Natural Product-Based Pesticide Discovery: Design, Synthesis and Bioactivity Studies of N-Amino-Maleimide Derivatives

Natural products are an important source of pesticide discovery. A series ofN-amino-maleimide derivatives containing hydrazone group were designed and synthesized based on the structure of linderone and methyllinderone which were isolated fromLindera erythrocarpaMakino. According to the bioassay results, compounds2and3showed 60% inhibition against mosquito (Culex pipiens pallens) at 0.25 µg·mL−1. Furthermore, the results of antifungal tests indicated that most compounds exhibited much better antifungal activities against fourteen phytopathogenic fungi than linderone and methyllinderone and some compounds exhibited better antifungal activities than commercial fungicides (carbendazim and chlorothalonil) at 50 µg·mL−1. In particular, compound12exhibited broad-spectrum fungicidal activity (>50% inhibitory activities against 11 phytopathogenic fungi) and compounds12and14displayed 60.6% and 47.9% inhibitory activity againstRhizoctonia cerealisat 12.5 µg·mL−1respectively. Furthermore, compound17was synthesized, which lacks N-substituent at maleimide and its poor antifungal activity againstSclerotinia sclerotiorumandRhizoctonia cerealisat 50 µg·mL−1showed that the backbone structure ofN-amino-maleimide derivatives containing hydrazone group was important to the antifungal activity.Keywords:maleimide;linderone;methyllinderone;antifungal activity