In connection with our long-standing interest in the chemical constituents of Formosan octocorals, we have investigated the octocorals Briarium excavatum and Junceella fragilis, collected at southern Taiwan coast. During the investigation, four new metabolites brianthiens D‐G (1‐4), have been isolated from Briareum excavatum. In addition, four 11,20-epoxybriaranes including three new metabolites, fragilides B‐D (5‐7), along with a known briarane (¡V)-11£\,20£\-epoxy-4-deacetoxyjunceellolide D (8), have been obtained from J. fragilis. The structure of 8 was revised as (¡V)-11£],20£]-epoxy-4-deacetoxyjunceellolide D (8) by detailed spectral data analysis. The structures, including the relative configurations of the new briaranes 1‐7, were elucidated by spectroscopic methods. The structure of fragilide B (5) was further confirmed by X-ray diffraction analysis. The relationship between 13C NMR chemical shifts and conformation of the cyclohexane ring in briaranes possessing 11,20-epoxy group, are also described.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0810105-165417 |
| Date | 10 August 2005 |
| Creators | Chen, Yu-Pei |
| Contributors | Jhy-Horng Sheu, Ping-Jyun Sung, Yang-Chang Wu, Wei-Hsien Wang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0810105-165417 |
| Rights | withheld, Copyright information available at source archive |
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