Pyridine ester compound containing urea structure as well as preparation method and application of pyridine ester compound

Abstract

The invention provides a pyridine ester compound containing a urea structure as well as a preparation method and application of the pyridine ester compound, and belongs to the technical field of chemical molluscicides. The pyridine ester compound containing the urea structure, provided by the invention, has a good killing effect on ampullaria gigas, is almost non-toxic to non-target organisms, and is environment-friendly. Results of the embodiment show that the pyridine ester compounds with the structures shown as D-1-D-15 provided by the invention have certain molluscicide activity as molluscicide, the molluscicide activity of D-1, D-2, D-3, D-6, D-7 and D-8 on pomacea canaliculata is similar to that of niclosamide after soaking for 72 hours, that is, the death rate of the pomacea canaliculata after 72 hours is more than 87.5% of that of niclosamide under the drug concentration of 2mg / L, and the pomacea canaliculata molluscicide can be used for preparing the molluscicide for the pomacea canaliculata molluscicide. And compared with niclosamide, the fish poison is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical molluscicides, and particularly relates to a pyridine ester compound containing a urea structure, a preparation method and an application thereof. Background Art

[0002] The golden apple snail, also known as the apple snail and the large bottle snail, is a large freshwater snail native to the Amazon Basin in South America. As an alien species, the golden apple snail has a strong adaptability to the environment, thus causing irreparable damage to agricultural production and ecology. Today, when food security is becoming increasingly important, the management of the golden apple snail is imminent.

[0003] Niclosamide is a chemical molluscicide introduced in 1972 and widely used to kill Oncomelania hupensis, but it is highly toxic to non-target aquatic animals, especially fish. In recent years, some plant extracts have also been used to kill golden apple snails, but they are difficult to extract and difficult to mass produce. Recently, golden apple snails have also been controlled by biological and physical methods, such as introducing natural enemies (such as ducks).

[0004] However, the above methods are usually highly toxic or time-consuming and labor-intensive, and it is difficult to eradicate the problem of golden apple snail infestation. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a pyridine ester compound containing a urea structure and a preparation method and application thereof. The pyridine ester compound containing a urea structure provided by the present invention has a good killing effect on Pomacea canaliculata and is almost non-toxic to non-target organisms, and is environmentally friendly; at the same time, the preparation method of the present invention is simple.

[0006] The present invention provides a pyridine ester compound containing a urea structure, having a structure shown in any one of Formulas I to III. The pyridine ester compound containing a urea structure provided by the present invention has a good killing effect on golden apple snails and is almost non-toxic to non-target organisms, and is environmentally friendly. The results of the embodiments show that the pyridine ester compounds with structures shown in D-1 to D-15 provided by the present invention have certain molluscicidal activity as molluscicides, among which D-1, D-2, D-3, D-6, D-7, and D-8 have a molluscicidal activity against golden apple snails similar to that of niclosamide after 72 hours of immersion, that is, at a drug concentration of 2 mg / L, the snail mortality rate after 72 hours is more than 87.5% of that of niclosamide, and the fish toxicity is significantly reduced compared with niclosamide.

[0007] The present invention provides a method for preparing the pyridine ester compound described in the above scheme. The preparation method provided by the present invention is simple, has a high yield (>65.2%), and a high purity (>95%). BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0009] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the product D-1 obtained in Example 1 of the present invention; Figure 2 This is the carbon NMR spectrum of the product D-1 obtained in Example 1 of the present invention; Figure 3 This is the high-resolution mass spectrum of the product D-1 obtained in Example 1 of the present invention; Figure 4 This is the hydrogen nuclear magnetic resonance spectrum of the product D-2 obtained in Example 2 of the present invention; Figure 5 This is the carbon NMR spectrum of the product D-2 obtained in Example 2 of the present invention; Figure 6 This is the high-resolution mass spectrum of the product D-2 obtained in Example 2 of the present invention; Figure 7 This is the hydrogen nuclear magnetic resonance spectrum of the product D-3 obtained in Example 3 of the present invention; Figure 8 This is the carbon NMR spectrum of the product D-3 obtained in Example 3 of the present invention; Fig. 9 This is the high-resolution mass spectrum of the product D-3 obtained in Example 3 of the present invention; Fig.10 This is the hydrogen nuclear magnetic resonance spectrum of the product D-4 obtained in Example 4 of the present invention; Fig.11 This is the carbon NMR spectrum of the product D-4 obtained in Example 4 of the present invention; Fig.12 This is the high-resolution mass spectrum of the product D-4 obtained in Example 4 of the present invention; Fig.13 This is the hydrogen nuclear magnetic resonance spectrum of the product D-5 obtained in Example 5 of the present invention; Fig.14 This is the carbon NMR spectrum of the product D-5 obtained in Example 5 of the present invention; Fig.15 This is the high-resolution mass spectrum of the product D-5 obtained in Example 5 of the present invention; Fig.16 This is the hydrogen nuclear magnetic resonance spectrum of the product D-6 obtained in Example 6 of the present invention; Fig.17 This is the carbon NMR spectrum of the product D-6 obtained in Example 6 of the present invention; Fig.18This is the high-resolution mass spectrum of the product D-6 obtained in Example 6 of the present invention; Fig.19 This is the hydrogen nuclear magnetic resonance spectrum of the product D-7 obtained in Example 7 of the present invention; Fig. 20 This is the carbon NMR spectrum of the product D-7 obtained in Example 7 of the present invention; Fig.21 This is the high-resolution mass spectrum of the product D-7 obtained in Example 7 of the present invention; Fig. 22 This is the hydrogen nuclear magnetic resonance spectrum of the product D-8 obtained in Example 8 of the present invention; Fig.23 This is the carbon NMR spectrum of the product D-8 obtained in Example 8 of the present invention; Fig.24 This is the high-resolution mass spectrum of the product D-8 obtained in Example 8 of the present invention; Fig.25 This is the hydrogen nuclear magnetic resonance spectrum of the product D-9 obtained in Example 9 of the present invention; Fig.26 This is the carbon NMR spectrum of the product D-9 obtained in Example 9 of the present invention; Fig. 27 This is the high-resolution mass spectrum of the product D-9 obtained in Example 9 of the present invention; Fig.28 This is the hydrogen nuclear magnetic resonance spectrum of the product D-10 obtained in Example 10 of the present invention; Fig.29 This is the carbon NMR spectrum of the product D-10 obtained in Example 10 of the present invention; Fig.30 This is the high-resolution mass spectrum of the product D-10 obtained in Example 10 of the present invention; Fig.31 This is the hydrogen nuclear magnetic resonance spectrum of the product D-11 obtained in Example 11 of the present invention; Fig.32 This is the carbon NMR spectrum of the product D-11 obtained in Example 11 of the present invention; Fig.33 This is the high-resolution mass spectrum of the product D-11 obtained in Example 11 of the present invention; Fig.34 This is the hydrogen nuclear magnetic resonance spectrum of the product D-12 obtained in Example 12 of the present invention; Fig.35 This is the carbon NMR spectrum of the product D-12 obtained in Example 12 of the present invention; Fig.36 This is the high-resolution mass spectrum of the product D-12 obtained in Example 12 of the present invention; Fig.37 This is the hydrogen nuclear magnetic resonance spectrum of the product D-13 obtained in Example 13 of the present invention; Fig.38This is the carbon NMR spectrum of the product D-13 obtained in Example 13 of the present invention; Fig.39 This is the high-resolution mass spectrum of the product D-13 obtained in Example 13 of the present invention; Fig.40 This is the hydrogen nuclear magnetic resonance spectrum of the product D-14 obtained in Example 14 of the present invention; Fig.41 This is the carbon NMR spectrum of the product D-14 obtained in Example 14 of the present invention; Fig.42 This is the high-resolution mass spectrum of the product D-14 obtained in Example 14 of the present invention; Fig.43 This is the hydrogen nuclear magnetic resonance spectrum of the product D-15 obtained in Example 15 of the present invention; Fig.44 This is the carbon NMR spectrum of the product D-15 obtained in Example 15 of the present invention; Fig.45 This is the high-resolution mass spectrum of the product D-15 obtained in Example 15 of the present invention. DETAILED DESCRIPTION

