A simple and expedient synthesis of functionalized pyrido[2,3-c] coumarin derivatives using molecular iodine catalyzed three-component reaction
作者:Abu T. Khan、Deb K. Das、Kobirul Islam、Pradipta Das
DOI:10.1016/j.tetlet.2012.09.051
日期:2012.11
A wide variety of substituted pyrido[2,3-c] coumarin derivatives have been accomplished from 3-aminocoumarins, aromatic aldehydes, and alkynes in the presence of 10 mol % molecular iodine in acetonitrile under reflux conditions through one-pot Povarov reactions. Good yields, no need of aqueous work-up procedure and chromatographic separation, environmentally benign are some of the salient features of the present protocol. (C) 2012 Elsevier Ltd. All rights reserved.
CuI–Zn(OAc) 2 catalyzed C(sp 2 )–H activation for the synthesis of pyridocoumarins through an uncommon Cu I –Cu III switching mechanism: A fast, solvent-free, combo-catalytic, ball milling approach
作者:Nazia Kausar、Asish R. Das
DOI:10.1016/j.tetlet.2017.05.074
日期:2017.6
a flexible propargylic amine intermediate, which leads to a rapid C(sp2)–H activation for cyclization involving transient CuIII species. The in-situ formation of transient CuIII species was confirmed through ultraviolet–visible spectroscopy (UV–Vis), electrosprayionizationmassspectrometry (ESI-MS), and X-ray photoelectron spectroscopy (XPS) analyses of the reaction mixture.
CuI–Zn(OAc)2催化后,已经开发出一种快速,无溶剂的合成方案,用于通过C(sp 2)–H活化氧化C–C和C–N 。在这项工作中,在非常温和的条件下,通过较绿的球磨工艺,将醛,末端炔烃和3-氨基香豆素偶联在一起以形成吡啶香豆素骨架。与常用的亚胺-炔环化反应相反,这种罕见的温和的Cu I –Cu III转换组合催化有望通过形成柔性炔丙基胺中间体来进行,从而导致快速的C(sp 2)–H涉及瞬态Cu III的环化活化物种。通过反应混合物的紫外-可见光谱(UV-Vis),电喷雾电离质谱(ESI-MS)和X射线光电子能谱(XPS)分析确认了瞬态Cu III物种的原位形成。