Metal-Free Synthesis of 2-Aminobenzothiazoles via Iodine-Catalyzed and Oxygen-Promoted Cascade Reactions of Isothiocyanatobenzenes with Amines
Yuanshuang Xu, Bin Li, Xinying Zhang* and Xuesen Fan*
*School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China, Email: xinyingzhanghtu.cn, xuesen.fanhtu.cn
Y. Xu, B. Li, X. Zhang, X. Fan, J. Org. Chem., 2017, 82, 9637-9646.
DOI: 10.1021/acs.joc.7b01683 (free Supporting Information)
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A cascade reaction of isothiocyanatobenzenes with primary or secondary amines provides 2-aminobenzothiazoles using iodine as a catalyst and oxygen as an oxidant via formation of a benzothiourea intermediate followed intramolecular cross dehydrogenative coupling. This method eliminates the use of ortho-halo-substituted precursors, expensive transition-metal catalysts, and hazardous oxidants.
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