A selective herbicide based on bispyribac and its preparation method and application

Abstract

The present invention discloses a selective herbicide based on bispyribac, and its preparation method and application. The herbicide has the following molecular structure expression, and its preparation method includes: mixing bispyribac and mercaptoethylamine hydrochloride in a solvent, adding a catalyst and an acid binding agent, and heating to 120-170°C for reaction; after the reaction, purifying to obtain a product; the bispyribac derivatives in the present invention have significantly improved selective weed control ability against grass weeds, and can ensure the weed control effect when used at a lower concentration, which fundamentally controls the probability of phytotoxicity in cereal crops and reduces the degree of damage to crop growth caused by the drug;.

Description

Technical Field

[0001] The present invention relates to a new substance with high-efficiency herbicidal activity, and in particular to a selective herbicide based on bispyribac, and a preparation method and application thereof. Background Art

[0002] With the widespread use of chemical herbicides, resistance in rice field weeds is becoming increasingly serious. Bispyribac [(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-[methyl(prop-2-ynyl)amino]pyrazole-4-carbonitrile], with its unique mechanism of action and broad-spectrum herbicidal activity, has shown great potential in managing resistant weeds, particularly those resistant to sulfonylurea herbicides. Its mechanism of action involves inhibition of protoporphyrinogen oxidase (PPO), a process that can affect weed photosynthesis and thus growth, making it a rapidly emerging herbicide in rice fields.

[0003] Another aspect of plant protection products that can be used as herbicides is that they must not only be effective against harmful weeds but also compatible with the corresponding beneficial crops. Studies have shown that bispyribac is relatively safe for rice and does not significantly affect it. Therefore, the emergence of bispyribac offers new possibilities for addressing this issue and demonstrates strong future market competitiveness.

[0004] However, studies have found that in terms of biocompatibility, the safety of bispyribac on rice is not absolute, and there is still a certain growth inhibition on it. In particular, there is still much room for improvement in its destructiveness to other beneficial plants such as corn, soybeans, potatoes, etc., and a satisfactory selective effect has not yet been achieved. Summary of the Invention

[0005] To address the above technical problems, the present invention provides a selective herbicide based on pyraclostrobin, its preparation method, and its application. The inventors unexpectedly discovered that by structurally modifying pyraclostrobin, its herbicidal activity could be enhanced, thereby making it possible to reduce the herbicide's concentration and improve the tolerance of beneficial plants.

[0006] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0007] According to the first aspect of the present invention, a selective herbicide based on bispyribac is first provided, which has the following molecular structure expression:

[0008]

[0009] In their ongoing research on cereal herbicides, the inventors discovered that the structure shown in the above formula not only retains the main molecular structure of bispyribac, but more surprisingly, exhibits superior application effects in its activity against a variety of grass weeds. In particular, it can achieve relatively ideal weed control performance when used at lower concentrations. This is expected to improve the simultaneous damage of existing herbicides to cereal crops and is suitable for promotion and application.

[0010] According to the second aspect of the present invention, there is also provided a method for preparing a selective herbicide based on bispyribac as described above, comprising the following steps:

[0011] After mixing bispyribac and mercaptoethylamine hydrochloride in a solvent, adding a catalyst and an acid binding agent, heating to 120-170° C. to carry out a reaction; and after the reaction, purifying to obtain a product.

[0012] As a preferred embodiment of the preparation method provided by the present invention, the catalyst is selected from one or more of copper trifluoromethanesulfonate, zinc acetate, and trichloroisocyanuric acid;

[0013] Preferably, the added amount of the catalyst is 1-20% of the molar amount of bispyribac, such as 1%, 5%, 8%, 10%, 15%, 18%, 20%, etc.

[0014] As a preferred embodiment of the preparation method provided by the present invention, the acid binding agent is selected from one or more of potassium carbonate, sodium carbonate, sodium acetate, triethylamine, pyridine, and piperidine;

[0015] Preferably, the amount of the acid binding agent is 1.2-2 times the molar amount of bispyribac, for example, 1.2 times, 1.4 times, 1.5 times, 1.8 times, 2.0 times, etc.

[0016] As a preferred embodiment of the preparation method provided by the present invention, the mixing amount of the bispyribac and mercaptoethylamine hydrochloride is 1:(1-6) in a molar ratio, for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, etc.

[0017] As a preferred embodiment of the preparation method provided by the present invention, the solvent is selected from one or more of water, tetrahydrofuran, ethanol, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0018] As a preferred embodiment of the preparation method provided by the present invention, the reaction time is recommended to be 12 hours or longer, such as 12 hours, 15 hours, 18 hours, 20 hours, 24 hours, 30 hours, etc. However, the reaction time should not be too long, otherwise it will affect the production efficiency.

[0019] As a preferred embodiment of the preparation method provided by the present invention, after the reaction is completed, the reaction is filtered, the solution is evaporated to dryness or extracted without evaporation to dryness, the organic layer is collected, dried by spin drying, recrystallized, and purified to obtain the product.

