Trifluoromethyl-containing nicotinamide compound as well as preparation method and application thereof

Abstract

The invention relates to the field of pesticide bactericides, and discloses trifluoromethyl-containing nicotinamide compounds as shown in a formula I and a formula II as well as a preparation method and application thereof. The compound provided by the invention is obtained by further structural optimization on the basis of the prior art. The trifluoromethyl-containing nicotinamide compounds as shown in the formula I and the formula II disclosed by the invention are low in raw material cost and high in synthesis yield, and have a more ideal control effect on crop diseases such as rice sheath blight disease, sclerotinia rot of colza, soybean rust disease and the like. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the field of pesticide fungicides, and particularly relates to a trifluoromethyl nicotinamide compound, a preparation method thereof, and the application of the compound in controlling crop diseases such as rice sheath blight and soybean rust. Background Art

[0002] Among the more than 200 commercially available fungicides listed by the Fungicide Resistance Action Committee (FRAC), succinate dehydrogenase inhibitor (SDHI) fungicides are the fastest-growing new products. Due to their advantages such as high efficiency, broad spectrum, low toxicity, and environmental friendliness, these fungicides have been highly favored and have become a research hotspot in the development of new fungicides.

[0003] In 2003, BASF first launched a broad-spectrum SDHI fungicide - boscalid. This product is a nicotinamide compound, which shows significant activity against almost all types of fungal diseases, especially in controlling powdery mildew, gray mold, sclerotinia, and various rot diseases. However, with the increase in field application, the problem of resistance has become increasingly prominent.

[0004] In order to seek a new nicotinamide fungicide that can replace boscalid, our laboratory has carried out a large number of synthesis and activity screening works through literature research and on the basis of existing technologies, and obtained two trifluoromethyl nicotinamide compounds with high fungicidal activity.

[0005] The prior art CN110776457 A discloses the following four trifluoromethylpyridinecarboxamide compounds.

[0006]

[0007] However, the above-mentioned trifluoromethylpyridinecarboxamide compounds described in the prior art have been tested for biological activity and have broad-spectrum antibacterial activity at high concentrations, but the inhibitory effects on common plant pathogenic fungi such as Rhizoctonia solani of rice, Sclerotinia sclerotiorum of rapeseed, and Rhizoctonia solani of wheat are not ideal at low concentrations. However, high-concentration application not only causes the problem of increased cost, but also significantly reduces the safety of drug use. Summary of the Invention

[0008] The purpose of the present invention is to provide a trifluoromethyl nicotinamide compound with broad spectrum, high efficiency and relatively lower synthesis cost. This compound can effectively control diseases such as rice sheath blight, soybean rust, wheat sheath blight, and rapeseed sclerotinia.

[0009] Based on the prior art, the inventors of the present invention conducted in-depth screening and research on nicotinamide compounds and unexpectedly found that a trifluoromethyl-containing nicotinamide compound not disclosed in the prior art (as shown in Formula I and Formula II) has higher inhibitory effects on pathogenic fungi such as Rhizoctonia solani than other trifluoromethyl-containing nicotinamide compounds in the prior art. It can effectively control diseases such as rice sheath blight and soybean rust, and the raw material cost required for its synthesis is relatively lower, making it more competitive in the market. Based on the above findings, the inventors of the present invention completed the technical solution of the present invention.

[0010] To achieve the above object, in the first aspect of the present invention, a trifluoromethyl-containing nicotinamide compound is provided, and this compound has the structures shown in the following Formula I and Formula II:

[0011]

[0012] In the second aspect of the present invention, a preparation method of the compound described in the first aspect is provided, as shown in Reaction Scheme (1):

[0013]

[0014] Reaction Scheme (1) is the synthetic route for preparing the compound in the present invention, and Reaction Scheme (2) is the synthetic route disclosed in the prior art CN110776457 A; through comparison, it is found that the raw material Formula A compound in Reaction Scheme (1) not only has a lower raw material price than the raw material Formula B compound in Reaction Scheme (2), but also has a higher yield in this step of the reaction under the same conditions.

