85950-49-8Relevant articles and documents
An Unusual O-Methylation in the Allan-Robinson Synthesis of Purpurascenin, a 3,5,6,7,8,2',4',5'-Octamethoxyflavone
Patwardhan, Sarita A.,Gupta, Amrit S.
, p. 3786 - 3795 (2007/10/02)
In the Allan-Robinson synthesis of 3,5,6,7,8,2',4',5'-octamethoxyflavone (Purpurascenin, I), from 2,4,6-trihydroxy-3,5,ω-trimethoxyacetophenone (IV) and asarylic anhydride, the expected intermediate, 5,7-dihydroxy-3,6,8,2',4',5'-hexamethoxyflavone (III) unusually gets further methylated to give 5-hydroxy-3,6,7,8,2',4',5'-heptamethoxyflavone (II) during the course of reaction.The possible mechanism of methylation is discussed.