A quinoline derivative for controlling agricultural diseases, and a preparation method and application thereof

Abstract

The application discloses a quinina derivative for preventing and treating agricultural diseases, a preparation method and application thereof, and relates to a compound with a structural formula as shown in formula I, or a pharmaceutically acceptable salt, a solvate and a tautomer thereof. It is found that the quinina derivative has excellent inhibitory effect on Xanthomonas oryzae and Xanthomonas citri, has great development value in treating plant pathogenic bacteria, and provides more choices for preventing and treating agricultural diseases.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, and in particular to a cinchona alkaloid derivative for the prevention and control of agricultural diseases, its preparation method, and its application. Background Technology

[0002] Plant bacterial diseases are among the most difficult problems to control during crop growth, causing not only large-scale crop damage but also severe economic losses. For example, rice bacterial blight can reduce rice yield by 20% to 50%, while citrus canker poses a significant threat to major citrus fruits worldwide. Since the 1960s, chemical pesticides have become one of the main means of controlling pests. However, with the long-term and widespread use of chemical fungicides, plant pathogenic bacteria have gradually developed resistance to these drugs, which not only increases the difficulty of control but also poses a serious threat to human health and environmental safety. Therefore, the development of new control strategies and alternative pesticides is urgently needed.

[0003] Quinine, also known as cinchona alkaloid, is an alkaloid extracted from the bark of the cinchona tree (a member of the Rubiaceae family) and related species. Studies show that the bark of the cinchona tree is particularly rich in alkaloids, with quinine content reaching up to 70% in the dried bark. This class of alkaloids also includes hydrogenated quinine, quinidine, cinchona alkaloid, and hydrogenated quinidine. These compounds all contain chiral 1-bicyclic [2.2.2] octane and quinoline ring structures, providing a natural chiral environment and exhibiting excellent stereoselectivity in asymmetric catalytic reactions. Currently, research on these alkaloids and their derivatives mainly focuses on antimalarial treatment. However, there are few reports on their application in the control of agricultural bacterial diseases.

[0004]

[0005] The inventors found that the effects of using quinine, hydrogenated quinine, quinidine, cinquerin, and hydrogenated quinidine to control rice bacterial blight and citrus canker were not outstanding. It is of great research value to find new compounds that can be optimized to produce more options and show good inhibition rates against both types of agricultural bacteria, such as rice bacterial blight and citrus canker. Summary of the Invention

[0006] Purpose of the invention

[0007] To overcome the above shortcomings, the present invention aims to provide a cinchona alkaloid derivative for the prevention and control of agricultural diseases, its preparation method, and its application. The cinchona alkaloid derivative of the present invention exhibits potential inhibitory effects against two types of agricultural bacteria: rice bacterial blight pathogen and citrus canker pathogen, significantly outperforming the control drugs thiabendazole and thiabendazole copper, and is expected to be developed into a novel agricultural drug against plant pathogenic bacteria.

[0008] Solution

[0009] To achieve the objectives of this invention, the technical solution adopted is as follows:

[0010] In a first aspect, the present invention provides a cinchona alkaloid derivative for the prevention and control of agricultural diseases, comprising a compound with the structural formula shown in Formula I, or a pharmaceutically acceptable salt thereof, a solvate thereof and a tautomer thereof;

[0011]

[0012] In formula I, R1 can be any of the following groups:

[0013] R2 is one of the substituted phenyl groups or C3 to C10 alkyl groups; substituted phenyl groups include halophenyl groups, haloalkyl-substituted phenyl groups, oxyalkyl-substituted phenyl groups, cyanophenyl groups, or C1 to C5 alkyl-substituted phenyl groups.

[0014] Optionally, R1 is

[0015] Optionally, R2 includes a halophenyl, a trifluoromethyl-substituted phenyl, or a tert-butyl-substituted phenyl; or R2 includes an iodophenyl, a fluorophenyl, a chlorophenyl, a trifluoromethyl-substituted phenyl, or a tert-butyl-substituted phenyl; or R2 includes p-iodophenyl, p-fluorophenyl, p-chlorophenyl, p-trifluoromethylphenyl, or p-tert-butylphenyl.

[0016] Optionally, it includes at least one of compounds with structural formulas such as K1-K4 and K6-K15, or a pharmaceutically acceptable salt thereof, its solvate, and its tautomer:

[0017]

[0018]

[0019] Optionally, it may be selected from at least one of compounds with structural formulas such as K2-K4, K6, K7, K9-K11, or a pharmaceutically acceptable salt thereof, its solvate, and its tautomer.

[0020] Optionally, it is selected from at least one of compounds with structural formulas such as K2, K6, K9 to K11, or pharmaceutically acceptable salts, solvates and tautomers thereof;

[0021]

[0022] Optionally, it is selected from at least one of compounds with structural formulas such as K2, K10, and K11, or their pharmaceutically acceptable salts, solvates, and tautomers:

[0023]

[0024] In a second aspect, a method for preparing the cinchona alkaloid derivative described in the first aspect is provided, comprising: dissolving quinine alkaloids and amines in an organic solvent, adding acyl chloride compounds, stirring the reaction, purifying, and obtaining the cinchona alkaloid derivative;

[0025] Quinine alkaloids are selected from one or more of quinine sulfate, hydrogenated quinine, quinidine, cinchonine, and hydrogenated quinidine;

[0026] Acyl chloride compounds are selected from one or more of 4-chlorobenzoyl chloride, 4-trifluoromethylbenzoyl chloride, p-methoxybenzoyl chloride, p-cyanobenzoyl chloride, p-fluorobenzoyl chloride, p-iodobenzoyl chloride, p-tert-butylbenzoyl chloride, n-butyryl chloride, n-valeryl chloride, hexanoyl chloride, and isobutyryl chloride;

[0027] Optionally, the amine is triethylamine;

[0028] Optionally, the organic solvent is a chlorinated alkane, or alternatively, dichloromethane.

