Pombo-Villar, Esteban (1985) Some chemistry relating to turmerones. PhD thesis, University of Warwick.

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Abstract

The current ideas relating to the biosynthesis of turmerones are discussed, and a biosynthetic pathway leading to α- and β-turmerones is proposed. The conformation of β-turmerone assigned by Japanese workers is shown to be based on erroneous assumptions; their data are insufficient for assignment of the absolute stereochemistry of β-turmerone. A chemical correlation to juvabione is proposed, and all current methodology is inadequate for the selective transformation of a 1, 3-diene to an α β-unsaturated methyl ester. It is shown that this transformation can be performed via the addition of a sulphenyl halide to the 1, 3-diene. Addition of phenylsulphenyl chloride to 2, 3-dimethyl-l, 3-butadiene gives the 1, 2-adduct: 2-chloro-2, 3-dimethyl-l-(phenylthio) but-3-ene. This adduct rearranges thermally to the 1, 4-adduct. The 1, 2-adduct is converted into a variety of β-substituted sulphides by replacing the chloride with a suitable nucleophile: MeOˉ , AcOˉ , ˉCN, ˉOH. Hydride transfer to the tertiary centre is slow, and rearrangement to the 1, 4-adduct is a competing process. Conversion of β-hydroxy- sulphides from 1, 3-dienes to alkenylepoxides is achieved, and the epoxides rearrange to aldehydes by acid treatment. This constitutes an oxidative monofunctionalisation of 1, 3-dienes, and similar transformations are obtained with 4,4-dimethyl-l-methylenecyclohex-2-ene, and with trans-penta-1,3-diene. The thermolysis of (2-hydroxy-l-phenyl- ethyl)pyridinecobaloxime is studied by 1 HNMR, and employed to synthesise l-(carboxymethyl)ethylpyridinecobaloxime. No alkylcobalt species is obtained in the reaction with dienes or unactivated olefins.

Finally, the determination of the structure of a new lignan from Virola elongata is described.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QK Botany S Agriculture > SB Plant culture
Library of Congress Subject Headings (LCSH):	Plant products -- Synthesis , Turmeric -- Analysis, Virola (Genus)
Official Date:	September 1985
Dates:	Date Event September 1985 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry and Molecular Sciences
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Golding, Bernard T. ; Samuel, Christopher J.
Sponsors:	Icetex ; Quest International ; Overseas Research Scholarship ; COBE. S. A. ; Imperial Chemical Industries, ltd. ; Procter & Gamble Company
Extent:	1 volume (various pagings) : illustrations
Language:	eng

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