Divaccinosides A–D (1–4), four rare iridoid glucoside cyclodimers in the truxillate forms, were characterized from the leaves of Vaccinium bracteatum. They were presumably biosynthesized from two known iridoid glucoside monomers, vaccinoside (5) and 10-O-trans-p-coumaroyl-6α-hydroxyl-dihydromonotropein (6), via a [2+2] cycloaddition reaction. The structures of the new compounds were established by
Divaccinosides A-d(1 - 4),在truxillate形成四个罕见环烯醚萜甙cyclodimers,从叶,其特征在于乌饭。他们推测,从两个已知环烯醚萜苷的单体,vaccinoside(
生物合成5)和10- ø -反式- p -coumaroyl-6 α -羟基- dihydromonotropein(6),通过[2 + 2]环加成反应。通过综合光谱测量,
化学转化和单晶X射线晶体学分析,确定了新化合物的结构。