Synthesis of novel 9S‐acyloxy derivatives of quinidine and dihydroquinidine as insecticidal agents

Endeavor to discover biorational natural products-based insecticides, two series (30) of novel 9 S -acyloxy derivatives of quinidine and dihydroquinidine were prepared and assessed for their insecticidal activity against Mythimna separata in vivo by the leaf-dipping method at 1 mg/mL. Among all the compounds, especially derivatives 3k , 3m , 3u , and 4k exhibited the best insecticidal activity with final mortality rates of 71.4%, 75.0%, 71.4%, and 75.0%, respectively. Relatively speaking, 9-hydroxyl group is well tolerated, and the results showed that after modification of hydroxyl group with acyloxy, the insecticidal activity was significantly increased; the configuration of C8/9 position is important for insecticidal activity, and 9 S -configuration is optimal; modification of out-ring double-bond is acceptable, and hydrogenation of double-bond enhances insecticidal activity. These preliminary results will pave the way for further modification of quinidine in the development of potential new insecticides.