Synthesis and antifungal activity of coumarin oxime esters

In order to discover high antifungal activity oxime esters compound, based on our previous studies, 18 novel coumarin oxime esters were designed and synthesized. The antifungal activity was evaluated and the structure-activity relationship was analyzed. The in vitro bioassay results showed that the target compounds showed antifungal activities against Botrytis cinerea, Valsa mali and Rhizoctonia solani. Especially, compound 4n displayed excellent activity against B. cinerea (EC₅₀ = 4.44 μg/mL) and R. solani (EC₅₀ = 3.65 μg/mL), which are better than or similar to those of coumarin and trifloxystrobin.