JPH0625133B2 - Pyrazole derivative, its production method and selective herbicide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a compound of the general formula (I): [Wherein R ¹ represents a lower alkyl group having 2 or more carbon atoms which may be substituted with a halogen atom, a lower alkenyl group which may be substituted with a halogen atom or an aralkyl group, and X represents a halogen atom, a nitro group, a lower group Represents an alkyl group, a trifluoromethyl group or a methanesulfonyl group, n is 1 to
Indicates an integer of 3. When n is 2 or more, X may be the same or different. Z is a hydrogen atom, a lower alkyl group optionally substituted with a halogen atom, a lower alkenyl group optionally substituted with a halogen atom, a lower alkynyl group optionally substituted with a halogen atom, a cyanomethyl group, and the following formula: (In the formula, R represents a hydrogen atom or a lower alkyl group, m
Represents an integer of 0 or 1.

R ² represents a lower alkyl group, a halogen atom, a nitro group, a phenyl group which may be substituted with up to five different or different substituents selected from a trifluoromethyl group or a lower alkyl group. . ) Or an organic acid residue. ], A method for producing the same, and a selective herbicide containing one or more of the compounds as an active ingredient, and a compound represented by the general formula (I) above. General formula (IV), which is an important intermediate in production: (Wherein R ¹ has the same meaning as described above) and a method for producing the same.

A novel pyrazole derivative represented by the above general formula (I), which has not been published in the literature (hereinafter referred to as the compound (I) of the present invention), is useful as an active ingredient compound for herbicides, and is a feature that causes weeds to whiten and die. It has a strong herbicidal effect even when applied to very difficult to control weeds in conventional paddy fields, even if applied in an extremely small amount. Conventionally, a large number of compounds are known as pyrazole derivatives, and among them, pyrazolates (generic name) represented by the following structural formulas have been already commercialized as commercial herbicides for paddy fields and are commercially available. and so on.

(Pyrazolate) On the other hand, in addition to pyrazole derivatives, many herbicides have been put to practical use as herbicides for paddy fields and are widely used as single agents or complex agents. However, perennial weeds that occur in paddy fields generally have a strong growth, and their development period is long and it is very difficult to control them. There are many herbicides effective for annual weeds. The current situation is that there are few. In addition, recent paddy rice cultivation has become a suitable condition for weed development due to factors such as introduction of mechanization and early transplantation.
It is difficult to expect complete control of annual and perennial weeds with only one herbicide treatment.

In recent years, various single agents or mixed agents have been tried to control all weeds by spraying chemicals once before and after rice planting in paddy rice cultivation, but the herbicidal effect is extremely unsatisfactory and therefore impossible. When the effect is obtained by only one treatment, a large amount of the applied drug per unit area is required.

In order to solve the above problems, there is a long-awaited demand for a single-treatment herbicide having an extremely low dose and effective for a wide range of weeds.

As a result of various investigations, the present inventors have shown effectiveness against a wide range of weeds, and among these weeds, such as Mizugaya-tsuri and Kurogwai, which have been difficult to control in the past and effective herbicides have been close to none. The present invention has been completed by discovering the compound (I) of the present invention having extremely high potency against the perennial weeds of the present invention. Further, the compound (I) of the present invention has an effect that it can be used safely without any chemical damage to paddy rice.

The compound (I) of the present invention has the general formula (I) as described above: [In the formula, R ¹ , X, n and Z have the same meanings as described above. ] It is a pyrazole derivative represented by these.

Conventionally, some compounds are known as pyrazole derivatives having herbicidal activity, and for example, Japanese Patent Publication No. 54-3.
6648 and Japanese Patent Publication No. 56-28885 describe that 4-benzoyl derivatives are useful as herbicides.

Commercially available and commercially available pyrazole derivatives include the above-mentioned pyrazolate (generic name) and pyrazoxifene (generic name) represented by the following formula.

In the pyrazole derivative described in Japanese Patent Publication No. 56-28885, the 3-position of the pyrazole ring of the compound represented by the formula (I) has only CH ₈ group.

