An isopropanolamine-containing azobenzene compound, a preparation method and application thereof
By preparing azobenzene compounds containing isopropanolamine, the problem of difficult control of mango angular leaf spot was solved, achieving efficient and environmentally friendly crop protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUIZHOU UNIV
- Filing Date
- 2026-05-29
- Publication Date
- 2026-07-31
AI Technical Summary
Existing fungicides are not very effective in controlling mango angular leaf spot, and they also pose risks of drug resistance and environmental safety, resulting in serious crop losses.
Azobenzene compounds containing isopropanolamine were developed, and compounds 7, 8, 13 and 14 were prepared by specific chemical synthesis methods. These compounds were then used to prepare various formulations such as emulsifiable concentrates and powders for the prevention and control of mango angular leaf spot.
Compound 14 has a significant inhibitory effect on mango angular leaf spot pathogen, with an EC50 of 6.2 µg/mL, which is significantly better than existing drugs. The inhibition rate is as high as 94%, effectively reducing crop losses.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of medicinal chemistry technology, specifically relating to an azobenzene compound containing isopropanolamine, its preparation method, and its application. Background Technology
[0002] Bacterial plant diseases are caused by infection with pathogenic fungi. They seriously threaten the healthy development of agriculture, resulting in reduced crop yields and significantly lower quality worldwide. Mango angular leaf spot, also known as bacterial black spot, is a common and important disease affecting mangoes. It is prevalent in mango-producing areas such as Hainan, Guangdong, Guangxi, and Fujian in my country, primarily damaging mango branches, leaves, and fruits. It impacts fruit appearance and commercial value, and severe outbreaks can cause branch necrosis, fruit drop, and post-harvest rot, resulting in fruit losses exceeding 50%. It is currently one of the most critical diseases affecting mango production. Agricultural fungicides have become the most important means of controlling bacterial plant diseases and a major measure for ensuring high and stable crop yields in my country. However, due to the frequent use of traditional fungicides and their limited antimicrobial action, the problem of drug resistance and antimicrobial tolerance among plant bacterial pathogens is becoming increasingly serious. Furthermore, traditional fungicides have other drawbacks, such as cross-resistance and environmental safety concerns. Currently, the control of plant pathogens has become a key scientific issue in pesticide research and development, and the development of novel and highly efficient antimicrobial drugs to replace traditional fungicides has become an important research direction.
[0003] Currently, mango angular leaf spot remains a significant and difficult-to-control disease, and there is an urgent need to develop new, highly effective drugs to combat mango angular leaf spot fungus in order to reduce crop losses and improve economic benefits. Summary of the Invention
[0004] In view of this, one of the objectives of the present invention is to provide an azobenzene compound containing isopropanolamine, which has a specific inhibitory effect on the plant bacterial disease *Mango angular leaf spot*, selected from the following compounds or their salts (the numbers below the structural formulas of the following compounds are the compound numbers corresponding to those in Table 1 of the Specific Embodiments section):
[0005] ;
[0006] ;
[0007] ;
[0008] .
[0009] Preferably, the isopropanolamine-containing azobenzene compound is:
[0010] .
[0011] A second objective of this invention is to provide an intermediate for preparing the above-mentioned isopropanolamine-containing azobenzene compounds, wherein the intermediate is selected from:
[0012] ;
[0013] , where Et represents ethyl.
[0014] A third objective of this invention is to provide a method for preparing the above-mentioned isopropanolamine-containing azobenzene compounds, comprising the following chemical reaction steps:
[0015] R1 and R2 represent replaceable groups, and the specific groups are shown in the corresponding parts of the structural formulas of compounds 7, 8, 13 and 14 above.
[0016] Furthermore, the preparation method further includes the following chemical reaction steps:
[0017] or .
[0018] A fourth objective of the present invention is to provide a composition comprising the above-mentioned isopropanolamine-containing azobenzene compounds.
[0019] Furthermore, the dosage form of the composition is selected from emulsifiable concentrates, powders, wettable powders, granules, aqueous solutions, suspensions, ultra-low volume sprays, soluble powders, microcapsules, fumigants, water emulsions, and water-dispersible granules.
[0020] The fifth objective of this invention is to provide the application of the above-mentioned azobenzene compounds or compositions containing isopropanolamine substructures in inhibiting mango angular leaf spot pathogens.
[0021] The sixth objective of this invention is to provide the application of the above-mentioned azobenzene compounds or compositions containing isopropanolamine substructures in the prevention and control of mango angular leaf spot.
