which ammonia is dissolved, or benzene, toluene, xylene, diethyl ether, dioxane, tetrahydrofuran, methylene chloride, chloroform, acetonitrile or the like. The compound represented by the general formula (X) can be obtained by carrying out a reaction with a primary amine in an inert solvent under atmospheric pressure or, if necessary, under pressure, at room temperature or under heating, followed by ordinary post-treatment. However, this method tends to produce by-products and generally has a much lower yield. Further, the compound represented by the general formula (XI) is obtained by converting the compound represented by the general formula (X) into benzene, toluene, xylene, diethyl ether, dioxane, tetrahydrofuran, methylene chloride, chloroform, acetonitrile, ethyl acetate by the step (f). In an inert solvent such as n-hexane or the like, a slightly excessive amount of sulfonyl halide or sulfonic anhydride and an organic base such as triethylamine, pyridine, N, N-dimethylaniline or potassium carbonate, sodium carbonate, sodium hydrogencarbonate or the like is used. The reaction can be carried out in the presence of an inorganic base at room temperature or under ice-cooling or heating as necessary, and can be obtained by carrying out a usual post-treatment.In general, the yield is low, and sulfonyl chloride or sulfonic anhydride can be obtained. Depending on the type, the object (XI) may not be obtained at all.

For the purpose of overcoming the above drawbacks, the present inventors have studied a general production method for synthesizing (XI) from (VIII), and as a result, the following production method (ii) (Formula 13) is shown. I found a route.

[0021]

Embedded image

That is, after the (VIII) is converted into an acetate to give (XII), the compound represented by the general formula (V)

[0023]

(XI) is reacted with a sulfonamide represented by R ² NHSO ₂ R ³ (V) (wherein R ² and R ³ represent the above-mentioned meanings) to give (XI) with high purity and high yield. Was found.

That is, the compound represented by the general formula (XII) can be obtained by converting the compound represented by the general formula (VIII) in step (g) into benzene, toluene, xylene, diethyl ether, dioxane, tetrahydrofuran, methylene chloride. ,
Dissolved in an inert solvent such as chloroform, acetonitrile, n-hexane and the like, and a slight excess of the corresponding acetic chloride or acetic anhydride and triethylamine, pyridine, N,
An organic base such as N-dimethylaniline or an inorganic salt such as potassium carbonate, sodium carbonate, sodium hydrogencarbonate or the like is added, and the reaction is carried out at room temperature or, if necessary, under ice-cooling or heating, followed by ordinary post-treatment. It can be obtained in yield.

In the step (h), the compound represented by the general formula (XI) is obtained by converting the compound represented by the general formula (XII) and the sulfonamide represented by the general formula (V) into acetonitrile, carbon disulfide, methylene chloride. , Chloroform, nitrobenzene, n-hexane, etc., dissolved in an inert solvent, such as aluminum chloride, aluminum bromide, aluminum iodide, chloride (II), chloride (II), CF ₃ SO ₂ OSiMe ₃ ,
_{BF 3 · O (C 2 H} 5) a Lewis acid catalyst ₂ such as adding, the reaction was carried out under ice cooling or under heating if room temperature or necessary, be obtained in good yield by conducting a normal post-treatment it can.

The general formulas (VI), (VII) and (VII)
Compounds shown in I), (IX), (X), (XI) and (XII), when R ¹ is a methyl group, those having a methyl group at the 6-position and those having a methyl group at the 7-position A mixture of things,
In any step, a desired methyl compound at the 7-position can be obtained from each mixture by a separation means such as recrystallization or silica gel column chromatography, and finally can be led to a desired compound represented by the general formula (I).

JP-B-55-45523 and JP-A-53-98936 disclose a compound of the present invention having a 2,3-dihydrobenzofuran skeleton and a halogen-substituted alkylsulfonate at the 5-position. Although chloromethanesulfonate and 3-chloropropanesulfonate which are considered to be similar are disclosed, there is no disclosure of trifluoromethanesulfonate such as the compound of the present invention. These known chlorine atom-substituted alkylsulfonates have no herbicidal activity or other superiority compared to the corresponding unsubstituted alkylsulfonates from the test examples in the publication.

