Trifluoromethyl-containing nicotinamide compounds, methods of making and using the same

Abstract

The application relates to the field of pesticide bactericides, and discloses a trifluoromethyl-containing nicotinamide compound as shown in formula I and formula II, a preparation method and application thereof. The compound is obtained through further structural optimization on the basis of the prior art. The trifluoromethyl-containing nicotinamide compound as shown in formula I and formula II disclosed by the application has low raw material cost, high synthesis yield, and shows more ideal prevention effect on crop diseases such as rice sheath blight, rapeseed sclerotinia disease and soybean rust.

Description

Technical Field

[0001] This invention relates to the field of pesticides and fungicides, specifically to a trifluoromethylnicotinamide compound, its preparation method, and its application in controlling crop diseases such as rice sheath blight and soybean rust. Background Technology

[0002] Among the more than 200 marketed fungicides listed by the Fungicide Resistance Action Committee (FRAC), succinate dehydrogenase inhibitors (SDHIs) are the fastest-growing new products. These fungicides are highly favored due to their high efficiency, broad spectrum, low toxicity, and environmental friendliness, and have become a research hotspot in the development of novel fungicides.

[0003] In 2003, BASF launched its first broad-spectrum SDHI fungicide, boscalid. This product is a nicotinamide amine compound that exhibits significant activity against almost all types of fungal diseases, particularly effective in controlling powdery mildew, gray mold, sclerotinia rot, and various types of rot. However, with increased field application, resistance has become a growing problem.

[0004] In order to find a new nicotinamide fungicide that can replace boscalid, our laboratory conducted extensive synthesis and activity screening work based on literature review and existing technology, and obtained two trifluoromethyl nicotinamide compounds with high fungicidal activity.

[0005] Prior art CN110776457 A discloses the following four compounds containing trifluoromethylpyridine amides:

[0006] ;

[0007] However, while the aforementioned trifluoromethylpyridine amide compounds described in the prior art exhibit broad-spectrum antibacterial activity at high concentrations in bioactivity tests, their inhibitory effects on common plant pathogenic fungi such as rice sheath blight, rapeseed sclerotinia stem rot, and wheat sheath blight at low concentrations are not ideal. Furthermore, high-concentration application not only increases costs but also significantly reduces safety. Summary of the Invention

[0008] The purpose of this invention is to provide a broad-spectrum, highly efficient, and relatively low-cost trifluoromethylnicotinamide compound. This compound can effectively control diseases such as rice sheath blight, soybean rust, wheat sheath blight, and rapeseed sclerotinia stem rot.

[0009] Based on existing technologies, the inventors of this invention conducted in-depth screening research on nicotinamide compounds and unexpectedly discovered that a trifluoromethylnicotinamide compound (as shown in Formulas I and II), not disclosed in existing technologies, not only exhibits higher inhibitory activity against pathogenic fungi such as rice sheath blight pathogens compared to other trifluoromethylnicotinamide compounds in the prior art, effectively controlling diseases such as rice sheath blight and soybean rust, but also has relatively lower raw material costs for synthesis, making it more competitive in the market. Based on the above findings, the inventors of this invention completed the technical solution of this invention.

[0010] To achieve the above objectives, a first aspect of the present invention provides a trifluoromethylnicotinamide compound having the structures shown in Formulas I and II:

[0011] ; .

[0012] A second aspect of the present invention provides a method for preparing the compound described in the first aspect, as shown in reaction formula (1):

[0013] .

[0014] Reaction (1) is the synthetic route for preparing the compound in this invention, and reaction (2) is the synthetic route disclosed in prior art CN110776457A. By comparison, it was found that the raw material compound A in reaction (1) is not only cheaper than the raw material compound B in reaction (2), but also has a higher yield under the same conditions in reaction (1).

[0015] A third aspect of the present invention provides the use of the compounds described in the first aspect in the preparation of reagents for the prevention and control of plant diseases, wherein the plant disease is at least one of rice sheath blight, soybean rust, wheat sheath blight, rapeseed sclerotinia stem rot, wheat scab, cucumber powdery mildew, corn rust, corn sheath blight, rice blast, cucumber downy mildew, tomato early blight, tobacco red spot disease, and strawberry gray mold.

