89971-04-0Relevant articles and documents
Use of acyl substituents to favour 2,3-epoxidation of 5,7-dioxygenated flavones with dimethyldioxirane
Compton, Benjamin J.,Larsen, Lesley,Weavers, Rex T.
, p. 718 - 726 (2011/03/19)
The reaction of 5,7-dimethoxyflavone with dimethyldioxirane (DMDO) gives the 2,3-epoxide rapidly at first. However, low levels of ring A hydroxylated by-products are also formed. With increasing proportions of DMDO, demethylation at C-5 becomes apparent and consumption of substrate is not matched by further significant build-up of the epoxide. Deactivation of ring A by the use of acyl groups removes this complication. 5,7-Diacylflavones give excellent yields of epoxides and monoacyl derivatives also react in good yield. Ionization potential maps derived from density functional theory calculations (B3LYP/6-31G), provide good visual indicators of the relative reactivity of the key nucleophilic loci. The epoxides may be isolated as such, or transformed into flavonols by treatment with p-toluenesulfonic acid.
Obtaining new flavanones exhibiting antifungal activities by methyltrioxorhenium-catalyzed epoxidation-methanolysis of flavones
Bernini, Roberta,Mincione, Enrico,Provenzano, Gianfranco,Fabrizi, Giancarlo,Tempesta, Sabrina,Pasqualetti, Marcella
, p. 7561 - 7566 (2008/12/20)
New 3-hydroxy-2-methoxyflavanones have been obtained through epoxidation-methanolysis of the corresponding flavone with urea-hydrogen peroxide (UHP)/methyltrioxorhenium (CH3ReO3, MTO) catalytic system in methanol as nucleophilic solv