[0020] The above preparation method, designed to streamline production processes, produces the desired product in a single step, offering advantages of simplicity and low production costs. However, this method should not be construed as limiting the production of the selective herbicide. Those skilled in the art can select different preparation processes based on practical needs to obtain the same product, which generally does not affect the product's basic properties.

[0021] According to the third aspect of the present invention, there is also provided a use of the aforementioned selective herbicide based on bispyribac as described above or the selective herbicide based on bispyribac obtained by the aforementioned method in herbicides, especially in cereal crop herbicides.

[0022] The present invention provides a bispyribac-1 derivative having significantly improved selective weed control ability against grass weeds and can ensure weed control effects when used at relatively low concentrations. This fundamentally controls the probability of phytotoxicity in cereal crops and reduces the degree of damage to crop growth caused by the drug. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0026] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0027] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0028] Unless otherwise specified, the raw materials and reagents in the following examples of the present invention can be purchased from commercial sources. Among them, bispyribac was purchased from Hefei Aishang Agricultural Technology Co., Ltd.; mercaptoethylamine hydrochloride, zinc acetate, and triethylamine were purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.; and trichloroisocyanuric acid (TCCA) was purchased from Titan Technology Exploration Platform.

[0029] In the following examples of the present invention, room temperature refers to 25±2°C.

[0030] [Example 1]

[0031] At room temperature, bispyribac and mercaptoethylamine hydrochloride (molar ratio 1:1.2) were mixed and dissolved in tetrahydrofuran. Zinc acetate (2% molar weight of bispyribac) and triethylamine (200%) were added, and the mixture was reacted at 160°C for 24 hours. After completion of the reaction, the mixture was filtered, the solvent was partially evaporated, and the mixture was extracted with water. The organic layer was further evaporated to dryness, recrystallized, and the product was collected.

[0032] 1 H NMR (600MHz, CDCl3): δ7.62(s,1H),4.44(t,J=9.5Hz,2H),4.24(t,J=9.5Hz,2H),4.04(t,J=6.1 Hz,2H),3.80(s,2H),3.28(s,1H),3.21(s,3H),2.72(t,J=6.5Hz,2H),2.05(s,2H),1.89(s,2H).

[0033] [Example 2]

[0034] At room temperature, bispyribac and mercaptoethylamine hydrochloride (molar ratio 1:5) were mixed and dissolved in ethanol. Copper trifluoromethanesulfonate (10% of the molar amount of bispyribac) and triethylamine (120%) were added, and the mixture was reacted at 120°C for 32 hours. After the reaction, the mixture was filtered, the solvent evaporated, and extraction was performed with water and ethyl acetate. The organic layer was further evaporated to dryness, recrystallized, and the product was collected.

[0035] [Example 3]

[0036] At room temperature, bispyribac and mercaptoethylamine hydrochloride (molar ratio 1:3) were mixed and dissolved in N,N-dimethylformamide. Trichloroisocyanuric acid (18% of the molar amount of bispyribac) and triethylamine (150%) were added, and the mixture was reacted at 150°C for 28 hours. After the reaction, the mixture was filtered, the solvent evaporated, and extraction was performed with water and ethyl acetate. The organic layer was further evaporated to dryness, recrystallized, and the product was collected.

[0037]

Application Testing

[0038] Test weeds: Echinochloa crus-galli, Leptochloa chinensis, Digitaria sanguinalis, Japanese Alopecurus mume, and Lolium multiflorum.

[0039] Test crops: corn, rice, soybean, potato, wheat.

[0040] Sowing: Prepare multiple foam boxes (40 × 35 × 30 cm) and label them according to crop / weed species. For each sample, assign 12 foam boxes to each sample and divide them into four groups of three for parallel testing. Label each group as: high-concentration experimental group, low-concentration experimental group, control group, and blank group. Plant the corresponding crop / weed in the foam boxes according to the labeling, sowing 48 seeds evenly per box.

[0041] Dispensing:

[0042] High-concentration preparation: accurately weigh and dissolve 1 g of the herbicide (prepared in Example 1) in 4 mL of dimethyl sulfoxide, add Tween and assist with ultrasonic oscillation. The Tween amount is configured to 3% of the total volume to obtain a high-concentration experimental group solution.

[0043] Low-concentration preparation: accurately weigh and dissolve 0.5 g of the herbicide (prepared in Example 1) in 4 mL of dimethyl sulfoxide, add Tween and assist with ultrasonic oscillation. The Tween amount is configured to 3% of the total volume to obtain a low-concentration experimental group solution.

[0044] Preparation of the control group: accurately weigh and dissolve 1 g of bispyribac in 4 mL of dimethyl sulfoxide, add Tween and assist with ultrasonic oscillation. The amount of Tween is configured to be 3% of the total volume to obtain the control group solution.