[0029] Thirdly, a pesticide formulation is provided, the active ingredient of which includes the cinchona alkaloid derivatives described in the first aspect or the cinchona alkaloid derivatives prepared by the preparation method described in the second aspect.

[0030] Optionally, it may also include agronomically acceptable carriers;

[0031] Optionally, the weight percentage of cinchona alkaloid derivative in the pharmaceutical preparation is 1-99%;

[0032] Optionally, the pesticide formulation is in the form of a suspension concentrate, dry suspension concentrate, oil suspension concentrate, wettable powder, or water-dispersible granule.

[0033] Optionally, the pesticide formulation is used to control rice bacterial blight and / or citrus canker.

[0034] Fourthly, an application of cinchona alkaloid derivatives in the prevention and control of agricultural diseases is provided. The cinchona alkaloid derivatives include compounds with the structural formula shown in Formula I, or pharmaceutically acceptable salts thereof, their solvates and their tautomers.

[0035]

[0036] In formula I, R1 can be any of the following groups:

[0037] R2 is one of the substituted phenyl groups or C3 to C10 alkyl groups; substituted phenyl groups include halophenyl groups, haloalkyl-substituted phenyl groups, oxyalkyl-substituted phenyl groups, cyanophenyl groups, or C1 to C5 alkyl-substituted phenyl groups.

[0038] Optionally, R1 is

[0039] Optionally, R2 includes a halophenyl, a trifluoromethyl-substituted phenyl, or a tert-butyl-substituted phenyl; or R2 includes an iodophenyl, a fluorophenyl, a chlorophenyl, a trifluoromethyl-substituted phenyl, or a tert-butyl-substituted phenyl; or R2 includes p-iodophenyl, p-fluorophenyl, p-chlorophenyl, p-trifluoromethylphenyl, or p-tert-butylphenyl.

[0040] Optionally, it includes at least one of compounds with structural formulas as shown in any of formulas K1 to K15, or a pharmaceutically acceptable salt thereof, its solvate, and its tautomer:

[0041]

[0042]

[0043] Optionally, it is selected from at least one of the compounds with structural formulas such as K2-K6, K7, K9-K11, or a pharmaceutically acceptable salt thereof, its solvate and its tautomer;

[0044] Optionally, it is selected from at least one of compounds with structural formulas such as K2, K5, K6, K9 to K11, or pharmaceutically acceptable salts, solvates and tautomers thereof;

[0045]

[0046] Optionally, it is selected from at least one of compounds with structural formulas such as K2, K10, and K11, or their pharmaceutically acceptable salts, solvates, and tautomers:

[0047]

[0048] Optionally, the plant bacterial disease is one or more of rice bacterial blight and citrus canker.

[0049] Beneficial effects

[0050] (1) The present invention found that cinchona alkaloid derivatives exhibit excellent inhibitory effects on rice bacterial blight and citrus canker, and have great development value in the treatment of plant pathogenic bacteria, providing more options for the prevention and control of agricultural diseases.

[0051] (2) The cinchona alkaloid derivative of the present invention can be obtained by one-step esterification reaction. The synthesis steps are short and it has the characteristics of easy synthesis, simple structure and green efficiency. As a lead compound for the prevention and control of agricultural bacterial pathogens, it is worth further research and development. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Furthermore, to better illustrate the present invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In some embodiments, materials, methods, means, etc., well-known to those skilled in the art, are not described in detail in order to highlight the spirit of the present invention.

[0054] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0055] The cinchona alkaloid derivatives described in this invention are derivatives obtained by introducing ester groups into cinchona alkaloid. The pure product was obtained by conventional methods such as silica gel column chromatography, and the structure of the cinchona alkaloid derivatives was identified by techniques such as nuclear magnetic resonance spectroscopy and mass spectrometry. Activity screening results showed that the cinchona alkaloid derivatives exhibited good inhibitory effects against rice bacterial blight and citrus canker.

[0056] Experimental methods in the embodiments of this invention that do not specify specific conditions are generally performed under conventional conditions or as recommended by the raw material or product manufacturer. Reagents whose specific source is not specified are commercially available conventional reagents.

[0057] I. Synthesis Examples

[0058] Compounds K1-K4 and K6-K15 were prepared by esterification reactions of quinine derivatives with acyl chlorides of different substitutions, respectively. Compound K5 (hydroquinidine p-chlorobenzoate, CAS No. 113162-02-0) was purchased from Anaiji Chemical Reagent Co., Ltd.

