Design and Synthesis of a Series of Piperazine‐1‐carboxamidine Derivatives with Antifungal Activity Resulting from Accumulation of Endogenous Reactive Oxygen Species

In this study, we screened a library of 500 compounds for fungicidal activity via induction of endogenous reactive oxygen species (ROS) accumulation. Structure–activity relationship studies showed that piperazine-1-carboxamidine analogues with large atoms or large side chains substituted on the phenyl group at the R 3 and R 5 positions are characterized by a high ROS accumulation capacity in Candida albicans and a high fungicidal activity. Moreover, we could link the fungicidal mode of action of the piperazine-1-carboxamidine derivatives to the accumulation of endogenous ROS.