Studies on the interactions of 5-<i>R</i>-3-(2-pyridyl)-1,2,4-triazines with arynes: inverse demand aza-Diels–Alder reaction <i>versus</i> aryne-mediated domino process
作者:Dmitry S. Kopchuk、Igor L. Nikonov、Albert F. Khasanov、Kousik Giri、Sougata Santra、Igor S. Kovalev、Emiliya V. Nosova、Sravya Gundala、Padmavathi Venkatapuram、Grigory V. Zyryanov、Adinath Majee、Oleg N. Chupakhin
DOI:10.1039/c8ob00847g
日期:——
aza-Diels–Alder products or 1,2,4-triazine ring rearrangement (domino) products as major ones depending on the nature of both the substituents at the C5 position of the 1,2,4-triazine core or in the aryne moiety. The structures of the key products were confirmed based on X-ray data. Based on the density functional theoretical (DFT) studies of the Diels–Alder transitionstate geometries, the influence of the nature
已经研究了取代的5 - R -3-(吡啶基-2)-1,2,4-三嗪与原位生成的取代的芳烃中间体之间的相互作用。根据1,2,5碳原子上两个取代基的性质,反应可提供反需求(ID)的aza-Diels-Alder产品或1,2,4-三嗪环重排(domino)产品作为主要产品。 4-三嗪核或在芳烃部分。根据X射线数据确定了关键产品的结构。基于Diels–Alder过渡态几何的密度泛函理论(DFT)研究,提出了芳烃性质对1,2,4-三嗪转化方向的影响。
Consecutive nucleophilic substitution and aza Diels–Alder reaction—an efficient strategy to functionalized 2,2′-bipyridines
作者:Dmitry N. Kozhevnikov、Valery N. Kozhevnikov、Anton M. Prokhorov、Maria M. Ustinova、Vladimir L. Rusinov、Oleg N. Chupakhin、Grigory G. Aleksandrov、Burkhard König
DOI:10.1016/j.tetlet.2005.12.006
日期:2006.2
An efficient strategy for the synthesis of functionalized 2,2'-bipyridines is reported. The strategy is based on readily available 3-pyridyl-1,2,4-triazine 4-oxides and uses a reaction sequence of nucleophilic substitution of hydrogen and aza Diels-Alder reaction. (c) 2005 Elsevier Ltd. All rights reserved.
CuCl2 induced reactions of 6-ethynyl- and 6-cyano-5-aryl-2,2′-bipyridines with various N- and O-nucleophiles in comparison with the reactions of relative 1,2,4-triazines
作者:Anton M. Prokhorov、Pavel A. Slepukhin、Dmitry N. Kozhevnikov
DOI:10.1016/j.jorganchem.2008.02.016
日期:2008.5
Meanwhile 5-aryl-6-cyano-2,2'-bipyridines are very stable towards various nucleophiles, addition copper(II) chloride to the reactional mixture facilitates nucleophilic addition to the cyano group dramatically. The cyanobipyridines react easily with water, methanol, ethanolamine in the presence of CuCl2 yielding well-crystallized complexes containing carboxylates, carboximidates or carboxamidines as ligands. 5-Cyano-1,2,4-triazines are more active in the reactions due to higher electron-withdrawing properties of this heterocycle. Due to the same reason acetylene moiety of 5-ethynyl-3-pyridyl-1,2,4-triazine adds water quite easily but in the presence of copper chloride as well. (C) 2008 Elsevier B.V. All rights reserved.