AbstractAn improved method of isolation of betulin and lupeol from birch bark is developed and reported. The method afforded triterpenes with purity of 98.2% (betulin) and 96.3% (lupeol), respectively. Chromyl chloride was also investigated as an oxidating agent of O-acetylated betulin and lupeol. The transformation of isopropenyl moiety to aldehyde group was observed. Graphical abstract
for mono-oxygenase, gave the 11 alpha-hydroxyl derivative 3 as major product, along with 11-oxo derivative 4 and 12-oxo derivative 6. The reaction of lupane triterpenoid 2b with reagent system A gave only oxidative rearrangement compounds, (20R)-aldehyde 8 and (20S)-aldehyde 9 were epimeric isomers. Then, we have found that iron(III) picolinate complex, FeIII(PA)3 is efficient in effecting the rearrangement