[0022] This invention synthesizes azobenzene compounds containing isopropanolamine by introducing isopropanolamine fragments based on azobenzene. Among them, compounds numbered 7, 8, 13 and 14 have a specific inhibitory effect on mango angular leaf spot pathogen, which can be specifically used to control mango angular leaf spot and solve the problem of huge economic losses to crops caused by the difficulty in controlling mango angular leaf spot. Detailed Implementation
[0023] The present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of application of the present invention. The present invention is not limited to the following embodiments or examples. Any modifications and variations made without departing from the spirit of the present invention should be included within the scope of the present invention. Unless otherwise specified, the experimental materials or reagents used in the following embodiments are all conventional commercially available products.
[0024] Preparation Example 1: Preparation of intermediate diethyl(E)-((4-hydroxyphenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonate
[0025] 4-Aminoazobenzene (0.51 mmol) and p-hydroxybenzaldehyde (0.51 mmol) were added to a 15 mL pressure-resistant flask with diethyl phosphite (0.61 mmol). The mixture was stirred at 80 °C for 4 hours, and the reaction was monitored until completion. Extraction was performed using dichloromethane (30 mL), followed by solvent removal and column chromatography (D:M = 30:1) to give an orange-red solid in 85.1% yield. The structural formula is:
[0026] ;
[0027] The reaction formula is:
[0028] .
[0029] Preparation Example 2: Preparation of intermediate diethyl(E)-((4-(ethylene oxide methoxy)phenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonate
[0030] The intermediate diethyl(E)-((4-hydroxyphenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonate (0.52 mmol) and KOH (0.52 mmol) were dissolved in 3 mL of N,N-dimethylformamide. Then, epichlorohydrin (0.79 mmol) was added to a 25 mL round-bottom flask, and the reaction was carried out at room temperature for 5 h. The reaction was then stopped, extracted with ethyl acetate, and the solvent was removed. The solution was purified by column chromatography to give an orange-red oil in 68% yield. The structural formula is:
[0031] ;
[0032] The reaction formula is:
[0033] .
[0034] Preparation Example 3: Preparation of the target compound 4-diethyl(E)-((4-(3-((2,4-dichlorobenzyl)(methyl)amino)-2-hydroxypropoxy)phenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonate
[0035] Diethyl(E)-((4-(ethylene oxide methoxy)phenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonic acid (0.61 mmol), N-(2,4-dichlorobenzyl)methylamine (0.73 mmol), and K2CO3 (0.61 mmol) were dissolved in 6 mL of isopropanol and added to a 15 mL reaction flask. The reaction was stirred at 50 °C for 6 h and monitored by TLC. After the reaction was completed, the reaction was quenched with water, then extracted with ethyl acetate (30 mL), washed with water, dried over anhydrous Na2SO4, and the solvent was removed. The solution was then removed by column chromatography (CH2Cl2:CH3OH = 30:1, V / V) to give an orange-red oily substance with a yield of 56.4%.
[0036] The reaction formula is:
[0037] R1 and R2 represent replaceable groups, such as R1 being methyl and R2 being 2,4-dichlorobenzyl in this embodiment.
[0038] Preparation Example 4: Preparation of diethyl phosphonate of target compound 7 (E)-[[4-[3-((2-fluorobenzyl)amino)-2-hydroxypropoxy]phenyl][(4-benzanophenyl)amino]methyl]phosphonate
[0039] Diethyl(E)-((4-(ethylene oxide methoxy)phenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonic acid (0.61 mmol), 3-fluorobenzylamine (0.73 mmol), and K2CO3 (0.61 mmol) were dissolved in 6 mL of isopropanol and added to a 15 mL reaction flask. The reaction was stirred at 50 °C for 6 h and monitored by TLC. After the reaction was completed, the reaction was quenched with water, then extracted with ethyl acetate (30 mL), washed with water, dried over anhydrous Na2SO4, and the solvent was removed. The solution was then removed by column chromatography (CH2Cl2:CH3OH = 30:1, V / V) to give an orange-red oily substance with a yield of 42.8%.