[0016] A fourth aspect of the present invention provides a bactericide comprising an active ingredient and excipients, wherein the active ingredient includes at least one of the trifluoromethylnicotinamide compounds described in the first aspect of the present invention.

[0017] Preferably, the content of the active ingredient is 1 to 99.9% by weight.

[0018] Preferably, the formulation of the bactericide is selected from at least one of emulsifiable concentrate, suspension concentrate, powder, granule, and aqueous solution.

[0019] The results of the bactericidal activity tests showed that the compounds of this invention exhibited highly efficient bactericidal activity in both in vitro assays on drug-containing culture media and in vivo pot experiments. Compounds I and II showed significantly better in vitro inhibitory effects against rice sheath blight pathogens, rapeseed sclerotinia rot pathogens, and wheat sheath blight pathogens than commercially available fungicides such as cyazofamid, thifluzamide, and comparative compounds I1–I4. Cytotoxicity tests showed that compound I had very low cytotoxicity to human cells. Acute oral toxicity tests in rats showed that compound I had a low acute oral LD50 in both male and female SD rats. 50 The values ​​are all higher than 2500 mg / kg, classifying them as low toxicity. Therefore, Compound I of this invention has the potential to be developed into a green fungicide for the control of common crop diseases such as rice sheath blight, rapeseed sclerotinia stem rot, soybean rust, and wheat sheath blight.

[0020] The following detailed description of specific embodiments further illustrates the above-mentioned content of the present invention. However, this should not be construed as a limitation of the present invention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0022] Figure 1 The images show the in vitro (plate) effects of compound I and thifluzamide, as well as comparative compounds 1 and 2, against rice sheath blight pathogens in the embodiments of this invention. The images show the antibacterial effects at concentrations of 2 mg / L, 0.2 mg / L, 0.05 mg / L, 0.025 mg / L, 0.0125 mg / L, 0.00625 mg / L, and 0.003125 mg / L, respectively. CK is the blank control without any treatment.

[0023] Figure 2 The figures show the anti-infection effects of compound I, the similar fungicides boscalid and thifluzamide at a concentration of 100 mg / L on live leaves of rice sheath blight and rapeseed sclerotinia stem rot, respectively. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0025] Synthesis Example

[0026] Example 1: Preparation of 2-(4-bromo-2-(trifluoromethyl)phenoxy)aniline

[0027] .

[0028] Add 1.0 g (9.2 mmol) of 2-aminophenol, 1.8 g (7.4 mmol) of 5-bromo-2-fluorotrifluorotoluene, a catalytic amount of tetrabutylammonium bromide, 3.1 g (22.2 mmol) of anhydrous potassium carbonate, and 20 mL of [amount missing] to a single-necked reaction flask. N , N Dimethylformamide was reacted at 110°C for 8 hours with stirring, and then removed under reduced pressure. N , N Dimethylformamide was washed three times with 10% NaOH aqueous solution, extracted with ethyl acetate (30 mL × 3), the organic layers were combined and dried over anhydrous sodium sulfate and then dissolved to give 2.1 g of 2-(4-bromo-2-(trifluoromethyl)phenoxy)aniline, with a yield of 85.5%.

[0029] Example 2 Preparation of Compound I

[0030] .

[0031] 2-(4-bromo-2-(trifluoromethyl)phenoxy)aniline (0.66 g, 2.0 mmol) was added to a reaction flask and dissolved in 10 mL of dichloromethane. Then, triethylamine (0.61 g, 6.0 mmol) was added, and a solution of 2-(trifluoromethyl)nicotinyl chloride (0.50 g, 2.4 mmol) in 10 mL of dichloromethane was slowly added dropwise while stirring in an ice-water bath. After the addition was complete, the mixture was allowed to react at room temperature for 5 hours. After the reaction was complete, the reaction solution was poured into 30 mL of water and extracted with dichloromethane (20 mL × 3). The organic layers were combined, washed with saturated sodium bicarbonate solution and saturated brine, respectively, dried over anhydrous sodium sulfate, and the dichloromethane was recovered by rotary evaporation. The residue was purified by column chromatography to give 0.88 g of compound I, in 88% yield.

