A class of compounds containing isopropanolamine substructures, their preparation methods and applications

Abstract

This invention relates to a class of compounds containing isopropanolamine substructures, their preparation methods, and applications. These compounds have the structure shown in general formula (I). Based on 4-chlorothiophenol, this invention introduces a nitrogen-containing fragment into this system to synthesize a series of compounds containing isopropanolamine substructures. These compounds exhibit excellent inhibitory effects on plant pathogenic bacteria such as *Bacillus thuringiensis*, *Citrus canker*, *Rhizoctonia solani*, and *Ophiopogon japonicus*.

Description

Technical Field

[0001] This invention relates to the field of medicinal chemistry, and in particular to a class of compounds containing isopropanolamine substructures, their preparation methods, and applications. Background Technology

[0002] Bacterial leaf blight (BLB) and bacterial leaf streak (BLS) of rice, caused by *Xanthomonas oryzae* pv. oryzae (Xoo) and *Xanthomonas oryzae* pv. oryzicola (Xoc), are two major bacterial diseases of rice and remain unsolved problems, seriously threatening rice production and causing yield reductions of 20-50%. Control of rice bacterial diseases mainly relies on traditional chemical fungicides. Citrus bacterial canker (*Xanthomonas axonopodis* pv. Citri) causes citrus rot and is one of the world's most notorious and particularly difficult-to-manage agricultural diseases. These refractory bacterial infections are extremely difficult to control, resulting in huge economic losses to global agriculture year after year. Currently, few effective fungicides can control these infections. While high-dose and frequent use of traditional pesticides, including major ones like thiamethoxam (TC) and tebuconazole (BT), can mitigate bacterial infections in plants, the rapid development of pathogen resistance and the accumulation of harmful residues have adverse effects on already fragile ecosystems and agricultural products. Therefore, the development of novel, highly effective, low-toxicity, and safe green pesticides is of paramount importance.

[0003] Thioethers are organosulfur compounds that not only possess a variety of biological activities but also provide reaction sites for further derivatization (such as S to S=O and S(=O)2) and the environment. Among them, thioether derivatives containing the sulfoxide skeleton have been extensively studied. Sulfoxide is an important pharmaceutical and agricultural active unit. Compounds containing sulfide, sulfoxide, and sulfone structures have been widely used in materials, pharmaceuticals, and pesticides, exhibiting a wide range of biological activities, such as insecticidal, anticancer, antibacterial, antifungal, and herbicidal properties.

[0004] In order to find highly effective bactericidal active compounds, this invention uses 4-chloro-thiophenol as the parent compound, attaches propylene oxide, and then uses various primary and secondary amines to open the ring to obtain phenylthio- and phenylsulfonyl compounds containing isopropanolamine substructures. Their biological activity is tested, providing an important scientific basis for the research and development and creation of new pesticides.

[0005] The following is a review of the research progress on the bioactivity of phenylthio and phenyl sulfoxide compounds:

[0006] In 2022, Cai et al. (Apfel, C.; Banner, DW; Bur, D.; Dietz, M.; Hirata, T.; Hubschwerleh, C.; Locher, H.; Page, MGP; Pirson, W.; Rossé, G.; Speklin, J.-L., Hydroxamic Acid Derivatives as Potent Peptide Deformylase Inhibitors and Antibacterial Agents. Journal of Medicinal Chemistry 2000, 43, 2324-2331.) designed and synthesized a series of phenylpyridine-containing α-trifluorothioanisole derivatives to discover novel herbicide compounds with good activity. Preliminary screening of greenhouse weed control activity showed that the target compounds all exhibited good weed control activity. Among them, at 37.5 g ai / hm2, compound 11a showed greater than 85% inhibitory activity against broadleaf weeds Amaranthus retroflexus, Abutilon theofrasti, and Eclipta prostrate, slightly higher than that of flumethasone. At 150 g ai / hm2, compounds 11a and 11b exhibited 80% inhibitory activity against broadleaf weeds AT, AR, and EP.