[0010] The present invention provides a pyridine ester compound containing a urea structure, having a structure shown in any one of Formulas I to III: Formula I; Formula II; Formula III; In Formula I, R 1 is -Br, -Cl, -F or -OCH 3 , R 2 is -H or -Cl; In Formula II, R 3 is -Br, -Cl, -F or -OCH 3 , R 4 is -H or -Cl; In Formula III, R 5 -Br, -Cl, -F, -OCH 3 or -H,R 6 It is -H or -Cl.

[0011] In the present invention, the pyridine ester compound preferably has a structure shown in any one of the following D-1 to D-15: D-1; D-2; D-3; D-4; D-5; D-6; D-7; D-8; D-9; D-10; D-11; D-12; D-13; D-14; D-15.

[0012] The urea-structured pyridine ester compound provided by the present invention has a good killing effect on Pomacea canaliculata and is almost non-toxic to non-target organisms, and is environmentally friendly.

[0013] The present invention provides a method for preparing the pyridine ester compound described in the above scheme, comprising the following steps: 2-amino-3-hydroxypyridine, halogenated phenyl isocyanate and a first polar organic solvent are first mixed and subjected to a nucleophilic addition reaction to obtain a hydroxypyridine compound containing a urea structure; the halogenated phenyl isocyanate includes 4-chlorophenyl isocyanate, 4-bromophenyl isocyanate or 3,4-dichlorophenyl isocyanate; the hydroxypyridine compound containing a urea structure has a structure shown in any one of formulas a to c; Formula a; Formula b; Formula c; The urea-containing hydroxypyridine compound, the aryl-substituted acyl chloride, the acid-binding agent and the second polar organic solvent are mixed for a second time, and an esterification reaction is performed to obtain a pyridine ester compound having a structure shown in Formula I to Formula III; the aryl-substituted acyl chloride has a structure shown in any one of Formulas d to f; Formula d; Formula e; Formula f; When the urea-containing hydroxypyridine compound is of the structural formula a, the aromatic substituted acyl chloride is of the structural formula d; When the urea-containing hydroxypyridine compound is of the structural formula shown in formula b, the aromatic substituted acyl chloride is of the structural formula shown in formula e; When the urea-containing hydroxypyridine compound is of the structural formula shown in formula c, the aromatic substituted acyl chloride is of the structural formula shown in formula f.

[0014] Unless otherwise specified, the materials and equipment used in the present invention are commercially available products.

[0015] The invention first mixes 2-amino-3-hydroxypyridine, halogenated phenyl isocyanate and a first polar organic solvent, and performs a nucleophilic addition reaction to obtain a hydroxypyridine compound containing a urea structure.

[0016] In the present invention, the halogenated phenyl isocyanate includes 4-chlorophenyl isocyanate, 4-bromophenyl isocyanate or 3,4-dichlorophenyl isocyanate; and the first polar organic solvent preferably includes dichloromethane.

[0017] In the present invention, the temperature of the nucleophilic addition reaction is preferably room temperature; the time of the nucleophilic addition reaction is preferably 5 to 7 hours, and in the embodiments of the present invention, specifically can be 5 hours, 6 hours or 7 hours.

