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Abstract

The literature on the isolation, structure elucidation and biological activities of naturally occurring norditerpene dilactones is reviewed.

The isolation of non-lactone components from Podocarpus saligna is described and discussed in relation to previous literature reports. A new HPLC method has been devised for the analysis and preparative-scale separation of the dilactones in P. Saligna, leading to the isolation of several pure compounds in small quantities. The characterisation of these new compounds has been achieved, mainly by the pioneering use of recently-developed spectroscopic methods, including 400 MHz¹H NMR with nuclear Overhauser enhancement difference spectroscopy and Fast Atom Bombardment Mass Spectrometry.

In the second section of the work, literature methods for the synthesis of diterpenes are reviewed and a proposal is set out for the total synthesis of A-ring oxygenated norditerpene dilactones. This proposal involves a regiocontrolled Diels-Alder reaction, for which substantial literature support is presented. The synthetic approaches to establishing this route are described.

These involve firstly, the efficient synthesis of xyloquinone by catalytic oxidation of 2,6-dimethylphenol; secondly, the synthesis of appropriate dienes including 3-methyl-2-pyrone; and thirdly, the attempted cycloadditions between xyloquinone and the various dienes.

The third section presents some applications of HPLC to the analysis of steroid esters which are of potential interest as long-acting, injectable contraceptive agents in a World Health Organisation development programme.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science Q Science > QD Chemistry Q Science > QK Botany
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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