Synthesis of Substituted Coumarins and 2-Quinolinones by Cycloisomerisation of (Hydroxy/aminophenyl)propargyl Alcohols
作者:Maddi Sridhar Reddy、Nuligonda Thirupathi、Madala Hari Babu
DOI:10.1002/ejoc.201200782
日期:2012.10
A new cycloisomerization strategy for the synthesis of coumarins and quinolinones is described. The addition of ethoxyacetylide to 2-hydroxyacetophenones directly resulted in 4-substituted coumarins by 6-endo-dig cycloisomerisation of the intermediate 3-ethoxy-1-(2-hydroxyphenyl)-2-propyn-1-ols. Under similar conditions, 2-aminoacetophenone produced 2-ethoxyquinoline, a masked quinolinone, which was
描述了合成香豆素和喹啉酮的一种新的环异构化策略。通过中间体 3-乙氧基-1-(2-羟基苯基)-2-丙炔-1-醇的 6-endo-dig 环异构化,将乙氧基乙炔添加到 2-羟基苯乙酮中直接产生 4-取代香豆素。在类似条件下,2-氨基苯乙酮产生2-乙氧基喹啉,一种掩蔽的喹啉酮,通过酸处理转化为喹啉酮。N-保护的中间体 8 被分离并转化为喹啉酮 [使用 In(OTf)3 或 H2SO4] 或 3-iodo-2-quinolinone(使用 I2 和 H+)。