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。
Structural and conformational studies on euphohelioscopins A and B and related diterpenes
Two new toxic diterpenes (euphohelioscopins A and B) and two euphoscopin-type ones (euphoscopins C and D) have been isolated from the plant L., and their stereostructures and conformations also been elucidated on the basis of their spectral data and some chemical evidence, together with successful application of molecular mechanics calculations to such flexible molecules as described herein.
Heliojatrones A and B, Two Jatrophane-Derived Diterpenoids with a 5/10 Fused-Ring Skeleton from <i>Euphorbia helioscopia</i>: Structural Elucidation and Biomimetic Conversion
conversion, and X-ray diffraction analyses. Their plausible biosynthetic pathways were also proposed. Compounds 1 and 2 were biomimetically synthesized from 3 and 4 through a photochemicalrearrangement reaction of β,γ-unsaturated ketone, respectively. Compound 2 showed significant P-glycoprotein inhibitory activity compared with the positive control (cyclosporine A).