在此,我们报告了一种在混合研磨机中对吲哚和咪唑并[1,2- a ]吡啶进行亲电C-H硫氰化的无溶剂且可持续的方法。在研磨条件下,使用市售且更便宜的前体N-氯代琥珀酰亚胺和 NaSCN的组合,原位生成N-硫氰酸琥珀酰亚胺 (NTS),从而促进吲哚和咪唑上的 C-3 选择性硫氰化反应[1,2- a ]吡啶类。以硅胶为固体反应介质合成了一系列含有富电子环和缺电子环的硫氰化产物,并获得了良好至优异的收率。使用选定的克级底物验证了反应的可扩展性。此外,我们探索了通过双C-H活化的机械化学串联C-C和C-S键形成反应,从而可以从未取代的吲哚中轻松获得C-2芳基和C-3硫氰酸根化合物。此外,当前的方法还证明了-SCN前体机械化学转化为-SCF 3和5-取代的硫基四唑。
A convenient eco-friendly system for the synthesis of 5-sulfenyl tetrazole derivatives of indoles and pyrroles employing CeCl<sub>3</sub>·7H<sub>2</sub>O in PEG-400
作者:Margiani P. Fortes、Mariana M. Bassaco、Teodoro S. Kaufman、Claudio C. Silveira
DOI:10.1039/c4ra05625f
日期:——
efficient and eco-friendly promoter system for the convenientsynthesis of 5-sulfenyl tetrazoles derived from indoles and pyrroles, is reported. The synthesis entails the [3 + 2] cycloaddition reaction of NaN3 with 3-thiocyanato indoles (including 3,3′-di-thiocyanato-1H,1H′,2,2′-biindoles) and 2-thiocyanato pyrroles. The thiocyanates were conveniently obtained by the oxone-mediated thiocyanation of differently
据报道,在聚乙二醇400(PEG-400)中使用CeCl 3 ·7H 2 O作为有效和环保的促进剂体系,可方便地合成由吲哚和吡咯衍生的5-亚磺酰基四唑。合成需要使NaN 3与3-硫代氰基吲哚(包括3,3'-二硫代氰基-1 H,1 H ',2,2'-双吲哚)和2-硫代氰基吡咯进行[3 + 2]环加成反应。硫氰酸盐可通过不同取代的起始吲哚,1 H,1 H ',2,2'-双吲哚和N-芳基吡咯与NH 4的异丁酮介导的硫氰酸氰化反应方便地获得SCN。还研究了转换的范围和局限性。
Facile, efficient and eco-friendly synthesis of 5-sulfenyl tetrazole derivatives of indoles and pyrroles
作者:Bruna L. Kuhn、Margiani P. Fortes、Teodoro S. Kaufman、Claudio C. Silveira
DOI:10.1016/j.tetlet.2014.01.101
日期:2014.2
A concise, two-step eco-friendly approach towards the synthesis of 5-sulfenyl tetrazole derivatives of indoles and pyrroles, is reported. The synthesis comprises the oxone-mediated thiocyanation of the starting heterocycles towards intermediate 3-thiocyanato indoles and 2-thiocyanato pyrroles, and their subsequent treatment with sodium azide in 2-propanol/water under zinc bromide promotion.
The immobilization of RoseBengal onto Merrifield resin and its application in the light-driven metal-free thiocyanation of azaheterocycles in continuo were investigated. The supportedphotocatalyst was used in batch reactions under heterogeneous conditions, with different azaheterocycles, and proved to efficiently promote the reaction. Its recovery and recycle were also demonstrated for up to four