Abstract A series of novel 1,3,5-thiadiazine-2-thione derivatives bearing a hydrazide moiety were designed, synthesized and evaluated for their antifungal activities against Rhizoctonia solani (Rs), Fusarium graminearum (Fg), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The in vitro antifungal bioassays indicated that most of title compounds displayed good selectivity and specificity aganist Rs relative to Fg, Bc and Cc. Strikingly, the title compound N'-(4-chlorophenyl)-2-(5-phenyl-6-thioxo-1,3,5-thiadiazinan-3-yl)acethydrazide (5b) obviously inhibited the Rs growth in vitro with the EC50 value of 0.24 μg/mL, which is approximately 2-folds more effective than the commercialized fungicide carbendazim (0.55 μg/mL). The in vivo anti-Rs effects of title compound 5b were further evaluated on rice leaves with control efficacies of 98.58% at 200 μg/mL and 61.27% at 100 μg/mL. The above researches provide a significant reference for the further structural optimization of 1,3,5-thiadiazine-2-thione derivatives bearing a hydrazide moiety as potential fungicides.

中文翻译：

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含有酰肼部分的新型1,3,5-噻二嗪-2-硫酮衍生物：体外和体内对植物病原真菌的设计，合成和生物活性评估

摘要设计，合成并评估了一系列带有酰肼部分的新型1,3,5-噻二嗪-2-硫酮衍生物，它们对茄形枯萎病菌，禾谷镰刀菌（Fg），灰葡萄孢（Bc）和菜青虫具有抗真菌活性。辣椒炭疽病菌（Cc）。体外抗真菌生物测定表明，大多数标题化合物相对于Fg，Bc和Cc表现出良好的选择性和特异性。引人注目的是，标题化合物N'-（4-氯苯基）-2-（5-苯基-6-thioxo-1,3,5-噻二嗪基-3-基）乙酰肼（5b）明显抑制了Rs的体外生长。 EC50值为0.24μg/ mL，比商品化的杀菌剂多菌灵（0.55μg/ mL）高约2倍。在稻叶上进一步评估了标题化合物5b的体内抗Rs效应，控制效力为98。在200μg/ mL下为58％，在100μg/ mL下为61.27％。上述研究为进一步研究结构为酰肼部分的1,3,5-噻二嗪-2-硫酮衍生物作为潜在的杀菌剂提供了重要参考。