Synthesis, Antifungal Activity, and Action Mechanism of Anethole-Derived Amide-Urea Compounds

In order to develop new antifungal molecules and explore further applications of natural products, 25 novel amide-urea compounds were synthesized from anethole in this work by a few simple reactions, and structural confirmation was conducted using ¹H-nuclear magnetic resonance (¹H-NMR), ¹³C-NMR, high-resolution mass spectrometry, and Fourier transform infrared spectroscopy. Preliminary bioactivity tests were performed against eight plant pathogens. The results demonstrated that all compounds exhibited antifungal activity against the tested fungi, and 5p exhibited the most potent antifungal activity. To explore the action mechanism of the antifungal compounds, the inhibitory activity of 5p against succinate dehydrogenase (SDH) was evaluated and found to be comparable to that of boscalid. Furthermore, the binding mode of the compound to SDH was simulated by molecular docking, and similarities between 5p and boscalid's binding with SDH were identified. The results indicate that further investigation of compound 5p may prove beneficial in determining its potential as a fungicide.