Stereoselective oxidations of a β-methylglycal, anhydrodihydroartemisinin
摘要:
Anhydrodihydroartemisinin (1) was epoxidized with MCPBA-2KF and the resulting 11 beta,12 beta-epoxide (2) treated with acidic aqueous acetone to yield 11 beta-hydroxydihydroepiartemisinin (5). The major product of the reaction of 1 with catalytic quantities of osmium tetroxide using NMO as a co-oxidant was 11 alpha-hydroxydihydroartemisinin (4). Both 4 and 5 were oxidized to the corresponding 11-hydroxyartemisinins.