Synthesis, Crystal Structure, and Insecticidal Activity of Steroidal N-Piperidone.

A series of steroidal piperidone derivatives were synthesized, and their agricultural activities were evaluated against Myzus persicae , Aphis citricola , Brevicoryne brassicae Linn., and Bemisia tabaci (Gennadius). Most of the tested compounds exhibited potent insecticidal activity against these four pests. Compound I-9 displayed the highest activity against M. persicae , A. citricola, and Brevicoryne brassicae , with LC 50 values of 11.3, 10.4, and 8.68 μg/mL, respectively. The mode of action test indicated that these derivatives had superior contact and systemic insecticidal activity against M. persicae . In addition, we initially explored whether the foregut and midgut might be the action sites of the target derivatives against M. persicae . Furthermore, a field trial showed that the control of compound I-9 was similar to that of acetamiprid against M. persicae , at a dose of 50 μg/mL; the control rates were 97.8 and 99.2% after 14 and 21 days, respectively. The structure-activity relationship of these analogues provided some important insights for the discovery and development of new insecticides to solve the current pesticide resistance crisis.