Tetrahedron

Use of acyl substituents to favour 2, 3-epoxidation of 5, 7-dioxygenated flavones with dimethyldioxirane

BJ Compton, L Larsen, RT Weavers

Index: Compton, Benjamin J.; Larsen, Lesley; Weavers, Rex T. Tetrahedron, 2011 , vol. 67, # 4 p. 718 - 726

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Citation Number: 8

Abstract

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 ...