Studies in marine diterpene chemistry
This thesis comprises both a natural product investigation and a synthetic component. The natural product investigations are presented in Chapters Two and Three. In Chapter Two the isolation and spectroscopic identification of the new isocopalane diterpene 12S,13R,14Sisocopalan- 13-ol-12,14-diacetat...
Main Author: | |
---|---|
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
Rhodes University
2008
|
Subjects: | |
Online Access: | http://hdl.handle.net/10962/d1005019 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:4354 |
id |
ftrhodesunivcory:vital:4354 |
---|---|
record_format |
openpolar |
spelling |
ftrhodesunivcory:vital:4354 2023-05-15T13:57:13+02:00 Studies in marine diterpene chemistry Van Wyk, Albert Wynand Wincke 2008 309 leaves pdf http://hdl.handle.net/10962/d1005019 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:4354 English eng Rhodes University Faculty of Science, Chemistry vital:4354 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:4354 http://hdl.handle.net/10962/d1005019 Van Wyk, Albert Wynand Wincke Natural products Diterpenes Mollusks Marine metabolites Chemical oceanography Thesis Doctoral PhD 2008 ftrhodesunivcory 2022-12-26T14:14:42Z This thesis comprises both a natural product investigation and a synthetic component. The natural product investigations are presented in Chapters Two and Three. In Chapter Two the isolation and spectroscopic identification of the new isocopalane diterpene 12S,13R,14Sisocopalan- 13-ol-12,14-diacetate (2.1) and two known 3-(14S)-isocopal-12-ene-15-oyl-1- acetyl-sn-glycerol (2.2) and 3-(14S)-isocopal-12-ene-15-oyl-2-acetyl-sn-glycerol (2.3) from a single, large, unidentified sub-Antarctic nudibranch, collected near Marion Island, approximately 2000 km south of Cape Town are described. Chapter Three discusses the isolation, spectroscopic structure elucidation and anti-oesophageal cancer activity (3.1-3.4 only) of two known labdane diterpenes 6β,7α-diacetoxylabda-8,13E-dien-15-ol (3.1) and 2α,6β,7α-triacetoxylabda-8,13E-dien-15-ol (3.2) and one new 6β,7α,15-triacetoxylabda 8,13E-diene (3.3), as well as new 3α,11-dihydroxy-9,11-seco-cholest-4,7-dien-6,9-dione (3.4) and cholest 7-en-3,5,7-triol (3.5) from the endemic pulmonate mollusc, Trimusculus costatus. The absolute configuration of 3.2, and hence 3.1 and 3.3 (from biogenetic arguments) was determined through X-ray diffraction of a single crystal of the camphanate ester of 3.2. The absolute configuration of the secondary hydroxyl at C-3 of 3.4 was established using the Modified Mosher’s method. The synthetic component of the thesis commences in Chapter Four with the semi-synthesis of labdane diterpene nitriles 9α-cyano-15,16-epoxy-7β-hydroxylabda-13(16),14-dien-6-one (4.1), 9α-cyano-15,16-epoxy-7-hydroxylabda-7,13(16),14-trien-6-one (4.2) and 9α-cyano-15,16- epoxy-6β,7β dihydroxylabda-13(16),14-diene (4.3) from the terrestrial labdane diterpene, hispanolone (4.4). This work is an extension of previous synthetic studies directed towards the synthesis of T. costatus metabolites. Diterpenes 4.1-4.3 exhibited in planta activity against the economically important crop pathogens, Magnaporthea grisea and Puccinia recondita. Chapter Five describes the successful ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Marion Island Rhodes University Cory: Repository Antarctic |
institution |
Open Polar |
collection |
Rhodes University Cory: Repository |
op_collection_id |
ftrhodesunivcory |
language |
English |
topic |
Natural products Diterpenes Mollusks Marine metabolites Chemical oceanography |
spellingShingle |
Natural products Diterpenes Mollusks Marine metabolites Chemical oceanography Van Wyk, Albert Wynand Wincke Studies in marine diterpene chemistry |
topic_facet |
Natural products Diterpenes Mollusks Marine metabolites Chemical oceanography |
description |
This thesis comprises both a natural product investigation and a synthetic component. The natural product investigations are presented in Chapters Two and Three. In Chapter Two the isolation and spectroscopic identification of the new isocopalane diterpene 12S,13R,14Sisocopalan- 13-ol-12,14-diacetate (2.1) and two known 3-(14S)-isocopal-12-ene-15-oyl-1- acetyl-sn-glycerol (2.2) and 3-(14S)-isocopal-12-ene-15-oyl-2-acetyl-sn-glycerol (2.3) from a single, large, unidentified sub-Antarctic nudibranch, collected near Marion Island, approximately 2000 km south of Cape Town are described. Chapter Three discusses the isolation, spectroscopic structure elucidation and anti-oesophageal cancer activity (3.1-3.4 only) of two known labdane diterpenes 6β,7α-diacetoxylabda-8,13E-dien-15-ol (3.1) and 2α,6β,7α-triacetoxylabda-8,13E-dien-15-ol (3.2) and one new 6β,7α,15-triacetoxylabda 8,13E-diene (3.3), as well as new 3α,11-dihydroxy-9,11-seco-cholest-4,7-dien-6,9-dione (3.4) and cholest 7-en-3,5,7-triol (3.5) from the endemic pulmonate mollusc, Trimusculus costatus. The absolute configuration of 3.2, and hence 3.1 and 3.3 (from biogenetic arguments) was determined through X-ray diffraction of a single crystal of the camphanate ester of 3.2. The absolute configuration of the secondary hydroxyl at C-3 of 3.4 was established using the Modified Mosher’s method. The synthetic component of the thesis commences in Chapter Four with the semi-synthesis of labdane diterpene nitriles 9α-cyano-15,16-epoxy-7β-hydroxylabda-13(16),14-dien-6-one (4.1), 9α-cyano-15,16-epoxy-7-hydroxylabda-7,13(16),14-trien-6-one (4.2) and 9α-cyano-15,16- epoxy-6β,7β dihydroxylabda-13(16),14-diene (4.3) from the terrestrial labdane diterpene, hispanolone (4.4). This work is an extension of previous synthetic studies directed towards the synthesis of T. costatus metabolites. Diterpenes 4.1-4.3 exhibited in planta activity against the economically important crop pathogens, Magnaporthea grisea and Puccinia recondita. Chapter Five describes the successful ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Van Wyk, Albert Wynand Wincke |
author_facet |
Van Wyk, Albert Wynand Wincke |
author_sort |
Van Wyk, Albert Wynand Wincke |
title |
Studies in marine diterpene chemistry |
title_short |
Studies in marine diterpene chemistry |
title_full |
Studies in marine diterpene chemistry |
title_fullStr |
Studies in marine diterpene chemistry |
title_full_unstemmed |
Studies in marine diterpene chemistry |
title_sort |
studies in marine diterpene chemistry |
publisher |
Rhodes University |
publishDate |
2008 |
url |
http://hdl.handle.net/10962/d1005019 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:4354 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Marion Island |
genre_facet |
Antarc* Antarctic Marion Island |
op_relation |
vital:4354 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:4354 http://hdl.handle.net/10962/d1005019 |
op_rights |
Van Wyk, Albert Wynand Wincke |
_version_ |
1766264812062375936 |