Trifluoromethylpyridine thiourea derivatives: design, synthesis and inhibition of the self‐assembly of tobacco mosaic virus particles

Abstract BACKGROUND Devastating plant virus diseases leading to bad harvests and lower quality of crops have made feeding the beyond seven billion population a huge challenge. Nevertheless, growing resistance and cross resistance of crop protection agents have made this challenge harder. Therefore, an efficient crop protection agent with novel structure and mode of action showing higher efficiency and eco‐friendly is urgently needed. RESULTS The coat protein (CP) of a virus is a potential target for the discovery of new antiviral agents. Antiviral molecules can inhibit infection by obstructing the assembly of virus particles. A series of novel phthalamide‐like thiourea derivatives containing trifluoromethylpyridine was designed and synthesized. Most of the compounds exhibited good antiviral activity against tobacco mosaic virus (TMV). Compound 7b showed notable curative, protective and inactivation activities against TMV. Its inactivation half‐maximal effective concentration (EC 50 ) value (20.5 μg mL −1 ) was better even than commercial ningnanmycin (23.2 μg mL −1 ). Compound 7b also had stronger TMV‐CP binding ability than ningnanmycin and destroyed the external shape of TMV particles and hindered the self‐assembly of TMV‐CP and TMV‐RNA. CONCLUSION These phthalamide‐like thiourea derivatives especially compound 7b containing trifluoromethylpyridine are potential lead compounds and inhibitors of TMV particle self‐assembly. © 2021 Society of Chemical Industry.