1962 年 82 巻 11 号 p. 1503-1507
Dihydrothebainol-A methyl ether (XVI) is far more easily acetylated than dihydrothebainol-B methyl ether (XVIII). Catalytic reduction of dihydrothebainone 4-acetate (XXII) in glacial acetic acid over platinic oxide resulted in formation of dihydrothebainol-B 6-acetate (XXIV), besides dihydrothebainol-B 4-acetate (XXIII) which easily underwent acyl migration during alumina chromatography to transit to the 6-acetate (XXIV). These experimental evidences suggest that the hydroxyl group at 6-position of dihydrothebainol-B (XV) takes a configuration close to the hydroxyl at 4-position, i.e. axial configuration.