[0059] Example 1: Synthesis of compound K1:

[0060] Quinine sulfate (0.78 mmol) and triethylamine (1.15 mmol) were dissolved in dichloromethane (10 mL). 4-Chlorobenzoyl chloride (1.04 mmol) was added dropwise at 0 °C. The reaction mixture was stirred at room temperature for 3 hours. The reaction was quenched with a saturated sodium bicarbonate aqueous solution, extracted with dichloromethane, washed with water, dried, concentrated, and then purified by silica gel column chromatography to obtain a white solid, named K1. Yield of K1: 82%; white solid; K1 NMR data are as follows:

[0061] 1 H NMR(400MHz,Chloroform-d)δ8.73(d,J=4.5Hz,1H),8.05–7.99(m,3H),7.50(d,J=2.7Hz,1H),7.45(d,J=8.3Hz,2H), 7.40(d,J=4.6Hz,1H),7.39–7.36(m,1H),6.73(d,J=6.8Hz,1H),5.85(ddd,J=17.4,10.4,7.4Hz,1H),5.10–4.98(m,2 H),3.98(s,3H),3.50(q,J=7.9Hz,1H),3.18(dq,J=14.4,6.5Hz,1H),3.09(dd,J=13.8,10.0Hz,1H),2.77–2.62(m,2H ),2.32(d,J=11.3Hz,1H),2.03–1.85(m,2H),1.73(dtd,J=31.1,12.8,12.3,5.7Hz,2H),1.58(q,J=10.9,9.9Hz,1H). 13 C NMR(101MHz,Chloroform-d)δ164.79,158.05,147.48,144.84,141.66,140.05,131.94,131.03(2C),129.04(2C),128.17 ,126.93,121.94,118.67,114.67,101.36,74.71,59.40,56.72,55.70,42.59,39.67,29.72,27.91,27.60,24.30.MS-ESI m / z:463.1892[M+H] + .

[0062] Example 2 Synthesis of compound K2

[0063] The procedure is the same as in Example 1, where hydrogenated quinine is used instead of quinine sulfate to prepare compound K2 (which has a cis-trans structure with K5).

[0064] K2: Yield: 83%; White solid; K2 NMR data are as follows:

[0065] 1 H NMR(400MHz,Chloroform-d)δ8.70(d,J=4.5Hz,1H),8.05–8.01(m,3H),7.55(d,J=2.7Hz,1H),7.50 –7.44(m,2H),7.41–7.35(m,2H),6.95(s,1H),4.00(s,3H),3.50(td,J=8.7,4.9Hz,1H),3.32(s,1H) ,3.22(dd,J=13.6,10.1Hz,1H),2.88–2.78(m,1H),2.51(d,J=13.8Hz,1H),1.96(q,J=3.2Hz,1H),1 .86(s,3H),1.61(d,J=14.9Hz,2H),1.34(td,J=7.6,1.7Hz,1H),1.25(s,1H),0.86(t,J=7.3Hz,3H). 13 C NMR(101MHz,Chloroform-d)δ164.30,158.46,147.25,144.79,140.23,131.89,131.07,130.99(2C),129.15(2C), 128.10,128.03,126.61,122.39,118.09,101.15,58.96,57.98,56.09,42.77,36.83,27.59,25.20,11.97.MS-ESI m / z:465.2082[M+H] + .

[0066] Example 3 Synthesis of compound K3

[0067] The procedure is the same as in Example 1, where quinidine is used instead of quinine sulfate to prepare compound K3.

[0068] K3: Yield: 80%; White solid; K3 NMR data are as follows:

[0069] 1H NMR(400MHz,Chloroform-d)δ8.71(d,J=4.6Hz,1H),8.02(dd,J=8.9,5.1Hz,3H),7.49(d,J=2.7Hz,1H),7 .46–7.42(m,2H),7.38(dt,J=5.4,2.3Hz,2H),6.80(d,J=6.6Hz,1H),6.01(ddd,J=17.2,10.4,6.7Hz,1H), 5.17–5.04(m,2H),3.98(s,3H),3.43(td,J=9.0,6.5Hz,1H),2.95(dd,J=44.5,7.8Hz,3H),2.78(dt,J=13 .4,8.7Hz,1H),2.32(q,J=8.3Hz,1H),2.01(dd,J=13.4,9.1Hz,1H),1.91–1.87(m,1H),1.64–1.57(m,3H). 13 C NMR(101MHz,Chloroform-d)δ164.48,157.91,147.22,144.56,143.30,139.80(d,J=10.7Hz),131.69,130.95(2C),128.77(2C) ,127.90,126.73,121.87,118.18,114.93,101.08,74.02,59.10,55.52,49.62,49.00,39.11,27.39,25.99,23.22,0.84.MS-ESI m / z:463.1922[M+H] + .

[0070] Example 4 Synthesis of compound K4

[0071] The procedure is the same as in Example 1, except that cinkonin is used instead of quinine sulfate to prepare compound K4.

[0072] K4: Yield: 82%; White solid; K4 NMR data are as follows:

[0073] 1H NMR(400MHz,Chloroform-d)δ8.88(d,J=4.5Hz,1H),8.30(dd,J=8.5,1.4Hz,1H),8.14(dd,J=8.5,1.3Hz,1H),8 .05–7.98(m,2H),7.63(ddd,J=8.3,6.8,1.3Hz,1H),7.47–7.42(m,3H),6.79(d,J=6.9Hz,1H),5.84(ddd,J=17.4 ,10.4,7.4Hz,1H),5.15–4.91(m,2H),3.56–3.45(m,1H),3.19(dddd,J=13.1,10.2,5.4,2.4Hz,1H),3.07(dd,J= 13.9,10.0Hz,1H),2.74–2.59(m,2H),2.48–2.14(m,2H),1.94(ddp,J=20.0,9.8,3.4Hz,2H),1.83–1.54(m,3H). 13 C NMR(101MHz,Chloroform-d)δ164.53,149.79,148.45,144.88,141.37,139.84,130.85,130.38(2C),129.12,128.83(2C),127.9 3,126.86,125.70,123.04,118.30,114.51,74.66,59.67,56.51,42.31,39.41,27.63,27.41,24.20.MS-ESIm / z:433.1812[M+H] + .

