A pyridine ester compound containing a urea structure, and its preparation method and application

Abstract

The present invention provides a pyridine ester compound containing urea structure and its preparation method and application, which belong to the technical field of chemical molluscicides. The pyridine ester compound containing 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 of the structure shown in D-1~D-15 provided by the present invention all have certain molluscicidal activity as molluscicides, among which D-1, D-2, D-3, D-6, D-7, and D-8 are similar to niclosamide in molluscicidal activity against golden apple snails after 72h of immersion method, that is, under 2mg / L drug concentration, after 72h, the snail mortality rate is more than 87.5% of niclosamide, and the fish toxicity is significantly reduced compared with niclosamide.

Description

Technical Field

[0001] The present 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 or the giant bottle snail, is a large freshwater snail native to the Amazon basin in South America. As an invasive species, the golden apple snail possesses strong adaptability, causing irreparable damage to agricultural production and the ecosystem. With food security becoming increasingly important, the control of the golden apple snail is urgent.

[0003] Niclosamide, a chemical molluscicide introduced in 1972, is widely used to kill snails and other species, but it is highly toxic to non-target aquatic animals, particularly fish. In recent years, plant extracts have also been used to kill golden apple snails, but their extraction is difficult and cannot be mass-produced. Recently, golden apple snails have also been controlled through biological and physical methods, such as the introduction of 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 apple snail infestation. Summary of the Invention

[0005] In view of this, the present invention aims to provide a urea-containing pyridine ester compound, its preparation method, and its application. The urea-containing pyridine ester compound provided by the present invention has a good killing effect on golden apple snails and is almost non-toxic to non-target organisms, thus being environmentally friendly. Furthermore, 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 represented by 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 examples show that the pyridine ester compounds represented by structures D-1 to D-15 provided by the present invention all have certain molluscicidal activity as molluscicides. Among them, D-1, D-2, D-3, D-6, D-7, and D-8 have similar molluscicidal activity against golden apple snails as 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 to 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 following briefly introduces the drawings required for use in the embodiments. 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 any creative work.

[0009] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the product D-1 obtained in Example 1 of the present invention;

[0010] Figure 2 This is the carbon NMR spectrum of the product D-1 obtained in Example 1 of the present invention;

[0011] Figure 3 This is the high-resolution mass spectrum of the product D-1 obtained in Example 1 of the present invention;

[0012] Figure 4 This is the hydrogen nuclear magnetic resonance spectrum of the product D-2 obtained in Example 2 of the present invention;

[0013] Figure 5 This is the carbon NMR spectrum of the product D-2 obtained in Example 2 of the present invention;

[0014] Figure 6 This is the high-resolution mass spectrum of the product D-2 obtained in Example 2 of the present invention;

[0015] Figure 7 This is the hydrogen nuclear magnetic resonance spectrum of the product D-3 obtained in Example 3 of the present invention;

[0016] Figure 8 This is the carbon NMR spectrum of the product D-3 obtained in Example 3 of the present invention;

[0017] Figure 9 This is the high-resolution mass spectrum of the product D-3 obtained in Example 3 of the present invention;

[0018] Figure 10 This is the hydrogen nuclear magnetic resonance spectrum of the product D-4 obtained in Example 4 of the present invention;

[0019] Figure 11 This is the carbon NMR spectrum of the product D-4 obtained in Example 4 of the present invention;

[0020] Figure 12 This is the high-resolution mass spectrum of the product D-4 obtained in Example 4 of the present invention;

[0021] Figure 13 This is the hydrogen nuclear magnetic resonance spectrum of the product D-5 obtained in Example 5 of the present invention;

[0022] Figure 14 This is the carbon NMR spectrum of the product D-5 obtained in Example 5 of the present invention;

[0023] Figure 15 This is the high-resolution mass spectrum of the product D-5 obtained in Example 5 of the present invention;

[0024] Figure 16 This is the hydrogen nuclear magnetic resonance spectrum of the product D-6 obtained in Example 6 of the present invention;

[0025] Figure 17 This is the carbon NMR spectrum of the product D-6 obtained in Example 6 of the present invention;

[0026] Figure 18 This is the high-resolution mass spectrum of the product D-6 obtained in Example 6 of the present invention;

[0027] Figure 19 This is the hydrogen nuclear magnetic resonance spectrum of the product D-7 obtained in Example 7 of the present invention;

[0028] Figure 20 This is the carbon NMR spectrum of the product D-7 obtained in Example 7 of the present invention;

[0029] Figure 21 This is the high-resolution mass spectrum of the product D-7 obtained in Example 7 of the present invention;

[0030] Figure 22 This is the hydrogen nuclear magnetic resonance spectrum of the product D-8 obtained in Example 8 of the present invention;

[0031] Figure 23 This is the carbon NMR spectrum of the product D-8 obtained in Example 8 of the present invention;

[0032] Figure 24 This is the high-resolution mass spectrum of the product D-8 obtained in Example 8 of the present invention;

[0033] Figure 25 This is the hydrogen nuclear magnetic resonance spectrum of the product D-9 obtained in Example 9 of the present invention;

[0034] Figure 26 This is the carbon NMR spectrum of the product D-9 obtained in Example 9 of the present invention;

[0035] Figure 27 This is the high-resolution mass spectrum of the product D-9 obtained in Example 9 of the present invention;

[0036] Figure 28 This is the hydrogen nuclear magnetic resonance spectrum of the product D-10 obtained in Example 10 of the present invention;

[0037] Figure 29 This is the carbon NMR spectrum of the product D-10 obtained in Example 10 of the present invention;

[0038] Figure 30 This is the high-resolution mass spectrum of the product D-10 obtained in Example 10 of the present invention;

[0039] Figure 31 This is the hydrogen nuclear magnetic resonance spectrum of the product D-11 obtained in Example 11 of the present invention;

[0040] Figure 32 This is the carbon NMR spectrum of the product D-11 obtained in Example 11 of the present invention;

[0041] Figure 33 This is the high-resolution mass spectrum of the product D-11 obtained in Example 11 of the present invention;

[0042] Figure 34 This is the hydrogen nuclear magnetic resonance spectrum of the product D-12 obtained in Example 12 of the present invention;

[0043] Figure 35 This is the carbon NMR spectrum of the product D-12 obtained in Example 12 of the present invention;

[0044] Figure 36 This is the high-resolution mass spectrum of the product D-12 obtained in Example 12 of the present invention;

[0045] Figure 37 This is the hydrogen nuclear magnetic resonance spectrum of the product D-13 obtained in Example 13 of the present invention;

[0046] Figure 38 This is the carbon NMR spectrum of the product D-13 obtained in Example 13 of the present invention;

[0047] Figure 39 This is the high-resolution mass spectrum of the product D-13 obtained in Example 13 of the present invention;

[0048] Figure 40 This is the hydrogen nuclear magnetic resonance spectrum of the product D-14 obtained in Example 14 of the present invention;

[0049] Figure 41 This is the carbon NMR spectrum of the product D-14 obtained in Example 14 of the present invention;

[0050] Figure 42 This is the high-resolution mass spectrum of the product D-14 obtained in Example 14 of the present invention;

[0051] Figure 43 This is the hydrogen nuclear magnetic resonance spectrum of the product D-15 obtained in Example 15 of the present invention;

[0052] Figure 44 This is the carbon NMR spectrum of the product D-15 obtained in Example 15 of the present invention;

[0053] Figure 45 This is the high-resolution mass spectrum of product D-15 obtained in Example 15 of the present invention. DETAILED DESCRIPTION

[0054] The present invention provides a pyridine ester compound containing a urea structure, having a structure shown in any one of Formulas I to III:

[0055] Formula I; Formula II; Formula III;

[0056] In formula I, R1 is -Br, -Cl, -F or -OCH3, and R2 is -H or -Cl;

[0057] In formula II, R3 is -Br, -Cl, -F or -OCH3, and R4 is -H or -Cl;

[0058] In formula III, R5 is -Br, -Cl, -F, -OCH3 or -H, and R6 is -H or -Cl.

