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.
在
碳酸钾水溶液中,由
羽扇豆醇制备的3β-
四氢吡喃氧基巴
卡兰-18β-基
甲磺酸盐发生了D-环收缩。将溶剂解离产物
水解并乙酰化,得到Δ20-、Δ20(22)-, Δ17(20)-, 和Δ13(17)-
达玛烷-3β-基
乙酸酯以及(20S)-20-羟基
达玛烷-3β-基
乙酸酯,还有巴卡-13(18)-和-12-烯-3β-基
乙酸酯。