[0018] In the present invention, the molar ratio of the 2-amino-3-hydroxypyridine to the halogenated phenyl isocyanate is preferably 1:(1-1.2), and in the embodiments of the present invention, it can be specifically 1:1 or 1:1.2; the molar ratio of the 2-amino-3-hydroxypyridine to the first polar organic solvent is preferably 1 mmol:10 mL.

[0019] After the nucleophilic addition reaction is completed, the present invention preferably filters the obtained reaction solution to obtain the hydroxypyridine compound containing a urea structure.

[0020] After obtaining the hydroxypyridine compound containing a urea structure, the present invention secondly mixes the hydroxypyridine compound containing a urea structure, an aryl-substituted acyl chloride, an acid-binding agent and a second polar organic solvent to carry out an esterification reaction to obtain a pyridine ester compound having a structure shown in Formula I to Formula III.

[0021] In the present invention, the second mixing preferably includes: mixing the hydroxypyridine compound containing a urea structure, an acid binding agent and a second polar organic solvent, and then dropping an acyl chloride substituted with an aromatic group. In the present invention, the time for mixing the hydroxypyridine compound containing a urea structure, an acid binding agent and a second polar organic solvent is preferably 1 hour, and the temperature is preferably room temperature. Before dropping the acyl chloride substituted with an aromatic group, the present invention preferably cools the obtained reaction solution to 0-5°C. In the present invention, the time for dropping is preferably 10 minutes. The present invention preferably drops the acyl chloride substituted with an aromatic group after heating at a low temperature. The present invention has no special requirements for the heating temperature, as long as the acyl chloride substituted with an aromatic group can be melted.

[0022] In the present invention, the acid-binding agent preferably includes triethylamine; the second polar organic solvent preferably includes dichloromethane. In the present invention, the molar ratio of the hydroxypyridine compound containing a urea structure to the aryl-substituted acid chloride is preferably 1: (1-1.2), and in the embodiment of the present invention, it can be specifically 1: 1 or 1: 1.2; the molar ratio of the hydroxypyridine compound containing a urea structure to the acid-binding agent is preferably 1: (1.8-2), and in the embodiment of the present invention, it can be specifically 1: 1.8 or 1: 2. In the present invention, the molar amount of the hydroxypyridine compound containing a urea structure and the volume ratio of the second polar organic solvent are preferably 1 mmol: 10 mL.

[0023] In the present invention, the temperature of the esterification reaction is preferably room temperature; the time of the esterification reaction is preferably 1 to 1.5 hours, and in the embodiments of the present invention, it can be 1 hour, 1.2 hours or 1.5 hours. In the present invention, the time of the esterification reaction is preferably calculated from the completion of the dropwise addition of the aryl-substituted acyl chloride.

[0024] After the esterification reaction is completed, the present invention preferably quenches the reaction with water, and then post-treats the resulting mixture. In the present invention, the post-treatment preferably includes: extracting the mixture with dichloromethane, washing the organic phase with saturated brine, and then drying, concentrating under reduced pressure and recrystallizing in sequence to obtain the pyridine ester compound. In the present invention, the number of dichloromethane extractions is preferably three times, and the amount of solvent each time is preferably 10 mL; the number of washings is preferably three times; the drying is preferably carried out with anhydrous sodium sulfate; and the solvent for recrystallization is preferably ethanol. The present invention has no special requirements for the post-treatment method, and the method well known in the art can be used.

[0025] The preparation method provided by the invention is simple, has high yield (>65.2%) and high purity (>95%).

[0026] The present invention provides the use of the pyridine ester compound described in the above scheme or the pyridine ester compound prepared by the preparation method described in the above scheme as a molluscicide in killing Pomacea canaliculata snails.

[0027] The results of the examples show that the pyridine ester compounds with structures shown in D-1 to D-15 provided by the present invention all have certain molluscicidal activity as molluscicidal agents, among which the molluscicidal activity of D-1, D-2, D-3, D-6, D-7, and D-8 against Pomacea canaliculata snails after immersion for 72 hours is similar to that of niclosamide, that is, at a drug concentration of 2 mg / L, the snail mortality rate after 72 hours is more than 87.5% of that of niclosamide, and the fish toxicity is significantly reduced compared with niclosamide.

[0028] In order to further illustrate the present invention, a urea-containing pyridine ester compound provided by the present invention and its preparation method and application are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0029] Example 1 According to the chemical reaction equation shown in Formula 1, R 1 -Br, R 2-H; at room temperature, add 2-amino-3-hydroxypyridine (1 mmol, 110 mg) and 4-chlorophenyl isocyanate (1 mmol, 154 mg) to a 50 mL single-necked flask, dissolve in 10 mL of dichloromethane and stir for 6 h. After the reaction is completed, filter to obtain an off-white solid LA, i.e., a hydroxypyridine compound containing a urea structure, formula a, which can be directly carried out to the next step without purification; A 50 mL single-necked flask was charged with off-white solid LA compound (1 mmol) and triethylamine (1.8 mmol, 0.25 mL) in anhydrous CH 2 C1 2 The mixture was stirred at room temperature for 1 h, and then the reaction solution was cooled to (0-5 °C), and 4-bromobenzoyl chloride (1 mmol) was slowly added dropwise. The 4-bromobenzoyl chloride was melted at low temperature and then added dropwise. The dripping was completed within 10 min. The mixture was stirred at room temperature for another 1 h, and then quenched with 5 mL of water. The resulting mixture was quenched with CH 2 C1 2 The extraction was performed three times (10 mL of solvent each time), and the organic phase was washed three times with saturated brine, then dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain a crude product, which was recrystallized from ethanol to obtain the target product, a pyridine ester compound LB, recorded as D-1 (purity > 95%).

[0030] Formula 1; D-1 is a white powdery solid with a yield of 75.5%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 1 to 3 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.63 (s, 1H), 9.74 (s, 1H), 8.32 (dd, J =4.9, 1.6 Hz, 1H), 8.07 (d, J = 8.6 Hz, 2H), 7.82 (d, J = 8.7 Hz, 3H), 7.61 (d, J =8.9 Hz, 2H), 7.37 (d, J = 8.8 Hz, 2H), 7.24 – 7.19 (m, 1H); 13 C NMR (101 MHz, DMSO- d 6) δ 164.24, 152.39, 146.31, 144.28, 138.21, 135.30, 133.28, 132.61,132.17, 131.88, 130.61, 129.15, 129.10, 128.95, 128.32, 126.84, 121.39,118.66, 115.61; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 14 O 3 N 3 BCI + , 455.9907;found, 455.9899.

[0031] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-1, and its structure is shown in D-1 above.

[0032] Example 2 The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, R 1 -Cl, R 2 The target product, pyridine ester compound LB, was obtained and recorded as D-2 (purity> 95%).

[0033] D-2 is a white powdery solid with a yield of 85.6%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 4 to 6 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.62 (s, 1H), 9.77 (s, 1H), 8.33 (dd, J =4.9, 1.6 Hz, 1H), 8.16 (t, J = 1.9 Hz, 1H), 8.09 (dt, J = 7.8, 1.3 Hz, 1H), 7.84(d, J = 8.0 Hz, 2H), 7.74 – 7.54 (m, 3H), 7.48 – 7.29 (m, 2H), 7.22 (dd, J = 8.0,4.9 Hz, 1H); 13 C NMR (101 MHz, DMSO-d 6 ) δ 163.71, 152.41, 146.25, 144.36,138.21, 135.27, 134.02, 133.72, 133.30, 131.88, 131.08, 130.25, 129.27,129.15, 126.84, 121.40, 118.68; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 14 O 3 N 3 CI 2 + ,402.0412; found, 402.0411.

[0034] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-2, and its structure is shown in D-2 above.

[0035] Example 3 The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, R 1 OCH 3 , R 2 The target product, pyridine ester compound LB, was obtained and recorded as D-3 (purity> 95%).

[0036] D-3 is a white powdery solid with a yield of 69.2%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 7-9 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 11.55 (s, 1H), 9.61 (s, 1H), 8.31 (dd, J= 5.0, 1.6 Hz, 1H), 8.21 – 8.01 (m, 2H), 7.77 (dd, J = 8.0, 1.6 Hz, 1H), 7.67– 7.54 (m, 2H), 7.39 – 7.31 (m, 2H), 7.20 (dd, J = 8.0, 5.0 Hz, 1H), 7.16 –7.09 (m, 2H), 3.88 (s, 3H); 13C NMR (101 MHz, DMSO-d6) δ 164.37, 164.17,152.37, 146.38, 144.01, 138.28, 135.72, 133.21, 132.98, 129.14, 126.77,121.71, 121.33, 118.73, 114.37, 56.13; HR-MS (ESI), m / z: [M+H]+ calcd forC 20 H 17 O 4 N 3 Cl + , 398.0902; found, 398.0908.

[0037] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-3, whose structure is shown in D-3 above.

[0038] Example 4 The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, R 1 -Cl, R 2 The target product, pyridine ester compound LB, was obtained and recorded as D-4 (purity> 95%).

[0039] D-4 is a white powdery solid with a yield of 70.3%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 10-12 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.71 (s, 1H), 9.84 (s, 1H), 8.34 (dd, J =5.0, 1.6 Hz, 1H), 8.15 (d, J = 8.6 Hz, 2H), 7.95 (d, J = 2.1 Hz, 1H), 7.83 (dd, J =8.0, 1.6 Hz, 1H), 7.68 (d, J = 8.6 Hz, 2H), 7.59 – 7.50 (m, 2H), 7.23 (dd, J =8.0, 4.9 Hz, 1H); 13C NMR (101 MHz, DMSO- d 6 ) δ 164.02, 152.42, 146.07, 144.38,139.47, 139.21, 135.49, 133.40, 132.49, 131.53, 131.06, 129.22, 128.71,124.61, 120.97, 119.95, 118.92; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 13 O 3 N 3 CI 3 + ,436.0022; found, 436.0022.

[0040] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-4, whose structure is shown in D-4 above.

[0041] Example 5 The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, R 1 For -F, R 2 The target product, pyridine ester compound LB, was obtained and recorded as D-5 (purity> 95%).

[0042] D-5 is a white powdery solid with a yield of 68.2%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 13-15 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.62 (s, 1H), 9.73 (s, 1H), 8.32 (dd, J =5.0, 1.6 Hz, 1H), 8.22 (dd, J = 8.8, 5.5 Hz, 2H), 7.81 (dd, J = 8.0, 1.6 Hz, 1H),7.61 (d, J = 8.9 Hz, 2H), 7.44 (t, J = 8.8 Hz, 2H), 7.37 (d, J= 8.8 Hz, 2H), 7.21(dd, J = 8.0, 4.9 Hz, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 164.66, 163.90, 152.40,146.35, 144.23, 138.23, 135.37, 133.74, 133.65, 133.30, 129.16, 128.96,126.83, 126.44, 126.41, 121.39, 118.67, 116.31, 116.09, 115.61; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 14 O 3 N 3 FCI + , 386.0708; found, 386.0704.

[0043] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-5, and its structure is shown in D-5 above.

