Design, synthesis, and insecticidal activity of novel terpenoid ester compounds containing bicyclo[2.2.1] heptane against Aphis gossypii Glover

To discover novel and efficient compounds against Aphis gossypii Glover, a series of novel terpene ester derivatives containing the structure of bicyclo[2.2.1]heptane were designed and synthesized using tschimganin as the lead compound. Bioactivity assays showed that most tschimganin analogs exhibited moderate to outstanding insecticidal activity against A. gossypii. In particular, compound 56 (LC₅₀ = 0.28 μg mL⁻¹), identified as (1S,2S,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl nicotinate, exhibited the best activity, which was significantly superior to that of imidacloprid (LC₅₀ = 0.54 μg mL⁻¹) and sulfoxaflor (LC₅₀ = 0.70 μg mL⁻¹). The precise and dependable 3D-QSAR model suggests a promising direction for further design of more active tschimganin-based insecticides. Metabolomics showed that compound 56 disrupted detoxification, amino acid biosynthesis, and energy metabolism and may affect the central nervous system of A. gossypii. The results of this study indicated that tschimganin analogs are a potential new class of green insecticides that can be used for the integrated management of A. gossypii.