| 摘要 |
Allo isomers of the pentacyclic oxindolalkaloids of formula C21H24N2O4, in which the hydrogen atom is located in the alpha position on both carbon atom 3 and carbon atom 20, are converted using hydrogen ions. The hydrogen ions cause the hydrogen atom on carbon atom 3 or on carbon atom 20 to rotate from the alpha to the beta position. When this rotation takes place on carbon atom 3, an epiallo isomer is obtained and when it takes place on carbon atom 20, a normal isomer is obtained. To this end, preferably oxindolalkaloids, a mixture of oxindolalkaloids or a drug of plant origin containing oxindolalkaloids are dissolved in an acid, the hydrogen ions of which cause the rotation. If a drug of plant origin is macerated, the mixture of alkaloids enriched with epiallo isomers and/or normal isomers can then be alkalized and extracted preferably, several times, with an organic solvent, which is then separated from the non-organic phase and evaporated. The mixture of alkaloids so obtained can then be further processed to obtain therapeutic preparations. |