[0044] Example 6 According to the chemical reaction equation shown in Formula 2, R 3 -Br, R 4 -H; at room temperature, add 2-amino-3-hydroxypyridine (1 mmol) and 4-bromophenyl isocyanate (1 mmol) to a 50 mL single-necked flask, dissolve in 10 mL of dichloromethane and stir for 6 h. After the reaction is completed, filter to obtain an off-white solid LA, that is, a hydroxypyridine compound containing a urea structure, formula b, which can be directly carried out to the next step without purification; A 50 mL single-necked flask was charged with off-white solid LA compound (1 mmol) and triethylamine (0.25 mL) in anhydrous CH 2 C1 2 The mixture was stirred at room temperature for 1 h, and then the reaction solution was cooled to (0-5 °C), and 4-bromobenzoyl chloride (1 mmol) was slowly added dropwise within 10 min. The mixture was stirred at room temperature for another 1 h, and then quenched with 5 mL of water. The resulting mixture was quenched with CH 2 C1 2 The extraction was performed three times (10 mL of solvent each time), and the organic phase was washed three times with saturated brine, then dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain a crude product, which was recrystallized from ethanol to obtain the target product, a pyridine ester compound LB, recorded as D-6.

[0045] Formula 2; D-6 is a white powdery solid with a yield of 75.2%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 16-18 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.63 (s, 1H), 9.74 (s, 1H), 8.32 (dd, J =4.9, 1.6 Hz, 1H), 8.07 (d, J = 8.6 Hz, 2H), 7.82 (d, J = 8.7 Hz, 3H), 7.61 (d, J =8.9 Hz, 2H), 7.37 (d, J = 8.8 Hz, 2H), 7.24 – 7.19 (m, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 164.24, 152.39, 146.31, 144.28, 138.21, 135.30, 133.28, 132.61,132.17, 131.88, 130.61, 129.15, 129.10, 128.95, 128.32, 126.84, 121.39,118.66, 115.61; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 14 O 3 N 3 Br 2 + , 489.9402;found, 489.9393.

[0046] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-5, whose structure is shown in D-6 above.

[0047] Example 7 The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, R 3 -Cl, R 4The target product, pyridine ester compound LB, was obtained and recorded as D-7 (purity> 95%).

[0048] D-7 is a white powdery solid with a yield of 75.3%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 19 to 21 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.62 (s, 1H), 9.77 (s, 1H), 8.33 (dd, J =4.9, 1.6 Hz, 1H), 8.16 (t, J = 1.9 Hz, 1H), 8.09 (dt, J = 7.8, 1.3 Hz, 1H), 7.84(d, J = 8.0 Hz, 2H), 7.74 – 7.54 (m, 3H), 7.48 – 7.29 (m, 2H), 7.22 (dd, J = 8.0,4.9 Hz, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 163.71, 152.41, 146.25, 144.36,138.21, 135.27, 134.02, 133.72, 133.30, 131.88, 131.08, 130.25, 129.27,129.15, 126.84, 121.40, 118.68; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 14 O 3 N 3 CI 2 + ,445.9907; found, 445.9899.

[0049] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-7, and its structure is shown in D-7 above.

[0050] Example 8 The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, R 3OCH 3 , R 4 The target product, pyridine ester compound LB, was obtained and recorded as D-8 (purity> 95%).

[0051] D-8 is a white powdery solid with a yield of 68.3%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 22-24 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 11.54 (s, 1H), 9.61 (s, 1H), 8.31 (dd, J= 4.9, 1.6 Hz, 1H), 8.17 – 8.09 (m, 2H), 7.77 (dd, J = 8.0, 1.6 Hz, 1H), 7.59– 7.52 (m, 2H), 7.52 – 7.44 (m, 2H), 7.20 (dd, J = 7.9, 4.9 Hz, 1H), 7.15 –7.10 (m, 2H), 3.88 (s, 3H); 13C NMR (101 MHz, DMSO-d6) δ 164.36, 164.16,152.34, 146.35, 144.03, 138.72, 135.76, 133.22, 132.97, 132.04, 121.70,118.77, 114.71, 114.38, 56.13; HR-MS (ESI), m / z: [M+H] + Calculate for C 20 H 17 O 4 N 3 Br + ,442.0397; found, 442.0399.

[0052] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-8, and its structure is shown in D-8 above.

[0053] Example 9 The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, R 3 -Cl, R 4 The target product, pyridine ester compound LB, was obtained and recorded as D-9 (purity> 95%).

[0054] D-9 is a white powdery solid with a yield of 75.2%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 25 to 27 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.71 (s, 1H), 9.84 (s, 1H), 8.34 (dd, J =5.0, 1.6 Hz, 1H), 8.15 (d, J = 8.6 Hz, 2H), 7.95 (d, J = 2.1 Hz, 1H), 7.83 (dd, J =8.0, 1.6 Hz, 1H), 7.68 (d, J = 8.6 Hz, 2H), 7.59 – 7.50 (m, 2H), 7.23 (dd, J =8.0, 4.9 Hz, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 164.02, 152.42, 146.07, 144.38,139.47, 139.21, 135.49, 133.40, 132.49, 131.53, 131.06, 129.22, 128.71,124.61, 120.97, 119.95, 118.92; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 13 O 3 N 3 BCI 2 + , 479.9517; found, 479.9512.

[0055] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-9, and its structure is shown in D-9 above.

[0056] Example 10 The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, R 3 For -F, R 4The target product, pyridine ester compound LB, was obtained and recorded as D-10 (purity> 95%).

[0057] D-10 is a white powdery solid with a yield of 65.2%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 28 to 30 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.62 (s, 1H), 9.73 (s, 1H), 8.32 (dd, J =5.0, 1.6 Hz, 1H), 8.22 (dd, J = 8.8, 5.5 Hz, 2H), 7.81 (dd, J = 8.0, 1.6 Hz, 1H),7.61 (d, J = 8.9 Hz, 2H), 7.44 (t, J = 8.8 Hz, 2H), 7.37 (d, J = 8.8 Hz, 2H), 7.21(dd, J = 8.0, 4.9 Hz, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 164.66, 163.90, 152.40,146.35, 144.23, 138.23, 135.37, 133.74, 133.65, 133.30, 129.16, 128.96,126.83, 126.44, 126.41, 121.39, 118.67, 116.31, 116.09, 115.61; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 14 O 3 N 3 FCI + , 386.0708; found, 386.0704.

