Minor and Trace Sterols in Marine Invertebrates. XII. Occurrence of 24 (R + S)-isopropenylcholesterol, 24 (R + S)-methylcholesta-5, 25-dien-3β-ol, and 24 (R + S)-methylcholesta-7, 25-dien-3β-ol in the caribbean sponge, Verongia cauliformis
✍ Scribed by W. C. M. C. Kokke; C. S. Pak; William Fenical; Carl Djerassi
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- German
- Weight
- 563 KB
- Volume
- 62
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
In addition to the two new sterols verongulasterol 11 and 25‐dehydroaplysterol 13 of Verongia cauliformis^3^), which were reported earlier [2] [3], the minor and trace sterols of this sponge include five new sterols listed in the title (with the exception of the known 24 S‐methyl‐cholesta‐5, 25‐dien‐3β‐ol (codisterol, 1b). The isolation of the 24(R)‐epimer of codisterol is of interest, as this compound is a possibly biosynthetic precursor for aplysterol 12, 25‐dehydroaplysterol 13, and verongulasterol 11 (all 24__R__) which occur in the same sponge [2]. A partial synthesis from fucosterol (4) of 24 (R + S)‐isopropenylcholesterol (9), and of 24‐isopropylcholesterol (10) is described.