Synthesis of 6-substituted 2-phenacylpyridines from 2-(phenylethynyl)pyridine via isoxazolo[2,3-a]pyridinium salt
作者:Song Thi Le、Toshiki Fujimoto、Haruyasu Asahara、Nagatoshi Nishiwaki
DOI:10.1039/c6ob01942k
日期:——
When 2-(phenylethynyl)pyridine was oxidized, the formed N-oxide immediately cyclized at the ethynyl group to form isoxazolo[2,3-a]pyridinium salt. This salt underwent Reissert–Henze-type reactions with alcohol in the presence of a base to afford 6-substituted 2-phenacylpyridines, which are not easily synthesized through alternative procedures. When acetonitrile was used as a solvent, an amide functional
当2-(苯基乙炔基)吡啶被氧化时,形成的N-氧化物立即在乙炔基上环化,形成异恶唑并[2,3- a ]吡啶鎓盐。该盐在碱的存在下与酒精进行Reissert-Henze型反应,得到6-取代的2-苯并吡啶,很难通过替代方法合成。当使用乙腈作为溶剂时,将酰胺官能团引入到苯并吡啶骨架中。此外,在将反应混合物简单暴露于空气后,在6-位的杂原子促进了苯甲酰基的氧化以提供α-二酮。