The above publication discloses a compound having a dialkylamino group containing a hydroxyl group, a lower alkylcarbonyloxy group or a morpholino group at the 2-position in the 2,3-dihydrobenzofuran skeleton. There is no disclosure of a compound having a sulfonylamino group or an aminosulfonylamino group.

As described above, in the 2,3-dihydrobenzofuran skeleton, the compound of the present invention in which the 5-position is a trifluoromethanesulfonate compound and the 2-position is a sulfonylamino group and an aminosulfonylamino group is a completely novel compound.

In addition, as compared with the known similar compounds, the herbicidal activity was greatly improved, and at the same time, the safety against paddy rice was incomparably improved. Therefore, the same 2,3-
Despite having a dihydrobenzofuran skeleton, known analogous compounds and the compounds of the present invention are completely different in their properties, and even a person skilled in the art cannot easily guess.

The compound represented by the general formula (I) according to the present invention is extremely safe for paddy rice. On the other hand, annual weeds such as nobie, tamayatsuri, konagi and kikashigusa and fireflies, syringa purpurea, kurogwaii, matsubai and urikawa etc. Has strong herbicidal activity against perennial weeds and has excellent performance as a rice-like herbicide. Also,
By soil treatment or foliage treatment, crabgrass, chickweed, polyplum, silver bilberry, kogomeka-tsutsuri, suzurigiyu, noborogiku, shiroza, hamasuge, hirugao, tumexa, jaemgra, sparrow-nosed plow, spruce caterpillar, nazuna, enokorogusa, etc. Not only is it effective, but also as a field-acting herbicide and other non-agricultural land herbicides.

The compound represented by the general formula (I) according to the present invention may be used as it is for the plant to be treated, but is generally used by mixing with an inert liquid or solid. It is prepared and used in the form of a formulation, for example, powder, granule, wettable powder, emulsion, flowable formulation and the like.
If necessary for the preparation, an auxiliary agent can be added.

As the carrier, any solid or liquid carrier can be used as long as it is generally used for agricultural and horticultural medicines, and it is not limited to a specific one. For example, solid carriers include mineral powders such as clay, talc, bentonite, calcium carbonate, diatomaceous earth, and white carbon; vegetable powders such as soybean powder and starch; petroleum resins; polyvinyl alcohol; and polyalkylene glycols such as polyalkylene glycol. Molecular compounds, urea, waxes and the like. Examples of the liquid carrier include various oils, various organic solvents, water and the like.

As auxiliary agents, surfactants, binders, stabilizers and the like which are usually used for agricultural and horticultural drugs can be used alone or in combination as necessary. Further, in some cases, an industrial bactericide or a bactericidal / antifungal agent can be added for bactericidal / fungal control.

As the surfactant, nonionic, anionic, cationic and amphoteric surfactants can be appropriately used. Preferred examples include alkyl phenols, higher alcohols, alkyl naphthols, higher fatty acids, fatty acid esters, dialkyl phosphate amines and the like, which are obtained by polymerizing ethylene oxide and propylene oxide, alkyl sulfate salts (such as sodium lauryl sulfate), and alkyl sulfonate salts. (Eg, sodium 2-ethylhexenesulfonate) and aryl sulfonates (eg, sodium ligninsulfonate, sodium dodecylbenzenesulfonate).

The content of the compound represented by the general formula (I) in the herbicide according to the present invention varies depending on the form of preparation, but is usually 1 to 20% by weight for powders and 20 to 60% by weight for wettable powders. The amount is 1 to 30% by weight for granules, 1 to 50% by weight for emulsions, 10 to 50% by weight for flowable preparations, and 20 to 60% by weight for dry flowable preparations. The content of the adjuvant is from 0 to 80% by weight, and the content of the carrier is an amount obtained by subtracting the contents of the active ingredient compound and the adjuvant from 100% by weight.

