Design, Synthesis, Acaricidal/Insecticidal Activity, and Structure–Activity Relationship Studies of Novel Oxazolines Containing Sulfone/Sulfoxide Groups Based on the Sulfonylurea Receptor Protein-Binding Site

Enormous compounds containing sulfone/sulfoxide groups have been used in a variety of fields, especially in drug and pesticide design. To search for novel environmentally benign and ecologically safe pesticides with unique modes of action, a series of 2,4-diphenyl-1,3-oxazolines containing sulfone/sulfoxide groups as chitin synthesis inhibitors (CSIs) were designed and synthesized on the basis of the sulfonylurea receptor protein-binding site for CSIs. Their structures were characterized by H-1 and C-13 nuclear magnetic resonance and high-resolution mass spectrometry. The acaricidal and insecticidal activities of the new compounds were evaluated. It was found that most of the target compounds displayed wonderful acaricidal activities against spider mite (Tetranychus cinnabarinus) larvae and eggs. Especially compounds I-4, II-3, and II-4 displayed higher activities than commercial etoxazole at a concentration of 2.5 mg L-1. Some target compounds exhibited insecticidal activities against lepidopteran pests. The present work demonstrated that these compounds containing sulfone/sulfoxide groups could be considered as potential candidates for the development of novel acaricides in the future.