To explore more potential fungicides with new scaffolds, thirty‐seven norbornene carboxamide/sulfonamide derivatives were designed, synthesized, and assayed for inhibitory activity against six plant pathogenic fungi and oomycetes. The preliminary antifungal assay suggested that the title derivatives showed moderate to good antifungal activity against six plant pathogens. Especially, compound 6e presented excellent in vitro antifungal activity against Sclerotinia sclerotiorum (EC50 = 0.71 mg/L), which was substantially stronger than pydiflumetofen. In vivo antifungal assay indicated 6e displayed prominent protective and curative effects on rape leaves infected by S. sclerotiorum. The preliminary mechanism research displayed that 6e could damage the surface morphology and inhibit the sclerotia formation of S. sclerotiorum. In addition, the in vitro enzyme inhibition bioassay indicated that 6e displayed pronounced laccase inhibition activity (IC50 = 0.63 μM), much stronger than positive control cysteine. Molecular docking elucidated the binding modes between 6e and laccase. The bioassay results and mechanism investigation demonstrated that this class of norbornene carboxamide/sulfonamide derivatives could be promising laccase inhibitors for novel fungicide development.

中文翻译：

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降冰片烯甲酰胺/磺酰胺衍生物的合成和抗真菌活性作为潜在的漆酶杀菌剂

为了探索更多具有新支架的潜在杀菌剂，设计、合成了 37 种降冰片烯甲酰胺/磺酰胺衍生物，并测定了其对六种植物病原真菌和卵菌的抑制活性。初步抗真菌测定表明，标题衍生物对六种植物病原体表现出中等至良好的抗真菌活性。特别是，化合物6e对核盘菌表现出优异的体外抗真菌活性(EC50 = 0.71 mg/L)，其明显强于吡虫啉。体内抗真菌试验表明6e对核盘菌感染的油菜叶片具有显着的保护和治疗作用。初步机理研究表明，6e可破坏核盘表面形态，抑制核盘菌核形成。此外，体外酶抑制生物测定表明6e表现出明显的漆酶抑制活性（IC50 = 0.63 μM），远强于阳性对照半胱氨酸。分子对接阐明了 6e 和漆酶之间的结合模式。生物测定结果和机制研究表明，此类降冰片烯甲酰胺/磺酰胺衍生物可能成为新型杀菌剂开发的有前途的漆酶抑制剂。