In the pyrazole derivative described in Japanese Patent Publication No. 54-366648, the 3-position of the pyrazole ring of the compound represented by the formula (I) is almost a lower alkyl group, and the 5-position substituent is OH, SH, its salts or esters with certain organic acids. Among these, when the 3-position is a hydrogen atom, only one example is specifically described as an example, as shown below.

However, this compound A is the above-mentioned Japanese Patent Publication No. 54-3664.
As is clear from the description of the biological test data in JP-A-8, the herbicidal activity is inferior to the commercially available pyrazolate.

The present inventors have conducted comparative tests with the compound of the present invention and these pyrazolates and compound A, and have confirmed that the compound of the present invention has far superior herbicidal activity.

Although many pyrazole derivatives have been synthesized and tested for herbicidal activity, 3
The compound having a hydrogen atom at the − position was only the above compound A.

The reason is that a compound having a substituent such as alkyl at the 3-position (3-position alkyl derivative) is relatively easy to synthesize, but it is very difficult to synthesize when the 3-position is a hydrogen atom. It was thought that this was due to the fact that the herbicidal activity was lower and the practicability was poorer than that of the 3-position alkyl derivative.

As a result of various investigations on a compound in which the 3-position of the pyrazole ring is a hydrogen atom, the present inventors have found a method that can be easily synthesized, and as a result of various investigations on the substitution moiety at the 5-position, the above-mentioned general The compound of the present invention represented by the formula (I) (I)
It has a strong herbicidal activity and is very safe against paddy rice, and has been found to be an excellent herbicide for paddy rice.

In addition, the compound (I) of the present invention represented by the general formula (I) is remarkably difficult to control weeds in corn fields, soybean fields and the like, and is extremely remarkably effective against the peanut perennial weed, which is extremely difficult to control. It has high herbicidal activity and no phytotoxicity to corn and soybean, and is extremely useful as a field herbicide.

The compound (I) of the present invention can be easily synthesized according to the following reaction formula.

(1) (2) (In the formula, Q represents a halogen atom or a hydroxyl group, Ha represents a halogen atom, and R ¹ , X, n, and Z have the same meanings as described above.) The reaction formula (1) is an important intermediate in the present invention. The general formula of (I
By benzoylating the compound represented by V),
A reaction for obtaining a compound (hereinafter referred to as a compound (1 ′)) in which Z is a hydrogen atom in the compound (I) of the present invention is shown.

As an example of the reaction, the compound (IV) is treated with a dehydrohalogenating agent (preferably sodium hydroxide, potassium hydroxide, sodium carbonate, triethylamine, pyridine) in the presence of
Various benzoyl halides can be reacted in a solvent inert to the reaction to form an ester, which can be rearranged to give compound (I ′) in high yield. As a solvent for the esterification reaction, for example, dioxane, acetonitrile, benzene, toluene, chloroform and the like can be used alone, but, for example, water-toluene,
A two-phase system such as water-chloroform can also be used.

The rearrangement reaction is carried out without a solvent or in a solvent inert to the reaction (preferably dioxane, acetonitrile, etc.) in the presence of a Lewis acid such as aluminum chloride, tin chloride or zinc chloride or a base such as calcium hydroxide, potassium carbonate or sodium carbonate. It can proceed easily.

The reaction formula (2) shows a reaction in which the compound (I ′) is condensed with an appropriate halide to obtain the compound (I) of the present invention. This reaction is a solvent inert to the reaction (eg, ethers such as diethyl ether, tetrahydrofuran, dioxane, aromatic hydrocarbons such as benzene, toluene, xylene, ketones such as acetone and methyl ethyl ketone, dichloromethane, chloroform, carbon tetrachloride). Dehydrohalogenating agent (for example, sodium carbonate, potassium carbonate, etc.) in halogenated hydrocarbons such as ethyl acetate, ethyl acetate, N, N-dimethylformamide, acetonitrile, etc. can be used alone or as a mixture. Inorganic bases, organic bases such as pyridine, triethylamine, N, N-dimethylaniline, etc.) are preferable. The reaction temperature may range from room temperature to the boiling point of the solvent used, but it is most advantageous in operation to set it at the boiling point of the solvent. The compound (I) of the present invention can be obtained in a very good yield by carrying out the condensation reaction represented by the reaction formula (2) under appropriate conditions in consideration of the above conditions.

