Phenylaminothiazole derivative and application thereof as bactericide

Abstract

The invention discloses a phenylaminothiazole derivative as shown in a formula I and application of the phenylaminothiazole derivative to prevention and treatment of plant diseases. The phenylaminothiazole derivative has the advantages of simple and easily available raw materials, simple preparation method, convenient post-treatment and high product yield, and the compound as shown in the formula I has broad-spectrum and efficient anti-plant fungus activity. The bactericidal composition especially has a good bactericidal effect on rhizoctonia solani, sclerotinia sclerotiorum, alternaria solani, botryosphaeria dothidea, apple black beancurd skin fungi, rhizoctonia cerealis, fusarium graminearum and colletotrichum gloeosporioides. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of fungicides, and relates to a phenylaminothiazole derivative, and specifically relates to the application of such compounds against common plant pathogens such as Rhizoctonia solani, Sclerotinia sclerotiorum, and Alternaria solani. Background Art

[0002] In agricultural production, chemical pesticides remain the main means of controlling crop diseases. Their high efficiency, convenience, economy, and wide application make them occupy an important position in the industry (J. Agric. Food Chem. 2024, 72, 3342 - 3353). However, the overuse of pesticides has led to the development of drug resistance, environmental pollution, and negative impacts on non-target organisms. Therefore, the core task of pesticide researchers is to develop pesticides with new structures and new targets to continuously meet the growing market demand.

[0003] The thiazole heterocycle has rich electrons, enabling it to effectively interact with various biological targets, thereby enhancing biological activity. In particular, 2-aminothiazole derivatives are usually noted for their broad biological activities (J. Agric. Food Chem. 2022, 70, 10100 - 10110).

[0004] The prior art Bioorganic & Medicinal Chemistry Letters 29 (2019) 938–9 discovered a novel strigolactone (SL) agonist 113D10 and compounds 8 and 9 through a series of biological and biochemical assays. These novel SL agonists can be used to increase crop yields by controlling the number of branches without stimulating the seed germination of root parasitic plants.

[0005]

[0006] The prior art CN 118239903 A reported a preparation method of a 2-amino-4-trifluoromethylthiazole derivative.

[0007] There is no prior art on the phenylaminothiazole derivative as described in the present invention and its application in the field of fungicides. Summary of the Invention

[0008] The object of the present invention is to overcome the deficiencies in the prior art and provide a class of phenylaminothiazole derivatives with anti-plant pathogenic bacterium activity. In order to obtain thiazole compounds with simple structures, lower production costs, broader spectra and higher activities, the applicant has been committed to the research of thiazole compounds. Through several years of research, the applicant has discovered that a class of thiazole compounds with novel structures have high antibacterial activities. Although the structural skeletons in the prior art have similarities with those of the compounds of the present invention, there are no reports on any bactericidal activities of such compounds in the prior art, and the applicant has found that after introducing fluorine atoms at the meta-position of the benzene ring, the obtained compounds have unexpected antibacterial effects.

[0009] The present invention provides a phenylaminothiazole derivative with anti-plant pathogenic bacterium activity as shown in Formula I, and the compound is as shown in General Formula I:

[0010]

[0011] wherein, R is respectively selected from hydrogen and alkyl; R 1 is respectively selected from fluorine, chlorine, bromine, iodine, trifluoromethyl, trifluoromethoxy, difluoromethyl and difluoromethoxy; R 2 is respectively selected from hydrogen, fluorine, chlorine and bromine; X is respectively selected from hydrogen, fluorine, chlorine, bromine and iodine.

[0012] The preferred technical solution in the present invention is that the compound of Formula I is:

[0013] N-(3,5-difluorophenyl)-4-(trifluoromethyl)thiazol-2-amine;

[0014] N-(3-chloro-5-fluorophenyl)-4-(trifluoromethyl)thiazol-2-amine;

[0015] N-(3-bromo-5-fluorophenyl)-4-(trifluoromethyl)thiazol-2-amine;

[0016] N-(3-fluoro-5-(trifluoromethyl)phenyl)-4-(trifluoromethyl)thiazol-2-amine;