[0074] Example 5: Synthesis of Compound K6

[0075] Following the procedure in Example 1, only quinidine was used instead of quinine sulfate, and 4-trifluoromethylbenzoyl chloride was used instead of 4-chlorobenzoyl chloride to prepare compound K6.

[0076] K6: Yield: 80%; White solid; K6 NMR data are as follows:

[0077] 1H NMR(400MHz,Chloroform-d)δ8.73(d,J=4.5Hz,1H),8.20(d,J=8.1Hz,2H),8.02(d,J=9.2Hz,1H),7.74(d,J=8.2Hz, 2H),7.50(d,J=2.7Hz,1H),7.41(d,J=4.5Hz,1H),7.38(dd,J=9.3,2.7Hz,1H),6.80(d,J=7.2Hz,1H),3.99(s,3H),3 .45(q,J=8.5Hz,1H),2.95(dd,J=13.9,8.1Hz,1H),2.85(t,J=11.6Hz,1H),2.74(dt,J=13.1,8.4Hz,2H),1.90(t,J= 11.2Hz, 1H), 1.78 (d, J = 4.7Hz, 1H), 1.60 (dd, J = 9.0, 4.8Hz, 1H), 1.50 (dt, J = 10.9, 4.9Hz, 3H), 0.91 (t, J = 6.9Hz, 3H). 13 C NMR(101MHz,Chloroform-d)δ163.45,157.05,146.41,143.77,142.38,134.06,133.74,131.95,130.89,129.05(2C),126.01,124.63 (d,J=3.9Hz),123.84,120.97,117.54,100.32,73.62,58.42,54.64,49.79,48.91,36.24,26.01,25.05,24.42,22.52,10.87.MS-ESI m / z:499.2312[M+H] + .

[0078] Example 6 Synthesis of compound K7

[0079] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and p-methoxybenzoyl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K7.

[0080] K7: Yield: 81%; White solid; K7 NMR data are as follows:

[0081] 1H NMR(400MHz,Chloroform-d)δ8.69(d,J=4.5Hz,1H),8.09–8.03(m,2H),8.03–7.99(m,1 H),7.59(d,J=2.7Hz,1H),7.42–7.34(m,2H),7.05(s,1H),6.99–6.92(m,2H),4.01(s,3H ),3.85(d,J=13.6Hz,3H),3.44(td,J=9.2,5.0Hz,1H),3.12–2.85(m,4H),2.14(t,J=11. 4Hz,1H),1.87–1.83(m,1H),1.59(ddt,J=27.8,24.8,8.4Hz,6H),0.92(t,J=7.1Hz,3H). 13 C NMR(101MHz,Chloroform-d)δ164.75,163.87,158.41,147.22,144.71,143.17,131.74(2C),131.55,126.69,122.47,121.91 ,118.07,113.94(2C),113.12,101.18,72.71,59.05,56.14,55.55,55.32,50.27,49.65,36.68,26.09,25.26,11.75.MS-ESI m / z:461.2535[M+H] + .

[0082] Example 7 Synthesis of compound K8

[0083] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and p-cyanobenzoyl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K8.

[0084] K8: Yield: 79%; White solid; K8 NMR data are as follows:

[0085] 1H NMR(400MHz,Chloroform-d)δ8.73(d,J=4.6Hz,1H),8.21–8.14(m,2H),8.02(d,J= 9.2Hz,1H),7.80–7.74(m,2H),7.49(d,J=2.7Hz,1H),7.38(dd,J=9.1,3.3Hz,2H), 6.81(d,J=6.9Hz,1H),3.98(s,3H),3.45(q,J=8.6Hz,1H),2.98–2.67(m,4H),1.89 (t,J=11.2Hz,1H),1.78(d,J=4.5Hz,1H),1.69–1.42(m,6H),0.90(t,J=7.0Hz,3H). 13 C NMR(101MHz,Chloroform-d)δ164.50,158.57,147.85,145.23,143.61,133.97,132.87(2C),132.38,130.58(2C),127.4 5,122.46,118.20,117.35,101.76,75.19,59.86,56.14,51.23,50.33,37.63,27.39,26.48,25.90,24.00,12.33.MS-ESI m / z:456.2381[M+H] + .

[0086] Example 8: Synthesis of Compound K9

[0087] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and p-fluorobenzoyl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K9.

[0088] K9: Yield: 83%; White solid; K9 NMR data are as follows:

[0089] 1H NMR(400MHz,Chloroform-d)δ8.72(d,J=4.5Hz,1H),8.15–8.07(m,2H),8.01(d,J=9.2Hz,1H), 7.51(d,J=2.7Hz,1H),7.43–7.34(m,2H),7.14(t,J=8.6Hz,2H),6.82(d,J=6.8Hz,1H),3.99(s ,3H),3.43(q,J=8.5Hz,1H),2.97(dd,J=14.4,7.7Hz,1H),2.87(t,J=11.5Hz,1H),2.82–2.70( m,2H),1.94(t,J=11.2Hz,1H),1.78(d,J=4.6Hz,1H),1.66–1.44(m,6H),0.90(t,J=6.9Hz,3H). 13 C NMR(101MHz,Chloroform-d)δ167.75,165.12(d,J=20.1Hz),158.53,147.85,145.22,144.02,132.68(d,J=9.4Hz,2C),132.30,127.45,126.4 3(d,J=2.9Hz),122.51,118.93,116.39,116.17,101.80,74.45,59.87, 56.19,51.17,50.35,37.63,27.36,26.56,25.86,23.77,12.31.MS-ESI m / z:449.2329[M+H] + .