[0032] The synthesis method of compound II is the same as that of compound I.

[0033] NMR data for compound I: white solid, melting point 147.6–148.2 °C. 1 H NMR (400 MHz, Chloroform- d ) δ 8.79 (d, J =4.7Hz, 1H), 8.49 (d, J =8.1Hz, 1H), 7.95 (s, 1H),7.93 (d, J =8.2Hz, 1H), 7.78 (s, 1H), 7.63 – 7.56 (m, 2H), 7.29 (d, J=7.8Hz, 1H), 7.17 (t, J =7.8Hz, 1H), 6.95 (d, J =8.1Hz, 1H), 6.88 (d, J =8.8Hz, 1H). 13 CNMR (101 MHz, Chloroform- d ) δ 163.83, 153.44, 150.67, 144.99, 144.26 (d, J =34.9Hz), 137.18, 136.69, 131.66, 130.51 (q, J =5.1Hz), 129.37, 126.57, 125.73,122.92, 122.60, 122.44 (q, J =273.3Hz), 122.30, 121.31 (q, J =275.4Hz), 120.19,118.74, 116.21.

[0034] NMR data for Compound II: white solid, melting point 149.5–151.0 °C. 1 H NMR (400 MHz, Chloroform- d ) δ 8.79 (d, J =4.7Hz, 1H), 8.49 (d, J =8.2Hz, 1H), 7.96 (s, 1H),7.93 (d, J =7.8Hz, 1H), 7.63 (s, 1H), 7.59 (dd, J =7.9, 4.8 Hz, 1H), 7.45 (dd, J =8.9, 2.6Hz, 1H), 7.27 (t, J =7.8Hz, 1H), 7.16 (t, J =7.7Hz, 1H), 6.94 (d, J =8.5Hz, 2H). 13 C NMR (101MHz, Chloroform- d ) δ163.82, 152.83, 150.65, 145.11,144.25 (q, J=34.7Hz), 137.19, 133.69, 131.67, 129.34, 129.16, 127.64 (q, J =5.1Hz), 126.57, 125.68 (d, J =5.1Hz), 122.66 (d, J =3.5Hz), 122.55 (q, J =273.0Hz), 122.26, 121.13 (q, J =239.7Hz), 119.99, 118.63.

[0035] Preparation of comparative compounds

[0036] The following comparative compounds were prepared according to the methods reported in J. Mol. Struct., 1308(2024)138331 and CN 110776457A:

[0037] .

[0038] Test Example 1

[0039] This test example is used to determine the in vitro antifungal activity of the compounds prepared in the synthetic examples and the commercial fungicides cyproconazole and thiabendazole against a variety of plant pathogenic fungi.

[0040] The tested plant pathogenic fungus, rice sheath blight fungus ( Rhizoctonia solani ), rapeseed sclerotinia pathogen ( Sclerotonia sclerotiorum ), tomato early blight pathogen ( Alternaria solani ) and wheat sheath blight fungus ( Rhizoctonia cerealis ).

[0041] Experimental methods

[0042] The mycelial growth rate method was used. The target compound was weighed using a 1 / 100,000 analytical balance and dissolved in DMSO to prepare a stock solution with a concentration of 10 g / L. The stock solution was serially diluted as needed and added to PDA medium. Pure DMSO without the test compound was added to the PDA culture medium as a blank control, while thifluzamide and flufenoxuron-methyl were positive controls. Fresh mycelial discs with a diameter of 5 mm were taken from the edge of the fungal colony in the PDA culture and inoculated onto the above PDA medium. This was repeated three times. When the mycelial growth in the blank control group reached 2 / 3 of the diameter of the culture dish, the diameter of the mycelial discs (mm) was measured using a vernier caliper using the cross-cross method, and the average value was calculated. The relative inhibition rate (%) was calculated according to the following formula: .