[0015] In the third aspect of the present invention, an application of the compound described in the first aspect in the preparation of a reagent for controlling plant diseases is provided, wherein the plant diseases are at least one of rice sheath blight, soybean rust, wheat sheath blight, rape sclerotinia, wheat scab, cucumber powdery mildew, corn rust, corn sheath blight, rice blast, cucumber downy mildew, tomato early blight, tobacco brown spot, and strawberry gray mold.

[0016] In the fourth aspect of the present invention, a fungicide is provided, and this fungicide is composed of an active ingredient and an adjuvant, and the active ingredient includes at least one of the trifluoromethyl-containing nicotinamide compounds described in the first aspect of the present invention.

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

[0018] Preferably, the dosage form of this fungicide 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, whether in the in vitro determination test using a medicated medium or in the in vivo pot experiment, the compounds of the present invention exhibited high bactericidal activity. Among them, the in vitro inhibitory effects of Compounds I and II against Rhizoctonia solani of rice, Sclerotinia sclerotiorum of rapeseed, Rhizoctonia solani of wheat, etc. were superior to those of the commercial fungicides boscalid, thifluzamide, and Comparative Compounds I1 - I4; the cytotoxicity test showed that Compound I had very low cytotoxicity to human cells; the acute oral toxicity test on rats showed that the acute oral toxicity LD 50 values of Compound I for male and female SD rats were both higher than 2500 mg / kg, belonging to low toxicity. Therefore, Compound I of the present invention has the prospect of being developed into a green fungicide for controlling common crop diseases such as rice sheath blight, rapeseed sclerotinia blight, soybean rust, and wheat sheath blight.

[0020] The above content of the present invention will be further described in detail through specific embodiments below. However, this should not be construed as a limitation of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. Among them:

[0022] Figure 1 It is the in vitro test (plate) effect diagram of Compound I, thifluzamide, Comparative Compound 1, and Comparative Compound 2 of the present invention against Rhizoctonia solani of rice, showing 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 adding the medicament.

[0023] Figure 2 It is the in vivo leaf anti - infection effect diagram of Compound I, the fungicides boscalid and thifluzamide of the same type at a concentration of 100 mg / L against Rhizoctonia solani of rice and Sclerotinia sclerotiorum of rapeseed respectively. SPECIFIC EMBODIMENTS

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

[0025] SYNTHESIS EXAMPLES

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

[0027]

[0028] 1.0 g (9.2 mmol) of 2-aminophenol, 1.8 g (7.4 mmol) of 5-bromo-2-fluorobenzotrifluoride, a catalytic amount of tetrabutylammonium bromide, 3.1 g (22.2 mmol) of anhydrous potassium carbonate and 20 mL of N,N-dimethylformamide were added to a single-neck reaction flask. The temperature was raised to 110 °C under stirring and reacted for 8 h. N,N-dimethylformamide was removed under reduced pressure. It was washed three times with 10% aqueous NaOH solution, extracted with ethyl acetate (30 mL × 3), the organic layers were combined, dried over anhydrous sodium sulfate and then concentrated in vacuo to obtain 2.1 g of 2-(4-bromo-2-(trifluoromethyl)phenoxy)aniline, with a yield of 85.5%.

[0029] Preparation of Compound I in Example 2

[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 10 mL dichloromethane solution of 2-(trifluoromethyl)nicotinoyl chloride (0.50 g, 2.4 mmol) was slowly added dropwise with stirring under an ice-water bath. After the addition was complete, the reaction was carried out at room temperature for 5 h. After the reaction was completed, the reaction solution was poured into 30 mL of water, extracted with dichloromethane (20 mL × 3), the organic layers were combined, washed with saturated aqueous sodium bicarbonate solution and saturated brine respectively, dried over anhydrous sodium sulfate, and dichloromethane was recovered by rotary evaporation. The residue was purified by column chromatography to obtain 0.88 g of Compound I, with a yield of 88%.

