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. 2023 Feb 6;28(4):1567. doi: 10.3390/molecules28041567

2-Phenylpyridine Derivatives: Synthesis and Insecticidal Activity against Mythimna separata, Aphis craccivora, and Tetranychus cinnabarinus

Wenliang Zhang 1, Jingjing Chen 1, Xiaohua Du 1,*
Editor: Josphat Matasyoh1
PMCID: PMC9967329  PMID: 36838555

Abstract

The increase in the insecticide resistance of pests, such as Mythimna separata, Aphis craccivora Koch, and Tetranychus cinnabarinus, necessitates the development of new heterocyclic compounds with high insecticidal activity. A series of novel 2-phenylpyridine derivatives containing N-phenylbenzamide moieties were designed and synthesised with Suzuki–Miyaura cross-coupling, nucleophilic substitution, and amidation reactions. The reaction conditions in each step are mild, and the product is easy to separate (yield is about 85%). The structures of the compounds were characterised using 1H and 13C NMR spectroscopy and HRMS. Moreover, the insecticidal activity of the compounds was analysed using the leaf dipping method. The compounds 5a, 5d, 5g, 5h, and 5k at 500 mg/L exhibited 100% inhibition against Mythimna separata. Therefore, the 2-phenylpyridine moieties have the potential to lead to the discovery of novel and effective insecticides.

Keywords: insecticide synthesis, 2-phenylpyridine, N-phenylbenzamide, insecticidal activities

1. Introduction

Pyridine is a nitrogen-containing heterocyclic compound. Pyridine derivatives exhibit various biological activities and are generally used to protect crops. Herbicides [1,2], fungicides [3,4,5,6], insecticides [7,8,9], and plant growth regulators [10,11] generally contain pyridine-based compounds. Compounds containing 2-phenylpyridine have exhibited high biological activity [12,13]; hence, herbicides [14], fungicides [15], and insecticides [16] containing 2-phenylpyridine are frequently reported (Figure 1).

Figure 1.

Figure 1

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Structures of the reported pyridine-containing compounds.

Amide compounds are of fundamental importance in pesticide chemistry [17]. Many pesticides, such as insecticides [18,19], fungicides [20], and herbicides [21], contain amide-based compounds (Figure 2). Chlorantraniliprole [22,23], a commercial insecticide created by DuPont, is a new, efficient, and low-toxicity systemic insecticide that not only exhibits high activity against pests but is also safe for users and beneficial for insects. Owing to its excellent efficacy, chlorantraniliprole has been widely used to protect crops, such as soybean, rice, cotton, and corn.

Figure 2.

Figure 2

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Structures of the reported amide-based compounds.

The resistance of pests toward insecticides has increased and considerably affected the growth and harvest of crops [24,25]. Wang et al. demonstrated that flubendiamide exhibited certain insecticidal activity against a series of pests such as lepidoptera pests [26]. A class of chlorantraniliprole analogues was prepared by Ying et al. using pyridyl pyrazolidone carboxylic acid compounds and benzoic acid derivatives as the starting materials, which showed good insecticidal activity [27]. Liu et al. reported that a class of novel phenylpyridine derivatives exhibited excellent insecticidal activity against harmful mites such as Tetranychus cinnabarinus, etc., and can obtain very good effects at a very low dose. [16]. Phenylpyridine [13,14] and amide [17,18,19] are important components of pesticides; therefore, we designed a series of new chemicals whose structures were based on these two compounds. To obtain highly active compounds, 11 2-phenylpyridine compounds containing N-phenylbenzamide moieties were synthesised according to the substructure link principle. The synthesised compounds were analysed using high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy, and their insecticidal activity against Mythimna separata (MS.), Aphis craccivora Koch (AC.), and Tetranychus cinnabarinus was determined.

2. Results and Discussion

2.1. Chemistry

The compounds were synthesised as illustrated in Scheme 1. Compound 3 was synthesised using Suzuki–Miyaura cross-coupling of 2,3-dichloro-5-trifluoromethylpyridine (1) and 4-hydroxyphenylboronic acid (2), whereas 4 was synthesised using the nucleophilic substitution of 3 with 5-fluoro-2-nitrobenzoic acid. Using 4 and O-(1H-benzotriazol-1-yl)-N,N,N′,N′-tetramethyiuronium hexalfuorophosphate (HBTU) as the reactants and CH2Cl2 as the solvent, a series of designed compounds were obtained in high yields using an amidation reaction. The target compounds (5a–5k) were analysed using HRMS and NMR. All spectral and analytical data were consistent with the assigned structures (Supplementary Materials).

Scheme 1.

Scheme 1

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Overview of the optimization design of the novel 2-phenylpyridine derivatives.

2.2. Greenhouse Insecticidal Activity Assays

As shown in Table 1, all compounds exhibited high insecticidal activities against Mythimna separata but were ineffective against Tetranychus cinnabarinus. Among the tested compounds, 5b, 5d, 5g, 5h, and 5k displayed 100% inhibitory activities against Mythimna separata. However, the rest of the tested compounds showed lower inhibitory activities of ~70% against Mythimna separata.

Table 1.

Insecticide activities (percent inhibition/%) of 5a–5k at 500 mg/L.

Compound Chemical Structure Dosage/
(mg/L)		 Pest a
R MS AC TC
5a H 500 80 0 0
5b 3-Cl 500 100 70 0
5c 2.4-CH3 500 0 0 0
5d 2-OCH3 500 100 0 0
5e 2-CH3,3-Cl 500 70 0 0
5f 2-CH3,4-Cl 500 90 0 0
5g 2-CH3,5-Cl 500 100 0 0
5h 3-OCF3 500 100 0 0
5i 2.4-F 500 80 0 0
5j 3-CF3 500 100 0 0
5k 4-CH3CO 500 90 0 0
chlorantraniliprole / 500 100 100 100
CK / / 0 0 0
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a MS, Mythimna separata; AC, Aphis craccivora Koch; TC, Tetranychus cinnabarinus. CK, control check.

The relationship between the structure and activity of the compounds was investigated, and we found that when the substituent in the second position of the benzene was methoxy or in the third position was chlorine, trifluoromethyl, and trifluoromethoxy, the insecticidal activities of the synthesised compounds were optimal. Further studies on the insecticidal activity of 2-phenylpyridine compounds containing N-phenylbenzamide moieties are in progress.

3. Materials and Methods

3.1. Instrumentation

All reagents and other materials were purchased from commercial sources and used without additional purification unless otherwise noted. A B-545 melting point instrument was used to determine the melting point, without calibration. A Bruker AV-400 or AV-500 MHz spectrometer was used to generate NMR spectra, with CDCl3 as the solvent. An Agilent 6545 Q-TOF liquid chromatography-mass spectrometer was used for mass spectrometry.

3.2. Synthesis

The synthesis of the compounds is outlined in Scheme 2. Compound 3 was synthesised using Suzuki–Miyaura cross-coupling, 4 using nucleophilic substitution, and 5a–5k were synthesised using an amidation reaction.

Scheme 2.

Scheme 2

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Overview of the synthesis of the 2-phenylpyridine derivatives.

3.2.1. General Approach to the Synthesis of 3

To a stirred solution of 2,3-dichloro-5-(trifluoromethyl)pyridine (1.08 g, 5 mmol), 4-hydroxybenzeneboronic acid (0.76 g, 5.5 mmol), potassium carbonate (1.38 g, 10 mmol), and triphenylphosphine (0.13 g, 10 mol%) in acetonitrile (10 mL) and methanol (10 mL), palladium(II) acetate (0.06 g, 5 mol%) was added under a nitrogen atmosphere. The mixture was stirred at 50 °C for 6 h, and water was then slowly added to the reaction solution. The mixture was extracted thrice (30 mL × 3) with ethyl acetate, and the combined organic layers were then washed with brine and dried over MgSO4. The solution was concentrated in vacuo and 3 was obtained using recrystallisation in ethanol and water.

3.2.2. General Approach to the Synthesis of 4

Caesium carbonate (60 mmol) was added to a stirred solution of 4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl) phenol (20 mmol) in N,N-dimethylformamide (100 mL). The mixture was stirred for approximately 0.5 h and then 5-fluoro-2-nitrobenzoic acid (21 mmol) was added. The mixture was then stirred at 100 °C for 9 h. Water was then slowly added to the reaction solution to quench the reaction. The mixture was extracted thrice (30 mL × 3) with ethyl acetate. The combined organic layers were then washed with brine and dried over MgSO4. The solution was concentrated in vacuo, and 4 was used directly for the next reaction.

3.2.3. General Approach to the Synthesis of 5a–5k

Substituted aniline (2.2 mmol) was added to a stirred solution containing 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitrobenzoic acid (2 mmol), HBTU (2.2 mmol), and triethylamine (2.2 mmol) in CH2Cl2 (15 mL). The mixture was stirred at 25 °C for 8 h. A saturated potassium bisulphate solution was then added to the reaction solution, and the mixture was extracted thrice (30 mL × 3) with ethyl acetate. The combined organic layers were then washed with brine and dried over MgSO4. The solution was concentrated in vacuo and then subjected to silica gel column chromatography using petroleum ether/ethyl acetate (7:1, v/v) to obtain the target compounds (5a–5k).

Description of 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitro-N-phenylbenzamide (5a): White solid, yield 76.5%. m.p. 193.2–195.1 °C; 1H NMR (500 MHz, CDCl3) δ 8.85 (s, 1H), 8.11 (d, J = 9.1 Hz, 1H), 8.08 (d, J = 1.5 Hz, 1H), 7.92 (s, 1H), 7.87 (d, J = 8.6 Hz, 2H), 7.54 (d, J = 7.8 Hz, 2H), 7.34 (t, J = 7.8 Hz, 2H), 7.22 (d, J = 8.6 Hz, 2H), 7.16 (dd, J = 7.0, 3.8 Hz, 2H), 7.12 (dd, J = 9.1, 2.6 Hz, 1H); 13C NMR (101 MHz, CDCl3) 162.05, 155.47, 144.38, 137.14, 135.55, 131.91, 130.19, 129.21, 127.50, 125.30, 120.51, 120.14, 118.54, 117.00. HRMS calcd. for C25H14ClF3N3O4 [M–H]− 512.0630, found 512.0628.

Description of 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-N-(3-chlorophenyl)-2-nitrobenzamide (5b): White solid, yield 73.8%. m.p. 209.4–211.7 °C; 1H NMR (500 MHz, CDCl3) δ 8.77 (d, J = 1.1 Hz, 1H), 8.09 (d, J = 9.3 Hz, 1H), 8.00 (d, J = 1.6 Hz, 1H), 7.81 (d, J = 8.6 Hz, 2H), 7.60 (d, J = 6.5 Hz, 2H), 7.34 (d, J = 7.6 Hz, 1H), 7.21 (d, J = 8.0 Hz, 1H), 7.16 (s, 1H), 7.14 (s, 1H), 7.10 (s, 1H), 7.09–7.08 (m, 1H), 7.08–7.06 (m, 1H); 13C NMR (101 MHz, CDCl3) δ 163.96, 162.15, 158.52, 155.37, 144.37, 144.33, 144.29, 140.14, 138.28, 135.61, 135.57, 135.11, 134.84, 134.45, 131.92, 130.17, 127.53, 125.32, 120.56, 120.18, 118.66, 118.41, 116.86. HRMS calcd. for C25H13Cl2F3N3O4 [M–H]− 546.0241, found 5446.0239.

Description of 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-N-(2,4-dimethylphenyl)-2-nitrobenzamide (5c): White solid, yield 77.6%. m.p. 175.1–177.2 °C; 1H NMR (500 MHz, CDCl3) δ 8.77 (s, 1H), 8.04 (t, J = 8.7 Hz, 1H), 7.98 (dd, J = 9.5, 1.4 Hz, 1H), 7.83–7.74 (m, 2H), 7.51 (d, J = 7.9 Hz, 1H), 7.28 (d, J = 17.3 Hz, 1H), 7.15 (d, J = 5.7 Hz, 1H), 7.12 (dd, J = 14.7, 6.8 Hz, 2H), 7.03 (dd, J = 9.0, 2.6 Hz, 1H), 6.95 (d, J = 10.8 Hz, 2H), 2.22 (s, 3H), 2.15 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 164.31, 161.93, 158.57, 155.56, 144.34, 140.45, 136.20, 135.80, 135.58, 135.55, 134.31, 131.94, 131.87, 131.33, 130.74, 130.19, 127.45, 126.19, 124.43, 124.01, 120.06, 118.27, 117.45, 21.29, 17.65. HRMS calcd. for C27H18ClF3N3O4 [M–H]− 540.0943, found 540.0946.

Description of 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-N-(2-methoxyphenyl)-2-nitrobenzamide (5d): Yellow solid, yield 80.3%. m.p. 151.3–154.2 ℃; 1H NMR (500 MHz, CDCl3) δ 8.86 (d, J = 0.9 Hz, 1H), 8.45 (dd, J = 7.9, 1.2 Hz, 1H), 8.18 (d, J = 9.1 Hz, 1H), 8.08–8.03 (m, 2H), 7.89 (d, J = 8.6 Hz, 2H), 7.25 (s, 1H), 7.24–7.21 (m, 2H), 7.16 (dd, J = 9.1, 2.7 Hz, 1H), 7.13–7.10 (m, 1H), 7.02 (t, J = 7.4 Hz, 1H), 6.91 (d, J = 7.7 Hz, 1H), 3.86 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 163.40, 161.90, 158.56, 155.56, 148.01, 144.38, 144.34, 140.55, 135.76, 135.58, 134.31, 131.88, 130.17, 127.47, 127.17, 126.51, 124.66, 121.27, 120.22, 120.09, 118.41, 117.18, 110.08, 55.73. HRMS calcd. for C26H16ClF3N3O5 [M–H]− 542.0736, found 542.0741.

Description of N-(3-chloro-2-methylphenyl)-5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitrobenzamide (5e): White solid, yield 81.9%. m.p. 172.3–174.6 °C; 1H NMR (500 MHz, CDCl3) δ 8.86 (s, 1H), 8.15 (t, J = 8.6 Hz, 1H), 8.08 (d, J = 1.6 Hz, 1H), 7.88 (t, J = 7.6 Hz, 2H), 7.65 (d, J = 7.9 Hz, 1H), 7.53 (d, J = 12.6 Hz, 1H), 7.27 (s, 1H), 7.24 (d, J = 8.4 Hz, 2H), 7.21 (d, J = 2.0 Hz, 1H), 7.18 (t, J = 7.2 Hz, 1H), 7.14 (dd, J = 9.2, 2.4 Hz, 1H), 2.31 (s, 3H); 13C NMR 101 MHz, CDCl3) δ 164.36, 162.11, 158.52, 155.42, 144.36, 140.31, 135.71, 135.60, 135.56, 135.31, 135.09, 134.83, 134.45, 131.91, 130.20, 129.49, 127.58, 127.41, 127.16, 123.28, 120.11, 118.43, 117.25, 14.74. HRMS calcd. for C26H15Cl2F3N3O4 [M–H]− 560.0397, found 560.0399.

Description of N-(4-chloro-2-methylphenyl)-5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitrobenzamide (5f): White solid, yield 80.2%. m.p. 199.2–201.7 °C; 1H NMR (400 MHz, CDCl3) δ 8.88 (s, 1H), 8.21 (d, J = 9.1 Hz, 1H), 8.10 (s, 1H), 7.91 (d, J = 8.4 Hz, 2H), 7.82 (d, J = 8.3 Hz, 1H), 7.28–7.16 (m, 7H), 2.29 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 164.20, 162.10, 158.51, 155.44, 144.41, 144.37, 140.33, 135.60, 135.57, 135.40, 134.45, 133.24, 132.08, 131.91, 131.41, 130.48, 130.19, 127.58, 126.98, 125.35, 120.12, 118.47, 117.56, 117.23, 17.92. HRMS calcd. for C26H15Cl2F3N3O4 [M–H]− 560.0397, found 560.0402.

Description of N-(5-chloro-2-methylphenyl)-5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitrobenzamide (5g): white solid, yield 74.9%. m.p. 184.2–186.4 °C; 1H NMR (400 MHz, CDCl3) δ 8.88 (s, 1H), 8.21 (d, J = 9.1 Hz, 1H), 8.10 (s, 1H), 7.91 (d, J = 8.4 Hz, 2H), 7.82 (d, J = 8.3 Hz, 1H), 7.28–7.16 (m, 7H), 2.29 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 164.10, 162.14, 158.53, 155.41, 144.39, 140.25, 135.68, 135.60, 135.27, 134.46, 132.25, 131.92, 131.51, 130.20, 127.98, 127.56, 126.57, 126.24, 126.08, 123.61, 120.15, 118.49, 117.18, 17.32. HRMS calcd. for C26H15Cl2F3N3O4 [M–H]− 560.0397, found 560.0404.

Description of 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitro-N-(3-(trifluoromethoxy)phenyl)benzamide (5h): brown solid, yield 76.1%. m.p. 140.2–141.4 °C; 1H NMR (500 MHz, CDCl3) δ 8.85 (s, 1H), 8.12 (t, J = 7.6 Hz, 1H), 8.08 (d, J = 1.6 Hz, 1H), 7.87 (d, J = 7.0 Hz, 2H), 7.85 (d, J = 7.1 Hz, 1H), 7.46–7.42 (m, 4H), 7.22 (d, J = 8.6 Hz, 2H), 7.13 (dd, J = 8.4, 5.8 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 185.24, 164.30, 162.18, 158.52, 155.31, 144.34, 144.30, 139.95, 137.74, 135.62, 135.58, 134.93, 134.43, 131.90, 131.65, 130.23, 129.75, 127.45, 123.57, 121.76, 120.19, 118.61, 117.14, 116.82. HRMS calcd. for C26H13ClF6N3O5 [M–H]− 596.0415, found 596.0410.

Description of 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-N-(2,4-difluorophenyl)-2-nitrobenzamide (5i): White solid, yield 78.1%. m.p. 159.1–161.5 °C; 1H NMR (400 MHz, CDCl3) δ 8.84 (s, 1H), 8.25 (s, 1H), 8.09 (dd, J = 5.1, 3.7 Hz, 2H), 7.86 (d, J = 8.6 Hz, 2H), 7.52 (s, 1H), 7.42 (d, J = 8.1 Hz, 1H), 7.33 (t, J = 8.2 Hz, 1H), 7.22 (d, J = 8.5 Hz, 2H), 7.15 –7.10 (m, 2H), 7.02 (d, J = 8.1 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 163.78, 162.18, 158.52, 155.36, 144.36, 140.24, 135.60, 134.94, 134.50, 131.93, 130.20, 127.62, 126.25, 123.49, 123.38, 120.21, 118.70, 116.89, 111.70, 111.48, 103.80. HRMS calcd. for C25H13ClF5N3O4 [M–H]− 548.0422, found 548.0422.

Description of 5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitro-N-(3-(trifluoromethyl)phenyl)benzamide (5j): white solid, yield 74.3%. m.p. 146.1–148.7 °C; 1H NMR (400 MHz, CDCl3) δ 8.88 (s, 1H), 8.15 (d, J = 8.5 Hz, 1H), 8.10 (s, 1H), 7.89 (d, J = 8.7 Hz, 2H), 7.34 (d, J = 8.5 Hz, 2H), 7.22 (d, J = 8.7 Hz, 2H), 7.13 (d, J = 8.5 Hz, 2H), 6.91 (d, J = 8.6 Hz, 2H), 4.59 (d, J = 5.4 Hz, 2H), 3.82 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 164.24, 162.15, 158.53, 155.33, 149.53, 144.33, 144.29, 139.91, 138.62, 135.61, 135.58, 134.95, 134.39, 131.88, 130.22, 127.40, 126.57, 126.23, 120.16, 118.57, 118.44, 117.16, 116.83, 113.20. HRMS calcd. for C26H13ClF6N3O4 [M–H]− 596.0453, found 596.0447.

Description of N-(4-acetylphenyl)-5-(4-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)phenoxy)-2-nitrobenzamide (5k): white solid, yield 77.6%. m.p. 196.1–198.3 °C; 1H NMR (400 MHz, CDCl3) δ 8.86 (s, 1H), 8.19 (d, J = 8.9 Hz, 1H), 8.09 (s, 1H), 8.04 (s, 1H), 7.97 (d, J = 8.5 Hz, 2H), 7.89 (d, J = 8.5 Hz, 2H), 7.69 (s, 1H), 7.25–7.16 (m, 5H), 2.60 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 164.01, 162.17, 158.49, 155.34, 144.38, 144.34, 144.31, 141.60, 140.13, 135.58, 135.07, 134.49, 133.59, 131.93, 130.20, 129.82, 127.55, 120.16, 119.55, 118.73, 116.84, 29.71, 26.52. HRMS calcd. for C27H16ClF3N3O5 [M–H]− 554.0736, found 554.0737.

3.3. Insecticidal Activity Test

The insecticidal activities of 5a–5k against Mythimna separata, Aphis craccivora Koch, and Tetranychus cinnabarinus were evaluated according to a previously reported method [28,29,30]. First, all test compounds were dissolved in N,N-dimethylformamide containing 0.1% Tween-80 emulsifier and were then diluted to the corresponding dosage with distilled water. Appropriate amounts of corn leaves were fully soaked in liquid medicine for 10 s, dried naturally in the shade, and placed in a culture dish with filter paper. The larvae of Mythimna separata, Aphis craccivora Koch, and Tetranychus cinnabarinus were placed indoors on the processed corn leaves at 24–27 °C. The results were obtained after three days; the insect was touched with a brush, and it was regarded dead if there was no response. The control check (CK) group used only distilled water without any compounds, and the results of insecticidal activities are reported in Table 1.

4. Conclusions

A series of new 2-phenylpyridine derivatives containing N-phenylbenzamide moieties were designed and synthesised as possible insecticidal candidates. Compounds 5b, 5d, 5g, 5h, and 5k exhibited high insecticidal activities (100%) against Mythimna separata at 500 mg/L. Thus, the results of this study will provide a novel direction for the further use of 2-phenylpyridine derivatives as insecticides.

Acknowledgments

We are grateful to Dong-Song Han (Zhejiang Research Institute of Chemical Industry) for helping with the bioactivity assays.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules28041567/s1, Figures S1–S22: 1H NMR and 13C NMR spectra of target compounds 5a–5k.

Click here for additional data file. (2.7MB, zip)

Author Contributions

W.Z. and J.C. performed the experiments; W.Z. prepared the manuscript; X.D. designed the materials and supervised the project; and X.D. revised the paper. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

Funding Statement

This study received no external funding.

Footnotes

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References

  • 1.Zhu Q.-H., Chen L.-Y., Li L.-J., Li H.-Y., Zhang L.-Z., Zhao N.-X., Xu Y.-G. Preparation Method of Fluorochloropyridine Ester. CN 113603637. CN Patent. 2021 November 5;
  • 2.Jason S.K., David J.C., Abraham D.S., Megan E.D., Brian M., Ronald B.L. Method of Preparing Benzyl 4-amino-3-chloro-5-fluoro-6-(4-chloro-2-fluoro-3-methoxyphenyl)picolinate. US 20180162814. U.S. Patent. 2018 June 14;
  • 3.Yoshinobu J., Akihiro T. Herbicidal Agent Composition and Weed Control Method. US 20220322666. U.S. Patent. 2021 March 4;
  • 4.Mansfield A.J., Cooke T., Thomas P.S., Coqueron P.Y., Vors J.P., Briggs G.G., Lachaise H., Rieck H., Desbordes P., Grosjean M.C. Novel 2-pyridylethylbebzamide Derivative. WO 2004026088. WO Patent. 2004 February 26;
  • 5.Bristow J.T. Process for Preparing Boscalid. WO 2018024145. WO Patent. 2018 February 7;
  • 6.Yang C.-H., Geng L.-W., Zhou D.-F., Peng L., Zhang H., Cui D.-L., Li Z.-N., Wang L.-Q., Zang S.-G., Zhang Z.-Y. N-(2-substituted phenyl)-N-methoxy carbamates and their preparation and use thereof. EP 1845086. EP Patent. 2006 August 10;
  • 7.Yang G.-F., Li J. Preparation of Dichloroallyl ether Compound and Their Application as the Insecticide Agents. CN 104974083. CN Patent. 2015 October 14;
  • 8.Ke S.-Y., Yang Z.-W., Zhang Z.-G., Wang K.-M., Liang Y. Preparation of Bisamide Structure-Containing Heterocyclic Imine Derivatives Useful as Pesticides. CN 105622534. CN Patent. 2016 June 1;
  • 9.Jeschke P., Velten R., Schenke T., Schallner O., Beck M., Pontzen R., Malsam O., Reckmann U., Nauen R., Gorgens U. Preparation of 4-[(pyridin-3-ylmethyl)amino]-5H-furan-2-ones as Insecticides. DE 102006015467. DE Patent. 2007 October 4;
  • 10.Robert H., Christine G., Robert S. N-phenyl-N’-(pyridinyl-N-oxide)urea Plant Regulators. US 4787931. U.S. Patent. 1988 November 29;
  • 11.Yang S.-X., Chen R.-Y., Chen J.-L. Preparation of 3-(2-pyridyl) Propanol. CN 85102587. CN Patent. 1986 February 10;
  • 12.Cai Z.-F., Cao Y.-Y., Du X.-H. Synthesis of Novel a-Trifluoroanisole Derivatives Containing Phenylpyridine Moieties with Herbicidal Activity. Int. J. Mol. Sci. 2022;23:11083. doi: 10.3390/ijms231911083. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Cao Y.-Y., Mao D.-J., Wang W.-W., Du X.-H. Kresoxim-methyl derivatives: Synthesis and herbicidal activities of (pyridinylphenoxymethylene)phenyl methoxyiminoacetates. J. Agric. Food Chem. 2017;65:6114–6121. doi: 10.1021/acs.jafc.7b02710. [DOI] [PubMed] [Google Scholar]
  • 14.Cao Y.-Y., Cai Z.-F., Zhang W.-L., Du X.-H. Synthesis and herbicidal activity of novel β-methoxyacrylate derivatives containing a substituted phenylpyridine moiety. Chem. Res. Chin. Univ. 2019;35:1008–1011. doi: 10.1007/s40242-019-9128-z. [DOI] [Google Scholar]
  • 15.Xu Y., Wang H.-T., Du X.-H. Design, synthesis, and fungicidal activity of novel N-substituted piperazine-containing phenylpyridines against cucumber downy mildew. Pest Manag. Sci. 2022;78:1806–1814. doi: 10.1002/ps.6798. [DOI] [PubMed] [Google Scholar]
  • 16.Liu C.-L., Xie Y., Song Y.-Q., Xu Y., Li K.-K., Guan A.-Y., Yang J.-C., Yang F. Ayrl Pyridine(pyrimidine) Compound and Use Thereof. WO 2015032280. WO Patent. 2015 March 18;
  • 17.Jeanguenat A., Emery D., Hall R.G., Iosub V.A., Lechapelain C., Gagnepain J.D.H., Kilaru J.P., Phadte M., Pitterna T. Pesticidally Active Azole-Amide Compounds. WO 2021122645. WO Patent. 2021 June 24;
  • 18.Lahm G.P., Mccann S.F., Patel K.M., Selby T.P., Stevenson T.M. Method for Controlling Particular Inset Pests by Applying Anthranilamide Compounds. WO 03015518. WO Patent. 2003 February 27;
  • 19.Li B., Yang H.-B., Wang J.-F., Yu H.-B., Zhang H., Li Z.-N., Song Q. 1-Substituted Pyridyl-Pyrazolyl Amide Compousnds and Uses Thereof. US 8492409. US Patent. 2008 December 31;
  • 20.Elbe H.L., Rieck H., Dunkel R., Qin Z.-O., Mauler-Machnik A., Wachendorff-Neumann U., Kuck K.H. Pyrazolylcarboxanilides as Fungicides. WO 0300149. WO Patent. 2003 February 6;
  • 21.Munro D., Patel B. Preparation of Benzoic Acid-2′,4′-difluoroanilide Herbicidal Compounds. EP 0467473. EP Patent. 1992 January 22;
  • 22.Hao S.-L., Cai Z.-F., Cao Y.-Y., Du X.-H. Design, synthesis, and acaricidal activity of phenyl methoxyacrylates containing 2-alkenylthiopyrimidine. Molecules. 2020;25:3379–3390. doi: 10.3390/molecules25153379. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Panchal D.M., Desai J.K. Process for preparation of insecticidal anthranilamides. WO 2022149098. WO Patent. 2022 July 15;
  • 24.Zhao Y., Xiong L.-X., Xu L.-P., Wang H.-X., Xu H., Li H.-B., Tong J., Li Z.-M. Synthesis, crystal structure and biological activity of a novel anthranilic diamide insecticide containing allyl ether. Res. Chem. Intermed. 2013;39:3071–3088. doi: 10.1007/s11164-012-0820-6. [DOI] [Google Scholar]
  • 25.Jeffrey T.M., Yong-Jae K., Mike L., Chen X.-Q., Jeff D., Malgorzata W., Yu M., Fu J.-S., Chen X., Zhang A., et al. Discovery of a new class of ghrelin receptor antagonists. Bioorg. Med. Chem. Lett. 2012;22:2046–2051. doi: 10.1016/j.bmcl.2012.01.014. [DOI] [PubMed] [Google Scholar]
  • 26.Wang J.-K., Liu S.-J., Lu Y.-Q. Method for Synthesizing Flubendiamide. CN 1094855. CN Patent. 2019 March 19;
  • 27.Ying J.-W., Luo H., Song Y.-Q., Li B., Yang H.-B. Synthesis and insecticidal activity of cyclaniliprole. Mod. Agrochem. 2016;15:28–31. [Google Scholar]
  • 28.Li R., Cheng S.-H., Liang P.-Z., Chen Z.-B., Zhang Y.-J., Liang P., Zhang L., Guo X.-W. Status of the Resistance of Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) to Afidopyropen Originating from Microbial Secondary Metabolites in China. Toxins. 2022;14:750. doi: 10.3390/toxins14110750. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Moores G.D., Gao X.W., Denholm I., Devonshire A.L. Characterisation of insensitive acetylcholinesterase in insecticide-resistant cotton aphids, Aphis gossypii glover (Homoptera: Aphididae) Pestic. Biochem. Physiol. 1996;56:102–110. doi: 10.1006/pest.1996.0064. [DOI] [Google Scholar]
  • 30.Chen S.-L., Zhang Y., Liu Y.-X., Wang Q.-M. Highly Efficient Synthesis and Acaricidal and Insecticidal Activities of Novel Oxazolines with N-Heterocyclic Substituents. J. Agric. Food Chem. 2021;69:3601–3606. doi: 10.1021/acs.jafc.0c05558. [DOI] [PubMed] [Google Scholar]

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