KR970001479B1 - 2-(pyrimidin-2-yl) oxyacetophenone derivatives useful as a herbicide and process for preparation thereof - Google Patents

Abstract

2-(4,6-dimethoxypyridine-2-yl) oxyacetophenone derivative of general formula(I) is prepared by the following method. (1) A compound of general formula(II) reacts with alcohol, thiol or carboxyl acid in the presence basic and solvent. Or the compound(II) reacts to alcohol, thiole or carboxylic metal salts under solvent to produce a compound of general formula(III). (2) Then a compound(III) reacts to 2,6-dimethoxy-4-methylsulfonyl pyrimidine in the presence basic and solvent at 15~120degree C. In the formula, R is halogen, alkyl with carbon number 1~4, alkoxy group with carbon number 1~4, aryloxy or (4,6-dimethoxy pyrimidine-2-yl)oxy as substituents substituted at number 5 or 6 of benzene ring. X is halogen atom, hydroxy, alkylthio with carbon number 1~4, thiole, arylthio or nitro group.

Description

2- (pyrimidin-2-yl) oxy acetophenone derivatives useful as herbicides and methods for preparing the same

The present invention relates to a novel herbicidal pyrimidine derivative represented by the following general formula (I). More specifically, it relates to novel 2, 6- (4, 6-dimethoxypyrimidin-2-yl) oxy acetophenone derivatives, methods for their preparation and their use as herbicides.

In the above formula, R is a substituent substituted at the 5 or 6 position of the benzene ring, halogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, aryloxy or (4, 6-dimethoxypyrimidine- 2-yl) oxy, X represents halogen, hydroxy, alkoxy having 1 to 5 carbon atoms, acetyl, aryloxy, alkylthio having 1 to 5 carbon atoms, thiol, arylthio or nitiro.

It is well known that 2-phenoxy pyrimidine or (pyrimidin-2-yl) oxybenzene derivatives are useful as herbicides (see Agr. Biol. Chem., Vol. 30, p.896 (1966), Japan). Korean Patent Publication Nos. 79-55729, U.S. Patent Nos. 4, 248, 619 and 4, 427, 437). Of the compounds recently developed based on 2-phenoxypyrimidine, it has been found that derivatives of 2- (pyrimidin-2-yl) oxybenzoic acid show excellent herbicidal effects (see, for example, European Patent Application) 223, 406, 249,708, 287,072, 287,079, 315,889, 321,846, 330,990, 335,409, 346, 789, 363, 040, 402, 751 Nos. 435, 170, 435, 186, 457, 505, 459, 243, 268, 690, British Patent Nos. 2, 237, 570 and German Patent Nos. 3, 942 , 476). These known compounds show a similar mechanism of action to sulfonylurea derivatives, imidazolinol derivatives and triazolepyrimidine derivatives, which are well known as conventional amino acid biosynthesis inhibitors, and have the advantage of simplicity due to their simple structure. With the new structure of the amino acid biosynthesis inhibiting herbicides are of interest.

A feature of these compounds that has been developed recently is that carboxylic acid substituents or carboxyl ester substituents are essential to the benzene ring of the (pyrimidin-2-yl) oxybenzene derivative in order to have excellent herbicidal power. These herbicides, which have been recently developed, are therefore focused on derivatives of 2- (pyrimidin-2-yl) oxybenzoic acid.

In the course of research on the development of a novel amino acid biosynthesis inhibitor herbicide, the present inventors have described a new structure of 2- (pyrimidin-2-yl) oxyacetophenone instead of the existing 2- (pyrimidin-2-yl) oxybenzoic acid derivative. Developed. Although the herbicidal effects of these derivatives depend on which substituents are present at the 2'-position of the acetophenone structure, they have excellent herbicidal power as compared to known (pyrimidin-2-yl) oxybenzene derivatives.