[0017] N-(3,5-difluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0018] N-(3-chloro-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0019] N-(3-bromo-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0020] N-(3-fluoro-5-(trifluoromethyl)phenyl)-N-methyl-4-(trifluoromethane)thiazol-2-amine;

[0021] N-(3,5-Difluorophenyl)-5-fluoro-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0022] 5-Chloro-N-(3,5-difluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0023] 5-Bromo-N-(3,5-difluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0024] 5-Bromo-N-(3-chloro-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0025] 5-Bromo-N-(3-bromo-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0026] 5-Bromo-N-(3-fluoro-5-(trifluoromethyl)phenyl)-N-methyl-4-(trifluoromethane)thiazol-2-amine;

[0027] N-(3-(Difluoromethyl)-5-fluorophenyl)-4-(trifluoromethyl)thiazol-2-amine;

[0028] N-(3-(Difluoromethyl)-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0029] 5-Chloro-N-(3-(difluoromethyl)-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0030] 5-Bromo-N-(3-(difluoromethyl)-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine;

[0031] 4-(Difluoromethyl)-N-(3,5-difluorophenyl)thiazol-2-amine;

[0032] N-(3-Chloro-5-fluorophenyl)-4-(difluoromethyl)thiazol-2-amine;

[0033] N-(3-Bromo-5-fluorophenyl)-4-(difluoromethyl)thiazol-2-amine;

[0034] 4-(Difluoromethyl)-N-(3-fluoro-5-(trifluoromethyl)phenyl)thiazol-2-amine.

[0035] On the other hand, the present invention provides the use of the phenylaminothiazole derivative in the preparation of an anti-plant pathogen reagent, wherein the pathogen is at least one of Rhizoctonia solani, Sclerotinia sclerotiorum, Alternaria solani, Botryosphaeria dothidea, Valsa mali, Rhizoctonia cerealis, Fusarium graminearum, Botrytis cinerea, Alternaria alternata, Colletotrichum gloeosporioides, Blumeria graminis f. sp. tritici, Phakopsora pachyrhizi, and Puccinia sorghi.

[0036] The present invention also includes a bactericidal composition with the compound of general formula I as the active ingredient. The weight percentage of the compound of general formula I as the active ingredient in the bactericidal composition is between 1% and 99%. The bactericidal composition also includes an agriculturally or forestry-acceptable carrier.

[0037] Advantages of the present invention:

[0038] The compound of the present invention not only has simple synthesis, easily available raw materials and low cost, but also has a very broad-spectrum bactericidal activity, and has good antibacterial effects on plant pathogens such as Rhizoctonia solani, Sclerotinia sclerotiorum, Alternaria solani, Botryosphaeria dothidea, Valsa mali, Rhizoctonia cerealis, Fusarium graminearum, Botrytis cinerea, and Colletotrichum gloeosporioides. Description of the drawings

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings 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 according to these drawings. Among them:

[0040] Figure 1 It is the in-vivo control effect diagram of compound I-1, positive control pyrimethanil and carbendazim at a concentration of 100 mg / L against Sclerotinia sclerotiorum and Alternaria solani in the embodiments of the present invention. Detailed implementation manners

[0041] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the embodiments of the specification.

[0042] Synthesis examples

[0043] Example 1 Preparation of N-(3,5-difluorophenyl)-4-(trifluoromethyl)thiazol-2-amine (I-1)

[0044]

[0045] 0.52 g (6.83 mmol) of ammonium thiocyanate and 15 mL of acetone were added to a reaction flask and dissolved completely. While stirring magnetically at room temperature, 0.96 g (6.83 mmol) of benzoyl chloride was slowly added dropwise. After the addition was complete, the temperature was raised to 60 °C and stirred for 30 minutes. Then, a solution of 0.83 g (6.44 mmol) of 3,5-difluoroaniline in 15 mL of acetone was slowly added dropwise using a constant pressure dropping funnel. After the addition was complete, the reaction was continued at 60 °C for 5 hours. Acetone was recovered by distillation under reduced pressure. The residue was added to 50 mL of water, stirred and ground thoroughly, then filtered by suction and dried to obtain 1.59 g of the intermediate N-(3,5-difluorophenyl)carbamoyl)benzamide with a yield of 85%.

