Conversion of Lupeol into Dammarane Derivatives

Abstract

On treatment with potassium carbonate in aqueous dioxane, 3β-tetrahydropyranyloxybaccharan-18β-yl mesylate, prepared from lupeol, underwent D-ring contraction. The solvolytic products were hydrolyzed and acetylated to give Δ20-, Δ20(22)-, Δ17(20)-, and Δ13(17)-dammaren-3β-yl acetates and (20S)-20-hydroxydammaran-3β-yl acetate together with bacchar-13(18)- and -12-en-3β-yl acetates.

Triterpenoids

“…73 Solvolysis of the mesylate of 3P-tetrahydropyranyloxybaccharan-1 8p-01 (76) afforded, after hydrolysis and acetylation, (20S)-3~-acetoxy-20-hydroxydammarane (77) and the 3p-acetoxydammarenes (78)-(8 l). 74 Investigation of the saponins of ginsengs continues unabated. Majonosides R1 and R2, from Zu-Tziseng (the rhizomes of Panax japonicus), are, respectively, the 6-O+-sophoroside and 6-O-~-xylopyranosyl-(1+2)-~-~-glucopyranoside of (20s' 24S)-20,24-epoxy-3p,6a, 12p,25-tetrahydro~ydammarane.~5 Malonyl-ginsenosides-Rb, ,-Rb2,-Rc, and -Rd have been isolated from the root of P. ginseng.…”