In this study, thirty 1,3,4-oxadiazole sulfone derivatives containing 3,4-dichloroisothiazolamide moiety were designed and synthesized, and their antibacterial activities were evaluated. Bioassay results showed that some compounds exhibited excellent antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) in vitro and in vivo. Notably, the EC50 values of compounds 2 and 3 against Xoo were 0.79 and 0.85 μg/mL, respectively, which were superior to those of the control agents isotianil, bismerthiazol, and thiodiazole copper. In addition, in vivo antibacterial activities revealed that the compound 2 at 50 μg/mL possessed protective and curative activities of 43.99% and 41.06% against Xoo, respectively, which were better than positive controls. Furthermore, the preliminary mechanism study disclosed that compound 2 exhibited effective antibacterial activity against Xoo by inhibiting the formation of extracellular polysaccharides from Xoo, increasing cell permeability, and changing the shape of cells. This study suggested that 1,3,4-oxadiazole sulfone derivatives containing 3,4-dichloroisothiazolamide moiety displayed excellent antibacterial activity and could be further explored and developed as commercial pesticides.

中文翻译：

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含3,4-二氯异噻唑基酰胺部分的新型1,3,4-恶二唑砜化合物的设计合成及水稻细菌活性评价

本研究设计合成了30种含有3,4-二氯异噻唑酰胺部分的1,3,4-恶二唑砜衍生物，并对其抗菌活性进行了评价。生物测定结果表明，某些化合物对米黄单胞菌 pv 表现出优异的抗菌活性。oryzae (Xoo) 和 Xanthomonas oryzae pv。oryzicola (Xoc) 体外和体内。值得注意的是，化合物 2 和 3 对 Xoo 的 EC50 值分别为 0.79 和 0.85 μg/mL，优于对照剂异噻菌胺、双甲基噻唑和硫二唑铜。此外，体内抗菌活性显示50 μg/mL的化合物2对Xoo的保护和治疗活性分别为43.99%和41.06%，优于阳性对照。此外，初步机制研究表明，化合物2通过抑制Xoo胞外多糖的形成，增加细胞通透性，改变细胞形态，对Xoo表现出有效的抗菌活性。该研究表明，含有 3,4-二氯异噻唑酰胺部分的 1,3,4-恶二唑砜衍生物显示出优异的抗菌活性，可以进一步探索和开发为商业农药。