[0046] 1.50 g (5.14 mmol) of N-(3,5-difluorophenyl)carbamoyl)benzamide, 15 mL of methanol and 15 mL of ammonia water were successively added to a reaction flask. The temperature was raised to 70 °C and refluxed for 1 hour. After most of the solvent was removed by distillation under reduced pressure, it was extracted with ethyl acetate (30×3). The organic layers were combined, dried over anhydrous sodium sulfate, and ethyl acetate was recovered by distillation under reduced pressure. The solid residue was slurried with petroleum ether, filtered by suction, and the filter cake was dried to obtain 0.96 g of the intermediate 1-(3,5-difluorophenyl)thiourea with a yield of 97%.

[0047] 0.80 g (4.25 mmol) of 1-(3,5-difluorophenyl)thiourea and 20 mL of absolute ethanol were added to a reaction flask and dissolved completely. 1.22 g (6.38 mmol) of 3-bromo-1,1,1-trifluoro-2-propanone was added dropwise, and then the temperature was raised to reflux and reacted for 19 hours. The solvent was removed by distillation under reduced pressure. It was extracted with ethyl acetate (30 mL×3), the organic layers were combined, the organic layer was dried over anhydrous sodium sulfate, and ethyl acetate was recovered by distillation under reduced pressure. The residue was subjected to flash column chromatography to obtain 0.89 g of the target compound I-1 with a yield of 75%.

[0048] The preparation of N-(3-fluoro-5-(trifluoromethyl)phenyl)-4-(trifluoromethyl)thiazol-2-amine (I-2) and the preparation methods of Comparative Compounds 1 to 12 are the same as those of Compound I-1.

[0049] 1H NMR data of Compound I-1: White solid, melting point 125.8–127.4 °C. 1 1H NMR (400 MHz, DMSO-d6) δ 10.98 (s, 1H), 7.76 (s, 1H), 7.30 (d, J = 9.8 Hz, 1H), 6.80 (td, J = 9.4, 2.1 Hz, 1H). 1313C NMR (101 MHz, DMSO-d6) δ 164.43, 162.80 (dd, J = 243.1, 15.7 Hz), 142.63 (t, J = 14.0 Hz), 138.47 (q, J = 36.2 Hz), 120.47 (q, J = 269.7 Hz), 113.22, 100.42–99.65 (m), 96.86 (t, J = 26.3 Hz).

[0050] 1H NMR data of Compound I-2: Pale yellow solid, melting point 109.4–111.2 °C. 1 1H NMR (400 MHz, Chloroform-d) δ 8.05 (s, 1H), 7.55 (d, J = 10.2 Hz, 1H), 7.35 (s, 1H), 7.19 (s, 1H), 7.05 (d, J = 8.2 Hz, 1H). 13 13C NMR (101 MHz, Chloroform-d) δ 165.06, 163.34 (d, J = 248.6 Hz), 141.84 (d, J = 10.9 Hz), 141.19 (q, J = 37.5 Hz), 133.58 (q, J = 33.6 Hz), 133.48 (q, J = 33.7 Hz), 123.13 (q, J = 272.7 Hz), 120.24 (q, J = 270.2 Hz), 111.25–110.91 (m), 108.95 (d, J = 26.1 Hz), 107.76 (ddd, J = 25.0, 7.5, 3.7 Hz).

[0051] The structures of Comparative Compounds 1-12 are as follows:

[0052]

[0053]

[0054] Examples of Biological Activity Assay

[0055] Example 2 In vitro Plate Antibacterial Activity Test

[0056] This example is used to determine the in vitro antibacterial activities of the compounds prepared in Example 1 and the comparative compounds against various plant pathogenic fungi.

[0057] Tested phytopathogenic fungi: *Rhizoctonia solani*, *Sclerotonia sclerotiorum*, *Alternaria solani*, *Botryosphaeria dothidea*, *Valsa mali*, *Rhizoctonia cerealis*, *Gibberella zeae* and *Colletotrichum gloeosporioides*.

