Use of a compound having a diaminopyrroloquinazoline skeleton for the control of plant pathogenic bacteria

Abstract

The application belongs to the field of pharmaceutical chemistry, and discloses an application of a compound with a diaminopyrroloquinazoline skeleton in preventing and treating plant bacterial diseases caused by Xanthomonas oryzae ACCC 11602, Xanthomonas axonopodis pv.Citr, Pseudomonas sollamacearum and Erwinia aroideae. The structural general formula is as follows: wherein R is an alkyl group, a para-substituted phenyl group, an ortho-substituted phenyl group or a meta-substituted phenyl group; A is hydrogen, a methyl group, an isopropyl group, a phenyl group, a methoxy group, a trifluoromethoxy group, a trifluoromethyl group, halogen or a cyano group; B is hydrogen or halogen; and C is hydrogen or halogen.

Description

Technical Field

[0001] This invention belongs to the field of medicinal chemistry and discloses a novel use of a compound with a diaminopyrimidine skeleton in the prevention and control of bacterial diseases of plants caused by Xanthomonas oryzae ACCC 11602 (rice bacterial blight pathogen), Xanthomonas axonopodis pv. Citr (citrus canker pathogen), Pseudomonas sollamacearum (tomato bacterial wilt pathogen), and Erwinia aroideae (soft rot pathogen). Background Technology

[0002] Microbial infection is a major factor in plant and animal disease. Within the vast family of bacteria, pathogenic bacteria seriously threaten human health and crop production. Currently, chemical control remains one of the main measures to combat bacterial infections. However, in agricultural production practices, the long-term and excessive use of antibiotics has led to drug resistance in pathogenic bacteria, causing significant crop yield reductions and incalculable economic losses. Therefore, developing novel agricultural fungicides with entirely new skeletons and novel mechanisms of action has become one of the most pressing tasks in current pesticide research and development.

[0003] In 2020, the Zemer Gitai research group at Princeton University discovered that the compound SCH-79797, with a diaminopyrroloquinazoline skeleton, exhibited good inhibitory effects against both Gram-negative and Gram-positive bacteria (Cell, 2020, 181, 71518-1513). During our previous screening and optimization of lead compounds, our group also found that compounds with a diaminopyrroloquinazoline skeleton showed excellent inhibitory effects against plant pathogenic bacteria (CN114097804A). Based on this, our group continued to use this as a model lead structure system to design and synthesize a class of compounds with a diaminopyrroloquinazoline skeleton and tested their antibacterial activity against plant pathogenic bacteria. Experimental results showed that these compounds with a diaminopyrroloquinazoline structure have significant antibacterial activity against plant pathogenic bacteria, and their simple structure and ease of synthesis make them potential development values ​​as agricultural fungicides. Summary of the Invention

[0004] The purpose of this invention is to provide the use of compounds with a diaminopyrroloquinazoline skeleton in the fight against plant pathogenic bacteria, for the prevention and control of plant diseases caused by rice bacterial blight pathogen, citrus canker pathogen, tomato bacterial wilt pathogen and soft rot pathogen.

[0005] To achieve the above objectives, the present invention provides the following technical method:

[0006] The use of a compound with a diaminopyrroloquinazoline skeleton in the resistance to plant pathogenic bacterial infections; the general structural formula I of this type of compound is as follows:

[0007]

[0008] in,

[0009] R is an alkane group or a para-substituted phenyl group. ortho-substituted phenyl meta-substituted phenyl

[0010] A can be hydrogen, methyl, isopropyl, phenyl, methoxy, trifluoromethoxy, trifluoromethyl, halogen, or cyano.

[0011] B is hydrogen or halogen.

[0012] C is hydrogen or halogen.

[0013] Plant bacteria include Xanthomonas oryzae ACCC 11602, the pathogen of rice bacterial blight, Xanthomonas axonopodis pv. Citri, Pseudo-monassollamacearum, and Erwinia aroideae.

[0014] The present invention provides a compound having a diaminopyrroloquinazoline skeleton as a novel bactericide, which has the following advantages:

[0015] 1) A compound with a diaminopyrroloquinazoline skeleton has excellent inhibitory effects on plant pathogenic bacteria and is characterized by simple structure, inexpensive raw materials, and easy synthesis.

[0016] 2) A compound with a diaminopyrroloquinazoline skeleton has high bactericidal activity.

[0017] 3) A compound with a diaminopyrroloquinazoline skeleton has a broad bactericidal spectrum. Detailed Implementation

[0018] To better understand the present invention, the following specific embodiments further illustrate the above-described content of the present invention. However, this should not be construed as a limitation of the present invention. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods.

[0019] Example 1: Synthesis of a compound with a diaminopyrimidine structure and its derivatives:

[0020]

[0021] The synthesis method of the compound described in this invention is carried out according to the following reaction formula:

[0022] (1) The preparation methods of the compounds involved in general formula I are as follows:

[0023]

[0024] Experimental section:

[0025] Under inert gas protection at room temperature, 300 mg (1.85 mmol) of 5-nitroindole was added to a round-bottom flask, followed by 10 mL of anhydrous N,N-dimethylformamide. NaH (2.23 mmol) was added in portions, and the mixture was stirred for 1.5 h. Different substituted bromides (2.23 mmol) were then added, and the mixture was stirred for another 3 h at room temperature. After the reaction was complete, a saturated ammonium chloride solution was added to quench the reaction. The mixture was extracted three times with ethyl acetate, washed twice with distilled water, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure to obtain the crude product. The crude product was purified by column chromatography to obtain intermediate I.