The herbicide according to the present invention can be used for treating flooded soil,
It is effective in all treatment methods such as soil treatment, soil mixed layer treatment, foliage spraying treatment, and the application rate is 0.01 kg to
Although it can be used in a wide range of 10 kg / ha, it is preferably used in a wide range of 0.1 kg to 5 kg / ha.

In the present invention, the herbicide can be used in combination with one or more other herbicides, a pesticide such as an insecticide, a plant growth regulator, a soil conditioner or a fertilizer. However, it is also possible to prepare a mixed preparation with these, and a synergistic effect can be expected in some cases. In this case, it is particularly advantageous to use it as a mixture with other herbicides.

Other herbicides include, for example, phenoxyacetic acid herbicides, benzoic acid herbicides, chlorinated carboxylic acid herbicides, carbamate herbicides, urea herbicides, sulfonylurea herbicides, acid amide herbicides. Herbicides, heterocyclic herbicides (triazine herbicides, diazine herbicides), phenolic herbicides, diphenyl ether herbicides, dipyridinium herbicides, dinitroaniline herbicides, organophosphate herbicides, Examples include phosphorus-containing amino acid herbicides, imidazolidinone herbicides, pyridine herbicides, quinoline herbicides, sulfonamide herbicides, cyclohexanone herbicides, other organic herbicides, and inorganic herbicides.

[0040]

Next, the present invention will be described in more detail with reference to examples. Reference Example 1 Production of 2-amino-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2,3-dihydrobenzofuran (Comparative Compound C) (1) 5-Hydroxy-2-morpholino-3,3 7-
Production of trimethyl-2,3-dihydrobenzofuran 1) Production of enamine To a solution of 15.8 g of isobutyraldehyde and 50 ml of toluene was added 9.6 g of morpholine with stirring. This mixture was heated under reflux for 3 hours while continuously separating and removing water to prepare enamine.

(2) 5-hydroxy-2-morpholino-
Production of 3,3,7-trimethyl-2,3-dihydrobenzofuran 15.2 g of 2-methyl-1,4-benzoquinone in 15 m
The whole amount of the enamine solution obtained by the above method was gradually added to the suspension in 1 l of toluene, and the mixture was heated and stirred under reflux for 30 minutes. After completion of the reaction, the residue obtained by distilling off toluene from the reaction solution was sludged with a small amount of ether and hexane, then the solid substance was separated by filtration, washed with a small amount of toluene and dried, and dried. Its regioisomer, 5-hydroxy-2-morpholino-3,3,7-
A mixture of trimethyl-2,3-dihydrobenzofuran was obtained. This was purified twice by silica gel chromatography (developing solvent; n-hexane: ethyl acetate = 8: 2 and chloroform: methanol = 40: 1) to obtain the desired 5-hydroxy-2-morpholino-3,3. There was obtained 11.9 g of 4,7-trimethyl-2,3-dihydrobenzofuran (yield 45%).

(3) 2-morpholino-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-
Production of 2,3-dihydrobenzofuran 5-hydroxy-2-morpholino- obtained by the above method
7.0 g of 3,3,7-trimethyl-2,3-dihydrobenzofuran was dissolved in 60 ml of acetonitrile, and 5 ml of triethylamine was added. 3.1 ml of trifluoromethanesulfonyl chloride was gradually added dropwise thereto under ice cooling,
Subsequently, the mixture was stirred at 30 ° C. for 4 hours to complete the reaction. After allowing the reaction mixture to cool, the insolubles were removed by filtration and the solvent was distilled off under reduced pressure.The residue obtained was redissolved in ethyl acetate, washed with water and dried, and then the solvent was distilled off under reduced pressure to give an oil. Was obtained. The crude product was purified by silica gel chromatography (developing solvent; n-hexane: ethyl acetate = 9: 1) to give oily 2-morpholino-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2, 8.4 g of 3-dihydrobenzofuran was obtained (80% yield).