[0058] 1. Experimental method

[0059] The mycelial growth rate method was adopted. The target compound was weighed with an analytical balance of one over one hundred thousand and dissolved in DMSO to prepare a stock solution with a concentration of 10 g / L. The stock solution was added to the PDA medium. The initial screening concentration of the target compound was 20 mg / L. Pure DMSO without the compound to be tested was added to the PDA culture medium as a blank control, and the commercial fungicides pyrimethanil, thifluzamide and carbendazim were used as positive controls. Fresh fungal discs with a diameter of 5 mm were taken from the edge of the fungal colonies cultured on PDA and inoculated onto the above PDA medium. Three identical fungal discs were evenly inoculated on each plate according to an equilateral triangle. The diameter (mm) of the fungal discs was measured with 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:

[0060]

[0061] 2. Experimental results

[0062] The results of the antibacterial activity test are shown in Table 1, where Rs represents *Rhizoctonia solani*, Ss represents *Sclerotonia sclerotiorum*, As represents *Alternaria solani*, Bd represents *Botryosphaeria dothidea*, Vm represents *Valsa mali*, Rc represents *Rhizoctonia cerealis*, Gz represents *Gibberella zeae*, and Cg represents *Colletotrichum gloeosporioides*. It can be clearly seen from the data in Table 1 that the compounds I-1 and I-2 of the examples have very broad-spectrum and high-efficiency antibacterial activities, and their antibacterial activities at a concentration of 20 mg / L are significantly better than those of the commercial fungicides pyrimethanil and thifluzamide, and are comparable to carbendazim. Through the study of the structure-activity relationship with the comparative compounds, it was found that the fluorine atom at the 3rd position of the benzene ring is of great significance for improving the activity, and unexpected antibacterial effects can be obtained by further introducing substituents at the 5th position of the benzene ring.

[0063] Table 1

[0064]

[0065] Example 3: In vitro leaf and fruit inoculation test

[0066] This example is used to verify the antibacterial effects of compound I-1 prepared in Example 1, commercial fungicides pyrimethanil and carbendazim against Sclerotinia sclerotiorum of rapeseed and Alternaria solani of tomato

[0067] The test method is as follows: Dissolve compound I-1, pyrimethanil and carbendazim in DMSO and dilute them to 100 mg / L with an aqueous solution containing 0.1% Tween-80. Select several rapeseed leaves and tomato fruits with uniform size, smooth surface and good health, and wash them successively with sterile water and 75% aqueous ethanol solution. After air-drying at room temperature, spray the above-mentioned agents on the rapeseed leaves and tomato fruits respectively with a small sprayer, and let them dry naturally after treatment. Then, pierce the cutin layer on the surface of the rapeseed leaves and tomato fruits with a sterilized needle respectively, and inoculate a 5-mm diameter cake of Sclerotinia sclerotiorum of rapeseed and Alternaria solani of tomato on the rapeseed leaves and tomato fruits respectively. Incubate in a light incubator at 25°C and 95% relative humidity. When the disease in the blank group is obvious, measure the diameter of the disease spots with a vernier caliper and calculate the control effect according to the corresponding formula

[0068] The test results are as Figure 1 shown in Figure 1 Table 2. It can be clearly seen from

[0069] Table 2 that compound I-1 shows good control effects against Sclerotinia sclerotiorum of rapeseed and Alternaria solani of tomato. The control effects of compound I-1 against Sclerotinia sclerotiorum of rapeseed and Alternaria solani of tomato are better than those of pyrimethanil. Although the control effect of compound I-1 against Sclerotinia sclerotiorum of rapeseed is not as good as that of carbendazim, its control effect against Alternaria solani of tomato is significantly better than that of carbendazim

[0069] Table 2

[0070]

[0071] Example 4: Cytotoxicity test

[0072] This test example is used to determine the cytotoxicities of compound I-1 of this example and thifluzamide, also a thiazole fungicide

[0073] The test method is as follows: Culture the transformed human hepatic epithelial cells (THLE-2) and human normal lung epithelial cells (BEAS-2B) in a 1640 complete medium in a CO2 incubator at 37°C and 5% CO2 until the logarithmic growth phase, then inoculate the cells into 96-well plates respectively. After overnight incubation, discard the old medium, add the medium containing the compound to be tested (add an equal proportion of diluted DMSO solvent to the control group), place it in a CO2 constant temperature incubator and culture for 24 h. Then discard the medium in the 96-well plates, add 90 μL of fresh medium and 10 μL of CCK8 working solution to each well, continue to incubate in the incubator for 2 h, then shake it in the dark for 15 min, and use an enzyme-linked immunosorbent assay (ELISA) reader to measure the absorbance of the solution at a wavelength of 490 nm

[0074] The cytotoxicity data of the compound against THLE-2 and BEAS-2B cells are shown in Table 3 below.

