KR930006768B1 - Process for preparing of pyrazole derivatives - Google Patents

Abstract

Pyrazole derivs. of formula (I) are new. In the cpds. (I), R1 and R2 each are H, halogen methyl, ethyl, methoxy or ethoxy; A=O or S; n = 1-3. Also claimed is the prepn. of (I) which comprises (a) treating a cpd. of formula (III) with a base, and (b) reacting the obtd. cpd. with a cpd. of formula (II). The cpd. of formula (II) is prepd. by reacting 4-(2',4'-dichlorophenyl carbonyl)-1,3- dimethyl pyrazolone with dihalogen alkane. The cpds. (I) are useful as a herbicide.

Description

[Name of invention]

Novel pyrazole derivatives, preparation method thereof and herbicide composition containing the same

Detailed description of the invention

The present invention relates to novel pyrazole derivatives of the general formula (I) below, useful as herbicides, methods for their preparation and herbicide compositions containing them.

In the above formula, R ₁ and R ₂ each independently represent a hydrogen, halogen, methyl, ethyl, methoxy or ethoxy group; A represents O or S; n represents the integer of 1-3.

In cultivating crops, weeds have not only inhibited the intake of moisture and soil nutrients to the crops, but also blocked sunlight and disrupted the photosynthesis of the crops, causing as much damage as pests and effectively inhibiting the growth of these weeds. Efforts have been made to make this happen. However, most of the herbicides that have been developed and used so far are useful for inhibiting the growth of weeds. However, many herbicides are harmful to not only weeds but also adjacent useful crops when the effective amount is used. .

As representative herbicides known in the art, German Patent Publication No. 2,513,750 discloses substituted pyrazole derivatives represented by the following general formula (A), and is widely used as a class having a wide range of herbicidal activity.

Wherein Rn '"is hydrogen, methyl, propyl; R' is methyl, isopropyl, ethyl, allyl; R '" is halogen, methyl, methoxy, cyano, acetyl; R is alkanoyl, ClCH ₂ CO, Me ₂ NCO, benzyl, MeCH: CHCO, cinnamoyl, cyclohexylcarbonyl, 4-MeC ₆ H ₄ SO ₂ , PhSO ₂ , MeSO ₂ , MeO ₂ C, PrO ₂ C, PhCH ₂ O ₂ C and the like.

In addition, US Pat. No. 4,298,749 describes substituted pyrazole ether derivatives comprising pyrazolephenyl ethers having herbicidal power.

However, in the art, these pyrazole derivatives still present many problems, particularly in herbicidal selectivity.

Accordingly, the present inventors have focused on the selectivity of pyrazole-based herbicidal compounds. As a result, the present inventors have developed a novel pyrazole derivative (I) having high herbicidal activity and hardly damaging useful crops. It was completed.

The present invention also provides a process for preparing pyrazole derivatives of the following general formula (I), characterized by reacting a compound of the following general formula (III) with a base and then reacting with a compound of the following general formula (II). .

Wherein n, R ₁ , R ₂ and A are as defined above and X represents a halogen atom such as chlorine or bromine.

On the other hand, the reaction process of the production method according to the invention can be described by the following scheme.

In the scheme, n, R ₁ , R ₂ and A are the same as described above.

The compound of formula (II) used in the reaction was subjected to a known compound 4- (2 ', 4'-dichlorophenylcarbonyl) -1,3-dimethylpyrazolone and then reacted with dihalogen alkanes. It can manufacture.

As a base used in the manufacturing method of this invention, alkali metal bases, such as potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, etc., are suitable. Moreover, acetonitrile, acetone, dimethyl sulfoxide, etc. are suitable as a solvent.

The herbicidal pyrazole derivatives of general formula (I) according to the present invention are particularly effective in selectively inhibiting the growth of weeds against seizures, and the benefits of such representative compounds are represented by the following structural formulas (Ia), (Ib), ( Ic) and (Id).

In order to use the compound of the present invention as a herbicide, generally, a suitable carrier, for example, a solid such as clay, talc, diatomaceous earth, or a liquid such as water, alcohol, benzene, toluene, ether, ketones, esters, acids, amides, etc. It can be applied in combination with the emulsifier, dispersant, penetrant, electrodeposition agent, stabilizer, etc., if necessary, and can be practically used in any formulation such as liquid, emulsion, hydrating agent, powder, granule, etc.

The compound of the present invention can be applied to the control of various weeds in non-crop fields such as sports fields, vacant lands, tracks, banks, roads, etc. in addition to the agricultural and horticultural fields such as fields, rice fields, orchards, and the amount of use thereof is applicable to the application field, time of use, Although there are differences depending on the method of use, target weeds and cultivated crops, the effective ingredient per hectare is generally 1.0 ~ 4.0㎏.

