Antifungal activity of simple compounds with maleic anhydride or dimethylmaleimide structure against Botrytis cinerea

Compounds with maleic anhydride or maleimide presented considerable antifungal activity, and several maleimide derivatives have been reported to possess marginal or null zootoxic activity. In order to research the antifungal activity of the maleic anhydride or maleimide structure in these compounds, 44 related compounds were purchased or synthesized, and their MICs against Botrytis cinerea were investigated. The results showed that most maleic anhydrides and maleimides presented antifungal activity against B. cinerea. 2,3-Dimethyl maleic anhydride had the highest activity (MIC=3 µg/mL) among the 27 simple compounds with maleic anhydride. Meanwhile, N-3,5-dichloroaniline-3,4-dimethylmaleimide was the best (MIC=0.1 µg/mL) of the 17 maleimide derivatives, with activities nearly equal to those of dichloran. Furthermore, the data in this article reveals that the polarity and steric hindrance of maleic anhydride derivatives could affect their antifungal activities.