In addition, the pyrazole derivative represented by the general formula (IV) (hereinafter referred to as the compound (IV) of the present invention), which is an important intermediate of the present invention used in the reaction formula (1), is a novel compound which has not been published in the literature. In the synthesis of the compound (I) of the present invention, pesticides, pharmaceuticals, etc., its utility is expected to be particularly high in the future. As described above, the compound (IV) of the present invention is
A pyrazole derivative having a substituent such as an alkyl group at the -position is relatively easy to synthesize, but when the 3-position of the pyrazole is a hydrogen atom, it has been very difficult to synthesize the pyrazole derivative until now. It is considered that no synthetic example was reported. The method for producing the compound (IV) of the present invention investigated by the present inventors is shown in the reaction scheme as follows.

(3) (Four) (In the reaction formula, R ¹ has the same meaning as described above.) In the reaction shown in the above reaction step (3), both the hydrazine derivative (V) and the ethoxymethylenemalonic acid diethyl ester (VI) are added. A cyclization reaction was carried out, and the corresponding 4-substituted 1-position
Ethoxycarbonyl-5-hydroxypyrazole (VII)
The reaction to obtain This reaction can be carried out without solvent, but it is desirable to carry out in a suitable organic solvent (eg, methanol, ethanol, etc.). The reaction temperature is preferably low at the start of the reaction and is preferably heated to accelerate the ring-closing reaction as the reaction approaches the end. In the reaction represented by the reaction formula (4), the compound (VII) obtained in the reaction formula (3) is used as a raw material, and the compound and the mineral acid are heated in the presence of water,
The compound of the present invention (I
The reaction for obtaining V) is shown. At the end of the reaction, the compound of the present invention is obtained in the form of a mineral acid salt, but the compound of the present invention can be easily obtained by neutralizing with a suitable base.

As described above, the compounds (I) and (IV) of the present invention are very useful and novel, and the method for producing them is completely novel and considered to be valuable. . Hereinafter, the present invention will be described with specific examples. However, the present invention is not limited to these.

[Example 1] Synthesis of 1-normal butyl-5-hydroxypyrazole 10.8 g of ethoxymethylene malonic acid diethyl ester (0.
A 20 m solution of ethanol (05 mol) was cooled to 0 ° C., and 14.7 g (0.05 mol) of a 30% aqueous solution of normal butylhydrazine was added dropwise while maintaining the reaction temperature at 5 ° C. or lower. After the completion of dropping, the mixture was stirred at room temperature for 1 hour and then refluxed for 8 hours. After completion of the reaction, the solvent was distilled off under reduced pressure and the mixture was concentrated. To the residue was added 35% hydrochloric acid (20 m), and hydrolysis and decarboxylation were carried out at reflux temperature for 3 hours. After the reaction was completed, the solvent was distilled off under reduced pressure and the residue was dried to obtain 6.2 g of the desired 1-normal-butyl-5-hydroxypyrazole as a hydrochloride.

Properties: Oily substance yield: 70% ¹ H-NMR (δ, ppm.CDC ₃ -DMSO-d ₆ ): 0.92 (3H, t, J = 7Hz, -C H ₈ ), 1.16-1.90 (4H, 4H, m, -C H ₂ -C H ₂ -CH
₃ ), 4.18 (2H, t, J = 7Hz, 5.99 (1H, d, J = 3.5Hz, 7.91 (1H, d, J = 3.5Hz, 11.45 (2H, broads, -O H , H C) Next, an example of the compound included in the present invention, which is synthesized according to Example 1, is shown in Table 1 below as its hydrochloride salt. Are not limited to these.

