Synthesis and antifungal activities of novel thiophene‐based stilbene derivatives bearing an 1,3,4‐oxadiazole unit

Abstract BACKGROUND Natural stilbenes (especially resveratrol and its derivatives) are well‐known phytoalexins that are active against many plant diseases. However, oxidative degradation and low bioavailability limit their exogenous application as fungicides on crops. In this study, a new class of resveratrol‐inspired thiophene‐based stilbene derivatives bearing an 1,3,4‐oxadiazole unit was synthesized and the derivatives' antifungal activities against phytopathogenic fungi were investigated. RESULTS The results revealed that compounds 5h and 5j exhibited improved antifungal activity against Botrytis cinerea with median effective concentrations (EC 50 ) of 168.5 and 155.4 µ g mL −1 , respectively, which were superior to the EC 50 of resveratrol (263.1 µ g mL −1 ). Compound 5j was shown to effectively control disease development in B. cinerea ‐infected tomatoes in vivo . Notably, considerably abnormal mycelial morphology and increased cell membrane conductivity were observed in the presence of compound 5j . CONCLUSION A new class of thiophene‐containing stilbene derivatives was designed and synthesized. Bioassay results showed that compound 5j exhibited promising antifungal activity, suggesting practical potential for fungal disease control. © 2018 Society of Chemical Industry