[0040] Preparation Example 5: Preparation of diethyl phosphonate of target compound 8(E)-[[4-[3-(benzyl(methyl)amino)-2-hydroxypropoxy]phenyl][(4-benzanophenyl)amino]methyl]phosphonate
[0041] Diethyl(E)-((4-(ethylene oxide methoxy)phenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonic acid (0.61 mmol), N-methyl-1-benzylamine (0.73 mmol), and K2CO3 (0.61 mmol) were dissolved in 6 mL of isopropanol and added to a 15 mL reaction flask. The reaction was stirred at 50 °C for 6 h and monitored by TLC. After the reaction was completed, the reaction was quenched with water, then extracted with ethyl acetate (30 mL), washed with water, dried over anhydrous Na2SO4, and the solvent was removed. The solution was then removed by column chromatography (CH2Cl2:CH3OH = 30:1, V / V) to give an orange-red oil with a yield of 54.7%.
[0042] Preparation Example 6: Preparation of diethyl phosphonate of target compound 13 (E)-[[4-(2-hydroxy-3-((4-methoxybenzyl)amino)propoxy)phenyl][(4-benzanophenyl)amino]methyl]phosphonate
[0043] Diethyl(E)-((4-(ethylene oxide methoxy)phenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonic acid (0.61 mmol), 4-methoxybenzylamine (0.73 mmol), and K2CO3 (0.61 mmol) were dissolved in 6 mL of isopropanol and added to a 15 mL reaction flask. The reaction was stirred at 50 °C for 6 h and monitored by TLC. After the reaction was completed, the reaction was quenched with water, then extracted with ethyl acetate (30 mL), washed with water, dried over anhydrous Na2SO4, and the solvent was removed. The solution was then removed by column chromatography (CH2Cl2:CH3OH = 30:1, V / V) to give an orange-red oil with a yield of 57.8%.
[0044] Preparation Example 7: Preparation of diethyl phosphonate of target compound 14 (E)-[[4-(2-hydroxy-3-((2-methoxybenzyl)(methyl)amino)propoxy)phenyl][(4-benzanophenyl)amino]methyl]phosphonate
[0045] Diethyl(E)-((4-(ethylene oxide methoxy)phenyl)((4-(azophenyl)phenyl)amino)methyl)phosphonic acid (0.61 mmol), N-methyl-2-methoxybenzylamine (0.73 mmol), and K2CO3 (0.61 mmol) were dissolved in 6 mL of isopropanol and added to a 15 mL reaction flask. The reaction was stirred at 50 °C for 6 h and monitored by TLC. After the reaction was completed, the reaction was quenched with water, then extracted with ethyl acetate (30 mL), washed with water, dried over anhydrous Na2SO4, and the solvent was removed. The solution was then removed by column chromatography (CH2Cl2:CH3OH = 30:1, V / V) to give an orange-red oil with a yield of 70.6%.
[0046] Other target compounds can be synthesized using appropriate starting materials or substituents, following the steps outlined in the examples above. The structures and NMR spectra (1H, 1C, fluorine, and phosphorus) of the synthesized isopropanolamine-containing azobenzene compounds are shown in Table 1, and their physicochemical properties are shown in Table 2.
[0047] Table 1. NMR data of synthesized isopropanolamine-containing azobenzene compounds
[0048]
[0049]
[0050]
[0051]
[0052]
[0053] Table 2. Physicochemical properties of synthesized isopropanolamine-containing azobenzene compounds
[0054]
[0055] Pharmacological Examples:
[0056] The inhibition rate of the target compound against plant pathogenic bacteria was tested using the turbidimetric method. The test subject was *Aureobasidium mangoeum* (Xcm), the causal agent of mango angular leaf spot. DMSO was dissolved in the culture medium as a blank control. *Aureobasidium mangoeum* (Xcm) was transferred from NA solid medium to NB medium and cultured in a shaker at 28 ℃ and 180 rpm until the logarithmic growth phase. Different concentrations (e.g., 50, 25, 12.5 μg / mL) of the agent (compound) containing the pathogen were prepared and added to test tubes. 40 µL of NB liquid medium containing the plant pathogenic bacteria was added to each tube, and the tubes were cultured in a shaker at 28 ℃ and 180 rpm for 48 h. 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 was also determined. 595 value.
[0057] 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 .
[0058] The effective medium concentration (EC) of the target compound against plant pathogens was determined using a turbidimetric method. 50 The experimental subject was mango angular leaf spot (Xcm). DMSO was dissolved in the culture medium as a blank control. Plant bacteria were placed in NB medium and cultured in a shaker at 28 ℃ and 180 rpm until the logarithmic growth phase. Mango angular leaf spot (Xcm) was placed on solid medium and then placed in NB medium, and cultured in a shaker at 28 ℃ and 180 rpm until the logarithmic growth phase. 5 mL of NB liquid medium containing different concentrations of the compound (e.g., 50, 25, 12.5, 6.25, 3.125 μg / mL) was added to each test tube, followed by 40 µL of NB liquid medium containing the plant disease bacteria. The tubes were cultured in a shaker at 28 ℃ and 180 rpm for 48 h. 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 NB-containing liquid culture medium was also determined. 595 value.