In order to test the herbicidal effect of the compound of the present invention, pollen experiments were conducted under greenhouse conditions, and the effect was determined by the moonshine evaluation.

The herbicidal effect test uses tomato, wheat, soybeans, corn and orchard glass as field crops, and weeds such as barley, hairy mantle, sesame, mole, moth, turmeric, ragweed, hyacinth, purslane and soy bean curd. Assay. The tadpoles and blood were tested for rice weeds and rice for crops.

The following shows a blending example of a herbicide containing the compound of the present invention as an active ingredient, and the herbicide composition of the present invention and its preparation method are not limited to these methods.

[Formulation example 1 (2.0㎏ / ha, field conditions)]

Dissolve 6.0 mg of the compound of the present invention in 7.0 ml of an organic solvent (acetone), dilute with 7.0 ml of distilled water, and add a nonionic surfactant Tween 20 to 0.1%.

[Combination Example 2 (2.0 kg / ha, rice field condition)]

2.0 mg of the compound of the present invention was dissolved in 2.2 ml of an organic solvent (acetone), diluted with 2.2 ml of distilled water, and the nonionic surfactant Tween 20 was added to 0.1%.

Experimental Example 1

[Experiment of herbicidal effect by soil treatment]

1) Field conditions

Sterilized field soil (sand loam, pH 6.5 ~ 7.0) is put into plastic pots of 21.5cm × 15.5cm × 7.0㎝ so that the surface area is 300㎠, sowing the above-mentioned crops and weeds and covering 1.0cm Spray the soil surface uniformly so that the amount of ingredients is in a predetermined ratio, and after 3 weeks of spraying the chemical solution, the herbicidal effects on the weeds and weeds of the crops will be examined by the criteria.

2) argument

Put the sterilized paddy soil (plow, pH 6.5 ~ 7.0) into plastic pots of 14.0cm × 9.0cm × 5.5cm to make the surface area 100cm2, sow the above crops and weeds and cover 0.5cm Spray the soil surface uniformly so that the amount of ingredients is in a predetermined ratio, and after 3 weeks of spraying the chemical solution, the herbicidal effects on the weeds and weeds of the crops will be examined by the criteria.

Experimental Example 2

[Experiment of herbicidal effect by foliage treatment]

1) Field conditions

Experimental Example 1-1) and sowing in the same manner as the plants were cultured at the time when the leaves of the soybean leaves are treated with the chemical solution and investigated in the same way.

2) argument

After seeding in the same manner as in Experimental Example 1-2), the plants were cultured and treated with the chemical solution at the time when the leaflets of the soybean were developed and irradiated with the same method.

The criteria for herbicidal effect upon application of the compound are as follows.

[Criteria]

5: 90% or more kill rate

4: 70 ~ 90% kill rate

3: 40 ~ 70% kill rate

2: 20 ~ 40% kill rate

1: 5-20% kill rate

0: 5% or less of killing rate

However, the above-described killing rate is obtained by the following formula for the ratio of those that survived on the ground among those that survived on the ground and those that survived the ground among the treated plants.

In addition, the herbicidal effect test results are as described in Tables 1 and 2, and the result of treating 2 kg per hectare.

TABLE 1

Comparison Table of Herbicidal Effects of Field Conditions

TABLE 2

Comparison table of herbicide effect of rice field condition

Usage: 2㎏ / ㏊

According to the results shown in the above table, the compound of the present invention showed a selectivity to the field crops at the level of 2 kg per hectare, and showed an effect on the sprouts, purslane and soybean wax of the field weeds.

Referring to the preparation method of the compound of the present invention as follows.

Example 1

Preparation of 4- (2 ', 4'-dichlorophenylcarbonyl) -1,3-dimethyl-5- (2-phenoxyethoxy) pyrazole (Compound Ia)

713 mg (2.5 mmol) of 4- (2 ', 4'-dichlorophenylcarbonyl) -1,3-dimethyl pyrazolone and 280 mg (2.5 mmol) of t-butoxypotassium 10 ml of tetrahydro Dissolve in furan and reflux for 30 minutes. After tetrahydrofuran was distilled off under reduced pressure, the reaction was dissolved in 10 ml of N, N-dimethylformamide. The mixture solution of 3.5 ml of 1,2-dibromoethane and 10 ml of N, N-dimethylformamide was heated to 90 ° C., and the reaction solution was added dropwise for 30 minutes. After stirring for 10 hours at 90 ℃ solvent is distilled off under reduced pressure. The reaction was dissolved in 30 ml of ethyl acetate, washed with 30 ml of 5% aqueous sodium hydroxide solution and 30 ml of water, respectively, and then the organic layer was dehydrated with 5 g of magnesium sulfate and filtered. Concentration again under reduced pressure afforded 784 mg (2 mmol) of 5- (2-bromoethoxy) -4- (2 ', 4'-dichlorophenylcarbonyl) 1,3-dimethylpyrazole. This is dissolved in 25 ml of N, N-dimethylformamide.