[0058] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-10, and its structure is shown in D-10 above.

[0059] Embodiment 11 According to the chemical reaction equation shown in formula 3, R 5 -Br, R 6 -H; at room temperature, add 2-amino-3-hydroxypyridine (1 mmol) and 3,4-dichlorophenyl isocyanate (1 mmol) to a 50 mL single-necked flask, dissolve in 10 mL of dichloromethane and stir for 6 h. After the reaction is completed, filter to obtain an off-white solid LA, that is, a hydroxypyridine compound containing a urea structure, formula c, which can be directly carried out to the next step without purification; A 50 mL single-necked flask was charged with off-white solid LA compound (1 mmol) and triethylamine (0.25 mL) in anhydrous CH 2 C1 2 The mixture was stirred at room temperature for one hour, and then the reaction solution was cooled to (0-5°C), and 4-bromobenzoyl chloride (1 mmol) was slowly added dropwise within 10 min. The mixture was stirred at room temperature for another 1 h, and then quenched with 5 mL of water. The resulting mixture was quenched with CH 2 C1 2 The extraction was performed three times (10 mL of solvent each time), and the organic phase was washed three times with saturated brine, then dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain a crude product, which was recrystallized from ethanol to obtain the target product, a pyridine ester compound LB, recorded as D-11.

[0060] Formula 3; D-11 is a white powdery solid with a yield of 68.2%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 31-33 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.71 (s, 1H), 9.84 (s, 1H), 8.34 (dd, J =5.0, 1.6 Hz, 1H), 8.15 (d, J = 8.6 Hz, 2H), 7.95 (d, J = 2.1 Hz, 1H), 7.83 (dd, J =8.0, 1.6 Hz, 1H), 7.68 (d, J = 8.6 Hz, 2H), 7.59 – 7.50 (m, 2H), 7.23 (dd, J =8.0, 4.9 Hz, 1H); 13C NMR (101 MHz, DMSO- d 6 ) δ 164.02, 152.42, 146.07, 144.38,139.47, 139.21, 135.49, 133.40, 132.49, 131.53, 131.06, 129.22, 128.71,124.61, 120.97, 119.95, 118.92; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 13 O 3 N 3 BCI 2 + , 479.9517; found, 479.9512.

[0061] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-11, and its structure is shown in D-11 above.

[0062] Example 12 The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, R 5 -Cl, R 6 The target product, pyridine ester compound LB, was obtained and recorded as D-12 (purity> 95%).

[0063] D-12 is a white powdery solid with a yield of 75.5%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 34-36 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.71 (s, 1H), 9.84 (s, 1H), 8.34 (dd, J =5.0, 1.6 Hz, 1H), 8.15 (d, J = 8.6 Hz, 2H), 7.95 (d, J = 2.1 Hz, 1H), 7.83 (dd, J =8.0, 1.6 Hz, 1H), 7.68 (d, J= 8.6 Hz, 2H), 7.59 – 7.50 (m, 2H), 7.23 (dd, J =8.0, 4.9 Hz, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 164.02, 152.42, 146.07, 144.38,139.47, 139.21, 135.49, 133.40, 132.49, 131.53, 131.06, 129.22, 128.71,124.61, 120.97, 119.95, 118.92; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 13 O 3 N 3 CI 3 + ,436.0022; found, 436.0013.

[0064] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-12, and its structure is shown in D-12 above.

[0065] Example 13 The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, R 5 OCH 3 , R 6 The target product, pyridine ester compound LB, was obtained and recorded as D-13 (purity> 95%).

[0066] D-13 is a white powdery solid with a yield of 68.5%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 37-39 The structural characterization data are as follows: 1H NMR (400 MHz, DMSO-d6) δ 11.62 (s, 1H), 9.71 (s, 1H), 8.32 (dd, J= 4.9, 1.6 Hz, 1H), 8.15 – 8.08 (m, 2H), 7.95 (d, J = 2.1 Hz, 1H), 7.78 (dd,J = 8.0, 1.6 Hz, 1H), 7.58 – 7.50 (m, 2H), 7.22 (dd,J = 8.0, 4.9 Hz, 1H), 7.14 – 7.09 (m, 2H), 3.87 (s, 3H); 13C NMR (101 MHz, DMSO-d6) δ 164.33,164.17, 152.40, 146.14, 144.14, 139.54, 135.94, 133.32, 132.94, 131.51,131.05, 124.53, 121.70, 120.92, 119.89, 119.02, 114.38, 56.13; HR-MS (ESI), m / z: [M+H] + Calculate for C 20 H 16 O 4 N 3 CI 2 + , 432.0512; found, 432.0517.

[0067] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-13, whose structure is shown in D-13 above.

[0068] Embodiment 14 The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, R 5 For -H, R 6 The target product, pyridine ester compound LB, was obtained and recorded as D-14 (purity> 95%).

[0069] D-14 is a white powdery solid with a yield of 76.3%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 40 to 42 The structural characterization data are as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 11.71 (s, 1H), 9.84 (s, 1H), 8.34 (dd, J =5.0, 1.6 Hz, 1H), 8.15 (d, J = 8.6 Hz, 2H), 7.95 (d, J = 2.1 Hz, 1H), 7.83 (dd, J =8.0, 1.6 Hz, 1H), 7.68 (d, J = 8.6 Hz, 2H), 7.59 – 7.50 (m, 2H), 7.23 (dd, J =8.0, 4.9 Hz, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 164.02, 152.42, 146.07, 144.38,139.47, 139.21, 135.49, 133.40, 132.49, 131.53, 131.06, 129.22, 128.71,124.61, 120.97, 119.95, 118.92; HR-MS (ESI), m / z: [M+H] + Calculate for C 19 H 13 O 3 N 3 CI 3 + ,436.0022; found, 436.0017.