(4) 2-hydroxy-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-
Production of 2,3-dihydrobenzofuran 2-morpholino-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2,3- obtained by the above method.
5.5 g of dihydrobenzofuran in 4.5 ml of 35% hydrochloric acid
And 11 ml of water and reacted at 90 ° C. for 10 minutes with vigorous stirring. After completion of the reaction, the reaction mixture was left to cool, the oily substance was extracted with ether, washed with water, dried, and the solvent was distilled off. The residue obtained was subjected to silica gel column chromatography (developing solvent; n-hexane: ethyl acetate = 8: 2). Then, 4.1 g of oily 2-hydroxy-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2,3-dihydrobenzofuran was obtained (yield: 91%).

(5) 2-chloro-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2,3
-Production of dihydrobenzofuran 2-hydroxy-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2,
1.6 g of 3-dihydrobenzofuran was added to dichloromethane 1
After dissolving in 0 ml and adding 0.5 ml of pyridine, 0.4 ml of thionyl chloride was added dropwise under ice cooling. Subsequently, after stirring at 20 ° C. or lower for 3 hours, the reaction solution was discharged into water. The dichloromethane layer obtained by liquid separation was washed with aqueous sodium hydrogen carbonate, further washed with water and dried, and the solvent was distilled off. The obtained crude product was purified by silica gel chromatography (eluent: n-hexane: ethyl acetate = 19: 1) to give oily 2-chloro-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl. 1.4 g of -2,3-dihydrobenzofuran was obtained (yield 82%).

(6) 2-amino-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2,3
-Production of dihydrobenzofuran 2-chloro-5-trifluoromethanesulfonyloxy-3,3,7-trimethyl-2,2
3.4 g of 3-dihydrobenzofuran in 10 ml of acetone
Then, 50 ml of 28% aqueous ammonia was added, and the mixture was heated and stirred under reflux for 5 hours using a condenser cooled with dry ice and acetone to complete the reaction.

After the reaction solution was cooled, the liberated oily substance was extracted with ethyl acetate, washed sufficiently with water and dried, and the solvent was distilled off under reduced pressure to obtain an oily residue. The obtained residue was purified by silica gel column chromatography (developing solvent; n-hexane: ethyl acetate = 4: 1) to give 2-amino-
5-trifluoromethanesulfonyloxy-3,3,7
-Trimethyl-2,3-dihydrobenzofuran 0.38
g was obtained as crystals (yield 26%). [Melting point] 60-62 ° C [NMR spectrum] (CHCl ₃ ) δ: 1.16 (3H, s), 1.34 (3H, s), 1.55 (2H, s),
2.20 (3H, s), 5.16 (1H, t, J = 9.4Hz), 6.79 (1H, d, J = 2.5H
z), 6.84 (1H, d, J = 2.5Hz)

REFERENCE EXAMPLE 2 Preparation of 2-amino-3,3-dimethyl-5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran Except that benzoquinone was used instead of 2-methyl-1,4-benzoquinone, In a manner substantially similar to Reference Example 1, 2-
Amino-3,3-dimethyl-5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran was obtained. [Melting point] 134-136 ° C [NMR spectrum] (CHCl ₃ ) δ: 1.18 (3H, s), 1.36 (3H, s), 2.25 (2H, s),
5.19 (1H, s), 6.72 (1H, d, J = 9.0Hz), 6.9 ~ 7.1 (2H, m)

Example 1 Production of 3,3,7-trimethyl-2- (dimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran (Compound No. 1) (Production method (i)) 2-amino-3,3,7-trimethyl-5-trifluoromethanesulfonyloxy- obtained by the method of Reference Example 1
1.00 g of 2,3-dihydrobenzofuran and 0.47 g of triethylamine were dissolved and stirred in 10 ml of dichloromethane, and 0.55 g of dimethylsulfamoyl chloride was added under ice-cooling under a nitrogen atmosphere, followed by stirring at room temperature for 24 hours. After discharging into ice water, the organic layer extracted with dichloromethane was washed with dilute hydrochloric acid, water and a saturated aqueous solution of sodium hydrogen carbonate, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the obtained crude product was subjected to silica gel column chromatography (developing solvent; n-hexane: ethyl acetate = 3:
1 (volume ratio)) to give 3,3,7-trimethyl-2
0.07 g of-(dimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran was obtained as white crystals (yield 5%). [Mp] from 149.6 to 150.4 ° C. [ 'H-NMR spectrum] _{(CDCl 3) δ: 1.25 (} 3H, s), 1.40 (3H, s), 2.23 (3H, s), 2.93 (6H,
s), 5.30 (1H, d, J = 12.0Hz), 5.48 (1H, d, J = 12.0Hz), 6.
82 (1H, d, J = 2.2Hz), 6.90 (1H, d, J = 2.2Hz)

