1592-67-2Relevant articles and documents
Methylation of Dihydroquercetin Acetates: Synthesis of 5-O-Methyldihydroquercetin
Kiehlmann, Eberhard,Slade, Peter W.
, p. 1562 - 1566 (2007/10/03)
The major products of methylation of dihydroquercetin (1, dhq) with diazomethane have been identified as 7-O-methyldhq (9), 7,3′ -di-O-methyldhq (10), 7,4′-di-O-methyldhq (11), and 7,3′,4′ -tri-O-methyldhq (2). With dhq 3,7,3′,4′-tetraacetate (6), dhq 3,5,3′,4′-tetraacetate (5), dhq 3,3′,4′-triacetate (7), dhq 7,3′,4′-triacetate (8), and dhq 3-acetate (4) the same reaction affords mainly 5-O-methyldhq 3,7,3′,4′-tetraacetate (15), 7-O-methyldhq 3,5,3′,4′-tetraacetate (13), 7-O-methyldhq 3,3′,4′-triacetate (14), 5-O-methyldhq 7,3′,4′ -triacetate (25), and 7-O-methyldhq 3-acetate (12), respectively. The methylation of 8 is accompanied by intermolecular acetyl migration from phenolic oxygen to the hydroxy group of the heterocyclic ring. 5-O-Methyldhq (28) is accessible by deacetylation of 25. 5,7-Di-O-methyldhq (29), four known methyl ethers, 13 new and three known methyl ether acetates of dhq, and six new isomers with 2,3-cis stereochemistry were spectroscopically identified.