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

[0033] NMR and MS data of Compound I: White solid, melting point 147.6–148.2 °C. 1 H NMR(400MHz,Chloroform-d)δ8.79(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). 1313C NMR (101 MHz, Chloroform-d) δ 163.83, 153.44, 150.67, 144.99, 144.26 (d, J=34.9 Hz), 137.18, 136.69, 131.66, 130.51 (q, J=5.1 Hz), 129.37, 126.57, 125.73, 122.92, 122.60, 122.44 (q, J=273.3 Hz), 122.30, 121.31 (q, J=275.4 Hz), 120.19, 118.74, 116.21. HRMS (ESI): Calcd for C 19 H 12 BrF5N2O2S [M+Na] + : 526.9800, found 526.9797.

[0034] NMR and MS data of Compound II: White solid, melting point 149.5–151.0 °C. 1 1H NMR (400 MHz, Chloroform-d) δ 8.79 (d, J=4.7 Hz, 1H), 8.49 (d, J=8.2 Hz, 1H), 7.96 (s, 1H), 7.93 (d, J=7.8 Hz, 1H), 7.63 (s, 1H), 7.59 (dd, J=7.9, 4.8 Hz, 1H), 7.45 (dd, J=8.9, 2.6 Hz, 1H), 7.27 (t, J=7.8 Hz, 1H), 7.16 (t, J=7.7 Hz, 1H), 6.94 (d, J=8.5 Hz, 2H). 13 13C NMR (101 MHz, Chloroform-d) δ 163.82, 152.83, 150.65, 145.11, 144.25 (q, J=34.7 Hz), 137.19, 133.69, 131.67, 129.34, 129.16, 127.64 (q, J=5.1 Hz), 126.57, 125.68 (d, J=5.1 Hz), 122.66 (d, J=3.5 Hz), 122.55 (q, J=273.0 Hz), 122.26, 121.13 (q, J=239.7 Hz), 119.99, 118.63. HRMS (ESI): Calcd for C 19 H 12 BrF5N2O2S [M+Na] + : 483.0305, found 483.0301.

[0035] Preparation of the Comparative Compound

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

[0037]

[0038] Test Example 1

[0039] This test example was used to determine the in vitro antibacterial activities of the compounds prepared in the synthesis examples, the commercial fungicides boscalid and thifluzamide against various phytopathogenic fungi.

[0040] The tested phytopathogenic fungi were Rhizoctonia solani, Sclerotinia sclerotiorum, Alternaria solani and Rhizoctonia cerealis.

[0041] 1. Experimental method

[0042] The mycelial growth rate method was adopted. The target compound was weighed with an analytical balance of one over one hundred thousandth 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 the PDA medium. Pure DMSO without the test compound was added to the PDA culture medium as a blank control, and thifluzamide and fluxapyroxad were used as positive controls. A fresh mycelial disc with a diameter of 5 mm was taken from the edge of the fungal colony cultured on PDA and inoculated on the above PDA medium, with three replicates. When the mycelial growth in the blank control group reached 2 / 3 of the diameter of the petri dish, the diameter (mm) of the mycelial disc was measured with a vernier caliper by the cross method, and its average value was calculated. The relative inhibition rate (%) was calculated according to the following formula:

[0043]

[0044] 2. Experimental results

[0045] Through the antibacterial activity test of the compounds prepared in the synthesis examples, it was found that Compounds I and II not only had excellent inhibitory effects on Rhizoctonia solani, but also had ideal inhibitory effects on Sclerotinia sclerotiorum, Rhizoctonia cerealis, Alternaria solani and Alternaria alternata, etc.