[0059] Corrected OD value = OD value of sterile culture medium - OD value of sterile culture medium
[0060] Inhibition rate (%) = [(OD value of bacterial culture in the corrected control medium - OD value of the corrected virus-containing medium) / OD value of bacterial culture in the corrected control medium] × 100
[0061] 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 Tables 3 and 4.
[0062] Table 3. Inhibition rate (%) of azobenzene compounds containing isopropanolamine against mango angular leaf spot pathogen (Xcm).
[0063]
[0064] Table 4. EC5 activity of isopropanolamine-containing azobenzene compounds against *Xcm*, the causal agent of mango angular leaf spot. 50
[0065]
[0066] As shown in Tables 3 and 4, compounds 7, 8, 13, and 14 of the azobenzene series exhibit significant and excellent inhibitory activity against mango angular leaf spot pathogens, with compound 14 showing extremely superior activity against plant bacterial diseases. The antibacterial activity of compound 14 against mango angular leaf spot (Xcm) is shown in Tables 3 and 4. 50The concentration was 6.2 µg / mL, which was significantly better than the commercial drugs tebuconazole (84.9 µg / mL) and thiamethoxam (128.4 µg / mL).
[0067] Pharmacological comparison:
[0068] Following the method described in Pharmacological Example 1, the turbidimetric method was used to test the inhibition rate of the target compounds against the plant pathogenic bacteria *Bacillus cuspidata* (Bfb) and *Psl* (Psl). The results are shown in Table 5. The azobenzene compounds containing isopropanolamine showed inhibition rates of less than 65% against both *Bacillus cuspidata* and *Psl*, indicating poor inhibitory activity.
[0069] Table 5. Inhibition rate (%) of azobenzene compounds containing isopropanolamine against *Aureobasidium canariensis* and *Aureobasidium cuminis*.
[0070]
[0071] In summary, the azobenzene compounds 7, 8, 13, and 14 of this invention exhibit specific and significant inhibitory effects against *Aureobasidium mangoe*, a plant bacterial disease, with inhibition rates exceeding 94% within 24 hours. Compound 14, in particular, demonstrates an antibacterial activity of EC50. 50 With a concentration of only 6.2 µg / mL, it exhibits significant effects and can be used to prepare pesticides for treating mango angular leaf spot, a bacterial plant disease.
[0072] The conventional techniques and solutions not described in detail in the above embodiments are all well known in the art, and therefore will not be elaborated upon here. The above embodiments and / or experimental examples describe the preferred embodiments of the present invention in detail. 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 simple modifications all fall within the protection scope of the present invention.
Claims
1. An azobenzene compound containing isopropanolamine, characterized in that, Selected from the following compounds or their salts: ； ； ； 。 2. The isopropanolamine-containing azobenzene compound as described in claim 1, characterized in that, The compound is: 。 3. An intermediate for preparing the isopropanolamine-containing azobenzene compound as described in claim 1 or 2, characterized in that, The intermediate is selected from: ； 。 4. The method for preparing the isopropanolamine-containing azobenzene compound according to claim 1 or 2, characterized in that, The chemical reaction steps include the following: 。 5. The preparation method according to claim 4, characterized in that, It also includes the following chemical reaction steps: or .
6. A composition, characterized in that, It includes the isopropanolamine-containing azobenzene compound as described in claim 1 or 2, or the isopropanolamine-containing azobenzene compound prepared according to claim 4 or 5.
7. The composition according to claim 6, characterized in that, The dosage form of the composition is selected from emulsifiable concentrates, powders, wettable powders, granules, aqueous solutions, suspensions, ultra-low volume sprays, soluble powders, microcapsules, fumigants, water emulsions, and water-dispersible granules.
8. The use of the isopropanolamine-containing azobenzene compound of claim 1 or 2, or the isopropanolamine-containing azobenzene compound prepared according to claim 4 or 5, or the composition of claim 6 or 7 in inhibiting mango angular leaf spot pathogen.
9. The use of the isopropanolamine-containing azobenzene compound of claim 1 or 2, or the isopropanolamine-containing azobenzene compound prepared according to claim 4 or 5, or the composition of claim 6 or 7, in the prevention and control of mango angular leaf spot.