An economical nucleophilic route toward facile synthesis of pyrano[4,3-b]quinolin-1-ones via 6-endo-dig cyclization of o-alkynylquinoline esters
摘要:
Metal-free facile synthesis of pyrano[4,3-b]quinoline-1-ones is described from methyl 2-arylethynyl-quinoline-3-carboxylates via intramolecular cyclization in excellent yields. The cyclization reactions are facilitated using cheap and easily available KOH base in MeOH. The reaction conditions did not require dry solvent, inert atmosphere, and avoid further column chromatography purification of the products. These compounds could be further used as building blocks for the synthesis of 2H-benzo[b][1,6]naphthyridin-1-one and 1-chloro-benzo[b][1,6]naphthyridines. (C) 2013 Elsevier Ltd. All rights reserved.
TBHP-promoted oxidative cyclization of o-alkynylquinoline aldehydes: Metal/additive-free domino synthesis of pyrano[4,3-b]quinolin-1-ones
作者:Jay Bahadur Singh、Kalpana Mishra、Tanu Gupta、Radhey M. Singh
DOI:10.1016/j.tetlet.2018.01.083
日期:2018.3
TBHP-promoted domino synthesis of pyrano[4,3-b]quinolin-1-ones is described from o-alkynylquinoline aldehydes. The radical reaction proceeded without metal and additive via oxidation of aldehydic C-H bond into C-OH bond followed by intramolecular 6-endo-dig cyclization. The probable mechanism is discussed.
由邻炔基喹啉醛描述了TBHP促进的吡喃并[4,3 - b ]喹啉-1-酮的多米诺合成。自由基反应是在没有金属和添加剂的情况下进行的,方法是将醛键的CH键氧化为C-OH键,然后进行分子内6-内切环化。讨论了可能的机制。