Design, synthesis and antifungal evaluation of phenylthiazole-1,3,4-oxadiazole thione (ketone) derivatives inspired by natural thiasporine A.

Abstract

Plant pathogenic fungal infections have become a severe threat to the yield and quality of agricultural products, and new green antifungal agents with high-efficiency and low-toxicity are needed. In this study, a series of thiasporine A derivatives containing phenylthiazole-1,3,4-oxadiazole thione (ketone) structures were designed and synthesized, and their antifungal activities against six invasive and highly destructive phytopathogenic fungi were evaluated. The results showed that all compounds showed moderate to potent antifungal activity against six phytopathogenic fungi, and most of E the series compounds showed remarkable antifungal activity against S. sclerotiorum and C. camelliaet. In particular, compounds E1 - E5, E7, E8, E13, E14, E17, and E22 showed more significant antifungal activity against S. sclerotiorum, with EC50 values of 0.22，0.48, 0.56, 0.65, 0.51, 0.39, 0.60, 0.56, 0.60, 0.63, and 0.45 μg/mL, respectively, which were superior to that of carbendazim (0.70 μg/mL). Further activity studies showed that compound E1 showed superior curative activities against S. sclerotiorum in vivo and better inhibitory effects on sclerotia germination and formation of S. sclerotiorum compared to those of carbendazim. Therefore, this study indicates that these thiasporine A derivatives containing phenylthiazole-1,3,4-oxadiazole thione structures might be applied as antifungal agents against S. sclerotiorum. This article is protected by copyright. All rights reserved.