Example 2 Production of 3,3,7-trimethyl-2- (dimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran (Compound No. 1) (Production method (ii)) 1.17 g of 3,3,7-trimethyl-2-acetoxy-5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran and 0.74 g of N, N-dimethylsulfamoylamide were dissolved and stirred in 10 ml of anhydrous acetonitrile. Under a nitrogen atmosphere, 1 ml of boron trifluoride diethyl ether complex was added, and the mixture was stirred at room temperature for 2 hours.
After adding a small amount of potassium carbonate and stirring, the mixture was filtered and the solvent was distilled off under reduced pressure. The obtained residue was diluted with dichloromethane, washed and neutralized with a saturated aqueous solution of sodium hydrogen carbonate. The organic layer was further washed with water and saturated saline, and dried over anhydrous sodium sulfate. The crude product obtained by evaporating the solvent under reduced pressure was subjected to silica gel column chromatography (developing solvent; n).
-Hexane: ethyl acetate = 3: 1 (volume ratio)) to give 3,3,7-trimethyl-2- (dimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran. 06 g was obtained as white crystals (yield 77%).

Example 3 Preparation of 3,3,7-trimethyl-2- (N, N, N'-trimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran (Compound No. 2) (Production method (i)) A 50% methanol solution of methylamine 40% in a nitrogen atmosphere
of 2-chloro-3,3,7-trimethyl-5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran obtained by the method of Reference Example 1 under ice-cooling.
A solution of 52 g dissolved in 10 ml of tetrahydrofuran was added dropwise, and the mixture was stirred for 15 minutes, and then stirred at room temperature for 1 hour. Thereafter, the residue obtained by distilling off the solvent under reduced pressure was dissolved in dichloromethane, and filtered under reduced pressure through celite.
Furthermore, the residue obtained by evaporating the solvent under reduced pressure was dissolved in 15 ml of dichloromethane, 0.67 g of triethylamine was added and stirred, 0.79 g of dimethylsulfamoyl chloride was added dropwise under ice cooling, and the mixture was stirred at room temperature for 12 hours. did. The same post-treatment as in Example 1 was performed to obtain the desired 3,3,7-trimethyl-2- (N, N, N'-trimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydro 0.14 g of benzofuran was obtained as a pale yellow oil (yield 7%). [ 'H-NMR spectrum] _{(CDCl 3) δ: 1.34 (} 3H, s), 1.40 (3H, s), 2.26 (3H, s), 2.53 (3H,
s), 2.92 (6H, s), 5.97 (1H, s), 6.82 (1H, d, J = 2.2Hz), 6.
91 (1H, d, J = 2.2Hz)

Example 4 Production of 3,3,7-trimethyl-2- (N, N, N'-trimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran (Compound No. 2) (Production method (ii)) 3,3,7-
Trimethyl-2-acetoxy-5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran
60 g and 0.45 g of N, N, N'-trimethylsulfamyldiamide are dissolved and stirred in 10 ml of anhydrous acetonitrile, 0.6 ml of boron trifluoride diethyl ether complex is added under a nitrogen atmosphere, and then stirred at room temperature for 2 hours. did.
The same post-processing as in Example 2 was performed, and the desired 3,3,7
0.65 g of -trimethyl-2- (N, N, N'-trimethylaminosulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran was obtained as a pale yellow oil (yield 89%).

Examples 5 to 10 (Compound Nos. 3 to 8) (Production Method (ii)) Compounds 3 to 8 were synthesized in the same manner as in Example 2.
The compounds and their physical properties are shown in Table 1 (Table 1) and (Table 2).