[0046] Figure 1 This is a schematic diagram of the in vitro experiment (plate) of Compound I, thifluzamide, Comparative Compound 1 and Comparative Compound 2 against Rhizoctonia solani in the examples of the present invention. As Figure 1As shown, Compound I still has a very good inhibitory effect on *Rhizoctonia solani* at extremely low concentrations, and its inhibitory effect on *Rhizoctonia solani* is significantly better than that of thifluzamide, Comparative Compound 1, and Comparative Compound 2.

[0047] The results of the in vitro antibacterial activity assay of the compounds are shown in Tables 1 to 4.

[0048] As can be seen from the results in Table 1, the inhibitory effect of Compound I on *Rhizoctonia solani* is significantly better than that of the commercial fungicides thifluzamide, boscalid, and Comparative Compounds I1–I4.

[0049] Table 1

[0050]

[0051] As can be seen from the results in Table 2, Compounds I and II also showed very excellent inhibitory effects on *Sclerotinia sclerotiorum* of rapeseed, which are better than those of the same type of fungicides thifluzamide, boscalid, and Comparative Compounds I1–I4.

[0052] Table 2

[0053]

[0054]

[0055] As can be seen from the results in Table 3, Compound I also has a good inhibitory effect on *Alternaria solani* of tomato. Although its inhibitory effect on *Alternaria solani* of tomato is not as good as that of boscalid, it is better than the fungicides thifluzamide and Comparative Compounds I1–I4.

[0056] Table 3

[0057]

[0058] As can be seen from the results in Table 4, the inhibitory effect of Compound I on *Rhizoctonia cerealis* is significantly better than that of the commercial fungicides thifluzamide, boscalid, and Comparative Compounds I1–I4.

[0059] Table 4

[0060]

[0061]

[0062] Test Example 2

[0063] This test example aims to evaluate the preventive effects of Example Compound I, and the positive control drugs boscalid and thifluzamide on the living leaves of *Rhizoctonia solani* of rice and *Sclerotinia sclerotiorum* of rapeseed.

[0064] The test method is as follows: Dissolve Compound I, boscalid, and thifluzamide in DMSO respectively, and dilute them to 100 mg / L with an aqueous solution containing 0.1% Tween-80. Select several smooth and healthy rice and rapeseed leaves respectively, and wash them successively with sterile water and 75% aqueous ethanol solution. After air-drying at room temperature, spray the above-mentioned medicaments on the leaf surface with a small sprayer respectively, and let them dry naturally after treatment. Then, pierce the cuticle on the leaf surface with a sterilized needle respectively, and inoculate corresponding agar discs with a diameter of 5 mm at the pierced sites of rice leaves and rapeseed leaves respectively. Culture them in a light incubator at 25 °C and 95% relative humidity, with a light / dark cycle of 12 hours / 12 hours. When the disease in the blank group is obvious, measure the diameter of the lesions with a vernier caliper, and calculate the control efficacy according to the corresponding formula. The control efficacy results of the compound are shown in Table 5 and Figure 2 as shown below.

[0065] Table 5

[0066]

[0067] As can be seen from Table 5 and Figure 2 it can be seen that Compound I has outstanding control efficacy against rice sheath blight and rapeseed sclerotinia blight at a concentration of 100 mg / L, and its control efficacy is better than that of the commercial fungicides boscalid and thifluzamide. The in vivo leaf control efficacy test shows that the compound of the present invention has excellent in vivo antibacterial potential.

[0068] Test Example 3

[0069] This test example aims to further evaluate the control efficacy of Compound I of the example and the positive control drugs thifluzamide and fluxapyroxad against rice sheath blight (the data is provided by Shanghai Xiaoming Testing Technology Service Co., Ltd.).

