碩士 / 國立中山大學 / 海洋資源學系 / 81 / The chemical constituents of the brown alga Padina australis
collected from Peng-Hu were studied . The major purposes of our
studies are : (i) the isolation and idemtification of natural
products ; (ii) the screening of the cytotoxic activities of
these compounds ; (iii) the transformations of fucosterol(2)
into other bioactive substances via organic reactions. Through
MS , PMR and CMR spectral analyses , three steroids and a
polyunsaturated fatty acid were identified. They are
cholesterol(1) , 24-ethylcholesta-5,24(28)-dien-3β-ol
(fucosterol)(2) , 24-hydrperoxy-24-vinylcholesterol(3) and 5Z,8
Z,11Z14Z,17Z-eicosapentaenoic acid (EPA)(5) . It was found that
the chloroform solution of (3) can be efficiently transformed
into 29-hydroperoxystigmasta-5,24(28)-dien-3β -ol(4) at -5-0℃
. In order to convert fucosterol into other bioactuve
derivatives , the following reactions were carried out .
Fucosterol(2) was acetylated toform 3β-acetoxy-24-
ethylcholest-5,24(28)-dien-3β-ol(6) . Compound (6) was reacted
with osmium tetraoxide to give 24-ethylcholest-5- ene-3β,24ξ
,28ξ-triol . 5α,6α,24,28-Diepoxyfucosterol(8) was obtained
from the reaction of fucosterol(2) and m-chloroperoxy- benzoic
acid . The subsequent hydrolysis of (8) with Perchloric acid in
acetone gave 24-ethylcholestan-3β,5α,6β,24ξ,28ξ- pentol(9)
in high yield . The polyhydroxyl sterol 24-ethyl- cholstan-3β
,5α,6α,24ξ,28ξ-pentol(10) , was obtained from the reaction
of fucosterol(2) and osmium tetraoxide followed by the lithium
aluminium hydride reaction.
| Identifer | oai:union.ndltd.org:TW/081NSYSU277003 |
| Date | January 1993 |
| Creators | Chiu, Yen Hung, 邱彥鴻 |
| Contributors | Sheu, Jyh Horng, 許志宏 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 91 |
Page generated in 0.0053 seconds