The structures of asperuloside and pithomycolide / Phillip William Le Quesne

Abstract

The first part of this thesis is concerned with the structure, stereochemitry, and reactions of asperuloside, a labile glucoside widely distributed among plants of the family Rubiaceae. Its interest to this Departmen arose from its abundant, occurrence in Coprosma species, most of which are native to New Zealand. Since the aglycone of asperuloside is now known to possess the carbon skeleton (1) , asperuloside may be formally regarded as monoterpenoid. This Introduction therefore considers the structures, interrelationships, and biogenesis of cyclopentanoid monoterpenoids possessing the 1,2-dimethyl-3-isopropylcyc clopentane carbon skeleton (1). Cyclopentanoid Monoterpenoids: Although acyclic and cyclohexanoid monoterpenoids have been characterised for nearly eight years, naturally occurring compounds possessing the carbon skeleton (1) have been defined relatively recently. Despite their frequently unusual chemical behaviour and physiological actions, which have often been recorded in the early literature, progress in the elucidation of their structures has awaited the application of modern physical techniques. The carbon skeletons are frequently highly oxygenated, and the characteristic chemistry of the compounds arises from the interactions of contiguous functional groups. Since the chemistry of the type compounds, nepetalactone (2), iridomyrmecin (3), and iridodial (4) has been reviewed, only more recent work will be discusse below.