Novel Dioxolane Ring Compounds for the Management of Phytopathogen Diseases as Ergosterol Biosynthesis Inhibitors: Synthesis, Biological Activities, and Molecular Docking

Abstract

Thirty novel dioxolane ring compounds were designed and synthesized. Their chemical structures were confirmed by 1H NMR, HRMS, and single crystal X-ray diffraction analysis. Bioassays indicated that these dioxolane ring derivatives exhibited excellent fungicidal activity against Rhizoctonia solani, Pyricularia oryae, Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum, Physalospora piricola, Cercospora arachidicola and herbicidal activity against lettuce (Lactuca sativa), bentgrass (Agrostis stolonifera), and duckweed (Lemna pausicostata). Among these compounds, 1-((2-(4-chlorophenyl)-5-methyl-1,3-dioxan-2-yl)­methyl)-1H-1,2,4-triazole (D17), 1-(((4R)-2-(4-chlorophenyl)-4-methyl-1,3-dioxolan-2-yl)­methyl)-1H-1,2,4-triazole (D20), 1-((5-methyl-2-(4-(trifluoromethyl)­phenyl)-1,3-dioxan-2-yl)­methyl)-1H-1,2,4-triazole (D22), and 1-((2-(4-fluorophenyl)-1,3-dioxolan-2-yl)­methyl)-1H-1,2,4-triazole (D26) had broad spectrum fungicidal and herbicidal activity. The IC50 values against duckweed were 20.5 ± 9.0, 14.2 ± 6.7, 24.0 ± 11.0, 8.7 ± 3.5, and 8.0 ± 3.1 μM for D17, D20, D22, and D26 and the positive control difenoconazole, respectively. The EC50 values were 7.31 ± 0.67, 9.74 ± 0.83, 17.32 ± 1.23, 11.96 ± 0.98, and 8.93 ± 0.91 mg/L for D17, D20, D22, and D26 and the positive control difenoconazole against the plant pathogen R. solani, respectively. Germination experiments with Arabidopsis seeds indicated that the target of these dioxolane ring compounds in plants is brassinosteroid biosynthesis. Molecular simulation docking results of compound D26 and difenoconazole with fungal CYP51 P450 confirmed that they both inhibit this enzyme involved in ergosterol biosynthesis. The structure–activity relationships (SAR) are discussed by substituent effect, molecular docking, and density functional theory analysis, which provided useful information for designing more active compounds.

Synthesis and pesticidal activity of new 1,3,4-oxadiazole thioether compounds containing a trifluoromethylpyrazoyl moiety

“…The fungicidal activity of compounds 5ª–5 m was tested in vitro against G. zeae, P. infestans, P. capsici, S. sclerotiorum, R. solani, A. solani, B. cinerea, F. oxysporum, C. arachidicola, P. Piricola , and their relative percent inhibition (%) has been determined using the mycelium growth rate method according to the previous work [ 39 ], and fluxapyroxad was used as positive control. Each compound was dissolved in DMSO with 1% tween to prepare the 10,000 mg/L stock solution.…”

Isolation, Synthesis, and Fungicidal Activity of Isopropyl (3-methyl-1-oxo-1-((1-((4-(prop-2-yn-1-yloxy)phenyl)thio)propan-2-yl)amino)butan-2-yl)carbamate Diastereomers against Phytophthora capsici

“…Melting points were measured using an X-4 apparatus (Taike, Beijing, China) and were uncorrected. 1 H NMR and 13 C NMR spectra were recorded on the BRUKER Avance 400 MHz spectrometer using CDCl 3 as a solvent. HR-MS was determined on an FTMS 7.0 instrument.…”

“…To a mixture solution of 1S-methyl-2-p-hydroxyphenyl mercaptoethylamine 2 (0.18 g, 0.86 mmol) and Et 3 N (0.087 g, 0.86 mmol) in THF (10 mL), a solution of isopropyl carbonochloridate (0.11 g, 0.86 mmol) in THF (5 mL) was dropwised at 0 °C for 0.5 h. en, the mixture was stirred for another 2 h. After that, THF was evaporated, washed by saturated potassium carbonate aqueous solution (100 mL), exacted by CH 2 Cl 2 (50 mL), and HCl (50 mL, 1 mol/L) twice, dried and purified by column chromatography (PE:EA = 3: 1). e intermediate compound 3 was given with a yield of 19.9%, yellow oil, 1…”

“…In recent years, modern agriculture, including economic crops, flowers, fruits, trees, and vegetables, were affected by insects, weeds, and diseases. e effective tools to protect plants are pesticides [1][2][3][4][5], which have been an important work in modern agriculture. Phytophthora capsici is an important pathogenic fungal with a wide host range, which is very harmful and destructive to host plants, and often leads to serious losses in crop production.…”

Synthesis, Structure, and Antifungal Activities of 3-(Difluoromethyl)-Pyrazole-4-Carboxylic Oxime Ester Derivatives

“…Fungicidal activities of pyrazole-4carboxylic oxime ester derivatives 5a∼5o were tested according to reported work [31,32]. e antifungal activities of compounds 5a-5o and fluxapyroxad were tested in vitro against Gibberella zeae (GZ), Fusarium oxysporum (FO), Phytophthora infestans (PI), Phytophthora capsici (PC), Rhizoctonia solani (RS), Sclerotinia sclerotiorum (SS), Alternaria solani (AS), Physalospora piricola (PP), Cercospora arachidicola (CA), and Botrytis cinerea (BC).…”