[0043] Experimental results

[0044] Antibacterial activity tests on the compounds obtained from the synthetic examples revealed that compounds I and II not only exhibited excellent inhibitory effects against rice sheath blight pathogens, but also showed ideal inhibitory effects against rapeseed sclerotinia stem rot, wheat sheath blight pathogens, tomato early blight pathogens, and tobacco red spot pathogens.

[0045] Figure 1 This is a schematic diagram of the in vitro experiment (plate) of compound I and thifluzamide, as well as comparative compounds 1 and 2, against rice sheath blight pathogens in the embodiments of the present invention. Figure 1 As shown, compound I still exhibits excellent inhibitory effects against rice sheath blight pathogens at extremely low concentrations, and its inhibitory effect on rice sheath blight pathogens is significantly better than that of thifluzamide, control compound 1, and control compound 2.

[0046] Results of in vitro antibacterial activity assays of the compounds (see Tables 1 to 4).

[0047] As shown in Table 1, compound I exhibits significantly better inhibitory effects against rice sheath blight pathogens than commercial fungicides thifluzamide, cyazofamid, and comparative compounds I1–I4.

[0048] Table 1

[0049]

[0050] As shown in Table 2, compounds I and II also exhibited excellent inhibitory effects against Sclerotinia sclerotinia, which were superior to the aforementioned fungicides thifluzamide, cyazofamid, and comparative compounds I1–I4.

[0051] Table 2

[0052]

[0053] As shown in Table 3, compound I also has a good inhibitory effect on early blight pathogens of tomato. Although its inhibitory effect on early blight pathogens of tomato is not as good as that of cyprodinil, it is worse than that of fungicide thifluzamide and comparative compounds I1–I4.

[0054] Table 3

[0055]

[0056] As shown in Table 4, compound I exhibits significantly better inhibitory effects against wheat sheath blight pathogens than commercial fungicides thifluzamide, cyazofamid, and comparative compounds I1–I4.

[0057] Table 4

[0058]

[0059] Test Example 2

[0060] This test case aims to evaluate the preventive effects of compound I from Example 1, along with the positive control drugs cyprodinil and thifluzamide, on live leaves of rice sheath blight and rapeseed sclerotinia stem rot.

[0061] The test method is as follows: Compound I, cyazofamid, and thifluzamide were dissolved in DMSO and diluted to 100 mg / L with an aqueous solution containing 0.1% Tween-80. Several smooth and healthy rice and rapeseed leaves were selected and washed sequentially with sterile water and 75% ethanol aqueous solution. After air-drying at room temperature, the above-mentioned agents were sprayed onto the leaf surface using a small sprayer, and then allowed to air dry naturally. Next, the cuticle layer of the leaf surface was pierced with a sterilized needle, and corresponding mycelial cakes with a diameter of 5 mm were inoculated at the piercing sites on both rice and rapeseed leaves. The leaves were incubated in a light incubator at 25℃ and 95% relative humidity, with a light / dark cycle of 12 hours / 12 hours. When the control group showed obvious disease, the diameter of the lesions was measured with calipers, and the control efficacy was calculated according to the corresponding formula. The control efficacy results of the compounds are shown in Table 5 below. Figure 2 As shown.

[0062] Table 5

[0063]

[0064] From Table 5 and Figure 2 It can be seen that compound I exhibits outstanding control efficacy against rice sheath blight and rapeseed sclerotinia stem rot at a concentration of 100 mg / L, with efficacy superior to commercially available fungicides such as boscalid and thifluzamide. In vivo leaf efficacy tests demonstrate that the compounds of this invention possess excellent in vivo antibacterial potential.

[0065] Test Example 3

[0066] This test case aims to further evaluate the efficacy of compound I from Example 1, as well as the positive control drugs thifluzamide and flufenoxuronamide, against rice sheath blight (data provided by Shanghai Xiaoming Testing Technology Service Co., Ltd.).

