Extraction and Characterization of Betulin from Birch Bark

Betulin (BET) was separated through extraction from birch tree bark using the standard procedure [11 (link)]. The obtained substance was recrystallized from isopropyl alcohol and characterized using IR and NMR spectroscopy.
The IR specter (KBr, ν, cm^–1) of betulin is characterized by absorption bands in the 3368 cm^–1 area, which is typical for –OH groups, 1646 cm^–1 (C=C) and others: 2968–2864 (C–H), 1450, 1372, 1105, 1029, 878.
¹H NMR (400,17 MHz, CDCl₃, δ, ppm): the weaker fields area has isopropenyl group proton signals (4.51 and 4.61 ppm); 3.26 and 3.73 (p, 2H, C₂₈H₂-OH); 3.10–3.14 (m, 1H, C₃H-OH); 2.28–2.35 (m, 1H, C₁₉–H); in the 0.79–2.00 ppm area there are lupane skeleton proton signals, where C-H group proton signals are found in betulin structure (6CH₃, 10CH₂, 5CH).
¹³C NMR (100,63 MHz, CDCl₃, δ, m.f.): 150,51 (C-20); 109,71 (C-29); 78,98 (C-3); 64,46 (C-17); 60,51 (C-28); 55,28 (C-5); 50,38 (C-9); 48,74 (C-18); 47,79 (C-19); 42,71 (C-14); 40,91 (C-8); 38,87 (C-4); 38,69 (C-1); 37,30 (C-13); 37,15 (C-10); 34,22 (C-22); 33,98 (C-7); 29,74 (C-16); 29,16 (C-21); 27,99 (C-15); 27,38 (C-2); 27,04 (C-12); 25,37 (C-23); 25,19 (C-24); 20,83 (C-11); 19,09 (C-30); 18,30 (C-6); 16,12 (C-25); 15,98 (C-26); 15,38 (C-27).