In order for these novel acetophenone derivatives to have excellent herbicidal power, the presence of the substituent X defined in the general formula (I) is essential. For example, in the case of the acetophenone compound (X = H) having no substituent in the general formula (I), the herbicidal power was found to be 20 times lower than that of the compounds of the present invention.

To be more useful as a herbicide, it must be safe against useful crops as well as the herbicidal power to control weeds.

Compounds presented in the present invention has a characteristic that the crop selectivity varies depending on the R substituent in the general formula (I). For example, when the 6th position of the benzene ring in the general formula (I) is substituted with a chloro group, it is safe against cotton at the concentration controlling the problem weeds. When (4, 6-dimethoxypyrimidin-2-yl) oxy is substituted at the 6th position of the benzene ring in the general formula (I), it is useful as a water herbicide, at a concentration that completely controls perennial weeds. Safe to Yiyang and direct rice. When position 5 of the benzene ring in the general formula (I) is substituted with a fluoro group, it is safe for soybean at the concentration for controlling the problem weeds.

The present invention provides novel 2- (4,6-dimethoxypyrimidin-2-yl) oxyacetophenone derivatives represented by the following general formula (I).

Wherein R and X are as described above.

Compounds of formula (I) according to the invention are fluoro, chloro, methoxy or (4, 6-dimethoxy pyrimidin-2-yl) as substituents in which R is substituted at the 5 or 6 position of the benzene ring. Preference is given to compounds in which oxy represents, X represents bromine, hydroxy, methoxy, acetoxy, methylthio, thiol, phenylthio or nitro.

Representative examples of compounds represented by the general formula (I) according to the present invention are shown in Table 1.

The compound of general formula (I) according to the present invention can be synthesized according to the following scheme (I) or scheme (II).

From α-bromo-2-hydroxyacetophenone compound (II), a compound of the general formula (III) is obtained by reacting an alcohol, thiol or carboxylic acid compound with an appropriate base and a solvent depending on the substituent to be substituted. Or a metal salt of an alcohol, thiol or carboxylic acid compound is reacted with α-bromo-2- hydroxyacetophenone compound (II) in a suitable solvent to obtain a compound of formula (III).

At this time, metal hydride bases such as sodium hydride and potassium hydride, potassium carbonate, potassium bicarbonate, sodium carbonate and the like are suitable, and dichloromethane, tetrahydrofuran, chloroform, acetonitrile and dimethylformamide are suitable as the solvent.

The compound of formula (III) is reacted with 2, 6-dimethoxy-4-methylsulfonylpyrimidine in a suitable base and a solvent at a temperature of 15 to 120 캜 to obtain the target compound (I). At this time, sodium hydride, potassium hydride, sodium hydrogen carbonate, sodium carbonate and the like are suitable, and acetonitrile, tetrahydrofuran, dimethylformamide, methyl ethyl ketone or a mixed solvent thereof are most suitable as a solvent.

In the compound of general formula (I) in the said Table 1, (1)-(6), (16)-(22) compound were synthesize | combined based on reaction formula (I).

Compound (IV) is reacted with CuBr ₂ in a chloroform or ethyl acetate or a mixed solvent at a temperature in the range of 15 to 100 ° C. to obtain α-bromo acetophenone compound (V). The compound (V) is reacted with an alcohol, thiol or carboxylic acid compound in an appropriate base and solvent depending on the substituent to be substituted to obtain a compound of formula (I). Or a metal salt of an alcohol, thiol, carboxylic acid or amine compound is reacted with α-bromo-2-hydroxyacetophenone in a suitable solvent to obtain a compound of formula (I).

At this time, a metal hydride base such as sodium hydride and potassium hydride or an alkali metal carbonate or bicarbonate such as potassium carbonate, potassium hydrogen carbonate, sodium carbonate and the like is suitable. As a solvent, dichloromethane, tetrahydrofuran, methyl ethyl ketone, chloroform, aceto Nitrile, dimethylformamide, etc. are suitable.

Of the compounds of the general formula (I) in Table 1, compounds (7) to (15) were synthesized based on the reaction formula (II).

