Synthesis and antifungal activity of novel diphenylnorbornane derivatives

One primary approach for developing novel green pesticides is to discover agroactive lead compounds from natural products and modify their structures. In this study, a series of diphenylnorbornane derivatives were designed and synthesized using natural norbornane as a lead compound. Bioactivity results showed that the 22 synthesized target compounds displayed certain bioactivities against the tested plant pathogens at 50 μg/mL. Compounds 4a and 10d exhibited inhibition rates ranging from 80.5% to 100% against Botrytis cinerea, Fusarium graminearum, Phytophthora capsici, Rhizoctonia solani, Fusarium oxyspirum, Sclerotinia sclerotiorum and Valsa mali. Notably, their EC₅₀ values against B. cinerea were 3.31 and 4.02 μg/mL, respectively. Compounds 4a and 10d have characteristics of simple structures, good activity, and broad fungicidal spectrum. These compounds show potential as promising lead compounds for in-depth structural optimization research of fungicides.