The Reactivity of (Z)-5-Acetyl-3-aryl-2,3-dihydro-2-[(thioacyl)methylene]1,3,4-thiadiazoles: A Surprising Base-Induced Conversion into 3-(N-arylamino)thiophenes
作者:Tiziana Benincori、Tullio Pilati、Simona Rizzo、Mara Sada、Franco Sannicolò
DOI:10.1002/ejoc.200300048
日期:2003.7
nes 5, respectively. These very reactive species undergo either nucleophilic addition or [4+2] cycloaddition reactions involving the thioacyl function. The most surprising result was found in the reactions of the 5-acetyl-3-aryl-2,3-dihydro-2-[(thioacyl)methylene]-1,3,4-thiadiazoles 1a,d,e, which afford 3-(arylamino)thiophenes 2, 10, and 14 as the main products. This serendipitous transformation, which
我们报告了两类很少研究的杂环所显示的反应性,5-乙酰基-2,3-二氢-3-苯基-2-(苯基亚甲基)-1,3,4-噻二唑 (6) 和 5alkanoyl-3-芳基-2,3-二氢-2-[(硫代酰基)亚甲基]-1,3,4噻二唑1a-e。在这两种情况下,强碱促进噻二唑环的裂解,同时失去硫氰酸根阴离子,分别生成 N-芳基烯酮亚胺和 N-芳基(硫代酰基)烯酮亚胺 5。这些非常活泼的物质会发生亲核加成或 [4+2] 环加成反应,包括硫酰基官能团。最令人惊讶的结果是在 5-乙酰基-3-芳基-2,3-二氢-2-[(硫代酰基)亚甲基]-1,3,4-噻二唑 1a,d,e 的反应中发现的,得到 3 -(芳氨基)噻吩2、10和14为主要产品。这种偶然的转变,似乎相当普遍,可能涉及将底物的乙酰基转化为烯酮的中间步骤。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim