Abstract To find new lead compounds with high biological activity, a series of novel 4-methyl-1,2,3-thiadiazole-5-carboxaldehyde benzoyl hydrazone derivatives were designed and synthesized. Their structures were confirmed by 1 H NMR, 13 C NMR, IR spectrum and elemental analysis. Preliminary bioassay indicated that the title compounds exhibited moderate to strong fungicidal activity against six fungi in vitro at 50 μg/mL. Moreover, some of the title compounds exhibited good curative activity against TMV in vivo at 500 μg/mL. The structure-activity relationship analysis of compounds against Valsa mali showed that compounds containing halogen at the para position on phenyl exhibited the best activity. Especially compound 8k showed broad spectrum fungicidal activities against Valsa mali, Botrytis cinerea, Pythium aphanidermatum, Rhizoctonia solani, Fusarium moniliforme and Alternaria solani with the EC 50 values of 8.20, 24.42, 15.80, 40.53, 41.48, and 34.16 μg/mL, respectively.

中文翻译：

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4-甲基-1,2,3-噻二唑-5-羧甲醛苯甲酰衍生物的合成及生物学评价

摘要为了寻找具有高生物活性的新的先导化合物，设计并合成了一系列新型的4-甲基-1,2,3-噻二唑-5-羧甲醛苯甲酰衍生物。它们的结构通过1 H NMR，13 C NMR，IR光谱和元素分析证实。初步的生物测定表明，标题化合物在50μg/ mL的体外对六种真菌表现出中等至强的杀真菌活性。此外，一些标题化合物在500μg/ mL的体内对TMV表现出良好的治疗活性。化合物对Valsa mali的构效关系分析表明，在苯基对位上含有卤素的化合物表现出最好的活性。尤其是化合物8k对Valsa mali，Botrytis cinerea，Pythium aphanidermatum，Rhizoctonia solani，