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Abstract

This thesis describes an investigation of the biosynthesis of camphor. Camphor, a bicyclic monoterpene, has been shown to be bio-synthesised from.geranyl pyrophosphate or its isomers (neryl pyrophosphate or linaloyl pyrophosphate) and several mechanisms have been proposed for this cyclisation process. [diagrams not included] In an attempt to differentiate the origin of the C(8) and C(9) methyl groups,, feeding experiments with appropriately labelled pre- cursors were attempted. The two precursors used were [2-²H₂]-mevalonic acid and [8-²H₁]-linalool. It was shown that the expected products, [8-²H₁]- and [9-²H₁]-camphor, could be differentiated by ²H-n.m.r. using the shift reagent Eu(thd)₃ (Eu(thd)₃ = tris(2,2,6,6-tetramethyl- 3,5-heptanedionato)europium) . Feeding experiments with Rosemarinus officanalis using the cut stem method showed no incorporation of deuterium label into camphor extracted from the plant's essential oil. [diagrams not included]