Pyrrole‐containing acylhydrazone derivatives: Design, synthesis and antiviral activity

BACKGROUND Tobacco mosaic virus (TMV), a highly stable and contagious pathogen, severely threatens global agriculture, especially solanaceous crops, causing major yield losses. Developing highly effective and environmentally compatible novel pesticides is therefore urgently needed. To this end, we designed a series of novel derivatives by modifying the scaffold of chlorantraniliprole with antiviral acylhydrazone moieties, aiming to redirect bioactivity toward antiviral defense. RESULTS Anti‐TMV activity assays demonstrated that compound Y29 exhibited superior efficacy. Its curative activity (median effective concentration (EC 50 ) = 174.1 μg mL −1 ) was significantly higher than that of ningnanmycin (EC 50 = 191.9 μg mL −1 ), while its protective activity (EC 50 = 142.8 μg mL −1 ) also outperformed ningnanmycin (EC 50 = 178.1 μg mL −1 ). Mechanistic studies revealed that compound Y29 enhances systemic resistance by increasing defense‐related enzyme activities and elevating chlorophyll content. Transcriptomic and real‐time quantitative polymerase chain reaction (RT‐qPCR) analyses confirmed that compound Y29 up‐regulates the expression of defense‐related genes, thereby enhancing plant immunity. CONCLUSION This study designed and synthesized novel pyrrole acylhydrazone derivatives, which demonstrated significant protective and curative effects against TMV. Mechanistic investigation confirmed their potential as novel antiviral agents that activate plant defense responses.