Hereinafter, the present invention will be described in more detail with reference to Examples.

However, these examples are only for the understanding of the present invention and do not limit the present invention.

Synthesis of α-methylthio-6-chloro-2-hydroxy acetophenone (III-6, III; R = 6-, C1, X = XCH ₃ )

Dissolve 2.5 g (10 mmol) of α-bromo-6-chloro-2-hydroacetophenone (II-1) in 50 mol of tetrahydrofuran and stir 700 mg (10 mmol) of CH ₃ SNa for 10 minutes while stirring at room temperature. Add it down. After stirring for 2 hours at room temperature, half the mixture was poured into water, and the residue of the organic layer extracted with ethyl acetate was removed by distillation under reduced pressure. g (yield: 95%) of the desired compound (III-6) was obtained.

¹ H NMR (CDC1 ₃ , δ): 2.40 (s, 3H), 3.74 (s, 2H), 6.50-7.50 (m, 3H), 11.0 (s, 1H)

Synthesis of α-methylthio-6-chloro-2- (4, 6-dimethoxypyrimidin-2-yl) oxyacetophenone (I-6)

3.2 g (10 mmol) of α-methylthio-6-chloro-2-hydroxyacetophenone (III-6) obtained in Preparation Example 1, 1.8 g of potassium carbonate and 2.4 g (10 mmol) of 4,6-dimethoxy 2-Methylsulfonylpyrimidine was added to 50 ml of dimethylformamide and refluxed under stirring for 1 hour. The solvent was removed under reduced pressure, a saturated ammonium chloride aqueous solution was added to the reaction mixture, extracted with ethyl acetate, and the solvent of the organic layer was dried. The residue was removed under reduced pressure by chromatography on silica gel (eluent was hexane: ethyl acetate = 5: 1). 3.18 g (yield: 90%) of the desired compound (1-6) were obtained.

¹ H NMR (CDC1 ₃ , δ): 2.42 (s, 3H), 3.78 (s, 8H), 5.75 (s, 1H), 1.03-7.30 (m, 8H)

Synthesis of α-bromo-6-methoxy-2- (4, 6-dimethoxypyrimidin-2-yl) oxyacetophenone (I-7)

300 mg (1.0 mmol) of 6-methoxy-2- (4,6-dimethoxypyrimidin-2-yl) oxyacetophenone (IV) was dissolved in a mixed solvent of 10 ml of chloroform and 10 ml of ethyl acetate. 450 mg ( ₂ mmol) of CuBr ₂ was added dropwise while stirring, followed by stirring under reflux for 1 hour. After filtering the reaction mixture, the filtrate was distilled under reduced pressure and the residue was chromatographed on silica gel (eluent was hexane: ethyl acetate = 5: 1) to give 307 mg (yield: 80%) of the title compound (I-7). To obtain.

¹ H NMR (CDC1 ₃ , δ): 3.80 (s, 6H), 3.88 (s, 3H), 4.42 (s, 2H), 7.20-7.40 (m, 1H)

Synthesis of α-nitro-6-methoxy-2- (4, 6-dimethoxypyrimidin-2-yl) oxyacetophenone (I-10)

10 mol of 308 mg (1.0 mmol) of α-bromo-6-methoxy-2- (4,6-dimethoxypyrimidin-2-yl) oxyacetophenone (I-7) obtained in Preparation Dissolve in dimethylformamide and add 140 mg (2.0 mmol) of NaNo ₂ dropwise. The reaction mixture was stirred at room temperature for 12 hours, and then saturated aqueous ammonium chloride solution was added, extracted with ethyl acetate, and the solvent was dried under reduced pressure. The residue was chromatographed on silica gel (eluent hexane: ethyl acetate = 5: 1) to obtain 300 mg (yield: 85%) of the title compound (I-10).