[0007] In 2018, Li et al. (Li, P.; Tian, ​​P.; Chen, Y.; Song, X.; Xue, W.; Jin, L.; Hu, D.; Yang, S.; Song, B., Novel bisthioether derivatives containing a 1,3,4-oxadiazole moiety: design, synthesis, antibacterial and nematocidal activities. Pest ManagSci 2018, 74, 844-852.) designed and synthesized a series of novel disulfide derivatives containing a 1,3,4-oxadiazole moiety and evaluated their antibacterial and nematicidal activities. Among them, compound 8 showed the best antibacterial activity against rice bacterial blight (Xoo), rice bacterial leaf spot (Xoc), and citrus canker (Xac), with EC50 values ​​of 4.82, 11.15, and 16.57 μgmL⁻¹, respectively, which were superior to the control drugs thiabendazole and tebuconazole.

[0008] In 2018, Dai et al. (Dai, P.; Luo, K.; Yu, X.; Yang, W.-C.; Wu, L.; Zhang, W.-H., Tert-Butyl Nitrite Mediated Expeditious Methylsulfoxidation of Tetrazole-amines with DMSO: Metal-free Synthesis of Antifungal Active Methylsulfinyl-1H-tetrazole Derivatives. Advanced Synthesis & Catalysis 2018, 360, 468-473.) provided a rapid and simple procedure for constructing CS(O) bonds using tert-butyl nitrite-mediated methyl subalkylation of tetrazolium-amines, and preliminarily evaluated the antifungal activity of the target compounds against four plant pathogenic fungi. Some compounds showed potential antifungal activity at a concentration of 5 μg / mL (SI). The results showed that the EC of compound 7a containing 3,4-dichloro substituents... 50 The value was as low as 1.3701 μg / mL, compared to the positive control (Boscalid EC). 50 Compound 7b (EC = 2.9767 μg / mL) exhibits superior activity compared to other compounds. 50 =2.5439 μg / mL) has good antifungal activity.

[0009] In 2016, Yu et al. (Yu, X.; Liu, Y.; Li, Y.; Wang, Q., Design, Synthesis, Acaricidal / Insecticidal Activity, and Structure-Activity Relationship Studies of Novel Oxazolines Containing Sulfone / Sulfoxide Groups Based on the Sulfonylurea Receptor Protein-Binding Site. J Agric Food Chem 2016, 64, 3034-40.) designed and synthesized a series of 2,4-diphenyl-1,3-oxazoline chitin synthesis inhibitors (CSIs) containing sulfone / sulfoxide groups. The acaricidal and insecticidal activities of these compounds were tested. Most of the target compounds showed good acaricidal activity against both larvae and eggs of the carmine spider mite. In particular, compounds 6a and 6b (containing 4-chlorophenyl and 4-fluorophenylsulfoxide groups, respectively) showed good acaricidal activity at a concentration of 2.5 mg / L. -1It exhibited excellent acaricidal activity, exceeding that of the commercial drug etoxazole. 1 mg / L -1 The mortality rates were 87% and 83% respectively, both of which were better than etoxazole. Summary of the Invention

[0010] One of the objectives of this invention is to provide a class of compounds containing an isopropanolamine substructure, or their stereoisomers, or their salts or solvates.

[0011] Another object of the present invention is to provide intermediate compounds for preparing the above-mentioned compounds or their stereoisomers, their salts or their solvates, and methods thereof.

[0012] Another object of the present invention is to provide a composition containing the above-mentioned compound or its stereoisomer, its salt or its solvate.

[0013] Another object of the present invention is to provide the use of the above-mentioned compound or its stereoisomer, its salt or its solvate, or the composition thereof.

[0014] Another object of the present invention is to provide a method for controlling agricultural pests and diseases using the above-mentioned compound or its stereoisomer, its salt or its solvate, or the composition thereof.

[0015] To achieve the above objectives, the present invention adopts the following technical solution:

[0016] A class of compounds containing an isopropanolamine substructure, or their stereoisomers, salts, or solvates thereof, having a structure as shown in general formula (I):

[0017]

[0018] Wherein, R1 and R2 are each independently selected from hydrogen, dimethyl, diethyl, propyl, dipropyl, cyclopropyl, phenyl, tolyl, trifluoromethylphenyl, methoxyphenyl, fluorophenyl, tolyl, benzenemethyl, and hexylphenyl.

