Various flavones 1 were converted in excellent yields to the hitherto unknown corresponding epoxides 3 by epoxidation with dimethyldioxirane at subambient temperatures.
The synthesis of epoxides 2 by epoxidation of flavones 1 with isolated dimethyldioxirane (as acetone solution) at subambient temperatures is reported. These labile epoxides were isolated and completely characterized by UV, IR, H-1 and C-13 NMR, MS, and C, H analyses. Warming to room temperature led to rearrangement to afford quantitatively the 3-hydroxyflavones 3b,h,i,n. Treatment of the epoxides 2b,f with methanol led to the 3-hydroxy-2-methoxyflavanones 4b,f as a mixture of cis and trans isomers.
NOVEL METHOD FOR PREPARING PTEROCARPAN
申请人:Hur Hor-Gil
公开号:US20130130332A1
公开(公告)日:2013-05-23
The present invention relates to a novel method for preparing pterocarpan from isoflavan-4-ol.
With the use of the method of the present invention, the absolute configuration of C3 and C4 positions on the B-ring of isoflavan-4-ols is maintained identically also in pterocarpans, and thus, enantiopure pterocarpans can be efficiently prepared.
Various flavones 1 were converted in excellent yields to the hitherto unknown corresponding epoxides 3 by epoxidation with dimethyldioxirane at subambient temperatures.