[0070] The test method is as follows: First, weigh an appropriate amount of the compound to be tested and dissolve it in DMF, and then prepare a stock solution of 20000 mg / L with 0.1% Tween 80 aqueous solution. Then, dilute it successively with 0.1% Tween 80 solution to prepare the test medicament solution. Spray the medicament evenly on the rice leaves at the two-leaf-one-heart stage with a throat sprayer, and repeat each treatment group three times. After spraying, place the plants indoors to dry naturally. 24 hours after the medicament treatment, clamp 3 cm × 3 cm rice sheath blight mycelial blocks at the base of the rice seedling stems, place 2 mycelial blocks in each pot of seedlings, with the mycelial surface facing the rice stem, and then culture them in a glass humidity cabinet. The culture conditions are a temperature of 25-28 °C, a humidity of more than 90%, and a light / dark cycle of 12 hours / 12 hours. 6 days after inoculating the mycelial blocks, conduct a graded investigation based on the proportion of the mycelial growth height to the plant height. The control efficacy of the compound against rice sheath blight is shown in Table 6 below.

[0071] Table 6

[0072]

[0073] As can be seen from Table 6, Compound I has a good control effect on sheath blight of rice. It is worth noting that the control effect of the compound on sheath blight of rice at low concentrations (such as 0.2 mg / L) is better than that of thifluzamide and fluxapyroxad.

[0074] Test Example 4

[0075] This test example aims to evaluate the control effects of Compound I of the example and the positive control drugs prothioconazole and fluxapyroxad on soybean rust (the data is provided by Shanghai Xiaoming Testing Technology Service Co., Ltd.).

[0076] The test method is as follows: First, weigh an appropriate amount of the compound to be tested and dissolve it with DMF, and then dilute it with a 0.1% Tween 80 aqueous solution to prepare a stock solution of 20,000 mg / L. Then, dilute it successively with a 0.1% Tween 80 solution to prepare the test liquid. Select two-leaf-stage soybeans as the host plants for soybean rust (Phakopsora pachyrhizi) and cultivate them in a greenhouse. According to the designed concentration, perform foliar spray treatment on the plants, and set up a blank control group that sprays clear water, with the treatment repeated 3 times. Inoculate the pathogen 24 hours after the treatment. After inoculation, place the plants in an artificial climate chamber for moisturizing cultivation, set the temperature to 25°C during the day and 20°C at night, and the relative humidity to 95–99%. After cultivating the test materials for 24 hours, transfer them to the greenhouse for further cultivation. After the control plants are fully diseased after 11 days, evaluate the disease prevention effect of the compound.

[0077] Investigation method: The result investigation refers to "A Manual of Assessment Keys for Plant Diseases" compiled by the American Phytopathological Society. According to the disease severity of the control, use the visual method to investigate the bactericidal activity of the test samples, which is represented by 100–0, with "100" representing no disease and "0" representing the most severe disease severity.

[0078] The control effects of the compound on soybean rust are shown in Table 7 below.

[0079] Table 7

[0080]

[0081]

[0082] As can be seen from Table 7, the control effects of Compound I, prothioconazole, and fluxapyroxad on soybean rust all reached 100% at high concentrations. At low concentrations (0.25 mg / L), Compound I of the present invention showed a control effect on soybean rust comparable to that of prothioconazole and superior to that of fluxapyroxad.

[0083] Test Example 5

[0084] This test example is used to determine the cytotoxicity of the compound I in the example and the fungicide boscalid of the same kind.

[0085] Test method: The transformed human hepatic epithelial cells (THLE-2) and human normal lung epithelial cells (BEAS-2B) were cultured in a 1640 complete medium in an incubator at 37 °C and 5% CO2 until the logarithmic growth phase. Subsequently, the cells were respectively inoculated into 96-well plates. After overnight incubation, the old medium was discarded, and fresh medium containing the compound to be tested at the desired concentration was added (in the control group, DMSO solvent diluted in equal proportion was added). Then, the 96-well plates were placed in a CO2 constant temperature incubator and cultured for 24 hours. After the culture ended, the medium in the wells was discarded, 90 μL of fresh medium and 10 μL of CCK-8 working solution were added to each well, and the incubation was continued in the incubator for 2 hours. Subsequently, it was shaken for 15 minutes in the dark, and the absorbance of the solution was measured at a wavelength of 490 nm using a microplate reader.