[0019] R1 and R2 are linked to form an aliphatic or aromatic heterocycle, preferably with the following groups:

[0020]

[0021] The present invention also provides an intermediate for preparing the aforementioned phenylthio- or phenylsulfoxide-based compounds containing the isopropanolamine substructure, or their stereoisomers, salts, or solvates:

[0022]

[0023] The present invention also provides a method for preparing the aforementioned phenylthio, phenylsulfonyl, or stereoisomers thereof, or their salts thereof, or their solvates containing the isopropanolamine substructure, comprising the following steps:

[0024]

[0025] Wherein, R1 and R2 are each independently selected from one or more of hydrogen, alkyl or unsubstituted, amino, alkoxy or unsubstituted, cycloalkyl or unsubstituted, aryl or unsubstituted, heteroaryl or unsubstituted, benzyl or unsubstituted, and α-methyl-benzyl; R1 and R2 are each independently selected from one or more of hydrogen, alkyl or unsubstituted, amino, alkoxy or unsubstituted, cycloalkyl or unsubstituted, aryl or unsubstituted, heteroaryl or unsubstituted, benzyl or unsubstituted, and α-methyl-benzyl.

[0026] The present invention also provides a composition comprising the said compound or its stereoisomer, its salt or its solvate, and agriculturally usable adjuvants or fungicides, insecticides or herbicides; preferably, the formulation of the composition is selected from emulsifiable concentrates (EC), powders (DP), wettable powders (WP), granules (GR), aqueous solutions (AS), suspensions (SC), ultra-low volume sprays (ULV), soluble powders (SP), microcapsules (MC), fumigants (FU), emulsions (EW), and water-dispersible granules (WG).

[0027] The compound or its stereoisomer, its salt or its solvate, or the composition thereof can be used to prevent and control agricultural pests and diseases. Preferably, the agricultural pests and diseases are bacterial or fungal plant diseases; more preferably, the agricultural pests and diseases are plant leaf blight and plant canker; most preferably, the agricultural pests and diseases are rice bacterial leaf blight, cucumber bacterial leaf blight, konjac bacterial leaf blight, citrus canker, grape canker, tomato canker, kiwifruit canker, mango angular leaf spot, apple canker, cucumber gray mold, pepper wilt pathogen, rapeseed sclerotinia rot, wheat scab, and potato late blight.

[0028] This invention also provides a method for preventing and controlling agricultural pests and diseases, wherein the compound or its stereoisomer, its salt or its solvate, or the composition thereof acts on the harmful substance or its habitat; preferably, the agricultural pests and diseases are bacterial or fungal plant diseases; more preferably, the agricultural pests and diseases are rice bacterial blight, tobacco bacterial wilt, cucumber bacterial blight, konjac bacterial blight, citrus canker, grape canker, tomato canker, kiwifruit canker, mango angular leaf spot, apple canker, cucumber gray mold, pepper wilt pathogen, rapeseed sclerotinia, wheat scab, and potato late blight.

[0029] The present invention also provides a method for protecting plants from agricultural pests and diseases, comprising the method steps of contacting the plant with the compound or its stereoisomer, its salt or its solvate, or the composition thereof.

[0030] The term "alkyl" as used here refers to both branched and straight-chain saturated hydrocarbon groups having a specific number of carbon atoms. For example, "C..." 1-10 Alkyl (or alkylene) refers to C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10 alkyl groups. Additionally, for example, "C 1-6 "Alkyl" means an alkyl group having 1 to 6 carbon atoms. Alkyl groups can be unsubstituted or substituted, such that one or more of their hydrogen atoms are replaced by other chemical groups. Examples of alkyl groups include, but are not limited to, methyl (Me), ethyl (Et), propyl (such as n-propyl and isopropyl), butyl (such as n-butyl, isobutyl, tert-butyl), pentyl (such as n-pentyl, isopentyl, neopentyl) and the like.

[0031] The term "substituted" as used herein refers to the substitution of one or more hydrogen atoms on a specified atom or group by a chosen specified group, provided that the substitution does not exceed the general valence of the specified atom. Unless otherwise specified, substituents are named to the central structure. For example, it can be understood that when (cycloalkyl)alkyl is a possible substituent, the point of connection between the substituent and the central structure is within the alkyl moiety. Cyclic double bonds as used herein are double bonds formed between two adjacent ring atoms (e.g., C=C, C=N, or N=N). When substitution is mentioned, especially polysubstitution, it refers to the substitution of multiple substituents at various positions on a specified group, such as dichlorobenzyl referring to 2,3-dichlorobenzyl, 2,4-dichlorobenzyl, 2,5-dichlorobenzyl, 2,6-dichlorobenzyl, 3,4-dichlorobenzyl, and 3,5-dichlorobenzyl.

