We describe the isolation and structural elucidation of these compounds in this paper. In our ongoing search for secondary metabolites from this plant, we isolated 21 compounds from the petroleum ether and ethyl acetate fractions of I B. platyphylla i . Previous phytochemical studies on I B. platyphylla i revealed the isolation and identification of triterpenoids, including the lupane series, as well as phenolic compounds such as diarylheptanoids and arylbutanoids [[2]]. Birch bark (10 kg) was extracted with MeOH three times at room temperature and the extract was evaporated at low pressure to obtain the residue (1.4 kg), which was suspended in water and partitioned with petroleum ether (PE), EtOAc, and I n i -BuOH, successively. [Extracted from the article]