Studies related to natural products : biosynthesis of coumarins

This thesis describes a biosynthetic investigation of coumarins in turpentine-broom, Thamnosma montana Torr. and Frem. In contrast to simple coumarins, the biosynthetic pathways leading to the furanocoumarins were found to be in a state of confusion as indicated by existing published data. None of the results were internally consistent with any general postulate and there was considerable question concerning the actual meaning of a substantial portion of the experimental data. Studies as described here were performed in several different areas. In the initial investigations, a detailed study of isolation procedures for the many coumarins present in the plant was necessary. Subsequently, appropriate chemical degradative pathways were developed for umbelliprenin (11), isopimpinellin (2), and alloimperatorin methyl ether (8) to allow isolation of relevant carbon atoms in these coumarins. Finally, incorporation studies with DL-mevalonic-5-³ H acid were conducted and subsequent degradative reactions were performed on umbelliprenin (11) and alloimperatorin methyl ether (8). The implications of these preliminary experiments in terms of biosynthetic pathways are presented.Science, Faculty ofChemistry, Department ofGraduat