Example 2 4- (2,4-dichlorobenzoyl) -1-
Synthesis of ethyl-5-hydroxypyrazole Hydrochloride of 1-ethyl-5-hydroxypyrazole 14.85
g (0.1 mol), potassium hydroxide (purity 85%) 13.2
g (0.2 mol) was gradually added to an aqueous solution dissolved in 55 m of water while stirring under ice cooling, and neutralized to give a potassium salt. Then, while adding 60 m of chloroform to form two layers, 20.95 g (0.1 mol) of 2,4-dichlorobenzoyl chloride was added dropwise while keeping the temperature at 5 ° C or lower, and the temperature was kept at room temperature for 2 hours, and the temperature was further increased. The temperature was raised to 40 ° C. and stirred for 1 hour to complete the reaction. After cooling the reaction solution, the organic layer is separated, washed with 5% aqueous sodium hydrogen carbonate solution, water and saturated saline solution in that order, dried over anhydrous sodium sulfate, and the solvent is distilled off under reduced pressure to dryness. A crude product of 5- (2,4-dichlorobenzoyloxy) -1-ethylpyrazole was obtained.

Subsequently, 10 m of 1,4-dioxane was added to and dissolved in the crude ester obtained above, the reaction temperature was raised to 120 ° C., and 20.7 g (0.15 mol) of anhydrous potassium carbonate was added,
The reaction mixture solidified by continuing heating with stirring for about 1 hour. To the obtained solid, 50 m of water was added, heated to dissolve and then returned to room temperature, and hydrochloric acid was added to adjust the pH to <1.
The precipitated solid was taken, dried and recrystallized from n-hexane-benzene to obtain 22.5 g of the target 4- (2,4-dichlorobenzoyl) -1-ethyl-5-hydroxypyrazole.

Yield: 79% Melting point: 144-146 ° C ¹ H-NMR (δ, ppm.CDC ₃ ): 1.43 (3H, t, J = 7Hz, -C H ₃ ), 4.04
(2H, q, J = 7Hz, -C H _2- ), 7.30 ~ 7.47 (4H, m), 9.57 (1H, s, -O
H ) [Example 3] 4- (2,4-dichlorobenzoyl) -1-
Synthesis of ethyl-5-benzyloxypyrazole 4- (2,4-dichlorobenzoyl) -1-ethyl-5
Add 1.43 g (0.005 mol) of hydroxypyrazole to 30 m of benzene and add 0.51 g of triethylamine.
(0.005 mol) was added to make a uniform solution.

To the above solvent, 0.86 g (0.005 mol) of benzyl bromide was added with stirring at room temperature, and then heated and reacted at reflux temperature for 4 hours. After cooling the reaction mixture, the produced salt was separated, and the obtained benzene solution was washed successively with 5% aqueous sodium hydrogen carbonate solution, water and saturated brine, dried over anhydrous sodium sulfate, and benzene was removed under reduced pressure. Evaporation gave an oily residue. The resulting oil was purified by silica gel column chromatography (eluent: benzene) to give the desired 4- (2,4-dichlorobenzoyl) -1-ethyl-5-benzyloxypyrazole as a colorless oil. As a product, 1.41 g was obtained.

Yield: 75% ¹ H-NMR (δ, ppm.CDC ₃ ): 1.19 (3H, t, J = 7Hz, -C H ₃ ), 3.83
(2H, t, J = 7Hz, -C H ₂ , CH ₃ ), 5.48 (2H, s, -C H ₂ O-), 7.20 ~ 7.4
0 (m, 9H) Next, examples of compounds included in the present invention, which are synthesized by the same method as in Examples 2 and 3, including the compounds of Examples 2 and 3 are shown in Table 2 below. Inventive compounds are not limited to these.

Next, physical properties of the compounds listed in Table 2 are shown in Table 3.

Next, when the compound of the present invention is applied as a herbicide, generally, a suitable carrier, for example, solid carrier such as clay, talc, bentonite, diatomaceous earth or water, alcohols (methanol, ethanol, etc.), aromatic hydrocarbon It can be used by mixing with liquid carriers such as compounds, ethers, ketones, esters (ethyl acetate etc.), acid amides (dimethylformamide etc.), and if desired, emulsifiers, dispersants, suspending agents, penetrating agents. By adding agents, spreading agents, stabilizers, etc., it can be put to practical use in any dosage form such as emulsions, wettable powders, powders and granules. The content of the compound of the present invention in these preparations is not particularly limited, but is usually
0.1-95 weight% is desirable. In addition, other types of herbicides, such as Farm Chemical Handbook 70 , can be prepared or sprayed as needed.