[0059] In the present invention, the pyridine ester compound preferably has a structure shown in any one of the following D-1 to D-15:

[0060] 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.

[0061] The urea-structured pyridine ester compound 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.

[0062] The present invention provides a method for preparing the pyridine ester compound described in the above scheme, comprising the following steps:

[0063] 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;

[0064] Formula a; Formula b; Formula c;

[0065] 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 represented by Formula I to Formula III; the aryl-substituted acyl chloride has a structure represented by any one of Formulas d to f;

[0066] Formula d; Formula e; Formula f;

[0067] When the urea-containing hydroxypyridine compound is of the structural formula shown in formula a, the aromatic substituted acyl chloride is of the structural formula shown in formula d;

[0068] 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;

[0069] When the urea-containing hydroxypyridine compound has the structural formula shown in formula c, the aromatic substituted acyl chloride has the structural formula shown in formula f.

[0070] Unless otherwise specified, the materials and equipment used in the present invention are commercially available products.

[0071] 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.

[0072] 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.

[0073] 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 5 hours, 6 hours or 7 hours.

[0074] In the present invention, the molar ratio of the 2-amino-3-hydroxypyridine and the halogenated phenyl isocyanate is preferably 1: (1-1.2), and in embodiments of the present invention, it can be specifically 1: 1 or 1: 1.2; the molar amount of the 2-amino-3-hydroxypyridine and the volume ratio of the first polar organic solvent are preferably 1 mmol: 10 mL.

[0075] After the nucleophilic addition reaction is completed, the present invention preferably filters the obtained reaction solution to obtain the urea-containing hydroxypyridine compound.

[0076] After obtaining the urea-containing hydroxypyridine compound, the present invention further mixes the urea-containing hydroxypyridine compound, an aromatic substituted acid 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 represented by Formula I to Formula III.

[0077] In the present invention, the second mixing preferably comprises: mixing the urea-containing hydroxypyridine compound, an acid-binding agent, and a second polar organic solvent, and then dropwise adding the aryl-substituted acid chloride. In the present invention, the mixing time of the urea-containing hydroxypyridine compound, the acid-binding agent, and the second polar organic solvent is preferably 1 hour, and the temperature is preferably room temperature. Prior to dropwise adding the aryl-substituted acid chloride, the present invention preferably cools the resulting reaction solution to 0-5°C. In the present invention, the dropwise addition time is preferably 10 minutes. In the present invention, the aryl-substituted acid chloride is preferably heated at a low temperature before dropwise addition. The present invention does not particularly require the heating temperature; it only requires a temperature that melts the aryl-substituted acid chloride.

[0078] In the present invention, the acid-binding agent preferably comprises triethylamine; the second polar organic solvent preferably comprises dichloromethane. In the present invention, the molar ratio of the urea-containing hydroxypyridine compound to the aryl-substituted acid chloride is preferably 1:(1-1.2), and in embodiments of the present invention, it can be 1:1 or 1:1.2. The molar ratio of the urea-containing hydroxypyridine compound to the acid-binding agent is preferably 1:(1.8-2), and in embodiments of the present invention, it can be 1:1.8 or 1:2. In the present invention, the volume ratio of the urea-containing hydroxypyridine compound to the second polar organic solvent is preferably 1 mmol:10 mL.

[0079] In the present invention, the esterification reaction temperature is preferably room temperature; the esterification reaction time is preferably 1 to 1.5 hours, and in embodiments of the present invention, specifically 1 hour, 1.2 hours, or 1.5 hours. In the present invention, the esterification reaction time is preferably calculated from the completion of the dropwise addition of the aryl-substituted acid chloride.

[0080] After the esterification reaction is completed, the present invention preferably quenches the reaction with water, and then the resulting mixture is post-treated. 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, and the amount of solvent each time is preferably 10 mL; the number of washings is preferably three; anhydrous sodium sulfate is preferably used for drying; and ethanol is preferably used as the solvent for recrystallization. The present invention has no particular requirements for the post-treatment method, and methods well known in the art can be used.

[0081] The preparation method provided by the present invention is simple, has high yield (>65.2%) and high purity (>95%).

[0082] 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 golden apple snails.

[0083] The results of the examples show that the pyridinium ester compounds represented by the structures D-1 to D-15 provided by the present invention all have certain molluscicidal activity as molluscicidal agents. Among them, the molluscicidal activity of D-1, D-2, D-3, D-6, D-7, and D-8 against golden apple 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.

[0084] To further illustrate the present invention, a urea-containing pyridine ester compound provided by the present invention, its preparation method and application are described in detail below with reference to the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0085] Example 1

[0086] According to the chemical reaction equation shown in Formula 1, wherein R1 is -Br and R2 is -H, 2-amino-3-hydroxypyridine (1 mmol, 110 mg) and 4-chlorophenyl isocyanate (1 mmol, 154 mg) were added to a 50 mL single-necked flask at room temperature, dissolved in 10 mL of dichloromethane and stirred for 6 h. After the reaction was completed, the mixture was filtered to obtain an off-white solid LA, i.e., a hydroxypyridine compound containing a urea structure, Formula a, which was directly carried out to the next step without purification.

[0087] To a 50 mL single-necked flask, an off-white solid LA compound (1 mmol) and triethylamine (1.8 mmol, 0.25 mL) were added. The mixture was stirred in anhydrous CH2C12 (10 mL) at room temperature for 1 h. The reaction solution was then cooled to (0-5°C) and 4-bromobenzoyl chloride (1 mmol) was slowly added dropwise. The 4-bromobenzoyl chloride was melted at low temperature before being added dropwise. The addition 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 extracted three times with CH2C12 (10 mL of solvent each time). The organic phase was washed three times with saturated brine and then dried over anhydrous sodium sulfate. The crude product was concentrated under reduced pressure to obtain the target product, which was recrystallized from ethanol to obtain the target product, a pyridine ester compound LB, designated as D-1 (purity >95%).

[0088] Formula 1;

[0089] D-1 is a white powdery solid with a yield of 75.5%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 1-3 The structural characterization data are as follows:

[0090] 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] + calcd for C 19 H 14 O3N3BrCI + , 455.9907;found, 455.9899.

[0091] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-1, whose structure is shown in D-1 above.

[0092] Example 2

[0093] The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, wherein R1 is -Cl and R2 is -H, the target product pyridine ester compound LB is obtained, which is recorded as D-2 (purity > 95%).

[0094] D-2 was a white powdery solid with a yield of 85.6%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 4-6 The structural characterization data are as follows:

[0095] 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] + calcd for C 19 H 14 O3N3CI2 + ,402.0412; found, 402.0411.

[0096] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-2, whose structure is shown in D-2 above.

[0097] Example 3

[0098] The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, wherein R1 is -OCH3 and R2 is -H, the target product pyridine ester compound LB is obtained, which is recorded as D-3 (purity > 95%).

[0099] D-3 is a white powdery solid with a yield of 69.2%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 7-9 The structural characterization data are as follows:

[0100] 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); 13 C 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 O4N3Cl + , 398.0902; found, 398.0908.

[0101] 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.

[0102] Example 4

[0103] The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, wherein R1 is -Cl and R2 is -Cl, the target product pyridine ester compound LB is obtained, which is recorded as D-4 (purity >95%).

[0104] D-4 was a white powdery solid with a yield of 70.3%. The structure of the obtained product was characterized by H NMR spectrum, C NMR spectrum and high resolution mass spectrum. Figures 10-12 The structural characterization data are as follows:

[0105] 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), 8.15 (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] + calcd for C 19 H 13 O3N3CI3 + ,436.0022; found, 436.0022.

[0106] 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.

[0107] Example 5

[0108] The preparation steps are the same as those in Example 1, except that, according to the chemical reaction equation shown in Formula 1, where R1 is -F and R2 is -H, the target product pyridine ester compound LB is obtained, which is recorded as D-5 (purity >95%).

[0109] D-5 is a white powdery solid with a yield of 68.2%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 13-15 The structural characterization data are as follows:

[0110] 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] + calcd for C 19 H 14 O3N3FCI + , 386.0708; found, 386.0704.

[0111] 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-5 above.

[0112] Example 6

[0113] According to the chemical reaction equation shown in Formula 2, wherein R3 is -Br and R4 is -H, 2-amino-3-hydroxypyridine (1 mmol) and 4-bromophenyl isocyanate (1 mmol) were added to a 50 mL single-necked flask at room temperature, dissolved in 10 mL of dichloromethane, and stirred for 6 h. After the reaction was completed, the mixture was filtered to obtain an off-white solid LA, i.e., a hydroxypyridine compound containing a urea structure (Formula b), which was directly carried out to the next step without purification.

[0114] To a 50 mL single-necked flask, add the off-white solid LA compound (1 mmol) and triethylamine (0.25 mL). Stir in anhydrous CH2C12 (7.5 mL) at room temperature for 1 h. Then, cool the reaction solution to (0-5°C) and slowly add 4-bromobenzoyl chloride (1 mmol) dropwise within 10 min. Stir the mixture at room temperature for another 1 h and then quench with 5 mL of water. The resulting mixture is extracted three times with CH2C12 (10 mL of solvent each time). The organic phase is washed three times with saturated brine and then dried over anhydrous sodium sulfate. The crude product is then concentrated under reduced pressure to obtain the target product, pyridine ester compound LB, which is recrystallized from ethanol. D-6 is obtained.

[0115] Formula 2;

[0116] D-6 was a white powdery solid with a yield of 75.2%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 16-18 The structural characterization data are as follows:

[0117] 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] + calcd for C 19 H 14 O3N3Br2 +, 489.9402;found, 489.9393.

[0118] 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.

[0119] Example 7

[0120] The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, where R3 is -Cl and R4 is -H, the target product, a pyridine ester compound LB, is obtained, denoted as D-7 (purity > 95%).

[0121] D-7 is a white powdery solid with a yield of 75.3%. The structure of the obtained product was characterized by H NMR spectrum, C NMR spectrum and high resolution mass spectrum. Figures 19-21 The structural characterization data are as follows:

[0122] 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] + calcd for C 19 H 14 O3N3CI2 + ,445.9907; found, 445.9899.

[0123] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-7, whose structure is shown in D-7 above.

[0124] Example 8

[0125] The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, where R3 is -OCH3 and R4 is -H, the target product pyridine ester compound LB is obtained, which is recorded as D-8 (purity >95%).

[0126] D-8 is a white powdery solid with a yield of 68.3%. The structure of the obtained product was characterized by H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 22-24 The structural characterization data are as follows:

[0127] 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] + calcd for C 20 H 17 O4N3Br + ,442.0397; found, 442.0399.

[0128] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-8, whose structure is shown in D-8 above.

[0129] Example 9

[0130] The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, wherein R3 is -Cl and R4 is -Cl, the target product pyridine ester compound LB is obtained, which is recorded as D-9 (purity >95%).

[0131] D-9 is a white powdery solid with a yield of 75.2%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 25-27 The structural characterization data are as follows:

[0132] 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] + calcd for C 19 H 13 O3N3BrCI2 + , 479.9517; found, 479.9512.

[0133] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-9, whose structure is shown in D-9 above.

[0134] Example 10

[0135] The preparation steps are the same as those in Example 6, except that, according to the chemical reaction equation shown in Formula 2, wherein R3 is -F and R4 is -H, the target product pyridine ester compound LB is obtained, denoted as D-10 (purity >95%).

[0136] 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 28-30 The structural characterization data are as follows:

[0137] 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] + calcd for C 19 H 14 O3N3FCI + , 386.0708; found, 386.0704.

[0138] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-10, whose structure is shown in D-10 above.

[0139] Example 11

[0140] According to the chemical reaction equation shown in Formula 3, wherein R5 is -Br and R6 is -H, 2-amino-3-hydroxypyridine (1 mmol) and 3,4-dichlorophenyl isocyanate (1 mmol) were added to a 50 mL single-necked flask at room temperature, dissolved in 10 mL of dichloromethane and stirred for 6 h. After the reaction was completed, the mixture was filtered to obtain an off-white solid LA, i.e., a hydroxypyridine compound containing a urea structure (Formula C), which was directly carried out to the next step without purification.

[0141] To a 50 mL single-necked flask, add the off-white solid LA compound (1 mmol) and triethylamine (0.25 mL). Stir the mixture in anhydrous CH2C12 (7.5 mL) at room temperature for one hour. Then, cool the reaction solution to (0-5°C) and slowly add 4-bromobenzoyl chloride (1 mmol) dropwise within 10 minutes. Stir the mixture at room temperature for another hour and then quench with 5 mL of water. The resulting mixture is extracted three times with CH2C12 (10 mL of solvent each time). The organic phase is washed three times with saturated brine and then dried over anhydrous sodium sulfate. The crude product is then concentrated under reduced pressure to obtain the target product, pyridine ester compound LB, which is recrystallized from ethanol. This product is designated as D-11.

[0142] Formula 3;

[0143] D-11 is a white powdery solid with a yield of 68.2%. The structure of the obtained product was characterized by H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 31-33 The structural characterization data are as follows:

[0144] 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- d6) 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] + calcd for C 19 H 13 O3N3BrCI2 + , 479.9517; found, 479.9512.

[0145] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-11, whose structure is shown in D-11 above.

[0146] Example 12

[0147] The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, where R5 is -Cl and R6 is -H, the target product pyridine ester compound LB is obtained, which is recorded as D-12 (purity >95%).

[0148] D-12 was a white powdery solid with a yield of 75.5%. The structure of the obtained product was characterized by H NMR spectrum, C NMR spectrum and high resolution mass spectrum. Figures 34-36 The structural characterization data are as follows:

[0149] 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- d6) 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] + calcd for C 19 H 13 O3N3CI3 + ,436.0022; found, 436.0013.

[0150] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-12, whose structure is shown in D-12 above.

[0151] Example 13

[0152] The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, where R5 is -OCH3 and R6 is -H, the target product pyridine ester compound LB is obtained, which is recorded as D-13 (purity >95%).

[0153] D-13 is a white powdery solid with a yield of 68.5%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 37-39 The structural characterization data are as follows:

[0154] 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] + calcd for C 20 H 16 O4N3CI2 + , 432.0512; found, 432.0517.

[0155] 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.

[0156] Example 14

[0157] The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, where R5 is -H and R6 is -Cl, the target product, a pyridine ester compound LB, is obtained, denoted as D-14 (purity > 95%).

[0158] D-14 was a white powdery solid with a yield of 76.3%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 40-42 The structural characterization data are as follows:

[0159] 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] + calcd for C 19 H 13 O3N3CI3 + ,436.0022; found, 436.0017.

[0160] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-14, whose structure is shown in D-14 above.

[0161] Example 15

[0162] The preparation steps are the same as those in Example 11, except that, according to the chemical reaction equation shown in Formula 3, where R5 is -F and R6 is -H, the target product, a pyridine ester compound LB, is obtained, denoted as D-15 (purity > 95%).

[0163] D-15 is a white powdery solid with a yield of 76.1%. The structure of the obtained product was characterized by the H NMR spectrum, C NMR spectrum and high-resolution mass spectrum. Figures 43-45 The structural characterization data are as follows:

[0164] 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), 8.06 (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] + calcd for C 20 H 13 O3N3FCI2 + , 420.0318;found, 420.0319.

[0165] According to the above data and spectral analysis, the obtained product is the target product pyridine ester compound D-15, whose structure is shown in D-15 above.

[0166] Notice: Figures 1 to 45 The rightmost part of all the carbon NMR spectra is the solvent peak, which does not affect the analysis of the spectrum.

[0167] Preliminary laboratory test of the snail-killing properties of snailicides

[0168] Experimental subjects: Active golden apple snails from Dali City, Dali Bai Autonomous Prefecture, Yunnan Province.

[0169] Experimental method: The immersion method was used for the experiment. A control group was set up with niclosamide and pyspirulinarum as positive controls and DMSO as negative control.

[0170] After rinsing with tap water, golden apple snails were reared in dechlorinated tap water. Snails of uniform size, without obvious shell damage, and high vitality were selected for the experiment. Using an analytical balance, 12 mg, 30 mg, and 60 mg of the snailicide (D-1 to D-15) were accurately weighed and fully dissolved in DMSO (3 mL). Tween-20 (1 mL) and water (6 L) were then added and mixed to obtain 2 mg / L, 5 mg / L, and 10 mg / L solutions. Eight snails were placed in the center of the bottom of each concentration group, and one experiment was conducted for each concentration group.

[0171] 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, and DMSO (3 mL) was added to fully dissolve them. Tween 20 (1 mL) and water (6 L) were then 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.

[0172] DMSO negative control group experimental method (Control group): Add DMSO (3 mL), then add Tween 20 (1 mL) and water (6 L) and mix well, then place 8 snails in the center of the bottom and set up 1 experiment.

[0173] Cover the container with plastic mesh to prevent snails from escaping. The number of snail deaths after immersion for 24, 48, and 72 hours was recorded, and the mortality rate after 72 hours was also calculated. Specific data are summarized in Table 1.

[0174] Table 1 Preliminary laboratory test records of molluscicidal activity of compound D series

[0175] Time: 2023.08.29; Water temperature: 25℃; Weather: Sunny;

[0176]

[0177] On-site snail-killing test of D-2 and D-3 snailicides in Dali

[0178] 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). 2At least 5,000 viable adult golden apple snails with shell lengths of 25-40 mm were collected from Dali, Yunnan, China. Before drug administration, 20 ponds, 1 meter long, 1 meter wide, and 0.2 meter high, were formed by tying plastic sheeting to wooden sticks and inserting them into the mud. Plastic sheeting was buried in the mud at the bottom of the pond, and soil was piled outside to prevent water overflow. The water depth was maintained at an average of approximately 0.2 meter. Snail mortality was observed one, two, and three days after drug administration. Fine mesh was placed around each plot to prevent snail migration. Water was introduced and maintained at a depth of approximately 20 cm and allowed to settle for one day before testing. All naturally occurring golden apple snails in each plot were manually removed prior to the experiment. The experiment was divided into a clean water group (negative control), a target drug group, and a niclosamide group (positive control). Compounds D-2 and D-3 were prepared on-site at 2 mg / L, 5 mg / L, and 10 mg / L solutions (pond concentrations). 100 golden apple snails were released into the center of each test pond for each concentration. Three experiments were conducted for each concentration group, along with a corresponding negative control group and a 2 mg / L positive control group. The drug solution preparation method was the same as that used in the initial laboratory testing of the molluscicidal properties of the molluscicide. The experimental data for compound D-2 are summarized in Table 2, and the experimental data for compound D-3 are summarized in Table 3.

[0179] Table 2. On-site snail-killing activity test record of compound D-2 in Dali

[0180] Date: April 25, 2023; Water temperature: 25°C; Weather: Sunny;

[0181]

[0182] Table 3. On-site snail-killing activity test record of compound D-3 in Dali

[0183] Time: 2024.09.26; Water temperature: 25℃; Weather: Sunny;

[0184]

[0185] Test on the fish toxicity of D-2 and D-3 snailicides

[0186] Active common carp and grass carp were selected for the experiments, weighing between 1.34 g ± 0.37 g and 1.42 g ± 0.21 g, with an average length of 3.60 cm ± 0.25 cm and 4.36 cm ± 0.25 cm. Prior to the fish toxicity experiments, a 6-liter aquarium was filled with water and exposed to sunlight for two days to remove chlorine from the water. Newly purchased fish were acclimated to the dechlorinated water for at least one week. The water was changed every two days to maintain cleanliness, and appropriate feed (specialized goldfish feed) was provided to ensure the accuracy and reliability of the experimental data. A clear water control was established for each group as a negative control, and a commercially available molluscicide, niclosamide, was used as a positive control. Compound concentrations for the fish toxicity tests were 2 mg / L, 5 mg / L, and 10 mg / L in a test system containing DMSO (3 mL). After adding Tween 20 (1 mL) and water (6 L), the mixture was evenly mixed. Six active common carp or grass carp were then placed in the 6-liter aquarium for the fish toxicity tests. During this period, fish mortality was carefully recorded at 24, 48, and 72 hours. Dead fish were immediately removed from the tank and disposed of to prevent water contamination, thus ensuring the smooth progress of the experiment. The 72-hour data are summarized in Table 4.

[0187] Table 4 D-2, D-3 72h fish toxicity initial test data record

[0188] Time: 2023.05.25; Water temperature: 25℃; Weather: Sunny;

[0189]

[0190] Tables 1-4 show that the pyridinium ester compounds provided herein all exhibit moderate molluscicidal activity. Compounds D-2 and D-3 exhibited similar molluscicidal activity against Golden Apple snails after 72 hours of immersion, as compared to niclosamide. Specifically, at a concentration of 2 mg / L, the snail mortality rate after 72 hours was over 87.5% of that of niclosamide. These two series of molluscicidal compounds possess simple synthesis procedures and high yields, demonstrating their potential for commercial application as chemical molluscicides.

[0191] According to our previously issued patent ZL 2022 1 1388100.7, the patent applied for this time has made significant 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%.

[0192] Although the above embodiment provides a detailed description of the present invention, 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 scope of protection of the present invention.

Claims

1. A pyridine ester compound containing a urea structure, characterized in that: Having the structure shown in D-1, D-2, D-4, D-6, D-7, D-9 or D-11 below: D-1; D-2; D-4; D-6; D-7; D-9; D-11。 2. The method for preparing the urea-containing pyridine ester compound according to claim 1, 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 represented by Formula I to Formula III; the aryl-substituted acyl chloride has a structure represented by any one of Formulas d to f; Formula d; Formula e; Formula f; When the urea-containing hydroxypyridine compound is of the structural formula shown in formula a, the aryl-substituted acyl chloride is of the structural formula shown in formula d, and R1 is -Br or -Cl, and R2 is -H or -Cl; When the urea-containing hydroxypyridine compound is of the structural formula shown in formula b, the aryl-substituted acyl chloride is of the structural formula shown in formula e, and R3 is -Br or -Cl, and R4 is -H or -Cl; When the hydroxypyridine compound containing a urea structure is of the structural formula shown in formula c, the aryl-substituted acyl chloride is of the structural formula shown in formula f, and R5 is -Br, and R6 is -H.

3. The preparation method according to claim 2, characterized in that The time of the nucleophilic addition reaction is 5 to 7 hours.

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

5. The preparation method according to claim 2, characterized in that The esterification reaction time is 1 to 1.5 hours.

6. The preparation method according to claim 2 or 5, 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 dropwise adding an acyl chloride substituted with an aromatic group.

7. The preparation method according to claim 2 or 5, characterized in that The molar ratio of the urea-containing hydroxypyridine compound to the aryl-substituted acyl chloride is 1:(1-1.2).

8. The preparation method according to claim 2 or 5, characterized in that The molar ratio of the hydroxypyridine compound containing a urea structure to the acid binding agent is 1:(1.8-2).

9. Use of the urea-containing pyridine ester compound according to claim 1 or the urea-containing pyridine ester compound prepared by the preparation method according to any one of claims 3 to 8 as a molluscicide in killing golden apple snails.

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