[0053]

[Table 1]

[0054]

[Table 2]

Example 113 3,3,7-Trimethyl-2-
Production of (phenylsulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran (Compound No. 9) (Production method (i)) Reference example 1
2-amino-3,3,7-trimethyl-5 obtained by the method of
Trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran (1.00 g) and triethylamine (0.4 g)
7 g was dissolved and stirred in 10 ml of dichloromethane, and benzenesulfonyl chloride (0.6 g) was added under ice cooling under a nitrogen atmosphere.
5 g was added, followed by stirring at room temperature for 12 hours. After discharging into ice water, the organic layer extracted with dichloromethane was diluted with hydrochloric acid,
The extract was washed with water and a saturated aqueous solution of sodium hydrogen carbonate, and dried over anhydrous sodium sulfate. The crude product obtained by distilling off the solvent under reduced pressure was purified by silica gel column chromatography (developing solvent; n-hexane: ethyl acetate = 5: 1 (volume ratio)) to give 3,3,7-trimethyl-2-. 0.11 g of (phenylsulfonylamino) -5-trifluoromethanesulfonyloxy-2,3-dihydrobenzofuran was obtained as colorless powdery crystals (yield 8%). [Mp] 126.2 to 128.4 ° C. [ 'H-NMR spectrum] _{(CDCl 3) δ: 1.24 (} 3H, s), 1.36 (3H, s), 1.83 (3H, s), 5.48 (1H, d ,
J = 1.7Hz), 5.64 (1H, d, J = 1.7Hz), 6.77 (1H, d, J = 2.2Hz),
6.79 (1H, d, J = 2.2Hz), 7.5-7.7 (m, 3H), 7.9-8.0 (m, 2H)

Example 12 3,3,7-Trimethyl-2- (phenylsulfonylamino) -5-trifluoromethanesulfonyloxy-
Production of 2,3-dihydrobenzofuran (Compound No. 9) (Production method (ii)) 3,3,7-Trimethyl-2-acetoxy-5-trifluoromethanesulfonyloxy-2,
1.50 g of 3-dihydrobenzofuran and 1.28 g of benzenesulfonamide were dissolved and stirred in 20 ml of anhydrous acetonitrile, 1.5 ml of boron trifluoride diethyl ether complex was added under a nitrogen atmosphere, and then the mixture was stirred at room temperature for 2 hours. The same post-processing as in Example 2 was performed,
3,7-trimethyl-2- (phenylsulfonylamino) -5-trifluoromethanesulfonyloxy-2,
1.45 g of 3-dihydrobenzofuran was obtained as white powdery crystals (yield 77%).

Examples 13 to 22 (Compound Nos. 10 to 1)
9) It was synthesized in the same manner as in Example 12. Table 2 (Table 3), (Table 4), (Table 5)
It describes in.

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[Table 3]

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[Table 4]

[0060]

[Table 5]

[Formulation Examples and Test Examples] Next, preparations of herbicides according to the present invention and test examples of herbicidal activity are shown.

Formulation Example 1 (Wettable powder) Compound (1) of the present invention: 20 parts by weight, Neoperex (trade name, manufactured by Kao Atlas): 2 parts by weight, Neugen EA80
(Trade name, manufactured by Sanyo Chemical): 2 parts by weight, carplex (trade name, manufactured by Shionogi Pharmaceutical): 5 parts by weight, and Siegrite (trade name, manufactured by Kunimine Mining): 71 parts by weight are crushed, mixed and hydrated. Agent was obtained.

Formulation Example 2 (Wettable powder) Compound (5) of the present invention: 40 parts by weight, white carbon:
5 parts by weight, ammonium polyoxyethylene alkylphenyl ether sulfate: 4 parts by weight, sodium ligninsulfonate: 2 parts by weight, and diatomaceous earth: 49 parts by weight were pulverized and mixed to obtain a wettable powder.

Formulation Example 3 (Powder) Compound (2) of the present invention: 3 parts by weight, Emulgen 910 (trade name, manufactured by Kao): 0.5 part by weight, and Shinyo clay (trade name, manufactured by Asada Flour Milling): 96.5 The parts by weight were thoroughly mixed and pulverized to obtain a powder.