[0045] Preparation of blank group medicine: take 4 mL of dimethyl sulfoxide, add Tween and assist with ultrasonic oscillation, and the amount of Tween is configured according to 3% of the total volume to obtain the blank group medicine solution.

[0046] The above solutions were diluted with water to the same multiple before use.

[0047] Spraying experiment: 7 days after sowing, the spraying amount was 210g.ai / hm 2 Each group of samples was sprayed with pesticides. 21 days after sowing, the efficacy and damage of each pesticide were observed and calculated.

[0048] Efficacy experiments

[0049] (1) Calculate the herbicidal activity of the liquid on each weed by the number of weeds and fresh weight inhibition rate according to the following formula, and record it in Table 1; where the treatment group refers to the experimental group or control group of the corresponding test;

[0050] Plant number inhibition rate (%) = (T 空白组 -T 处理组 ) / T 空白組 x 100%

[0051] T represents the number of germinated weed seeds (unit: plant);

[0052] Fresh weight inhibition rate (%) = (G 空白组 -G 处理组 ) / G 空白組 x 100%

[0053] G represents the fresh weight of each weed seed after germination (unit: g);

[0054] Table 1. Results of drug efficacy experiments

[0055]

[0056]

[0057] (2) Calculate the plant number inhibition rate and fresh weight inhibition rate of the drug solution on each crop according to the following formula to characterize the phytotoxicity activity and record it in Table 2; where the treatment group refers to the experimental group or control group of the corresponding test;

[0058] Plant number inhibition rate (%) = (L 空白组 -L 处理组 ) / L 空白組 x 100%

[0059] Wherein, L represents the number of germinated plants of each crop seed (unit: cm)

[0060] Fresh weight inhibition rate (%) = (M 空白组 -M 处理组 ) / M 空白組 x 100%

[0061] Where M represents the fresh weight of each crop seed after germination (unit: g)

[0062] Table 2. Test results of pesticide damage experiment

[0063]

[0064] The above experimental results demonstrate that the selective herbicide provided by the present invention demonstrates significantly improved weed control against a variety of weeds compared to the original herbicide, pyraclostrobin, with particularly significant improvements against barnyardgrass, Japanese alopecuroides, and multiflora ryegrass. Even more surprising, even at lower herbicide concentrations, satisfactory weed control was still achieved. Furthermore, phytotoxicity experiments demonstrated that the use of low-concentration herbicides significantly reduced growth inhibition on various cereal crops, potentially increasing crop yields or reducing seed usage to save costs.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be considered within the scope of protection of the present invention.

Claims

1. A selective herbicide based on bispyribac, characterized in that It has the following molecular structure expression: 。 2. A method for preparing a selective herbicide based on bispyribac as claimed in claim 1, characterized in that: The following steps are involved: After mixing bispyribac and mercaptoethylamine hydrochloride in a solvent, adding a catalyst and an acid binding agent, heating to 120-170° C. to carry out a reaction; and after the reaction, purifying to obtain a product.

3. The method for preparing a selective herbicide based on bispyribac according to claim 2, wherein: The catalyst is selected from one or more of copper trifluoromethanesulfonate, zinc acetate, and trichloroisocyanuric acid.

4. The method for preparing a selective herbicide based on bispyribac according to claim 3, wherein: The added amount of the catalyst is 1-20% of the molar amount of bispyribac.

5. The method for preparing a selective herbicide based on bispyribac according to any one of claims 2 to 4, characterized in that: The acid binding agent is selected from one or more of potassium carbonate, sodium carbonate, sodium acetate, triethylamine, pyridine and piperidine.

6. The method for preparing a selective herbicide based on bispyribac according to claim 5, wherein: The amount of the acid binding agent is 1.2-2 times the molar amount of bispyribac.

7. The method for preparing a selective herbicide based on bispyribac according to any one of claims 2 to 4, characterized in that: The mixing amount of the bispyribac and mercaptoethylamine hydrochloride is 1:(1-6) in terms of molar ratio.

8. The method for preparing a selective herbicide based on bispyribac according to any one of claims 2 to 4, characterized in that: The solvent is selected from one or more of water, tetrahydrofuran, ethanol, N,N-dimethylformamide, and N,N-dimethylacetamide.

9. The method for preparing a selective herbicide based on bispyribac according to any one of claims 2 to 4, characterized in that: After the reaction is completed, the solution is filtered, evaporated to dryness or extracted without evaporation, and the organic layer is collected, dried by spin drying, recrystallized, and purified to obtain the product.

10. Use of the selective herbicide based on bispyribac as claimed in claim 1 or the selective herbicide based on bispyribac obtained by the method according to any one of claims 2 to 9 in herbicides.

11. Use of the selective herbicide based on bispyribac as claimed in claim 1 or the selective herbicide based on bispyribac obtained by the method according to any one of claims 2 to 9 in herbicides for cereal crops.

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