Montgomery, Laura Jane (2008) Investigations of the biosynthesis and biomimetic synthesis of bioactive natural products. PhD thesis, University of Warwick.

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Abstract

This thesis describes work towards the biomimetic synthesis and understanding the biosynthesis of two families of natural products: prodiginines and quartromicins. Prodiginines are a large family of red pigmented tripyrrole antibiotics. Although they have not been used clinically, the promising anti-cancer, immunosuppressive and antimalarial activity they display at non-toxic doses has generated renewed interest in their utilisation. The synthesis of an analogue of the proposed pyrrole-2-carboxyl-RedO intermediate in prodiginine biosynthesis has been achieved. The resulting NAC thioester and analogues of it have been used to investigate the prodiginine biosynthetic pathway in Streptomyces coelicolor, and to examine the production of prodiginine analogues by mutasynthesis. Quartromicins, novel anti-viral antibiotics, are a structurally unique group of spirotetronate natural products produced by Amycolatopsis species. They are unusual symmetric macro cyclic compounds which possess a 32-membered carbocyclic structure with four spirotetronic acid units connected by enone or dienone linkers in a head-to-tail fashion. These macrocyclic compounds are intriguing because they have alternating endo- and exo- spirotetronic acid units, with the opposite "comers" being identical. Although the quartromicins have therapeutic potential, very little is known about their biosynthesis. In this research a biosynthetic pathway to the quartromicins has been proposed based on hypothetical pathways to related natural products. The synthesis of the two putative key intermediates in quartromicin biosynthesis has been achieved. An improved method for the synthesis of exomethylene tetronates has been developed, and novel rearrangements have been discovered. The two putative key intermediates have been used to investigate the biomimetic synthesis of the carbon skeleton of the quartromicin algycone, and mass spectrometric evidence for formation of homo- and heterodimers, and a heterotetramer of the key intermediates has been obtained.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	R Medicine > RS Pharmacy and materia medica
Library of Congress Subject Headings (LCSH):	Biomimetics, Antibiotics -- Synthesis, Streptomyces coelicolor, Bioactive compounds
Date:	March 2008
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Challis, Gregory L.
Sponsors:	Engineering and Physical Sciences Research Council (EPSRC)
Extent:	xxiv, 202 leaves
Language:	eng
URI:	http://wrap.warwick.ac.uk/id/eprint/4420

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