GLYCOSYLATION OF TRITERPENOIDS OF THE DAMMARANE SERIES. X. REGIO- AND STEREOSELECTIVE SYNTHESIS OF 20(S)-PROTOPANAXADIOL 3-O-β-D-GLUCOPYRANOSIDE (GINSENOSIDE Rh2)

Article abstract of DOI:10.1007/BF00598267

The regio- and stereoselective synthesis of ginsenoside R_h2, which possesses anti-tumoral activity, has been effected by the glycosylation of 12β-acetoxydammar-24-ene-3β,20(S)-diol.Condensation with α-acetobromoglucose was carried out in the presence of silver oxide in dichloroethane at room temperature, and the yield of the desired glycoside amounted to 50percent.A method for the selective protection of the C-12-OH group of dammar-24-ene-3β,12β,20(S)-triol <20(S)-protopanaxadiol> has been proposed.