Formulation Example 4 (Granules) Finely pulverized compound (11) of the present invention: 3 parts by weight, neoperex: 2 parts by weight, sun extract p252 (trade name, manufactured by Sanyo Kokusaku pulp): 2 parts by weight, Sanritsu After well mixing 70 parts by weight of vent (trade name, manufactured by Mitsui Mining Industry) and 23 parts by weight of Sanritsu talc (trade name, manufactured by Mitsui Mining Industry), wet by adding an appropriate amount of water, and then a small injection molding machine. And extruded. This was air-dried at 30 to 60 ° C. and crushed, and then sized with a sizing machine to 0.3 to 2 mm to obtain granules.

Formulation Example 5 (Emulsion) Compound (11) of the present invention: 10 parts by weight, Solpol 800
A (trade name, manufactured by Toho Chemical): 10 parts by weight and o-xylene: 80 parts by weight were mixed and dissolved to obtain an emulsion.

Test Example 1 Flooded Soil Treatment Test (Pretreatment before Occurrence) Soil was packed in a 1/5000 arel wagner pot, and seeds or tubers of the Japanese radish, fireflies, pine stalks, and squirrels were sown and flooded. Two rice seedlings (2 to 3 leaf stage) that had been raised in advance were used as one strain.
The strain was transplanted and grown in a greenhouse. One day later (before the emergence of weeds), a predetermined amount of the test compound was treated with granules prepared according to the method described in Formulation Example 4, and after 30 days, the emergence of weeds and the state of phytotoxicity to rice were determined. Observed and investigated. Table 3 (Table 6), (Table 7), (Table 8)
The results are shown in (Table 9) and (Table 10). In the table, the degree of damage to the test plant and the degree of chemical damage to the crop are indicated by the following criteria as compared with the case where the growth state of the plant is not treated.

(6) Growth (%) 50 to 5 (dead) Death) 46-10 (Severely harmful) 311-40 (Medium harm) 241-70 (Small harm) 171-90 (Slightly harmful) 091-100 (No harm)） ────────────────

The comparative compounds A, B, C and D represent the following compounds (formula 15). (The same applies to Test Examples 2 and 3.)

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Embedded image

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[Table 6]

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[Table 7]

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[Table 8]

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[Table 9]

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[Table 10]

Test Example 2 Flooded soil treatment test (treatment during growing season) Soil was packed in 1/5000 are Wagner pots,
The seeds of tubers, fireflies, pine trees, and sedges were sowed and flooded. Two rice seedlings (2 to 3 leaf stage), which have been raised in advance, are used as one strain.
The two strains were transplanted and grown in a greenhouse. When the barnyard leaves become two leaves, a predetermined amount of the test compound is treated with granules prepared according to the method described in Formulation Example 4, and after 30 days, the occurrence of weeds and the state of phytotoxicity to rice are determined. Observed and investigated. The results are shown in Table 4 (Table 11), (Table 12),
The results are shown in (Table 13), (Table 14), and (Table 15).

In the table, the degree of damage to the test plant and the degree of chemical damage to the crop are indicated in the same manner as in Test Example 1.

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[Table 11]

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[Table 12]

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[Table 13]

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[Table 14]

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[Table 15]

Test Example 3 Chemical Injury Test 1/5000 are Wagner pots were filled with soil, flooded in a greenhouse, and transplanted with three rice seedlings (2 to 3 leaf stage) which had been raised in advance. Seven days later, a predetermined amount of the test compound was treated with the granules prepared according to the method described in Formulation Example 4. For 10 days after the treatment, a water leakage of 0.5 cm / day was given, and thereafter, no water leakage was controlled. Thirty days later, the growth status of the rice was observed and investigated. The results are shown in Table 5 (Table 16) and (Table 17).

In the table, the growth status of the paddy rice was measured by measuring the plant height, the number of stems and the weight of air-drying, and expressed in% as compared with the untreated group.