¹ H NMR (CDC1 ₃ , δ): 3.42 (s, 2H), 3.68 (s, 3H), 3.80 (s, 6H), 5.62 (s, 1H), 6.60-7.50 (m, 3H)

Physical properties of the compounds of Table 1 prepared according to Example I or Example 2 are shown in Table 2 below.

Assay in a greenhouse to assay the herbicidal efficacy of the novel herbicidal 2, 6- (4, 6-dimethoxypyrimidin-2'-yl) oxyacetophenone derivative represented by the general formula (I) according to the present invention Plants were carried out by pot cultivation and treatment methods, and efficacy evaluation was carried out according to the evaluation criteria of efficacy and weakness (Table 3).

For the efficacy test, weeds include Digitaria sanguinalis, Panicum dichotomiflorum, Sataria farberi, Echinochgloa crus-galli var, caudata, Sorghum bicolor, Aeschynomene indica ), Amaranthus retroflexus, Xanthium strumarium, Solanum migrum, Abutilon theophvasti, Caulistrgia japonica, Echinochloa crus-crusgallivar (oryzicola), Mantis Aneilema Keisak, Scirpus jumcoides, Swanfish (Monochoria vaginalis), Cyperus difformis, Sputum (Potamogeton distinctus), Peel (Sagittaria trifolia), Swallowtail (Eleocharis Kuroguwai), Sorgagittaria trifolia) and Olmi (Sagittaria pygmaea) were selected, and cotton (Gosshipium hirsutum), rice (Oryza sativar) and soybean (Glycine max) were selected as crops.

When the compound of the present invention is used, it is mixed with solid substances such as clay, talc, diatomaceous earth, and liquid substances of water, alcohol, benzene, toluene, ether, ketones, esters, and acid amides. It can be prepared and used in the formulation of, wherein an emulsifier, dispersant, penetrant, electrodeposition agent, stabilizer is added as necessary.

The following shows a part of the formulation examples of the herbicide containing the compound of the present invention as an active ingredient, which does not limit the present invention.

(Field conditions, 1 kg / ㏊)

320 mg of the compound of the present invention was dissolved in 640 ml of an organic solvent (acetone), and then diluted in 640 ml of distilled water containing 0.2% of the nonionic surfactant Tween 20 to prepare a blend.

(Field conditions, 1kg / ha)

320 mg of the compound of the present invention was dissolved in 320 ml of an organic solution (acetone), and then diluted with 320 ml of distilled water containing 0.2% of the nonionic surfactant Tween 20 to prepare a blend.

Evaluation of the efficacy and weakness in the following experimental example was evaluated according to the criteria of Table 3 below.

Test of herbicidal power before germination by soil treatment (field conditions)

Filling a rectangular plastic container (20 × 15 × 10㎝) with sterilized field soil (sand loam, ph5.5 to 6.0), and sowing 6 trillion weeds in one container with a surface area of 300㎠. Vomited at 0.5 cm. After 1 day of watering, in the solution of Formulation Example 1, a portion (12 ml per plastic container) containing the active ingredient (1 kg / dl) corresponding to the treatment amount was uniformly sprayed onto the soil surface. For 30 days after the treatment, herbicides on plant cultivation and weeding were observed according to the evaluation criteria.

The results are shown in Table 4.

Herbicidal test after germination by foliage treatment (field conditions)

After seeding the assay plants in the same manner as in Example 1 and cultivating for 10 to 14 days, when a real object reaches 3 to 4 leaf stage, a part (1 kg / ㏊) containing an active ingredient corresponding to the amount of the treatment in Formulation Example 1 was obtained. Spray the plant foliage evenly. For 30 days after the treatment, weeding and weeding resistance to weeds and crops were evaluated according to the evaluation criteria.

The results are shown in Table 5.

Herbicide efficacy and control drug experiments before germination

As a control agent, 2- (4,6-dimethoxypyrimidin-2-yl) oxyacetophenone compound (A), which is a compound having no substituent X in general formula (I), was synthesized, and was prepared in the method of Experimental Example I. The herbicidal efficacy of the compounds according to the present invention was compared and tested. As a result, it was confirmed that the novel acetophenone compound represented by the general formula (I) according to the present invention is far superior in herbicidal efficacy. In addition, the effective herbicidal concentration was confirmed to be safe for cotton and soybeans.