[0070] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-14, and its structure is shown in D-14 above.

[0071] Embodiment 15 The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, R 5 For -F, R 6 The target product, pyridine ester compound LB, was obtained and recorded as D-15 (purity> 95%).

[0072] D-15 is a white powdery solid with a yield of 76.1%. The structure of the obtained product was characterized, and the nuclear magnetic resonance hydrogen spectrum, nuclear magnetic resonance carbon spectrum and high-resolution mass spectrum were as follows: Figures 43 to 45 The structural characterization data are as follows: 1H NMR (400 MHz, DMSO- d 6 ) δ 11.71 (s, 1H), 9.84 (s, 1H), 8.34 (dd, J =5.0, 1.6 Hz, 1H), 8.06 (d, J = 8.6 Hz, 2H), 7.95 (d, J = 2.2 Hz, 1H), 7.88 – 7.78(m, 3H), 7.58 – 7.52 (m, 2H), 7.23 (dd, J = 8.0, 5.0 Hz, 1H); 13 C NMR (101 MHz, DMSO- d 6 ) δ 164.20, 152.42, 146.07, 144.39, 139.46, 135.48, 133.39, 132.58,132.18, 131.88, 131.53, 131.06, 130.61, 129.07, 128.35, 124.61, 120.98,119.95, 118.92; HR-MS (ESI), m / z: [M+H] + Calculate for C 20 H 13 O 3 N 3 FCI 2 + , 420.0318;found, 420.0319.

[0073] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-15, and its structure is shown in D-15 above.

[0074] Notice: Figures 1 to 45 The rightmost parts of all the carbon NMR spectra are solvent peaks, which do not affect the analysis of the spectra.

[0075] Preliminary laboratory test of the oncolytic properties of oncolytic drugs Experimental subjects: Active golden apple snails from Dali City, Dali Bai Autonomous Prefecture, Yunnan Province.

[0076] Experimental method: The experiment was conducted by immersion method, and a control group was set up, with niclosamide and pyspirulinarum as positive controls and DMSO as negative control.

[0077] After the snails were rinsed with tap water, they were kept in dechlorinated tap water. The snails with uniform size, no obvious damage to the shell, and strong vitality were selected for the experiment. 12 mg, 30 mg, and 60 mg of snailicide (D-1~D-15) were accurately weighed with an analytical balance, and DMSO (3 mL) was added to fully dissolve them. Then, Tween 20 (1 mL) and water (6 L) were added and mixed evenly to obtain 2 mg / L, 5 mg / L, and 10 mg / L drug solutions. Eight snails were placed in the center of the bottom of each concentration group, and one experiment was set up for each concentration group.

[0078] Test method for the positive control group of niclosamide: 12 mg, 30 mg and 60 mg of niclosamide were accurately weighed using an analytical balance, DMSO (3 mL) was added to fully dissolve them, and then Tween 20 (1 mL) and water (6 L) were added and mixed evenly to obtain 2 mg / L, 5 mg / L and 10 mg / L drug solutions. For each concentration group, 8 snails were placed in the center of the bottom, and one experiment was set up for each concentration group.

[0079] Experimental method of DMSO negative control group (Control group): Add DMSO (3 mL), then add Tween 20 (1 mL) and water (6 L) and mix well, then put 8 snails in the center of the bottom and set up an experiment.

[0080] The plastic mesh was covered to prevent the snails from escaping. The number of snail deaths after immersion for 24 h, 48 h, and 72 h was recorded, and the mortality rate after 72 h was counted. The specific data are shown in Table 1.

[0081] Table 1 Preliminary laboratory test records of molluscicidal activity of compound D series Time: 2023.08.29; Water temperature: 25℃; Weather: Sunny;

[0082] On-site snail-killing test of D-2 and D-3 snail-killing drugs in Dali A ditch with a length of about 60m, an average width of about 1.2m, and an average water depth of about 0.2m was selected in Nanjie Community, Nanjian Town, Nanjian County (with an area of ​​27885m in the Nanjian County Farming Park). 2), at least 5000 adult golden apple snails with good activity and shell length of 25-40mm were collected from Dali, Yunnan, China. Before drug administration, plastic sheets were tied to wooden sticks and inserted into the silt to form 20 ponds with a length, width and height of 1m and 0.2m. The plastic sheets at the lower end of the pond were buried in the silt, and soil was piled on the outside to prevent water overflow. The water depth was controlled to be about 0.2m on average. The death of golden apple snails was observed 1, 2, and 3 days after drug administration. There was a fine net around each plot to prevent the migration of golden apple snails. Water was introduced and maintained at a depth of about 20cm, and it was necessary to stand for one day before the experiment. Before the experiment, all the golden apple snails that appeared naturally in each plot were removed manually. This experiment was divided into a clean water group (negative control group), a target drug group, and a chloranil group (positive control group). Compounds D-2 and D-3 were prepared at 2mg / L, 5mg / L and 10mg / L solutions (concentration of the solution in the pool) on site, and 100 golden apple snails were placed in the center of the test pool in each concentration group. Three experiments were set up for each concentration group, and a corresponding negative control group and a 2 mg / L positive control group were set up at the same time. The preparation method of the drug solution was the same as the method in the initial laboratory test of the snail-killing properties of the snail-killing drug. The test data of compound D-2 are statistically shown in Table 2, and the test data of compound D-3 are statistically shown in Table 3.