[0090] Example 9: Synthesis of Compound K10

[0091] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and p-iodobenzoyl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K10.

[0092] K10: Yield: 80%; White solid; K10 NMR data are as follows:

[0093] 1H NMR(400MHz,Chloroform-d)δ8.72(d,J=4.5Hz,1H),8.01(d,J=9.2Hz,1H),7.86–7.75(m ,4H),7.49(d,J=2.7Hz,1H),7.42–7.33(m,2H),6.76(d,J=7.0Hz,1H),3.98(s,3H),3.41( q,J=8.5Hz,1H),2.94(dd,J=14.2,8.0Hz,1H),2.89–2.79(m,1H),2.74(dt,J=13.6,8.6Hz ,2H),1.94–1.84(m,1H),1.76(d,J=4.6Hz,1H),1.65–1.41(m,6H),0.90(t,J=7.0Hz,3H). 13 C NMR(101MHz,Chloroform-d)δ165.29,158.15,147.56,144.91,143.70,138.11(2C),132.00,131.15(2C),129.34,127. 15,122.12,118.68,101.49(2C),74.47,59.55,55.80,50.92,50.07,37.40,27.17,26.22,25.56,23.59,12.04.MS-ESI m / z:557.1329[M+H] + .

[0094] Example 10 Synthesis of compound K11

[0095] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and p-tert-butylbenzoyl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K11.

[0096] K11: Yield: 81%; White solid; K11 NMR data are as follows:

[0097] 1H NMR(400MHz,Chloroform-d)δ8.71(d,J=4.6Hz,1H),8.07–7.97(m,3H),7.52(d,J=2.7H z,1H),7.42(d,J=4.6Hz,1H),7.36(dd,J=9.2,2.7Hz,1H),6.77(d,J=7.0Hz,1H),3.98( s,3H),3.42(q,J=8.5Hz,1H),2.94(dd,J=13.7,8.7Hz,1H),2.89–2.68(m,3H),1.98–1. 88(m,1H),1.75(d,J=4.7Hz,1H),1.66–1.44(m,6H),1.34(s,9H),0.90(t,J=7.1Hz,3H). 13 C NMR(101MHz,Chloroform-d)δ165.40,157.74,157.03,147.25,144.57,143.83,131.60,129.39(2C),126.90,126.77,125.37(2C) ,121.76,118.45,101.24,73.70,59.28,55.46,50.59,49.77,37.16,34.96,30.89(3C),26.92,25.96,25.21,23.28,11.73.MS-ESI m / z:487.2994[M+H] + .

[0098] Example 11 Synthesis of compound K12

[0099] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and n-butyryl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K12.

[0100] K12: Yield: 80%; White solid; K12 NMR data are as follows:

[0101] 1H NMR(400MHz,Chloroform-d)δ8.71(d,J=4.5Hz,1H),8.00(d,J=9.2Hz,1H),7.44(d,J=2.7Hz,1H),7.3 6(dd,J=9.3,2.7Hz,1H),7.31(d,J=4.5Hz,1H),6.61(d,J=6.4Hz,1H),3.96(s,3H),3.26(td,J=8.9,6 .2Hz,1H),2.94(dd,J=13.7,8.3Hz,1H),2.86–2.68(m,3H),2.37(t,J=7.4Hz,2H),1.88–1.79(m,1H), 1.75 (s, 1H), 1.67 (h, J = 7.4Hz, 2H), 1.49 (dtt, J = 23.4, 13.4, 4.0Hz, 5H), 0.92 (td, J = 7.2, 3.5Hz, 7H). 13 C NMR(101MHz,Chloroform-d)δ172.86,158.44,147.75,145.14,144.22,132.16,127.38,122.46,118.82,1 01.78,73.47,59.39,56.18,51.02,37.54,36.80,27.30,26.45,25.81,23.37,18.79,14.12,12.36.MS-ESI m / z:397.2539[M+H] + .

[0102] Example 12 Synthesis of compound K13

[0103] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and n-valeryl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K13.

[0104] K13: Yield: 80%; White solid; K13 NMR data are as follows:

[0105] 1H NMR(400MHz,Chloroform-d)δ8.72(d,J=4.6Hz,1H),8.00(d,J=9.2Hz,1H),7.43(d,J=2.7Hz,1H),7.36 (dd,J=9.2,2.7Hz,1H),7.31(d,J=4.5Hz,1H),6.59(d,J=6.3Hz,1H),3.97(s,3H),3.26(td,J=8.9,6.1 Hz,1H),2.95(dd,J=13.8,8.5Hz,1H),2.88–2.66(m,3H),2.43–2.35(m,2H),1.89–1.79(m,1H),1.75(d ,J=4.8Hz,1H),1.67–1.60(m,2H),1.58–1.44(m,3H),1.44–1.24(m,3H),0.91(dt,J=11.0,7.2Hz,6H). 13 C NMR(101MHz,Chloroform-d)δ173.05,158.48,147.76,145.14,144.27,132.17,127.38,122.49,118.82,101.78,73.56, 59.32,56.18,51.01,50.21,37.59,34.68,28.00,27.35(d,J=3.0Hz),26.51,25.86,23.32,22.70,14.12,12.41.MS-ESI m / z:411.2694[M+H] + .

