SEMISYNTHETIC ANALOGUES OF GINSENOSIDES, GLYCOSIDES FROM GINSENG

Article abstract of DOI:10.1016/0008-6215(88)85045-6

Glycosylation of the dammar-24-ene-3,12β,20(S)-triols with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (A) in the presence of silver oxide in dichloromethane gives a mixture of the acetylated 3-, 12-, 20-, 3,12-di-, and 3,20-di-O-β-D-glucopyranosyl derivatives in a total yield of 83-84.5percent.Under similar conditions, the 3-O-acetyl derivatives of dammar-24-ene-3,12β,20(S)-triols give a mixture of 12- and 20-O-β-D-glucopyranosyl derivatives.Condensation of betulafolienetriol both with the glycosyl bromide A in the presence of mercuric cyanide in nitromethane and with 3,4,6,-tri-O-acetyl-β-D-glucopyranose 1,2-(tert-butyl ortoacetate) in the presence of 2,4,6-trimethyl-pyridinium perchlorate in chlorobenzene under azeotropic distillation results in dehydration and 20-dehydroxyglucosides are formed.