245 mg (2.6 mmol) of phenol and 146 mg (2.6 mmol) of potassium hydroxide are dissolved in 25 ml of benzene and heated to reflux for 1 hour. After distilling off benzene under reduced pressure, N, N-dimethylform of 5- (2-bromoethoxy) -4- (2 ', 4'-dichlorophenylcarbonyl) -1,3-dimethylpyrazole synthesized above Add the amide solution and stir at 90 ° C. for 6 hours. After distilling off the solvent under reduced pressure, the reaction product was dissolved in 30 ml of ethyl acetate, washed with 30 ml of 5% aqueous sodium hydroxide solution and 30 ml of water, respectively, and then the organic layer was dehydrated with 5 g of magnesium sulfate and filtered. It was concentrated again under reduced pressure and column chromatography gave 456 mg (yield = 45%) of the title compound on a yellow oil.

i) ¹ H-NMR (ppm, CDCl ₃ ): 1.99 (s, 3H), 3.64 (s, 3H), 4.07-4.5 (m, 4H), 6.8-7.52 (m, 8H)

Ii) Mass spectra: peaks appear at 249, 284, 369 and 404.

Example 2

Preparation of 4- (2 ', 4'-dichlorophenylcarbonyl) -1,3-dimethyl-5- (2- (2 ", 6" -dimethylphenoxy) ethoxy) pyrazole (Compound Ib)

318 mg (2.6 mmol) of 2,6-dimethylphenol was used in place of the phenol used in Example 1, and was carried out in the same manner as in Example 1 to obtain 596 mg (yield = 55%) of the title compound.

i) ¹ H-NMR (ppm, CDCl ₃ ): 2.0 (s, 3H), 2.24 (s, 6H), 3.73 (s, 3H), 3.88 ~ 4.47 (m, 4H), 7.0 ~ 7.24 (m, 6H )

Ii) Mass spectra: peaks at 173, 249, 284, 311, 397, 432.

Example 3

Preparation of 5- (2- (2 ', 4'-dichlorophenoxy) ethoxy) -4- (2 ", 4" -dichlorophenylcarbonyl) -1,3-dimethylpyrazole (Compound Ic)

In Example 1, using 424 mg (2.6 mmol) of 2,4-dichlorophenol instead of phenol, the same procedure as in Example 1 was carried out to obtain 616 mg (yield = 52%) of the title compound.

i) ¹ H-NMR (ppm, CDCl ₃ ): 1.93 (s, 3H), 3.68 (s, 3H), 4.12 ~ 4.57 (m, 4H), 6.76 ~ 7.47 (m, 6H)

Ii) Mass spectra: peaks at 173, 189, 249, 284, 311, 439 and 474.

Example 4

Preparation of 4- (2 ', 4'-dichlorophenylcarbonyl) -1,3-dimethyl-5- (2-thiophenoxyethoxy) parasol (Compound Id)

In Example 1, using 286 mg (2.6 mmol) of thiophenol instead of phenol and carrying out the same method as in Example 1 to obtain 558 mg (yield = 53%) of the title compound.

i) ¹ H-NMR (ppm, CDCl ₃ ): 2.06 (s, 3H), 3.12 (t, 2H), 3.72 (s, 3H), 4.27 (t, 2H), 7.24 ~ 7.5 (m, 8H)

Ii) Mass spectrum: peak at 420.

Claims (5)

A pyrazole derivative represented by the following general formula (I).

In the above formula, R ₁ and R ₂ each independently represent a hydrogen, halogen, methyl, ethyl, methoxy or ethoxy group; A represents O or S; n represents the integer of 1-3. A method of preparing a pyrazole derivative of the general formula (I), characterized by reacting a compound of the general formula (III) with a compound of the following general formula (II). A process for preparing the following general formula (II) compound, characterized in that it reacts with dihalogenalkane after base treatment of 4- (2 ', 4'-dichlorophenylcarbonyl) -1,3-dimethylpyrazolone.

Wherein X represents a halogen atom such as chlorine or bromine. A herbicide composition comprising an inert carrier and a herbicidally effective amount of the compound of claim 1. A method for preparing a herbicide composition by mixing the compound of claim 1 with an inert carrier and an excipient.