[0075] Table 3

[0076]

[0077] As can be seen from Table 3, both Compound I-1 and the commercial fungicide thifluzamide are thiazole compounds, and both have very low toxicity to THLE-2 and BEAS-2B cells. Therefore, the compound of the present invention, as a thiazole derivative, has a predictable low-toxicity advantage, reflecting its high safety for non-target cells.

[0078] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A class of phenylaminothiazole derivatives with anti - plant pathogenic bacteria activity, characterized in that: The structure of the anilinothiazole derivative is shown in general formula I as follows: Among them, R is independently selected from hydrogen and alkyl; R 1 is independently selected from fluorine, chlorine, bromine, iodine, trifluoromethyl, trifluoromethoxy, difluoromethyl, and difluoromethoxy; R 2 is independently selected from hydrogen, fluorine, chlorine, and bromine; X is independently selected from hydrogen, fluorine, chlorine, bromine, and iodine.

2. The phenylaminothiazole derivative according to claim 1, wherein The compounds shown in general formula I are: N-(3,5-difluorophenyl)-4-(trifluoromethyl)thiazol-2-amine; N-(3-chloro-5-fluorophenyl)-4-(trifluoromethyl)thiazol-2-amine; N-(3-bromo-5-fluorophenyl)-4-(trifluoromethyl)thiazol-2-amine; N-(3-fluoro-5-(trifluoromethyl)phenyl)-4-(trifluoromethyl)thiazol-2-amine; N-(3,5-difluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; N-(3-chloro-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; N-(3-bromo-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; N-(3-fluoro-5-(trifluoromethyl)phenyl)-N-methyl-4-(trifluoromethane)thiazol-2-amine; N-(3,5-difluorophenyl)-5-fluoro-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 5-chloro-N-(3,5-difluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 5-bromo-N-(3,5-difluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 5-bromo-N-(3-chloro-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 5-bromo-N-(3-bromo-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 5-bromo-N-(3-fluoro-5-(trifluoromethyl)phenyl)-N-methyl-4-(trifluoromethane)thiazol-2-amine; N-(3-(difluoromethyl)-5-fluorophenyl)-4-(trifluoromethyl)thiazol-2-amine; N-(3-(difluoromethyl)-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 5-chloro-N-(3-(difluoromethyl)-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 5-bromo-N-(3-(difluoromethyl)-5-fluorophenyl)-N-methyl-4-(trifluoromethyl)thiazol-2-amine; 4-(difluoromethyl)-N-(3,5-difluorophenyl)thiazol-2-amine; N-(3-chloro-5-fluorophenyl)-4-(difluoromethyl)thiazol-2-amine; N-(3-bromo-5-fluorophenyl)-4-(difluoromethyl)thiazol-2-amine; 4-(difluoromethyl)-N-(3-fluoro-5-(trifluoromethyl)phenyl)thiazol-2-amine.

3. Use of the phenylaminothiazole derivative according to claim 1 in the preparation of an anti-plant pathogenic bacterium reagent, wherein, The pathogenic bacteria are at least one of Rhizoctonia solani, Sclerotinia sclerotiorum, Alternaria solani, Botryosphaeria dothidea, Valsa mali, Rhizoctonia cerealis, Fusarium graminearum, Botrytis cinerea, Alternaria alternata, Colletotrichum gloeosporioides, Blumeria graminis f. sp. tritici, Phakopsora pachyrhizi, and Puccinia sorghi.

4. A fungicide, which is composed of an active ingredient and an auxiliary material, and the active ingredient includes at least one of the compounds described in claim 1.

5. The fungicide according to claim 4, wherein, The content of the active ingredient is 1 to 99.9% by weight.

6. The fungicide according to claim 4 or 5, wherein The dosage form of the fungicide is selected from at least one of emulsifiable concentrate, suspending agent, powder, granule, and aqueous solution.

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