to euphornin, three new toxic substances (euphornins A, B and C) have been isolated from the plant L., and their absolute stereostructures also been elucidated on the basis of their spectral data and some chemical evidence together with an X-ray crystallographic analysis of the p-bromobenzoate derived from euphornin. Furthermore, their conformations have also been discussed.
Abstract A number of diterpenes have been isolated fromEuphorbiahelioscopia and their stereostructures elucidated on the basis of the spectral data together with some chemical evidence. The absolute configuration of cuphoscopin A and euphornin in particular have been unambiguously determined by means of X-ray crystallographic analysis.
摘要 已从大戟属植物中分离出多种二萜,并根据光谱数据和一些化学证据阐明了它们的立体结构。通过 X 射线晶体学分析,明确地确定了cuphoscopin A 和特别是大黄素的绝对构型。