| 摘要 |
Prodn. of sennosides A and B (I) comprises oxidising rheinanthrone-8-glucoside (II) with oxygen or an oxygen source in the presence of active charcoal as the catalyst. The (I) obtd. are converted into their Ca salts by treatment with an aq. soln. contg. Ca ions. (I) are laxatives which occur naturally, e.g. in senna plants. Active charcoal is a more efficient catalyst than palladium black or a ferric salt previously used in the oxidn. of (II) and gives (I) in better purity and in yields which are > 30% higher. The Ca salts of (I) are more readily absorbed from the gastrointestinal tract.
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