作者:Sukumar Bepary、In Kwon Youn、Hee-Jong Lim、Ge Hyeong Lee
DOI:10.1002/ejoc.201200025
日期:2012.5
Intramolecular cyclization of thioureas or ureas tethered to amides afforded 2-iminohydantoins and 2-amino-1H-imidazol-4(5H)-ones in very high yields (87–100 %) regardless of the substituent (alkyls or aryls). This reaction proceeds through carbodiimides and iminium ions as intermediates. Among the reagents used to generate the carbodiimides, CBr4/Ph3P, CCl4/Ph3P, O,O′-bis(2′-pyridyl)thiocarbonate
无论取代基(烷基或芳基)如何,硫脲或与酰胺相连的脲的分子内环化均以非常高的产率(87-100%)得到 2-亚氨基乙内酰脲和 2-氨基-1H-咪唑-4(5H)-酮。该反应通过作为中间体的碳二亚胺和亚胺离子进行。在用于生成碳二亚胺的试剂中,研究了 CBr4/Ph3P、CCl4/Ph3P、O,O'-双(2'-吡啶基)硫代碳酸酯和 HgO。