[0106] Example 13 Synthesis of compound K14

[0107] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and hexanoyl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K14.

[0108] K14: Yield: 81%; White solid; K14 NMR data are as follows:

[0109] 1H NMR(400MHz,Chloroform-d)δ8.71(d,J=4.5Hz,1H),8.00(d,J=9.2Hz,1H),7.43(d,J=2.7Hz,1H),7.36(dd ,J=9.2,2.7Hz,1H),7.31(d,J=4.5Hz,1H),6.60(d,J=6.6Hz,1H),3.97(s,3H),3.27(td,J=8.9,6.2Hz,1H) ,2.94(dd,J=13.8,8.3Hz,1H),2.86–2.68(m,3H),2.38(dd,J=8.1,7.0Hz,2H),1.88–1.80(m,1H),1.76(s, 1H),1.69–1.59(m,2H),1.59–1.37(m,5H),1.27(qd,J=7.9,7.0,4.4Hz,5H),0.89(dt,J=25.6,7.1Hz,6H). 13 CNMR(101MHz,Chloroform-d)δ172.75,158.13,147.46,144.86,143.91,127.09,122.14,118.56,101.49,73. 21,59.17,55.88,50.80,50.02,37.27,34.59,31.38,27.02,25.53,24.68,23.12,22.39,13.98,12.07.MS-ESI m / z:425.2852[M+H] + .

[0110] Example 14 Synthesis of compound K15

[0111] The procedure was the same as in Example 1, except that hydrogenated quinidine was used instead of quinine sulfate, and isobutyryl chloride was used instead of 4-chlorobenzoyl chloride, to prepare compound K15.

[0112] K15: Yield: 80%; White solid; K15 NMR data are as follows:

[0113] 1H NMR(400MHz,Chloroform-d)δ8.71(d,J=4.6Hz,1H),8.00(d,J=9.2Hz,1H),7.42(d,J=2.7Hz,1H),7.36(dd,J=9 .2,2.7Hz,1H),7.31(d,J=4.5Hz,1H),6.54(d,J=6.8Hz,1H),3.96(s,3H),3.69(q,J=7.0Hz,1H),3.31–3.24(m, 1H),2.93(dd,J=13.8,8.4Hz,1H),2.80(ddt,J=12.5,9.6,2.7Hz,1H),2.75–2.66(m,2H),2.65–2.56(m,1H),1. 84–1.76(m,1H),1.74(d,J=4.7Hz,1H),1.61–1.40(m,6H),1.19(dd,J=12.6,7.0Hz,7H),0.91(t,J=7.1Hz,3H). 13 C NMR(101MHz,Chloroform-d)δ175.98,158.09,147.44,144.81,144.15,131.81,127.15,122.14,118.51,101.46,73. 28,59.18,55.78,50.71,49.86,37.35,34.34,27.08,26.23,25.50,23.29,18.99(d,J=4.0Hz),18.56,12.08.MS-ESI m / z:397.2538[M+H] + .

[0114] Test Example 1: Determination and Results of the Anti-Agricultural Pathogenic Bacteria Activity of Cinchonaine Derivatives

[0115] 1) Test reagents: Cinchona alkaloid derivatives K1~K15.

[0116] 2) Test strains: Xanthomonas oryzae ACCC 11602, the pathogen of rice bacterial blight, and Xanthomonas axonopodis pv. Citri, the pathogen of citrus canker, were provided by Guangxi Tianyuan Biochemical Co., Ltd. They are common pathogens of bacterial blight or citrus canker. Other strains may also be used.

[0117] 3) Antibacterial activity test:

[0118] 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 NA solid medium (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℃ until single colonies appeared. Single colonies from the solid medium were transferred to NB liquid medium (beef extract: 3g, peptone: 5g, yeast extract: 1g, sucrose: 10g, distilled water: 1L; sterilized at 121℃ for 20min) and incubated on a shaker at 28℃ and 180 rpm until the logarithmic growth phase was reached. The strains in the logarithmic growth phase were diluted with NB liquid medium to approximately 10... 6 Prepare CFU / mL solution. Dissolve compounds K1–K15 separately in DMSO, add them to 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°C for 24–48 h until the control bacterial culture became turbid. The OD value (OD) of the bacterial culture in each well was then 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:

[0119] Corrected OD value = OD value of bacterial culture medium - OD value of sterile culture medium;

[0120] 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%

[0121] All experiments were conducted in triplicate, and the inhibition rates of the compounds were measured and are shown in Table 1.

[0122] Table 1. Inhibition rate (%) of cinchona alkaloid derivatives against plant pathogenic bacteria at 100 μg / mL

[0123]

[0124]

[0125] As shown in Table 1, the cinchona alkaloid derivatives involved in this invention exhibit good antibacterial activity against *Bacillus oryzae*, the causal agent of rice bacterial blight, and *Citrus canker*, with some compounds showing high activity, especially K1-K11. Compared with the parent compounds quinine, hydroquinine, quinidine, cinchona alkaloid, and hydroquinidine, the antibacterial activity was significantly improved, especially against *Citrus canker*.

[0126] The drug-containing liquid culture medium was diluted in 96-well plates using a two-fold dilution method to obtain a series of 50 μL drug-containing media of different concentrations. The inhibition rates corresponding to these concentrations were then determined using the same experimental method described above. All experiments were performed in triplicate, and the MIC of the compound was determined. 90 The values ​​(the minimum drug concentration that inhibits 90% bacterial growth) are shown in Table 2.

[0127] Table 2. MIC90 (μg / mL) of cinchona alkaloid derivatives K1-K15 against plant pathogenic bacteria in vitro.

[0128]

[0129]

[0130] As shown in Table 2, the cinchonaine derivatives K1-K15 of this invention exhibited varying degrees of inhibitory activity against two plant pathogenic bacteria. K2, K10, and K11 all achieved a minimum inhibitory concentration (MIC90) of 6.25 μg / mL against *Bacillus thuringiensis*, the causal agent of rice bacterial blight, and *Bacillus canker*, the causal agent of citrus canker. K5, K6, and K9 also showed relatively superior antibacterial activity. These derivatives are significantly superior to the control drugs thiabendazole and thiabendazole copper, demonstrating a significant improvement in antibacterial activity compared to the parent compounds. These derivatives are readily available and easy to synthesize. The antibacterial activity of the hydrogenated quinidine aromatic ester compounds is significantly higher than that of the control drugs thiabendazole and thiabendazole copper, avoiding the complex preparation processes of other derivatives. This indicates that these compounds have potential for further development and are expected to become novel agricultural antibacterial agents.

[0131] The preparation methods of the dosage forms in the following formulation examples of the present invention are as follows:

[0132] The preparation method of the suspending agent is as follows: Weigh the wetting agent, dispersant, antifreeze, preservative, defoamer and deionized water according to the ratio and add them to the beaker. Mix them evenly, add the cinchona alkaloid derivative to the beaker, and then transfer it to a sand mill. Grind in the sand mill for 2-3 hours, add the thickener and continue grinding for 0.5 hours to control the particle size D95 to below 5 micrometers. Filter to obtain the suspending agent.

[0133] The laboratory preparation method of oil suspension is as follows: Weigh the dispersant, wetting agent, emulsifier, defoamer and solvent according to the ratio and add them to the beaker. Mix them evenly, add the cinchona alkaloid derivative to the beaker, and then transfer it to a sand mill for grinding for 2-3 hours. Add the thickener and continue grinding for 0.5 hours to control the particle size D95 to below 5 micrometers. Filter to obtain the suspension.

[0134] The preparation method of the dry suspension is as follows: Weigh the wetting agent, dispersant, filler and water according to the ratio, add them to a beaker and mix evenly. Then add the cinchona alkaloid derivative to the beaker, transfer it to a sand mill and grind for 2-3 hours to achieve a particle size D. 95 By controlling the micrometer size to below 5 micrometers, filtering the resulting material, and then drying it in a spray dryer, the desired product can be obtained.

[0135] The preparation method of wettable powder is as follows: weigh out the cinchona alkaloid derivative, wetting agent, dispersant and filler according to the ratio, add them to the mixer and mix evenly, and then pulverize them in an air jet mill to obtain the powder.

[0136] The preparation method of water-dispersible granules is as follows: weigh out the cinchona alkaloid derivative, wetting agent, dispersant, disintegrant, slow-release agent and filler according to the ratio, add them to the mixer and mix evenly, then put them into an air jet mill for pulverization, mix them again with a mixer, add an appropriate amount of water, and granulate them by extrusion with a granulator to obtain the final product.

[0137] The emulsifiable concentrate is prepared by weighing cinchona alkaloid derivative, emulsifier, solvent and filler according to the formula, adding them to a beaker and mixing them evenly.

[0138] Formulation Example 1: 20% Compound K10 Suspension

[0139] Compound K10 20%, nonylphenol polyoxyethylene ether 3%, alkyl naphthalene sulfonate 4%, calcium dodecylbenzene sulfonate 1.5%, ethylene glycol 2%, xanthan gum 1.2%, benzoic acid 1%, organosilicon 0.3%, water to make up to 100%.

[0140] Formulation Example 2: 60% Compound K10 Water Dispersible Granules

[0141] Compound K10 60%, sodium naphthalene sulfonate 3.4%, alkylphenol polyoxyethylene ether formaldehyde condensate 3.6%, sodium lignosulfonate 1.4%, modified starch 5%, sodium sulfate 4.2%, bentonite to make up 100%.

[0142] Formulation Example 3: 20% Compound K11 Suspension

[0143] Compound K11 20%, high molecular weight carboxylate 4.2%, EO-PO block polymer 1.8%, alkyl naphthalene sulfonate 2.6%, glycerol 2%, magnesium aluminum silicate 1.3%, Kathon 1%, organosilicon 0.5%, water to make up to 100%.

[0144] Formulation Example 4: 40% Compound K9 Wettable Powder

[0145] Compound K9 40%, sodium naphthalene sulfonate formaldehyde condensate 5%, sodium lignosulfonate 2%, silica 1%, kaolin to make up 100%.

[0146] Formulation Example 5: 10% Compound K5 Dry Suspension

[0147] Compound K5 10%, sodium dodecylbenzenesulfonate 2%, sodium naphthalenesulfonic acid formaldehyde condensate 3.8%, corn starch to make up to 100%.

[0148] Formulation Example 6: 30% Compound K6 Oil Suspension

[0149] Compound K6 30%, alkylbenzene polyoxyethylene ether phosphate 2%, sodium polycarboxylate 3%, calcium dodecylbenzene sulfonate 2%, organosilicon 1.8%, hydroxyethyl cellulose 2.6g, sodium benzoate 2%, N,N-dimethylformamide to make up to 100%.

