Darzens reaction of 2-bromo-4,6-dimethoxy-3(2<i>H</i>)-benzofuranone with aromatic aldehydes to form flavonoids
作者:Philipp A. Ottersbach、David Bolek、Eva Lepičová、Michael Gütschow、Martin Nieger
DOI:10.1002/jhet.5570450432
日期:2008.7
The applicability of 2-bromo-4,6-dimethoxy-3(2H)-benzofuranone (1) to produce flavonoid-derived epoxides in the course of the Darzens reaction with aldehydes was investigated. However, instead of the epoxides, flavonols 3 and, in certain cases, benzofuranyl-substituted flavonols 4 were isolated. The generation of 3 is assumed due to a ring expansion of the initially formed epoxides. These flavonols
研究了2-溴-4,6-二甲氧基-3(2 H)-苯并呋喃酮(1)在与醛类的Darzens反应过程中产生类黄酮衍生的环氧化物的适用性。然而,代替了环氧化物,分离了黄酮醇3,在某些情况下还分离了苯并呋喃基取代的黄酮醇4。假定生成3是由于最初形成的环氧化物的扩环。这些黄酮醇可与1反应生成次要产品,产生意想不到的1:2加合物4。六甲氧基衍生物4b(R 1 = H,R 2 = R 3 通过X射线晶体学分析确认=(OMe)。