[0067] The test method is as follows: First, weigh an appropriate amount of the test compound and dissolve it in DMF. Then, prepare a stock solution of 20000 mg / L using a 0.1% Tween 80 aqueous solution. Next, dilute the solution sequentially using the 0.1% Tween 80 solution to prepare the test solution. Use a throat sprayer to evenly spray the agent onto the leaves of rice plants at the two-leaf stage. Each treatment group was repeated three times. After spraying, the plants were placed indoors to air dry naturally. 24 hours after treatment, 3cm × 3cm mycelial blocks of rice sheath blight were placed at the base of the rice seedling stems, with two mycelial blocks per pot, mycelial side facing the rice stem. The plants were then cultured in a glass humidity chamber under the following conditions: temperature 25–28℃, humidity greater than 90%, and light / dark cycle of 12 hours / 12 hours. Six days after inoculation, the mycelial growth height was graded according to the ratio of mycelial growth height to plant height. The control efficacy of the compound against rice sheath blight is shown in Table 6 below.

[0068] Table 6

[0069]

[0070] Table 6 shows that compound I has a good control effect on rice sheath blight. It is worth noting that the compound is more effective against rice sheath blight at low concentrations (such as 0.2 mg / L) than thifluzamide and flufenoxuron.

[0071] Test Example 4

[0072] This test case aims to evaluate the efficacy of compound I from Example 1, as well as the positive control drugs prothioconazole and flufenoxuron, against soybean rust (data provided by Shanghai Xiaoming Testing Technology Service Co., Ltd.).

[0073] The test method is as follows: First, weigh an appropriate amount of the test compound and dissolve it in DMF, then dilute it with a 0.1% Tween 80 aqueous solution to prepare a stock solution of 20000 mg / L. Next, use the 0.1% Tween 80 solution to successively dilute the stock solution to prepare the test solution. Two-leaf stage soybeans were selected as the test sample for soybean rust (…). Phakopsora pachyrhizi The host plants were cultured in a greenhouse. Foliar spraying was applied to the plants according to the designed concentration, and a blank control group was sprayed with water. The treatment was repeated three times. The plants were inoculated with pathogens 24 hours after treatment. After inoculation, the plants were placed in an artificial climate chamber for humidified cultivation, with a daytime temperature of 25°C and a nighttime temperature of 20°C, and a relative humidity of 95–99%. After 24 hours of cultivation, the experimental materials were transferred to the greenhouse for further cultivation. The disease control effect of the compound was evaluated after 11 days, once the control group plants had fully developed the disease.

[0074] Methodology: Results were obtained by referring to "A Manual of Assessment Keys for Plant Diseases" compiled by the American Plant Pathology Association. Based on the disease severity of the control group, the bactericidal activity of the test samples was investigated by visual inspection and expressed as 100–0, with "100" representing no disease and "0" representing the most severe disease severity.

[0075] The efficacy of the compounds against soybean rust is shown in Table 7 below.

[0076] Table 7

[0077]

[0078] As can be seen from Table 7, Compound I, prothioconazole, and flufenoxuron all achieved 100% control efficacy against soybean rust at high concentrations. At low concentrations (0.25 mg / L), Compound I of this invention showed control efficacy against soybean rust comparable to prothioconazole and superior to flufenoxuron.

[0079] Test Example 5

[0080] This test case was used to determine the cytotoxicity of Compound I from Example and the similar fungicide boscalid.

[0081] Assay Method: Transformed human liver epithelial cells (THLE-2) and normal human lung epithelial cells (BEAS-2B) were cultured to the logarithmic growth phase in a 37°C, 5% CO2 incubator using 1640 complete medium. Cells were then seeded into 96-well plates, incubated overnight, and the old medium was discarded. Fresh medium containing the target concentration of the compound was added (for the control group, a proportionally diluted DMSO solvent was added). The 96-well plates were then incubated in a CO2 incubator for 24 hours. After incubation, the medium in each well was discarded, and 90 μL of fresh medium and 10 μL of CCK-8 working solution were added to each well. The plates were incubated for another 2 hours. Afterward, the plates were shaken in the dark for 15 minutes, and the absorbance was measured at 490 nm using a microplate reader.