[0032] Combinations of substituents and variables are permitted only when these combinations yield stable compounds or useful synthetic intermediates. A stable compound or stable structure implies that the compound is sufficiently stable to be isolated from the reaction mixture with useful purity, subsequently formulated to form an effective therapeutic agent.

[0033] The term "aryl" refers to a monocyclic or bicyclic aromatic hydrocarbon group, such as phenyl and naphthyl, having 6 to 12 carbon atoms in the ring moiety, each of which can be substituted.

[0034] The term "heteroaryl" refers to substituted and unsubstituted aromatic 5- or 6-membered monocyclic groups, 9- or 10-membered bicyclic groups, and 11- to 14-membered tricyclic groups, having at least one heteroatom (O, S, or N) in at least one ring, preferably having 1, 2, or 3 heteroatoms selected from O, S, and N. Each ring of a heteroaryl containing heteroatoms may contain one or two oxygen or sulfur atoms and / or 1 to 4 nitrogen atoms, provided that the total number of heteroatoms in each ring is 4 or less, and each ring has at least one carbon atom. The fused rings completing the bicyclic and tricyclic groups may contain only carbon atoms and may be saturated, partially saturated, or unsaturated. Nitrogen may optionally be oxidized and quaternized. Bicyclic or tricyclic heteroaryl groups must include at least one fully aromatic ring, and the other fused rings may be aromatic or non-aromatic. Heteroaryl groups may be attached to any available nitrogen or carbon atom in any ring.

[0035] Exemplary monocyclic heteroaryl groups include pyrrole, pyrazolyl, pyrazolinyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, thiadiazolyl, furanyl, thiophenyl, oxadiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, and their analogues.

[0036] Exemplary bicyclic heteroaryl groups include indolyl, benzothiazolyl, benzodioxazolyl, benzoxazolyl, benzothiophenyl, quinolinyl, tetrahydroisoquinolinyl, isoquinolinyl, benzoimidazolyl, benzofuranyl, indoleazinyl, benzofuranyl, crononeyl, coumarinyl, benzofuranyl, cenolinyl, quinoxalinyl, indazoleyl, pyrrolopyridyl, fluoropyridyl, dihydroisoindolyl, tetrahydroquinolinyl, and their analogues.

[0037] Unless otherwise specified, the compounds of this invention are understood to include both their free state and their salts. The term "salt" means an acidic and / or basic salt formed from an inorganic and / or organic acid and base. Additionally, the term "salt" may include zwitterions (internal salts), such as when a compound of formula I contains a basic segment such as an amine or pyridine or imidazole ring, and an acidic segment such as a carboxylic acid. Pharmaceutically acceptable (i.e., non-toxic, physiologically acceptable) salts are preferred, such as acceptable metal and amine salts, wherein the cation does not significantly contribute to toxicity or the biological activity of the salt. However, other salts may be useful, such as those prepared using separation or purification steps, and are therefore also included within the scope of this invention.

[0038] When referring to substituents as alkenyl, alkyl, aryl, benzyl, or cycloalkyl, or specifically a particular alkenyl, alkyl, aryl, benzyl, or cycloalkyl group, it refers to one to three of the aforementioned substituents. For example, chlorobenzyl refers to one to three chloro-substituted benzyl groups.

[0039] By adopting the above technical solution, this invention uses 4-chlorobenzylthiophenol as the starting material to synthesize a series of phenylthio- and phenylsulfonyl compounds containing isopropanolamine substructures. It was found that these compounds have good inhibitory effects on pathogenic plant bacteria, exhibiting good inhibitory effects against pathogenic bacteria [such as *Xanthomonas oryzae* pv. oryzae (Xoo), *Xanthomonas axonopodis* pv. citri (Xac), *Xanthomonas oryzae* pv. oryzicola (Xoc), and *Xanthomonas campestris* pv. mangiferae indicae (Xcm)], providing an important scientific basis for the research and development of new pesticides. Example

[0040] The present invention will be further illustrated below through examples. It should be understood that the methods described in the examples are merely illustrative and not intended to limit the invention. Simple modifications to the preparation methods of the present invention within the framework of the present invention's concept are all within the scope of protection claimed by the present invention. All raw materials and solvents used in the examples are commercially available products.