[0083] Table 2 Test record of on-site snail-killing activity of compound D-2 in Dali Time: 2023.04.25; Water temperature: 25℃; Weather: Sunny;

[0084] Table 3. Test record of on-site snail-killing activity of compound D-3 in Dali Time: 2024.09.26; Water temperature: 25℃; Weather: Sunny;

[0085] Test on the fish toxicity of D-2 and D-3 snail killers Carp and grass carp with good vitality were selected as experimental subjects, with a body weight of 1.34g±0.37g to 1.42g±0.21g and an average length of 3.60cm±0.25cm to 4.36cm±0.25cm. Before the fish toxicity experiment, the prepared 6L fish tank was filled with water and exposed to sunlight for two days to remove chlorine in the water. The newly purchased fish were placed in the prepared dechlorinated water for at least one week of adaptation training. The water was changed every two days to keep it clean, and appropriate feed (special goldfish feed) was provided to ensure the accuracy and reliability of the experimental data. A clear water group was set up for each group as a negative control, and a commercially available molluscicide-niclosamide was used as a positive control group. In the test system containing DMSO (3mL), the concentrations of the compounds for fish toxicity testing were 2mg / L, 5mg / L, and 10mg / L, respectively. After adding Tween 20 (1mL) and water (6L), they were evenly mixed. Then, six active carp or grass carp were placed in a 6L fish tank for fish toxicity testing. During this period, the mortality of fish at 24h, 48h and 72h was carefully recorded. Dead fish were immediately removed from the water tank and disposed of to prevent water contamination, thus ensuring the smooth progress of the experiment. The 72h test data are statistically shown in Table 4.

[0086] Table 4 D-2, D-3 72h fish toxicity initial test data record Time: 2023.05.25; Water temperature: 25℃; Weather: Sunny;

[0087] As shown in Tables 1 to 4, the pyridine ester compounds provided by the present invention all have certain molluscicidal activity, and the molluscicidal activity of compounds D-2 and D-3 against Pomacea canaliculata after immersion for 72 hours is similar to that of niclosamide, that is, at a drug concentration of 2 mg / L, the snail mortality rate after 72 hours is more than 87.5% of that of niclosamide. The above two series of molluscicidal compounds have the characteristics of simple synthesis process and high yield, and have certain commercial application potential in chemical molluscicides.

[0088] According to our previously issued patent ZL 2022 1 1388100.7, the patent applied for this time has made great improvements in both snail killing activity and non-targeted biological safety. The previous patent had a snail killing rate of only about 50% at a concentration of 2 mg / L. This time, our patent can achieve a snail killing rate of more than 85% at the same concentration. In addition, in terms of aquatic toxicity, this patent is almost non-toxic to fish at a concentration of 10 mg / L, and the survival rate of carp and grass carp can reach 100%.

[0089] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A pyridine ester compound containing a urea structure, having a structure shown in any one of Formulas I to III: Formula I; Formula II; Formula III; In formula I, R1 is -Br, -Cl, -F or -OCH3, and R2 is -H or -Cl; In formula II, R3 is -Br, -Cl, -F or -OCH3, and R4 is -H or -Cl; In formula III, R5 is -Br, -Cl, -F, -OCH3 or -H, and R6 is -H or -Cl.

2. The pyridine ester compound according to claim 1, characterized in that It has the structure shown in any one of the following D-1 to D-15: D-1; D-2; D-3; D-4; D-5; D-6; D-7; D-8; D-9; D-10; D-11; D-12; D-13; D-14; D-15。 3. The method for preparing the pyridine ester compound according to claim 1 or 2, comprising the following steps: 2-amino-3-hydroxypyridine, halogenated phenyl isocyanate and a first polar organic solvent are first mixed and subjected to a nucleophilic addition reaction to obtain a hydroxypyridine compound containing a urea structure; the halogenated phenyl isocyanate includes 4-chlorophenyl isocyanate, 4-bromophenyl isocyanate or 3,4-dichlorophenyl isocyanate; the hydroxypyridine compound containing a urea structure has a structure shown in any one of formulas a to c; Formula a; Formula b; Formula c; The urea-containing hydroxypyridine compound, the aryl-substituted acyl chloride, the acid-binding agent and the second polar organic solvent are mixed for a second time, and an esterification reaction is performed to obtain a pyridine ester compound having a structure shown in Formula I to Formula III; the aryl-substituted acyl chloride has a structure shown in any one of Formulas d to f; Formula d; Formula e; Formula f; When the urea-containing hydroxypyridine compound is of the structural formula a, the aromatic substituted acyl chloride is of the structural formula d; When the urea-containing hydroxypyridine compound is of the structural formula shown in formula b, the aromatic substituted acyl chloride is of the structural formula shown in formula e; When the urea-containing hydroxypyridine compound is of the structural formula shown in formula c, the aromatic substituted acyl chloride is of the structural formula shown in formula f.

4. The preparation method according to claim 3, characterized in that: The time of the nucleophilic addition reaction is 5 to 7 hours.

5. The preparation method according to claim 3 or 4, characterized in that: The molar ratio of the 2-amino-3-hydroxypyridine to the halogenated phenyl isocyanate is 1:(1-1.2).

6. The preparation method according to claim 3, characterized in that: The esterification reaction time is 1 to 1.5 hours.

7. The preparation method according to claim 3 or 6, characterized in that: The second mixing comprises: mixing the hydroxypyridine compound containing a urea structure, an acid binding agent and a second polar organic solvent, and then dropping an acyl chloride substituted with an aromatic group.

8. The preparation method according to claim 3 or 6, characterized in that: The molar ratio of the urea-containing hydroxypyridine compound to the aryl-substituted acyl chloride is 1:(1-1.2).

9. The preparation method according to claim 3 or 6, characterized in that: The molar ratio of the hydroxypyridine compound containing a urea structure to the acid binding agent is 1:(1.8-2).

10. Use of the pyridine ester compound according to claim 1 or 2 or the pyridine ester compound prepared by the preparation method according to any one of claims 3 to 9 as a molluscicide in killing Pomacea canaliculata snails.

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