METHOD OF SYNTHESIS OF BETULINIC ACID Russian patent published in 2002 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to the improved method of synthesis of betulinic acid. Method is based on oxidation of betuline with the following reduction of betulonic acid and recrystallization. For oxidation of betuline a pyridine dichromate complex with acetic anhydride in dimethylformamide is used in the ratio dimethylformamide : acetic anhydride = (2.5:1)-(3:1). The synthesized betulonic acid is reduced to α- 5%, and β- 95% isomers of betulinic acid with sodium boron hydride in C₂-C₄,-alcohol and a natural isomer of betulinic acid is separated from a α-isomer by recrystallization of betulinic acid from C₂-C₄,-alcohol. Crystals comprise a natural isomer and filtrate comprises a mixture of isomers from that betulonic acid can be obtained again. EFFECT: improved method of synthesis. 1 cl, 2 ex