[0041] Example 1: 2-(((4-chlorophenyl)thio)methyl)ethylene oxide

[0042] 13.8 mmol of 4-chlorothiophenol, 16.6 mmol of K₂CO₃, and 50 mL of DMF were added to a 100 mL round-bottom flask and stirred for 20 minutes in an ice bath. Then, 27.7 mmol of epichlorohydrin was slowly added dropwise. The reaction was stopped after 1 hour in an ice bath. Extraction was performed with 100 mL of ethyl acetate, followed by washing with 4 × 80 mL of saturated NH₄Cl aqueous solution, drying over anhydrous Na₂SO₄, solvent removal, and column chromatography (PE:EA = 50:1, V / V) to give a yellow liquid with a yield of 64.7%. The NMR data are as follows: 1H NMR (400MHz, CDCl3) δ7.39 (t, J=1.8Hz, 1H, Ar-H), 7.30-7.26 (m, 1H, Ar-H), 7.25-7.17 (m, 2H, Ar-H), 3.2 1-3.12 (m, 2H, S-CH2), 3.05-2.97 (m, 1H, -O-CH), 2.83-2.78 (m, 1H, -O-CH2), 2.58-2.56 (m, 1H, -O-CH2).

[0043] Example 2: 2-(((4-chlorophenyl)sulfinyl)methyl)ethylene oxide

[0044] 2-(((4-chlorophenyl)thio)methyl)ethylene oxide (2.5 mmol) from Example 1 was dissolved in 5 mL THF and 6 mL H₂O, and stirred at 55 °C for 20 minutes. Then, H₂O₂ (17.4 mmol) was added to the system. After reacting for a period of time, ammonium molybdate (0.006 g) dissolved in 0.1 g hydrogen peroxide was added, and the reaction was stopped after half an hour. The solution was removed by washing with dichloromethane and water (3 × 20 mL), drying with anhydrous Na₂SO₄, and column chromatography (PE:EA = 25:1, V / V) to give a white liquid with a yield of 77.2%. Its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.63-7.57 (m, 2H, Ar-H), 7.54-7.48 (m, 2H, Ar-H), 3.40-3.06 (m, 1H, -O-CH), 3.06-2.81 (m, 3H, S- CH2 &-O- CH2 ), 2.68-2.55 (m, 1H, -O-) CH2 ); 13 C NMR (101MHz, CDCl3) δ142.0, 141.1, 137.6, 137.6, 129.7, 129.6, 125.5, 125.2, 61.2, 58.7, 47.0, 46.2, 46.0, 45.2.

[0045] Example 3: 1-(benzylamino)-3-((4-chlorophenyl)thio)isopropanol (15)

[0046] 2-(((4-chlorophenyl)thio)methyl)ethylene oxide (2.49 mmol), K₂CO₃ (2.49 mmol), and benzylamine (4.98 mmol) were dissolved in 10 mL of isopropanol and added to a 15 mL reaction flask. The mixture was stirred at 55 °C. TLC was used to monitor the reaction. After the reaction was complete, the mixture was washed with ethyl acetate and saturated sodium chloride (3 × 20 mL). The organic phase was dried over anhydrous Na₂SO₄, dissolved, and then subjected to column chromatography (CH₂Cl₂∶CH₃OH=100∶1, V / V) to give a white solid in 72.4% yield. The NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.27-7.22 (m, 2H, Ar-H), 7.21-7.11 (m, 7H, Ar-H), 3.75-3.62 (m, 3H, NH- CH2 &-O-CH), 2.90 (d, J=6.2Hz, 2H, S-CH2), 2.74-2.70 (m, 2H, CH- CH2 &NH), 2.56-2.51 (m, 1H, CH-) CH2 ); 13 C NMR (101MHz, CDCl3) δ139.4, 134.3, 132.24130.8, 129.1, 128.5, 128.1, 127.2, 68.1, 53.6, 53.2, 39.1.