[0082] The cytotoxicity data of the compounds to THLE-2 and BEAS-2B cells are shown in Table 8 below.

[0083] Table 8

[0084] compound Concentration (μM) THLE-2 cell survival rate (%) BEAS-2B cell survival rate (%) I 100 92.1 96.3 20 97.7 98.5 4 97.9 100 0.8 100 100 0.16 100 100 0.032 100 100 0.0064 100 100 Cyclomethasone 100 94.3 97.3 20 96.8 98.9 4 98.6 100 0.8 100 100 0.16 100 100 0.032 100 100 0.0064 100 100

[0085] As can be seen from Table 8, Compound I of the present invention and cyazofamid, which is also a nicotinamide fungicide, both exhibit very low cytotoxicity to both THLE-2 and BEAS-2B cells, demonstrating high safety to non-target cells.

[0086] Test Example 6

[0087] This test case was used to determine the acute oral toxicity of compound I in rats.

[0088] The test method adopted GB / T15670.4—2017 "Toxicological Test Methods for Pesticide Registration Part 4: Probability Unit Method for Acute Oral Toxicity Test" for limit testing. The test dose was set at 2500 mg / kg, and 10 SPF-grade Sprague-Dawley (SD) rats were selected as experimental animals, with an equal number of males and females. The toxicity test was conducted by a single oral gavage, and the observation period was 14 days.

[0089] The experimental results showed that the experimental animals did not exhibit obvious symptoms of poisoning or die after exposure. During the 14-day observation period, the animals exhibited normal activity and sustained normal weight gain, with no deaths. At the end of the experiment, the rats were euthanized and grossly dissected; no visible lesions were found in any organs. Based on the limit method calculation, the oral LD50 of compound I of this invention in rats... 50 The value was greater than 2500 mg / kg. See Table 9 for detailed results.

[0090] Table 9

[0091] gender <![CDATA[Dose / (mg·kg -1 )]]> Number of animals / animals Number of deaths / animals mortality rate / % <![CDATA[LD 50 Value (mg·kg) -1 )]]> female 2500 5 0 0 >2500 male 2500 5 0 0 >2500

[0092] According to the data in Table 9, the acute oral toxicity of compound I of the present invention in rats is classified as low.

[0093] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, and all such modifications should be considered within the protection scope of the present invention.

Claims

1. A trifluoromethyl-containing nicotinamide compound characterized in that: The structure of the compound is shown in formula I and formula II, ； 。 2. The method for preparing trifluoromethylnicotinamide compounds according to claim 1, characterized in that... Prepared by the following reaction formula (1): ， Wherein, X is selected from bromine or chlorine; the method comprises contacting the compound of formula 1 with the compound of formula 2 under alkaline conditions and contacting the compound of formula 3 with the compound of formula 4 or formula 5.

3. The method of claim 2, wherein the contacting is performed under conditions comprising: The temperature is 0-150 DEG C, and the time is 1-24 h.

4. Use of the trifluoromethyl-containing nicotinamide compound according to claim 1 in the manufacture of an agent for controlling plant diseases, wherein The plant disease is at least one of rice sheath blight, soybean rust, wheat sheath blight, cabbage sclerotinia disease and tomato early blight.

5. A fungicide consisting of an active ingredient and an adjuvant, the active ingredient comprising at least one of the compounds of claim 1.

6. The sterilant of claim 5, wherein, The content of the active ingredient is 1-99.9% by weight.

7. The sterilant of claim 5 or 6, wherein, The dosage form of the fungicide is at least one of emulsifiable concentrate, suspension concentrate, powder, granule and water agent.

8. The sterilant of claim 5 or 6, wherein, The dosage form of the fungicide is at least one of wettable powder, mother powder and mother liquid.

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