Synthesis, Crystal Structure, and Biological Activity of 4-Methyl-1,2,3-thiadiazole-Containing 1,2,4-Triazolo[3,4-b][1,3,4]thiadiazoles

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• 作者：Zhijin Fan ; Zhikun Yang ; Haike Zhang ; Na Mi ; Huan Wang ; Fei Cai ; Xiang Zuo ; Qingxiang Zheng ; Haibin Song
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2010
• 出版时间：March 10, 2010
• 年：2010
• 卷：58
• 期：5
• 页码：2630-2636
• 全文大小：811K
• 年卷期：v.58,no.5(March 10, 2010)
• ISSN：1520-5118

文摘

Heterocyclic compounds play an important role as the main sources of lead molecules of agrochemicals. Synthesis and biological activity of thiadiazole-containing 1,2,4-triazolo[3,4-b][1,3,4]-thiadiazoles were seldom reported. To find novel lead compounds with various biological activities, a series of 6-substituted-3-(4-methyl-1,2,3-thiadiazolyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadizoles were rationally designed and synthesized according to the principle of combinations of bioactive substructures by the condensation of 3-(4-methyl-1,2,3-thiadiazolyl)-4-amino-1,2,4-triazole-5-thione with various carboxylic acids and phosphorus oxychloride. All newly synthesized compounds were identified by proton nuclear magnetic resonance (¹H NMR), infrared spectroscopy (IR), electroionization mass spectrometry (EI/MS), and elementary analysis. The crystal structure of 3-(4-methyl-1,2,3-thiadiazolyl)-6-(4-methylphenyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadizole was determined by X-ray diffraction crystallography. In this crystal, two intermolecular hydrogen bonds (N2···H−C12 and N3···H−C13), a weak intermolecular interaction (S···S), and the weak pπ−pπ intermolecular interaction were observed. Fungicide screening indicated that all of the target compounds showed certain extent of growth inhibition against fungi tested. 3-(4-Methyl-1,2,3-thiadiazolyl)-6-n-propyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole and 3-(4-methyl-1,2,3-thiadiazolyl)-6-trichloromethyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole were found to have potential wide spectrum of fungicide activity. The median effective concentrations (EC₅₀) detected for 3-(4-methyl-1,2,3-thiadiazolyl)-6-trichloromethyl[1,2,4]triazolo[3,4-b][1,3,4]thiadizole to six fungi were from 7.28 μmol/L against Pellicularia sasakii (Shirai) to 42.49 μmol/L against Alternaria solani. The results indicated that thiadiazole-containing 1,2,4-triazolo[3,4-b][1,3,4]-thiadiazoles were potential fungicide lead compounds.