The results are shown in Table 6.

Test of herbicidal effect before germination and soil control experiment by soil treatment (field conditions)

Sterilized paddy soil (paddy soil, ph5.5 to 6.0) is filled in a quadrangular pot (30 × 15 cm) and sown rice weeds and rice with a surface area of 450 ㎢ and mixed in soil. After one day of watering of 4 cm, a part of the solution containing the active ingredient corresponding to the amount of the treatment (16 g / kPa) was dipped in the solution of Formulation Example 2. After 4 weeks of treatment, cultivation and observation were conducted, and the herbicidal effects on the weeds and weeds on rice were evaluated according to the criteria.

The results are shown in Table 7.

Claims (10)

Novel 2- (4, 6-dimethoxypyrimidin-2-yl) oxyacetophenone derivatives of the general formula (I) below. Wherein R represents halogen, C ₁ -C ₄ alkoxy or (4,6-dimethoxypyrimidin-2-yl) oxy as a substituent substituted at the 5 or 6 position of the benzene ring, X is a halogen, Hydroxy, C ₁ -C ₅ alkoxy, acetoxy, C ₁ -C ₅ alkylthio, thiol, arylthio or nitro. The compound of claim 1, wherein R represents a fluoro, chloro, methoxy or (4,6-dimethoxypyrimidin-2-yl) oxy as a substituent substituted at the 5 or 6 position of the benzene ring. Compounds representing bromo, hydroxy, methoxy, acetoxy, methylthio, thiol, phenylthio or nitro. The compound of formula (II) is reacted with alcohol, thiol or carboxylic acid in the presence of a base and a solvent, or the metal salt of alcohol, thiol or carboxylic acid is reacted in a solvent to obtain a compound of formula (III) Next, the compound of formula (III) is reacted with 2,6-dimethoxy-4-methylsulfonylpyrimidine in the presence of a base and a solvent at a temperature of 15 ° C to 120 ° C. Process for the preparation of the compound of I). Wherein R and X are as defined in claim 1. 4. The method of claim 3 wherein the base is a hydride metal base such as sodium hydride, potassium hydride or a carbonate or bicarbonate of an alkali metal such as potassium carbonate, potassium bicarbonate or sodium carbonate. The method of claim 3. The solvent for preparing the compound of the general formula (III) from the compound of the general formula (II) is thichloromethane, tetrahydrofuran, chloroform, acetonitrile or dimethylformamide. The process according to claim 3, wherein the solvent for preparing the compound of the general formula (I) from the compound of the general formula (III) is acetonitrile, tetrahydrofuran, dimethylformamide or methyl ethyl ketone or a mixed solvent thereof. The compound of formula (IV) is reacted with cupric bromide (cuBr ₂ ) with chloroform or ethyl acetate or a mixed solvent at a temperature ranging from 15 ° C. to 100 ° C. to obtain a compound of formula (V). , In which the compound of formula (V) is reacted with the alcohol, thiol or carboxylic acid in the presence of a base and a solvent, or in the presence of a solvent with a metal salt of an alcohol, thiol, carboxylic acid or an amine compound. A process for preparing a compound of formula (I), characterized by reaction. Wherein R and X are as defined in claim 1. 8. The method of claim 7, wherein the base is a hydride metal base such as sodium hydride, potassium hydride or a carbonate or bicarbonate of an alkali metal such as potassium carbonate, potassium bicarbonate or sodium carbonate. 8. The process of claim 7, wherein the solvent for preparing the compound of formula (I) from the compound of formula (V) is dichloromethane, tetrahydrofuran, methylethylgetone, chloroform, acetonitrile or dimethylformamide. A herbicide composition characterized by containing the compound of formula (I) as defined in claim 1 as an active ingredient.