(1984), various insecticides, fungicides, synergists and the like may be mixed and applied.

Next, specific examples of formulation of the preparation when the compound of the present invention is used are shown. Parts indicate parts by weight. However, the formulation example of the present invention is
It is not limited to these.

Formulation 1 Granules After uniformly mixing and pulverizing the above, a small amount of water is added, the mixture is kneaded with stirring, granulated by an extrusion type granulator, and dried to give granules.

Formulation 2 Granules After uniformly mixing and pulverizing the above, a small amount of water is added, the mixture is kneaded with stirring, granulated by an extrusion granulator, and dried to give granules.

Formulation 3 Granules After uniformly mixing and pulverizing the above, a small amount of water is added, the mixture is kneaded with stirring, granulated by an extrusion type granulator, and dried to give granules.

Formulation 4 Granules After uniformly mixing and pulverizing the above, a small amount of water is added, the mixture is kneaded with stirring, granulated by an extrusion granulator, and dried to give granules.

Formulation 5 Granules After uniformly mixing and pulverizing the above, a small amount of water is added, the mixture is kneaded with stirring, granulated by an extrusion granulator, and dried to give granules.

Formulation 6 Granules After uniformly mixing and pulverizing the above, a small amount of water is added, the mixture is kneaded with stirring, granulated by an extrusion granulator, and dried to give granules.

Next, the usefulness of the compound of the present invention will be specifically described with reference to test examples.

Test Example 1 Herbicidal effect test in flooded condition After alluvial soil was put into a 1 / 10,000 are Neubauer pot,
Add tap water and mix to make a water depth of 2 cm.

The seeds of Taenia cinerea, broad-leaved weeds (Kokonagi, Azena, Nymphalidae) and firefly are mixed and sown in the above pot, and the pods of Urikawa, Mizugaya-tsuri and Kurowai are planted in the pot.

One day later, the drug diluted solution is dropped onto the surface of the water with a measuring pipette so that a predetermined amount of the drug is obtained. The herbicidal effect against various weeds was investigated 3 weeks after the dropping of the drug according to the following criteria.

The results are shown in Table 4.

Criteria 5… grass-killing rate 90% or higher (almost complete death) 4… 〃 70-90% 3… 〃 40-70% 2… 〃 20-40% 1… 〃 5-20% 0… 〃 5% or less (mostly) However, the above-mentioned herbicidal rate is obtained by measuring the above-ground vegetation weight of the chemical treatment area and the above-ground vegetation weight of the non-treatment area by the following formula.

Test Example 2 Herbicidal effect test and phytotoxicity test under submerged condition After alluvial soil was put into a 1 / 5,000 ares Wagner pot, tap water was added and mixed to obtain a submerged condition with a water depth of 2 cm.

Plant 5 or 3 of each of Spodoptera litura and Klogwai lumps collected from the perennial weed-prone paddy field in the previous year in the Wagner pot soil under the above-mentioned submerged conditions. Furthermore, the 2.5-leaf stage paddy rice grown in advance in a nursery box is transplanted. After the germination of Mizuhazuri and Kurogwai, the drug diluent is dropped onto the surface of the water with a measuring pipette so that the prescribed amount is obtained. The herbicidal effect against various weeds was investigated 3 weeks after the drug was dropped according to the criteria of Test Example 1.

The results are shown in Table 5.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-51-106738 (JP, A) J. Prakt. Chem. , 313 (1) 115-128 (1971)

Claims (6)

[Claims] 1. General formula (I): [In the formula, R ¹ represents a lower alkyl group having 2 or more carbon atoms or an aralkyl group which may be substituted with a halogen atom, and X 1
Represents a halogen atom, a nitro group, a lower alkyl group, a trifluoromethyl group or a methanesulfonyl group, and n is 1
Indicates an integer of ˜3. When n is 2 or more, X may be the same or different. Z is a hydrogen atom, a lower alkyl group optionally substituted with a halogen atom, a lower alkenyl group optionally substituted with a halogen atom, a lower alkynyl group optionally substituted with a halogen atom, a cyanomethyl group, and the following formula: (In the formula, R represents a hydrogen atom or a lower alkyl group, and m
Represents an integer of 0 or 1. R ² represents a lower alkyl group, a halogen atom, a nitro group, a phenyl group or a lower alkyl group which may be substituted with the same or different up to 5 substituents selected from the trifluoromethyl group. . ) Or an organic acid residue. ] The pyrazole derivative represented by these. 2. General formula (II): (In the formula, R ¹ represents a lower alkyl group having 2 or more carbon atoms which may be substituted with a halogen atom, or an aralkyl group, and X 1
Represents a halogen atom, a nitro group, a lower alkyl group, a trifluoromethyl group or a methanesulfonyl group, and n is 1
Indicates an integer of ˜3. When n is 2 or more, X may be the same or different. ) And a compound represented by the general formula (III): Hal-Z (III) [wherein, Z is a lower alkyl group optionally substituted with a halogen atom, a lower alkenyl group optionally substituted with a halogen atom, A lower alkynyl group optionally substituted with a halogen atom, a cyanomethyl group, and the following formula: (In the formula, R represents a hydrogen atom or a lower alkyl group, and m
Represents an integer of 0 or 1. R ² represents a lower alkyl group, a halogen atom, a nitro group, a phenyl group or a lower alkyl group which may be substituted with the same or different up to 5 substituents selected from the trifluoromethyl group. . ) Or an organic acid residue. Hal represents a halogen atom. ] The compound of general formula (I) characterized by reacting with the compound represented by: (In the formula, R ¹ , X, n and Z have the same meanings as described above.)
The manufacturing method of the pyrazole derivative represented by. 3. General formula (I): [In the formula, R ¹ represents a lower alkyl group having 2 or more carbon atoms or an aralkyl group which may be substituted with a halogen atom, and X 1
Represents a halogen atom, a nitro group, a lower alkyl group, a trifluoromethyl group or a methanesulfonyl group, and n is 1
Indicates an integer of ˜3. When n is 2 or more, X may be the same or different. Z is a hydrogen atom, a lower alkyl group optionally substituted with a halogen atom, a lower alkenyl group optionally substituted with a halogen atom, a lower alkynyl group optionally substituted with a halogen atom, a cyanomethyl group, and the following formula: (In the formula, R represents a hydrogen atom or a lower alkyl group, and m
Represents an integer of 0 or 1. R ² represents a lower alkyl group, a halogen atom, a nitro group, a phenyl group or a lower alkyl group which may be substituted with the same or different up to 5 substituents selected from the trifluoromethyl group. . ) Or an organic acid residue. ] The selective herbicide characterized by containing 1 type, or 2 or more types of the compound represented by these as an active ingredient. 4. General formula (IV): (In the formula, R ¹ represents a lower alkyl group having 2 or more carbon atoms or an aralkyl group which may be substituted with a halogen atom.)
And a compound represented by the general formula (V): (In the formula, Q represents a hydroxyl group or a halogen atom, X represents a halogen atom, a nitro group, a lower alkyl group, a trifluoromethyl group or a methanesulfonyl group, and n is 1 to 3).
Indicates an integer. When n is 2 or more, X may be the same or different. ) A compound represented by the general formula (II): (In the formula, R ¹ , X and n have the same meanings as described above.)
The manufacturing method of the pyrazole derivative represented by. 5. General formula (IV): (In the formula, R ¹ represents a lower alkyl group having 2 or more carbon atoms which may be substituted with a halogen atom or a lower alkenyl group which may be substituted with a halogen atom). 6. General formula (VI): R ¹ NHNH ₂ (VI) (In the formula, R ¹ is a lower alkyl group having 2 or more carbon atoms which may be substituted with a halogen atom, or may be substituted with a halogen atom. A hydrazine derivative represented by a lower alkenyl group or an aralkyl group), and a general formula (VII): R ³ OCH═C (COOR ⁴ ) ₂ (VI) (wherein R ³ and R ⁴ are lower alkyl, respectively). A compound represented by a group) is subjected to a condensation and cyclization reaction, and then heated, hydrolyzed and decarboxylated with a mineral acid, represented by the general formula (IV): (In the formula, R ¹ has the same meaning as described above.)