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[Table 16]

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[Table 17]

As described above, as shown in Tables 3 to 5, Compound A,
Although the compound of the present invention has a higher herbicidal effect as compared with B and D, the compound has very little or almost no phytotoxicity to rice, and can be used safely for rice. Further, the selectivity is significantly improved as compared with the compound C.

[0088]

EFFECTS OF THE INVENTION The compound of the present invention has a high herbicidal action as a herbicide, although the phytotoxicity to rice is greatly reduced as compared with the known compounds described in the above-mentioned literatures. It has the characteristic of showing a high herbicidal effect against important weeds such as fireflies. That is, the compound of the present invention has high applicability as a rice herbicide, and the present invention provides an extremely useful herbicide.

Continuing on the front page (72) Inventor Fumiaki Koizumi 1144 Togo, Mobara-shi, Chiba Prefecture, Mitsui Toatsu Chemicals Co., Ltd. (72) Inventor Tamotsu Asano, 1144 Togo, Togo, Mobara-shi, Chiba Prefecture, Mitsui Toatsu Chemicals Inc. (72 Inventor Yukihiro Yoshikawa 1144 Togo, Mogo-shi, Chiba Pref., Mitsui Toatsu Kagaku Co., Ltd. (72) Inventor Masami Koyamada, 1144 Togo, Togo, Mobara-shi, Chiba Pref. Reference JP-A-53-98936 (JP, A) JP-B-55-45523 (JP, B2) US Patent 3,689,507 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07D 307 / 82 A01N 43/12 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A compound of the general formula (I) [In the formula, R ¹ represents a hydrogen atom, a methyl group or a halogen atom, and R ² represents a hydrogen atom or a methyl group. R ³ is a lower alkyl group, a lower alkyl group substituted with a halogen atom, a phenyl group substituted with a methyl group or a methoxy group or a halogen atom, a benzyl group, a benzyl group substituted with a halogen atom, or a compound represented by the general formula (II) ( Chemical formula 2) (Wherein R ⁴ and R ⁵ represent a hydrogen atom, a lower alkyl group, a phenyl group, a benzyl group, a benzyl group substituted with a halogen atom or a pentamethylene group). A 2,3-dihydrobenzofuran derivative represented by the formula: 2. A compound of the formula (I) [In the formula, R ¹ represents a hydrogen atom, a methyl group or a halogen atom, and R ² represents a hydrogen atom or a methyl group. R ³ is a lower alkyl group, a lower alkyl group substituted with a halogen atom, a phenyl group substituted with a methyl group or a methoxy group or a halogen atom, a benzyl group, a benzyl group substituted with a halogen atom, or a compound represented by the general formula (II) ( Chemical formula 4) (Wherein R ⁴ and R ⁵ represent a hydrogen atom, a lower alkyl group, a phenyl group, a benzyl group, a benzyl group substituted with a halogen atom or a pentamethylene group). ] The herbicide characterized by containing the 2,3- dihydrobenzofuran derivative represented by these as an active ingredient. 3. A compound of the general formula (I) [In the formula, R ¹ represents a hydrogen atom, a methyl group or a halogen atom, and R ² represents a hydrogen atom or a methyl group. R ³ is a lower alkyl group, a lower alkyl group substituted with a halogen atom, a phenyl group substituted with a methyl group or a methoxy group or a halogen atom, a benzyl group, a benzyl group substituted with a halogen atom, or a compound represented by the general formula (II) ( (Chemical formula 6) (Wherein R ⁴ and R ⁵ represent a hydrogen atom, a lower alkyl group, a phenyl group, a benzyl group, a benzyl group substituted with a halogen atom or a pentamethylene group). In producing the compound represented by the general formula (III), (Wherein R ¹ represents the above-mentioned meaning) by converting the compound represented by the general formula (IV) (Wherein R ¹ represents the above-mentioned meaning), and then converted into an acetate represented by the general formula (V) (Chemical formula 9): R ² NHSO ₂ R ³ (V) (wherein R ² , R ³ represents the same meaning as defined above), which is characterized by the general formula (I)
A method for producing a compound represented by the formula: