Synthesis, Fungicidal, and Insecticidal Activities of β-Methoxyacrylate-Containing N-Acetyl Pyrazoline Derivatives

1-Acetyl-3,-5-diarylpyrazolines have received considerable interests from the fields of medicinal and agricultural chemistry due to their broad spectrum of biological activities. To discover new lead compounds exhibiting both fungicidal and insecticidal activities, a series of pyrazoline derivatives were designed and synthesized by introducing the β-methoxyacrylate pharmacophore into the scaffold of 1-acetyl-3,5-diarylpyrazoline. The fungicidal activities against Pseudoperoniospora cubensis, Sphaerotheca fuliginea, Botrytis cinerea, and Rhizoctonia solani and the insecticidal activities against Aphis medicagini, Nilaparvata legen, Mythima separata, and Tetranychus cinnabarnus were screened. The most potent compound 13, 1-aceto-3-{m-[o-(E-1-methoxycarboxyl-2-methoxy)-1-yl]benzyloxy}phenyl-5-(benzo-[1,3]-dioxolyl)-4,5-dihydro- pyrazoline, was identified. Its fungicidal IC₅₀ values against P. cubensis and S. fuliginea are 26.6 and 57.6 μg mL⁻¹, respectively, while its insecticidal LC₅₀ value against M. separata is 26.6 μg mL⁻¹. These results indicated that compound 13 could be used as a lead for further developing new pyrazoline type products exhibiting both fungicidal and insecticidal activities.