- A copper-catalyzed approach for the synthesis of asymmetrical disubstituted 1,2,4-thiadiazoles via elemental sulfur-mediated decarboxylative redox cyclization
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The variety of asymmetrical disubstituted 1,2,4-thiadiazoles are smoothly prepared by copper-catalyzed approach, which employed arylacetic acids and amidines as substrates, and elemental sulfur to mediate decarboxylative redox cyclization. The advantages of this method are simple, efficient, and ligand-free. In addition, this method can provide products in moderate to good yields.
- Liu, Yafei,Zhang, Yurong,Zhang, Jun,Hu, Liang,Han, Shiqing
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- Method for synthesizing 1,2,4-thiadiazole derivative
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The invention relates to a method for synthesizing a 1,2,4-thiadiazole derivative, and belongs to the technical field of chemical preparation. The method comprises the following steps: taking and dissolving a phenylacetic acid compound and a benzylamidine hydrochloride compound in an organic solvent according to a mass ratio of (1-2):1, adding a catalyst, an oxidant and an alkaline medium, and stirring at 130-140 DEG C for 18-24 h to react in order to obtain the 1,2,4-thiadiazole derivative; and cooling, extracting, drying, evaporating under reduced pressure to remove the solvent, and carryingout column chromatography to obtain the pure product. The method for synthesizing thiadiazole has the following advantages: (1) the reaction conditions are mild, the product selectivity is high, andthe substrate expansion range is wide; and (2) the used raw materials are low in price and cost, and the reaction operation is simple, safe and convenient.
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Paragraph 0083-0088
(2020/05/01)
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- An alternatively metal-free synthesis of 1,3,5-triazines or 1,2,4-thiadiazoles from benzyl chlorides and benzylamines mediated by elemental sulfur
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An elemental sulfur mediated reaction of benzyl chlorides with benzylamines is developed, which allows the practical synthesis of valuable 1,3,5-triazines. This protocol that is metal free, ligand free, and uses inexpensive elemental sulfur as oxidant or raw material displays mild reaction conditions, a broad substrate scope and moderate to good yields. Moreover, the modified sulfur-mediated reaction system can also be used to synthesize 1,2,4-thiadiazoles, by simply switching the stoichiometry of sulfur powder from 0.75 equivalents to 5 equivalents.
- Zhang, Yurong,Liu, Yafei,Zhang, Jun,Gu, Ren,Han, Shiqing
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supporting information
(2019/11/11)
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- Multicomponent reactions (MCRs) of arylmethyl bromides, arylamidines and elemental sulfur toward unsymmetric 3,5-diaryl 1,2,4-thiadiazoles
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A base-promoted three-component reaction between arylmethyl bromides, arylamidines and elemental sulfur was developed, leading to unsymmetric 3,5-diaryl-1,2,4-thiadiazoles in moderate to good yields with chemical diversity and complexity. This procedure shows broad substrates scope by employing elemental sulfur and commercially available starting materials under transition-metal free conditions.
- Zhou, Zhen,Liu, Miaochang,Sun, Song,Yao, En,Liu, Suqin,Wu, Zhiwen,Yu, Jin-Tao,Jiang, Yan,Cheng, Jiang
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supporting information
p. 2571 - 2573
(2017/06/13)
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