[0150] Formulation Example 7: 50% Compound K2 Water Dispersible Granules

[0151] Compound K2 50%, BX 3%, sodium dodecylbenzenesulfonate 2%, alkylphenol polyoxyethylene ether formaldehyde condensate 3.6%, modified starch 5%, ammonium sulfate 4%, diatomaceous earth 6%, bentonite to make up 100%.

[0152] Formulation Example 8: 20% Compound K3 Emulsifiable Concentrate

[0153] Compound K3 20%, alkylphenol polyoxyethylene ether 5%, calcium dodecylbenzenesulfonate 3.5%, cyclohexanone 10%, xylene to make up 100%.

[0154] V. Efficacy test of pesticides for controlling rice bacterial leaf blight:

[0155] Test reagents: 50% of compound K2 water-dispersible granules of formulation example 7, 20% of compound K3 emulsifiable concentrate of formulation example 8, 10% of compound K5 dry suspension of formulation example 5, 30% of compound K6 oil suspension of formulation example 6, 40% of compound K9 wettable powder of formulation example 4, 20% of compound K10 suspension of formulation example 1, and 20% of compound K11 suspension of formulation example 3.

[0156] Control agent: 20% thiabendazole copper suspension, registration certificate PD20086024, Zhejiang Longwan Chemical Co., Ltd., purchased from the market.

[0157] Experimental Design: The experiment included 8 treatments, with leaves dipped in the fungicide and then sprayed with water (CK1). There were a total of 9 treatments, with each treatment replicated 3 times, for a total of 27 plots, each plot being 2.16 m². 2 72 seedlings were planted. Each plot was arranged in a randomized block design with a spacing of more than 40 cm between plots and a protective row around the plots. No other fungicides were sprayed during the experiment.

[0158] The inoculum concentration was 3×10⁻⁶. 8 CFU / mL, 72 seedlings were inoculated in each plot on October 7, 2023. The first spraying was on the afternoon of October 8 (24 hours after artificial inoculation), and the second spraying was on the afternoon of October 15. At the time of the first spraying, sporadic cases of rice bacterial leaf disease were present. The water volume for each spraying was 50 kg / 667 m². 2 Apply the pesticide using a 3WBD-20L backpack manual sprayer.

[0159] No other fungicides were applied during the trial, which was conducted on October 22, 2023. Five samples were taken from each plot, and six seedlings were randomly surveyed at each sample point, for a total of 30 seedlings. The disease status of the upper two functional leaves of each seedling was graded.

[0160] The grading criteria are as follows:

[0161] Level 0: No symptoms;

[0162] Grade 1: Leaf lesions cover less than 10% of the leaf area;

[0163] Grade 3: Leaf lesions cover 11-25% of the leaf area;

[0164] Level 5: Leaf lesions cover 26-45% of the leaf area;

[0165] Level 7: Leaf lesions cover 46-65% of the leaf area;

[0166] Level 9: Leaf lesions cover more than 65% of the leaf area.

[0167] Disease index (%) = [∑(number of diseased leaves at each level × representative value at each level) / (total number of leaves surveyed × highest representative value)] × 100.

[0168] Relative efficacy (%) = (Control disease index - Treatment disease index) / Control disease index × 100.

[0169] The results are shown in Table 3.

[0170] Table 3. Results of field efficacy trials for controlling rice bacterial blight.

[0171] Test reagents Dosage for formulation (g / mu) Disease index Relative efficacy (%) % of synergistic effect compared to control 50% Compound K2 Water Dispersible Granules 50 0.37 92.00 29.33 20% Compound K3 Emulsifiable Oil 120 1.42 69.33 6.67 10% Compound K5 Dry Suspension 250 1.11 76.00 13.33 30% compound K6 oil suspension 120 1.05 77.33 14.67 40% Compound K9 Wettable Powder 90 0.99 78.67 16.00 20% Compound K10 Suspension 120 0.56 88.00 25.33 20% Compound K11 Suspension 120 0.49 89.33 26.67 20% Thiamethoxam Copper Suspension 180 1.73 62.67 Blank control / 4.63 / /

[0172] As shown in Table 3 above, the formulations containing cinchona alkaloid derivatives of this invention, such as 20% compound K3 emulsifiable concentrate, exhibit 6%-29.33% higher efficacy against rice bacterial blight than the control agent 20% thiabendazole copper suspension. In particular, the efficacy of compounds K2, K10, and K11 is increased by more than 25%. In summary, the cinchona alkaloid derivatives demonstrate superior antibacterial effects both in indoor and field efficacy trials compared to the conventional agent 20% thiabendazole copper suspension. This compound has potential for further development and may become a novel agricultural antibacterial agent.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The application of a cinchona alkaloid derivative in the preparation of pesticide formulations for the control of rice bacterial blight and / or citrus canker, wherein the cinchona alkaloid derivative is selected from compounds of any of formulas K2-K7 and K9-K11, or their pharmaceutically acceptable salts or tautomers: 。 2. The application according to claim 1, characterized in that, Pesticide formulations were prepared using cinchona alkaloid derivatives with any of the structural formulas K2~K7 and K9~K11.

3. The application according to claim 2, characterized in that, Pesticide formulations also include agronomically acceptable carriers.

4. The application according to claim 2, characterized in that, The weight percentage of cinchona alkaloid derivatives in pesticide formulations ranges from 1% to 99%.

5. The application according to claim 2, characterized in that, The pesticide formulation is a suspension concentrate.

6. The application according to claim 2, characterized in that, The pesticide formulation is in the form of a dry suspension, an oil suspension, a wettable powder, or a water-dispersible granule.

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