High Value-Added Application of Natural Plant Products in Crop Protection: Construction and Pesticidal Activities of Piperine-Type Ester Derivatives and Their Toxicology Study.

To discover new potential pesticide candidates, recently, structural modification of natural bioactive products has received much attention. In this work, a series of new piperine-type ester derivatives were regio- and stereoselectively synthesized based on a natural alkaloid piperine isolated from . Their structures were characterized by IR, mp, H NMR (C NMR), and high-resolution mass spectrometry (HRMS). Against Boisduval (Acari: Tetranychidae), compounds , , , and displayed the most significant acaricidal activity with LC values of 0.155, 0.117, 0.177, and 0.164 mg/mL, respectively. Particularly, compound showed >120-fold higher acaricidal activity than piperine (LC: 14.198 mg/mL). Notably, the acaricidal activity of was equivalent to that of the commercial acaricide spirodiclofen (LC: 0.115 mg/mL). Additionally, against Hausmann (Hemiptera: Aphididae), compounds and showed 1.8-fold aphicidal activity of piperine. Furthermore, the scanning electron microscope (SEM) imaging method, the obvious destruction of the construction of the cuticle layer of treated was observed. Compound could be further studied as a lead acaricidal agent.