[0047] Example 4: 1-(benzylamino)-3-((4-chlorophenyl)sulfinyl)isopropanol (31)

[0048] 2-(((4-chlorophenyl)sulfinyl)methyl)ethylene oxide (0.46 mmol), K₂CO₃ (0.23 mmol), and benzylamine (0.92 mmol) were dissolved in 4 mL of isopropanol and added to a 15 mL reaction flask. The mixture was stirred at 50 °C. TLC was used to monitor the reaction. After the reaction was complete, the mixture was washed with ethyl acetate and saturated sodium chloride (3 × 20 mL). The organic phase was dried over anhydrous Na₂SO₄, dissolved, and then subjected to column chromatography (CH₂Cl₂∶CH₃OH=100∶1, V / V) to give a white solid in 32% yield. The NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.59-7.49(m, 2H, Ar-H), 7.48-7.41(m, 2H, Ar-H), 7.30-7.24(m , 3H, Ar-H), 7.24-7.19 (m, 2H, Ar-H), 4.30-4.01 (m, 1H, -O-CH), 3.83-3.66 (m, 2H, NH- CH2 ), 3.03-2.90 (m, 2H, S-CH2), 2.87-2.76 (m, 1H, CH- CH2 ), 2.75-2.53 (m, 2H, CH-) CH2 &NH); 13 C NMR (101MHz, CDCl3) δ142.1, 142.0, 139.5, 137.5, 137.3, 129.7, 128.6, 128.2 , 127.3, 127.2, 125.6, 125.4, 66.4, 64.7, 61.8, 61.6, 53.9, 53.8, 53.7, 53.5.

[0049] Other target compounds were synthesized using appropriate starting materials or substituents, following the steps outlined in the examples above.

[0050] The structures and 1H and 1C NMR spectra of the synthesized phenylthio- and phenyl sulfoxide-based compounds containing isopropanolamine substructures are shown in Table 1, and their physicochemical properties are shown in Table 2.

[0051] Table 1. 1H and 1C NMR spectra of the compounds in this application.

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] Table 2 Physicochemical properties of the compounds in this application

[0058]

[0059]

[0060] Pharmacological Example 1:

[0061] EC 50 Median effective concentration (MEC) is an important indicator for evaluating the sensitivity of plant pathogens to compounds, and it is also a crucial parameter for setting the compound concentration when studying the mechanism of action of target compounds. In concentration gradient experiments, five appropriate concentrations were set using the two-fold dilution method. Finally, the inhibition rate of the agent against the plant pathogen and the agent concentration were converted into logarithmic values, and the toxicity curve was obtained through regression analysis using SPSS software to calculate the EC50. 50 .

[0062] The effective medium concentration (EC) of the target compound against plant pathogens was determined using a turbidimetric method. 50 The experimental subjects were *Xoo*, *Xac*, *Xoc*, and *Xcm*, the pathogens causing bacterial blight of rice. DMSO was dissolved in the culture medium as a blank control. *Xoo* (the pathogen on M210 solid medium) was placed in NB medium and cultured at 28°C and 180 rpm in a constant-temperature shaker until the logarithmic growth phase. *Xac* (on M210 solid medium) was placed in NB medium and cultured at 28°C and 180 rpm in a constant-temperature shaker until the logarithmic growth phase. Different concentrations (e.g., 100, 50, 25, 12.5, 6.25 μg / mL) of the agent (compound) containing NB liquid culture medium containing the pathogen were prepared and added to test tubes. 40 μL of NB liquid culture medium containing plant pathogen bacteria was added to each tube, and the tubes were shaken at 28℃ and 180 rpm. The cultures were then incubated for 36 h for *Bacillus oryzae* (rice bacterial blight pathogen), 48 h for *Citrus canker* (citrus scab pathogen), and 36 h for *Bacillus streak* (rice leaf streak pathogen). The OD values ​​of the bacterial solutions at each concentration were measured using a spectrophotometer. 595 The value was also measured, and the OD of the corresponding concentration of sterile NB liquid culture medium containing the toxin was also determined. 595 value.

[0063] Corrected OD value = OD value of sterile culture medium - OD value of sterile culture medium

[0064] Inhibition rate % = [(OD value of bacterial suspension in the corrected control medium - OD value of the corrected virus-containing medium) / OD value of bacterial suspension in the corrected control medium] × 100

[0065] The embodiments of this invention are provided to illustrate the technical solutions of this invention, but the content of the embodiments is not limited thereto. The experimental results of the target compound are shown in Table 3.

