Rad-Moghadam Kurosh, Sharifi-Kiasaraie Masoumeh, Taheri-Amlashi Homayun
Chemistry Department, University of Guilan, PO Box 41335-19141, Rasht, Iran.
Tetrahedron. 2010 Mar 27;66(13):2316-2321. doi: 10.1016/j.tet.2010.02.017. Epub 2010 Feb 6.
Three ionic liquids, [BMIM][BF] doped with 60 mol % of LiCl ([BMIM][BF]-LiCl), ,,,-tetramethylguanidinium trifluoroacetate (TMGT), and ,,,-tetramethylguanidinium triflate (TMGT) were found useful as catalyst solvents for controlled 3-indolylation of isatins. Our investigation revealed that the reaction between isatin and indoles in [BMIM][BF]-LiCl or TMGT media stops at the step of addition of the two components providing 3-indolyl-3-hydroxyindolin-2-ones while the ionic liquid TMGT runs the reaction further through accompanying Friedel-Crafts substitution to afford symmetrical 3,3-di(indol-3-yl)indolin-2-ones. To take advantage of the difference between the effects of these ionic liquids on the reaction progress, we planned a two-step protocol for the efficient synthesis of unsymmetrical 3,3-di(indol-3-yl)indolin-2-ones.
发现三种离子液体，即掺杂60摩尔%LiCl的[BMIM][BF]（[BMIM][BF]-LiCl）、三氟乙酸四甲基胍（TMGT）和三氟甲磺酸四甲基胍（TMGT），可用作异吲哚酮可控3-吲哚化反应的催化溶剂。我们的研究表明，在[BMIM][BF]-LiCl或TMGT介质中，异吲哚酮与吲哚之间的反应在添加这两种组分生成3-吲哚基-3-羟基吲哚啉-2-酮的步骤停止，而离子液体TMGT通过伴随的傅克取代反应使反应进一步进行，得到对称的3,3-二（吲哚-3-基）吲哚啉-2-酮。为利用这些离子液体对反应进程影响的差异，我们设计了一种两步法高效合成不对称3,3-二（吲哚-3-基）吲哚啉-2-酮的方案。
