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[摘要]:Regio-controlled cyclization of gem-dicyanoepoxides with 2-aminothiophenol and its hydrochloride to form 1,4-benzothiazine-2-one or 3-one is described. The cyclization is highly regioselective and the reaction of the epoxides with 2-aminothiophenol under neutral reaction condition gave 1,4-benzothiazine-2-one as a sole cyclized product, whereas that with hydrochloride of 2-aminothiophenol afforded 1,4-benzothiazine-3-one predominantly. The regioselectivity resulted from the reaction condition is discussed. |
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