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‐Mediated Synthesis of 1,2,4‐Thiadiazole Derivatives in Ethanol at Room Temperature
作者:Xian‐Ting Cao、Zuo‐Ling Zheng、Jie Liu、Yu‐He Hu、Hao‐Yun Yu、Shasha Cai、Guannan Wang
DOI:10.1002/adsc.202101455
日期:2022.2
Herein, we report the H2O2-mediated synthesis of 1,2,4-thiadiazole derivatives under metal-free conditions at roomtemperature with ethanol as the sole solvent. Various substrates could undergo the reaction smoothly, providing the expected yields of the desired products. Moreover, the target products were obtained by filtration or extraction instead of column chromatography, which requires a large
在此,我们报告了 H 2 O 2介导的 1,2,4-噻二唑衍生物在室温下无金属条件下以乙醇为唯一溶剂的合成。各种底物可以顺利进行反应,提供预期产物的预期产率。此外,目标产物是通过过滤或萃取代替柱层析获得的,在纯化过程中需要大量的有机溶液和硅胶。所开发的合成方法可用于大规模制备 1,2,4-噻二唑衍生物作为农用化学品、药物和功能材料。
External oxidant-free electrooxidative intramolecular S-N bond formation for one-pot synthesis for 3,5-disubstituted 1,2,4-thiadiazoles
作者:Qihao Zhong、Shouri Sheng、Junmin Chen
DOI:10.1080/10426507.2020.1768093
日期:2020.12.1
amidines or guanidines to give the corresponding imidoyl thioureas, which are further cyclized in situ via electrooxidativeintramolecular S-N bondformation to promote the final products. This protocol features a metal- and external oxidant-free approach, broad substrate scope, good functional group tolerance, excellent yields, and one-pot operation/reaction without the isolation of the intermediates
摘要 已在未分离的电解条件下开发了用于合成 5-氨基和 3,5-二氨基取代的 1,2,4-噻二唑衍生物的电化学氧化反应方案。新开发的一锅法涉及异硫氰酸酯与脒或胍反应生成相应的亚氨基硫脲,通过电氧化分子内 SN 键的形成进一步原位环化以促进最终产物。该协议具有无金属和无外部氧化剂的方法、广泛的底物范围、良好的官能团耐受性、优异的产量和一锅操作/反应,无需隔离中间体。图形概要
Hypervalent Iodine(III) Mediated Synthesis of 3-Substituted 5-Amino-1,2,4-thiadiazoles through Intramolecular Oxidative S–N Bond Formation
An efficient synthesis of 3-substituted-5-arylamino-1,2,4-thiadiazoles through intramolecular oxidative S–N bond formation of imidoyl thioureas by phenyliodine(III) bis(trifluoroacetate) is reported. The protocol features a metal-free approach, broad substrate scope, very short reaction times, good to excellent yields, and simple starting materials.
An oxidative N–S bondformation reaction has been established for 1,2,4-thiadiazole synthesis employing molecular iodine as the sole oxidant. The features of the present reaction include no use of transition metals, mild reaction conditions, simple operation, and short reaction time. This versatile synthetic approach is broadly applicable to a variety of imidoyl and guanyl thiourea substrates to produce
has been developed by the reaction of isothiocyanates with amidines. This protocol which is free of metal, catalyst and iodine involves O2 oxidative S–N bond formation for the synthesis of various 5-amino-1,2,4-thiadiazole derivatives with excellent to good yields. High regioselectivity, mild reaction conditions, broad substrate scope and good functional group tolerance are the highlights of the report