[0066] Table 3. EC50 of the compounds in this application against plant pathogenic bacteria. 50

[0067]

[0068]

[0069] As shown in Table 3, in in vitro experiments, target compound 22 exhibited good inhibitory activity against plant pathogens (such as *Bacillus thuringiensis*, *Citrus canker*, *Rhizoctonia solani*, and *Hymenochloa mangoe*). Most compounds containing benzyl and phenyl groups showed EC50 activity against *Bacillus thuringiensis*, *Citrus canker*, *Rhizoctonia solani*, and *Hymenochloa mangoe*. 50All values ​​were below 10, especially compound 22, which exhibited extremely excellent activity against rice bacterial blight and citrus canker. EC 50 The concentrations were 2.73 and 1.94 μg / mL, respectively; meanwhile, compound 26 also showed excellent inhibitory activity against rice leaf streak pathogen, EC 100%. 50 The concentration was 2.30 μg / mL. Therefore, this type of compound shows great research potential and can be used to prepare pesticides against plant pathogenic bacteria.

[0070] Pharmacological Example 2:

[0071] Compound 22 showed the best activity against rice bacterial blight pathogen (EC). 50 A live pot experiment was conducted on compound 22 against rice bacterial blight (2.73 μg / mL). Based on this experiment, β-cyclodextrin was added to compound 22 to obtain 22@β-cyclodextrin (molar ratio 1:1). The results showed that its therapeutic and protective activities were slightly improved. The specific experimental steps are as follows: Protective activity: Compound 22, 22@β-cyclodextrin and the control drug thiabendazole (20% content) were respectively prepared into 200 μg / mL (active ingredient) solutions with less than 1% Tween 20 solution. Two more 200 μg / mL solutions were prepared. The prepared solutions were sprayed on the surface of rice leaves that had grown for 8 weeks until droplets fell. After 24 hours, OD20 solution was applied to the leaves 2 cm away from the leaf tip. 595 For rice bacterial blight pathogens with a concentration of 0.6-0.8, the leaf tips were cut off with scissors. An equal amount of DMSO without pesticides was used as a control. Each treatment had three replicates. After 14 days, the disease incidence was checked, and the length and total length of lesions on rice leaves were recorded. The disease index and control efficacy were calculated.

[0072] First, measure the area of ​​the spots on each leaf and the total leaf area. Then, calculate the leaf area as a percentage of the total spot area. Next, classify these leaves according to the following grading standards: Grade 1, lesions cover less than 5% of the total leaf area; Grade 3, lesions cover 6-10% of the total leaf area; Grade 5, lesions cover 11-20% of the total leaf area; Grade 7, lesions cover 21-50% of the total leaf area; Grade 9, lesions cover more than 50% of the total leaf area.

[0073] The method for calculating the disease index is as follows:

[0074] Disease index = ∑(number of leaves at each level × corresponding level) / (total number of leaves × highest level)

[0075] The method for calculating the effectiveness is as follows:

[0076] Efficacy % = (Disease index of control group - Disease index of treatment group) / Disease index of control group × 100%

[0077] Therapeutic activity: Apply OD-coated solution 2cm from the leaf tip. 595 Cut off the leaf tips of rice bacterial blight pathogens with scissors in the range of 0.6-0.8. 24 hours later, spray the prepared above-mentioned solution onto the surface of rice leaves that have grown for 8 weeks until droplets fall. Set an equal amount of DMSO without the agent as a control. Each treatment has three replicates. Check the disease status after 14 days, record the length and total length of lesions on rice leaves, and calculate the disease index and control efficacy. The calculation method is the same as above.

[0078] The embodiments of this invention are provided to illustrate the technical solutions of this invention, but the content of the embodiments is not limited thereto. The experimental results of the target compound are shown in Table 4.

[0079] Table 4. Protective and curative activities of the compounds of this application and the addition of β-cyclodextrin against bacterial blight in rice.

[0080]

[0081] As shown in Table 4, in the in vivo test, compound 22 exhibited good therapeutic activity (38.10%) and protective activity (43.90%) against rice bacterial blight, which was superior to the control drug thiabendazole (therapeutic activity 33.33%; protective activity 37.40%). The experiment revealed that adding the main component β-cyclodextrin to compound 22 slightly increased its in vivo activity, raising the therapeutic activity to 40.48% and the protective activity to 46.75%. Therefore, this type of compound shows great research potential and can be used to prepare pesticides with high resistance to plant pathogenic bacteria.

