13C Nuclear Magnetic Resonance Spectra of Several Triterpenoids of Taraxerane and Ursane Series

Taraxeranes and ursanes are widely distributed in plant kingsdom. From the methanol extract of the bark of Pieris japonica D. Don (Japanese name asebi, Ericaceae), taraxeryl acetate (1), taraxerol (2), taraxerone (3), 3β-acetoxy-28-hydroxyurs-12-ene (4), 3β, 28-dihydroxyurs-12-ene (5) and 3β-acetoxyurs-12-en-28-al (6) were obtained. The proton nuclear magnetic resonance (1H-NMR) and carbon-13 nuclear magnetic resonance (13C-NMR) spectra of these triterpenoids and 3β, 28-diacetoxyurs-12-ene (7) were measured and all the methyl proton resonances in (2) and (3), and all the carbon resonances of (1)(7) were assigned.