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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Biomimetic rearrangements of humulene

Bryson, I. January 1981 (has links)
No abstract, first paragraph of introduction: Simple terpenoids have been known for many centuries as plant constituents whose fragrance commended them to the early investigators. Within this group of naturally-occurring compounds the C15 sesquiterpenes were of particular interest, largely as a result of their relatively high abundance. In 1895, Chapman isolated a new sesquiterpene, humulene (1), from oil of hops and by the preparation of various derivatives distinguished this hydrocarbon, previously called α-caryophyllene, from caryophyllene. The carbon skeleton of this hydrocarbon was established but the placement of the three olefinic bonds proved difficult. The structure was deduced correctly by degradative experiments and the analysis of the nmr spectrum suggested that all the double bonds were endocyclic and had a trans configuration. The structure was confirmed beyond doubt by an X-ray study of the bis-silver nitrate adduct.
12

Synthetic studies of sesquiterpenoid furanoeudesmanes.

January 2002 (has links)
Tsang Tsun-keung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 73-78). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.i / CONTENTS --- p.ii / ABSTRACT --- p.iv / ABBREVIATIONS --- p.vii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- General Background --- p.1 / Chapter 1.1.1 --- Characteristics of sesquiterpenoid furanoeudesmanes --- p.1 / Chapter 1.1.2 --- Examples of trans-fused natural sesquiterpenoid furanoeudesmanes --- p.2 / Chapter 1.1.3 --- Examples of cis-fused natural sesquiterpenoid furanoeudesmanes --- p.3 / Chapter 1.1.3.1 --- Tubipofuran and 15-acetoxytubipofuran --- p.3 / Chapter 1.1.4 --- Examples of C9-C10 unsaturated natural sesquiterpenoid furanoeudesmanes --- p.6 / Chapter 1.2 --- Biosynthesis of Sesquiterpenoid Furanoeudesmanes --- p.7 / Chapter 1.3 --- Synthesis of Sesquiterpenoid Furanoeudesmanes --- p.9 / Chapter 1.3.1 --- Synthetic examples of trans-fused sesquiterpenoid furanoeudesmanes --- p.9 / Chapter 1.3.2 --- Synthetic examples of cis-fused sesquiterpenoid furanoeudesmanes --- p.10 / Chapter 1.3.2.1 --- "Linearly fused A/B trans- and A/B cis- furo[3,2-b] and furo[2,3-b] decalin derivatives" --- p.10 / Chapter 1.3.2.2 --- "(±)-14-Norfuranoeudesmane-4,5-dione" --- p.11 / Chapter 1.3.2.3 --- Tubipofuran and 15-acetoxytubipofuran --- p.12 / Chapter CHAPTER 2 --- RESULTS AND DISCUSSION --- p.18 / Chapter 2.1 --- Aim of Present Work --- p.18 / Chapter 2.2 --- C ring + A ring →AC ring → ABC ring Scheme A --- p.20 / Chapter 2.2.1 --- Preparation of C ring in Scheme A --- p.20 / Chapter 2.2.2 --- Preparation of A ring in Scheme A --- p.22 / Chapter 2.2.3 --- Formation of B ring in Scheme A --- p.26 / Chapter 2.3 --- C ring + A ring → AC ring → ABC ring Scheme B --- p.37 / Chapter 2.3.1 --- Preparation of C ring in Scheme B --- p.37 / Chapter 2.3.2 --- Preparation of A ring in Scheme B --- p.37 / Chapter 2.3.3 --- Formation of B ring in Scheme B --- p.38 / Chapter CHAPTER 3 --- CONCLUSION --- p.51 / Chapter CHAPTER 4 --- EXPERIMENTAL SECTION --- p.52 / REFERENCES --- p.73 / APPENDIX --- p.79 / Chapter I --- List of X-ray Crystallographic Data / Chapter II --- List ofNMR Spectra
13

Synthetic study of sesquiterpenoid furanoeudesmanes. / CUHK electronic theses & dissertations collection

January 1999 (has links)
by Yick Chung Yan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (p. 109-116). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
14