[0082] Pharmacological Example 3:

[0083] Compound 22 showed optimal activity against Citrus canker (EC). 50 The concentration of compound 22 was 1.94 μg / mL. An in vivo pot experiment was conducted on citrus canker using this compound. The specific experimental steps are as follows:

[0084] Protective activity: Compounds 22, 22@β-cyclodextrin, and the control drug thiabendazole (20% concentration) were each prepared into solutions with a concentration of 200 μg / mL using less than 1% Tween 20 solution. First, 12 holes were evenly punctured on the upper surface of citrus leaves using a sterile needle. Then, the prepared drug solution was used to moisten filter paper, which was then applied to the punctured areas on the citrus leaf surface, ensuring no air bubbles were left. The filter paper was allowed to dry naturally and fall off. After 24 hours, the OD... 595 The solution of citrus canker pathogens in the range of 0.6-0.8 was centrifuged and the OD value was adjusted. 595=0.01. After wetting the filter paper with the bacterial solution, apply it tightly to the wound. A control with an equal amount of DMSO without the added agent was included. Each treatment had three replicates. The disease incidence was checked after 14 days. Observe the disease infection status at the injured sites on citrus leaves.

[0085] Therapeutic activity: First, use a sterile needle to evenly prick 12 holes on the upper surface of the citrus leaf, and then insert OD... 595 The solution of citrus canker pathogens in the range of 0.6-0.8 was centrifuged and the OD value was adjusted. 595 =0.01. After wetting the filter paper with the bacterial solution, apply it tightly to the wound. 24 hours later, prepare solutions of compounds 22, 22@β-cyclodextrin, and the control drug thiabendazole (20% concentration) with less than 1% Tween 20 solution to a concentration of 200 μg / mL. Then, wet the filter paper with the prepared solutions and apply it to the perforated areas on the citrus leaf surface, ensuring no air bubbles are left. Allow the filter paper to dry naturally and fall off. An equal volume of DMSO control without any drugs was included. Each treatment had three replicates. Disease incidence was checked after 14 days. Observe the susceptibility of the injured areas on the citrus leaves.

[0086] Cut the injured parts of the leaves evenly, weigh 100 mg of each component, and then soak them in 10 mL of a mixed solution (95% acetone: 95% ethanol = 1:1). After 24 hours, measure the absorbance (OD) value. 663 and OD 645 The calculation formula is as follows:

[0087] Chlorophyll a = (12.7 × OD) 663 -2.69×OD 645 )×0.1; Chlorophyll b=(22.9×OD 645 -4.68×OD 663 )×0.1

[0088] Total chlorophyll = (8.02 × OD) 663 +20.21×OD 645 )×0.1

[0089] Efficacy % = (Symptom range in control group - Symptom range in treatment group) / Symptom range in control group × 100%

[0090] Table 4. Protective and therapeutic activities of compound 22 against citrus canker.

[0091]

[0092]

[0093] As shown in Table 4, in the in vivo experiment, compound 22 exhibited good (protective activity 71.52%) and (therapeutic activity 52.61%) effects against citrus canker. This was significantly superior to the control drug thiabendazole (protective activity 56.98%) and (therapeutic activity 41.79%). Adding the adjuvant β-cyclodextrin to compound 22 (molar ratio 1:1) resulted in improved (therapeutic activity 69.39%) and (protective activity 81.36%) effects, demonstrating promising research potential.

Claims

1. A class of compounds containing an isopropanolamine substructure or a salt thereof, characterized in that: Selected from the following compounds:

2. A composition, characterized in that... The composition contains the compound of claim 1 or a salt thereof, and agriculturally available adjuvants or fungicides, insecticides or herbicides; the formulation of the composition is selected from emulsifiable concentrates (EC), powders (DP), granules (GR), aqueous solutions (AS), suspensions (SC), ultra-low volume sprays (ULV), microcapsules (MC), fumigants (FU), and emulsions (EW).

3. Use of the compound of claim 1 or its salt, or the composition of claim 2, in the prevention and control of agricultural pests and diseases, wherein the agricultural pests and diseases are rice bacterial blight fungus, citrus canker fungus, mango angular leaf spot fungus, and rice stripe fungus.

4. A method for preventing and controlling agricultural pests and diseases, characterized in that: The compound of claim 1 or its salt, or the composition of claim 2, is applied to a harmful substance or its living environment; the agricultural pests and diseases are rice bacterial blight fungus, citrus canker fungus, mango angular leaf spot fungus, and rice stripe fungus.

5. A method for protecting plants from agricultural pests and diseases, comprising the method step of contacting the plant with the compound of claim 1 or a salt thereof, or the composition of claim 2.

Images