[0086] The cytotoxicity data of the compound against THLE-2 and BEAS-2B cells are shown in Table 8 below.

[0087] Table 8

[0088]

[0089]

[0090] As can be seen from Table 8, the compound I of the present invention and boscalid, a fungicide of the same kind as nicotinamide, have very low cytotoxicity to both THLE-2 and BEAS-2B cells, showing high safety to non-target cells.

[0091] Test Example 6

[0092] This test example is used to determine the acute oral toxicity of the compound I in the example to rats.

[0093] The test method was carried out using the limit test in GB / T 15670.4—2017 "Test Methods for Pesticide Registration Toxicology - Part 4: Acute Oral Toxicity Test - Probit Method". The set dose for this test was 2500 mg / kg. Ten SPF-grade Sprague-Dawley (SD) rats were selected as experimental animals, with half males and half females. The toxicity test was carried out by single oral gavage, and the observation period was 14 days.

[0094] The test results showed that no obvious poisoning symptoms or deaths occurred in the experimental animals after exposure to the toxicant. During the 14-day observation period, the animals were active normally, their body weights continued to increase normally, and no deaths occurred. At the end of the test, the rats were sacrificed and subjected to gross dissection, and no macroscopic lesions were found in each organ. According to the calculation of the limit method, the oral LD 50 value of Compound I of the present invention for rats was greater than 2500 mg / kg, and the detailed results are shown in Table 9.

[0095] Table 9

[0096]

[0097] According to the relevant standards for the toxicity classification and labeling of pesticide products in the "Regulations on Pesticide Registration Data" (Order No. 10 of the Ministry of Agriculture of the People's Republic of China (2007)), Compound I of the present invention, as shown in the data of Table 9, is classified as low-toxic for acute oral toxicity to rats.

[0098] The above content elaborates in detail the preferred embodiments of the present invention. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these modifications should all be regarded as within the protection scope of the present invention.

Claims

1. A compound containing trifluoromethyl nicotinamide, characterized in that: The structure of the compound is shown in Formula I and Formula II, 2. The preparation method of the trifluoromethyl nicotinamide compound according to claim 1, wherein and it is prepared by the following reaction formula (1): Reaction formula (1):

3. According to the method described in claim 2, the method includes subjecting the compound of Formula 1 and the compound of Formula 2 to a contact reaction under alkaline conditions and subjecting the compound of Formula 3 and the compound of Formula 4 or Formula 5 to a contact reaction.

4. The conditions for the contact reaction according to claim 3 include: The temperature is 0 to 150 °C and the time is 1 to 24 h.

5. Use of the trifluoromethyl nicotinamide compound according to claim 1 in the preparation of a reagent for preventing and controlling plant diseases, wherein, The plant diseases are at least one of sheath blight of rice, soybean rust, sheath blight of wheat, sclerotinia rot of rape, scab of wheat, powdery mildew of cucumber, corn rust, sheath blight of corn, rice blast, downy mildew of cucumber, early blight of tomato, and brown spot of tobacco.

6. A fungicide, which consists of an active ingredient and an adjuvant, and the active ingredient includes at least one of the compounds described in claim 1.

7. The fungicide according to claim 6, wherein, The content of the active ingredient is 1 to 99.9% by weight.

8. The fungicide according to claim 6 or 7, wherein The dosage form of the fungicide is selected from at least one of emulsifiable concentrates, suspension concentrates, powders, granules, and aqueous solutions.

9. The fungicide according to claim 6 or 7, wherein, The dosage form of the fungicide is selected from at least one of wettable powders, mother powders, and mother liquors.

Images