Synthesis of furanoeremophilane sesquiterpenoids

Shanmugham, Meenakshi Sundaram 13 January 2004 (has links)
Two approaches to the tricyclic core of the furanoeremophilane sesquiterpenoids are described. The first approach entails a projected Diels-Alder/retro Diels-Alder reaction of an acetylenic oxazole 64. Construction of the pivotal aldehyde 67 commenced from ketone 68. The acetyenic moiety was then introduced via a Felkin-Ahn addition of lithiopropyne to aldehyde 67. The final conversion of the cyclohexanone 83 to the acetylenic triflate 65 was unsuccessful. Attempts at addition of lithiated 2-methyloxazole 88 to ketone 83 were also unsuccessful. The second approach exploited a new annulation strategy. The aldehyde 64 was advanced to the 2, 4, 6-triisopropylbenzene sulfonylhydrazone 102 and a Shapiro reaction of 102 then provided alcohol 96. The furyl stananne 114 was readily prepared via a six-step sequence from acetylacetaldehyde dimethyl acetal 106. Unification of allylic bromide 90 and stannane 114 was accomplished through a Stille cross coupling methodology and the resulting product 113 was advanced to the aldehyde 116. However, attempts at further oxidation of this aldehyde to the required acid 89 failed. An alternative furyl stananne 124 with a tert-butyldimethylsilyl substituent at the C2 position was prepared from 3-furoic acid. An analogous sequence to that used with 113 led to aldehyde 131 which was successfully cyclized with the aid of trimethylsilyl trifluromethanesulfonate and 2, 6-lutidine to the tricyclic structure 132. Oxidation of the epimeric mixture of alcohols, followed by stereoselective reduction and removal of the tert-butyldimethylsilyl group from alcohol 134, gave (±)-6β-hydroxyeuroposin (4). Oxidation experiments with 134 were shown to convert the furan in this structure to a butenolide characteristic of the eremophilenolides. / Graduation date: 2004
15

Origins of isoprenoid diversity a study of structure-function relationships in sesquiterpene systems /

Greenhagen, Bryan T. January 2003 (has links) (PDF)
Thesis (Ph. D.)--University of Kentucky, 2003. / Title from document title page (viewed onJune 1, 2004). Document formatted into pages; contains x, 145 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 126-143).
16

Structural studies on tumor inhibitory sesquiterpene lacones

Kelsey, John Edward, January 1969 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
17

The biological properties of three trichothecene mycotoxins produces by fusaris

Janse Van Rensburg, Daniel Francois January 1986 (has links)
The highly toxic fungal metabolite, neosolaniol monoacetate, was isolated and purified from cultures of Fusarium sambucinum. Since little is known about its toxic properties, the biological effects of this trichothecene were compared to those caused by diacetoxy-scirpenol in male Wistar rats. The lesions caused by the two toxins were very similar. Chronic exposure to either toxin led to a significant decrease (P<0.05) in red blood cell counts and a significant increase (P<0.05) in platelet size. The major pathological lesions observed were atrophy of the actively dividing cells of the bone marrow, thymus, spleen and lymph nodes. The reported species difference in T-2 toxin toxicity was investigated by determining the deacylation rate of T-2 toxin to HT-2 toxin, one of the first steps in the detoxification of this trichothecene. The high deacylation rate catalysed by rat microsomes correlated with the low sensitivity of this species to T-2 toxin, whereas the low deacylation rates with cat and monkey microsomes agreed with their high sensitivity. In contrast to this, the apparently high toxicity of T-2 toxin to humans does not correlate with the high deacylation rate observed in human hepatic microsomes. Involvement of the UDP-glucuronyltransferases in the detoxification of T-2 toxin was studied with rat and pig hepatic microsomes. T-2 toxin and two of its metabolites, HT-2 toxin and T-2 tetraol, did not appear to act as substrates for these enzymes under the in vitro conditions used.
18

Aspects of enol-y- lactone chemistry : approaches towards the synthesis of a [beta]-furanosesquiterpene

Price, Martyn Frederick. January 1980 (has links) (PDF)
Photocopy of typescript
19

Aspects of enol-y- lactone chemistry : approaches towards the synthesis of a [beta]-furanosesquiterpene / by Martyn Frederick Price

Price, Martyn Frederick January 1980 (has links)
Photocopy of typescript / v, 182 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Organic Chemistry, 1981
20

Aspects of enol-y- lactone chemistry : approaches towards the synthesis of a [beta]-furanosesquiterpene /

Price, Martyn Frederick. January 1980 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Organic Chemistry, 1981. / Photocopy of typescript.

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