[0026] Intermediate I (1.50 mmol), iron powder (7.50 mmol), and ammonium chloride (15.00 mmol) were added to ethanol-water (4:1) (25 mL), and the mixture was refluxed and stirred for 6 h. The solvent was removed under reduced pressure, and the mixture was dissolved again in water. The pH was adjusted to 8 with saturated sodium bicarbonate solution. The mixture was extracted three times with ethyl acetate, washed twice with distilled water, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure to obtain crude intermediate II.

[0027] Intermediate II (1.40 mmol) was added to a round-bottom flask, followed by 10 mL of anhydrous N,N-dimethylformamide, p-toluenesulfonic acid (1.40 mmol), and NaN(CN)₂ (5.60 mmol). The mixture was stirred overnight at 50 °C. After the reaction was complete, approximately four times the volume of water was added to the reaction mixture, which was then stirred, filtered, and the filter cake was dried to obtain crude intermediate III.

[0028] Intermediate III (1.25 mmol) was added to a round-bottom flask, followed by 20 mL of ethylene glycol dimethyl ether. The reactor was placed in an ice bath, and boron trifluoride diethyl ether (6.25 mmol) was added. The mixture was stirred overnight at 60 °C. After the reaction was complete, the solvent was removed under reduced pressure, a trace amount of methanol was added to dissolve the solid, 1 M sodium hydroxide solution was added, the mixture was stirred, filtered, and the filter cake was dried to obtain the crude product. The crude product was purified by column chromatography to obtain the final product.

[0029] Table 1. Structural formulas and structural characterizations of the compounds described in this patent.

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] Example 2: Determination of the antibacterial activity of a class of compounds with a diaminopyrimidine structure and their derivatives against plant pathogenic bacteria.

[0037] The bacterial strains used in this experiment were cryopreserved in the laboratory at -80℃ with 30% glycerol. The cryopreserved strains were removed and streaked onto NB solid medium for plant bacteria (beef extract: 3g, peptone: 5g, yeast extract: 1g, sucrose: 10g, agar: 15g, distilled water: 1L, pH 7.0; sterilized at 121℃ for 20min), and incubated at 28℃ (37℃) until single colonies appeared. Single colonies from the solid medium were then transferred to NB liquid medium for plant bacteria (beef extract: 3g, peptone: 5g, yeast extract: 1g, sucrose: 10g, distilled water: 1L; sterilized at 121℃ for 20min) and incubated at 28℃ (37℃) with shaking at 180 rpm until the logarithmic growth phase. The strains in the logarithmic growth phase were diluted with the appropriate liquid medium to approximately 10... 6 CFU / mL is prepared for use. Dissolve the compounds separately in DMSO, add them to the liquid culture medium, mix thoroughly, and prepare a drug-containing liquid culture medium with a concentration of 200 μg / mL. Take 50 μL of the drug-containing culture medium and the same volume of approximately 10... 6 CFU / mL bacterial culture was added to the wells of a 96-well plate, resulting in a final drug concentration of 100 μg / mL. A control of 100 μL of bacterial culture containing an equal amount of DMSO was used. The 96-well plates were incubated at 28℃ (37℃) for 24-48 h until bacterial growth was observed in the control group. The OD value (OD) of the bacterial culture in each well was measured using a microplate reader. 600 In addition, the OD values ​​of 100 μL of liquid culture medium and a 100 μg / mL drug concentration were measured to correct for the OD values ​​caused by the culture medium and the drug itself. The formulas for calculating the corrected OD value and inhibition rate are as follows:

[0038] Corrected OD value = OD value of bacterial culture medium - OD value of sterile culture medium;

[0039] Inhibition rate = (OD value of bacterial suspension in the control medium after correction - OD value of bacterial suspension in the drug-containing medium after correction) / OD value of bacterial suspension in the control medium after correction × 100%

[0040] All experiments were conducted in triplicate. The drug-containing liquid culture medium of the active compound was diluted in 96-well plates using a two-fold dilution method to obtain a series of 50 μL drug-containing media concentrations. The inhibition rate corresponding to each concentration was then determined according to the experimental method described in Example 2. The inhibition rate of the obtained compound was measured, and the MIC was... 90 The minimum inhibitory concentration (MIC) values ​​for 90% inhibition rate are shown in Table 2.

[0041] Table 2. Antibacterial activity of a compound with a diaminopyrroloquinazoline skeleton against plant pathogenic bacteria.

[0042]

[0043] As shown in Table 2, the bioactivity test results indicate that the compound with a diaminopyrroloquinazoline skeleton involved in this invention exhibits excellent inhibitory activity against the tested strains. Specifically, compound ZH-7 showed a significant inhibitory effect on the MIC of the tested strain *Bacillus oryzae*. 90 The MIC of compounds ZH-7, ZH-8, and ZH-10 against the test strain *Citrus canker* was 3.12 μg / mL. 90 The MIC of compound ZH-7 against the test strain *Streptococcus soft rotans* was 1.56–3.12 μg / mL. 90 It is 3.12 μg / mL.

[0044] In summary, the compound with a diaminopyrroloquinazoline skeleton described in this invention exhibits excellent inhibitory activity against plant pathogenic bacteria, with antibacterial activity significantly superior to commercially available positive control agents. It has value for further research and development.

Claims

1. The use of a compound with a diaminopyrroloquinazoline skeleton in the control of plant pathogenic bacteria, having the following molecular structural features: in, R is a para-substituted phenyl group. A is trifluoromethyl, halogen, wherein the halogen is bromine or iodine; the application of the method for controlling plant pathogenic bacteria is to control the pathogen of rice bacterial blight ( ). Xanthomonas oryzae ACCC 11602), citrus canker pathogen ( Xanthomonas axonopodis pv. Citri), Tomato bacterial wilt ( Pseudo-monas sollamacearum Its uses in the treatment of soft rot pathogen of Chinese cabbage (Erwinia aroideae).

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