Synthesis of Piperine-Based Ester Derivatives with Diverse Aromatic Rings and Their Agricultural Bioactivities against Tetranychus cinnabarinus Boisduval, Aphis citricola Van der Goot, and Eriosoma lanigerum Hausmann.

Exploration of plant secondary metabolites or by using them as leads for development of new pesticides has become one of the focal research topics nowadays. Herein, a series of new ester derivatives of piperine were prepared via the Vilsmeier-Haack-Arnold (VHA) reaction, and their structures were characterized by infrared spectroscopy (IR), melting point (mp), proton nuclear magnetic resonance spectroscopy (H NMR), and carbon nuclear magnetic resonance spectroscopy (C NMR). Notably, the steric configurations of compounds and were confirmed by single-crystal analysis. Against , compounds and exhibited 47.6- and 45.4-fold more pronounced acaricidal activity than piperine. In particular, compounds and also showed 2.6-fold control efficiency on the fifth day of piperine. In addition, compound (>10-fold higher than piperine) displayed the most potent aphicidal activity against . Furthermore, some derivatives showed good aphicidal activities against . Moreover, the effects of compounds on the cuticles of were investigated by the scanning electron microscope (SEM) imaging method. This study will pave the way for future high value added application of piperine and its derivatives as botanical pesticides.