Polarographic chemical analysis, although invented only twenty-five years ago, has already become a standard method ror the research worker and industrial analyst alike. The variety or topics in pure, bio- and commercial chemistry which may be investigated easily with the polarograph, as well as its application to microchenistry, has found it a place in laboratories throughout the world. The invention offthe method, and much or the pioneer development are due to Jaroslav Heyrovsky and his colleagues at Charles University, Prague, (Phil. Mag., 1923, 45, 303; Trans. Faraday Soc., 1923, 19, 692 et seq.) Kucera, also of Charles University, noticed peculiar inflections in the electrocapillary curve of mercury under certain conditions, and devised the "dropping mercury electrode", now commonly used; to investigate these, (Ann. Physik., 1903,11, 529). Further work on this subject by Heyrovsky led ultimately to the development of polarography, (Ohemo Listy, 1922, 12, 256.)

2-Oxonanoyl oxide (27) has been converted to the 2-hydroxy ether (65) and the 2-oxo ether (66) both of which Possess ambergris-type odours similar to that of the odiferous compound (1). The route which affords the highest yield is via the intermediates (64), (75), (43) and (36), and this gives 23% of the 2-oxo ether (66) and 17% of the hydroxy ether (65) from 2-oxomanoyl oxide. A two-step transformation of manoyl oxide (26) into the Perfume (1) has been achieved by oxidising manoyl oxide with chromium trioxide in acetic acid, and then reducing the resulting lactone (55) directly to its cyclic ether (1). Attempts were made to synthesise new ambergris-type perfumes, and successful preparation of the internal ketal (108) showed that contrary to expectations this ketal is odourless. Comparison of the mass spectra of the lactones (54), (55), (56), and (145), with those of their c8 epimers (57), (58), (59), and (146) respectively, showed that the trans-fused lactones lose carbon dioxide upon electron-impact while the cis-fused isomers do not.

Following the classical work of Werner whose co-ordination theory provided the first rational foundation for the study of transition metal complexes, chemists have endeavoured to discover the underlying principles involved in these compounds. Thus, while Werner noticed the directional property of the bonds between metal and ligand, it was not until Pauling (1931) and others were able to apply a wave mechanical treatment, that an explanation for the rigid stereochemical requirements of the metal was found. With this growth in fundamental knowledge the interpretation and use of the physical properties of complex compounds has become possible. For example, the magnetic susceptibility has been related to the electronic configuration of the metal atom, (Pauling loc. cit.) enabling predictions to be made about the type of metal-ligand bond.

The crystal structures of four coordination compounds of copper(II) have been investigated by three-dimensional X-ray methods. The structure of one crystalline form of bis-(N-ethyl-salicylaldiminato) copper(II) has revealed that the copper atom in such a compound may adopt a tetrahedrally-distorted coordination geometry under less severe steric conditions than had previously been supposed. The structures of a methylamine perchlorate adduct of NN’-ethylenebis-(acetylacetoneiminato) copper(II) and p-nitrophenol and chloroform adducts of NN’-ethylenebis-(salicylaldiminato) copper(II) have indicated that the bonding requirements of the copper atom can be modified by hydrogen bonding involving a ligand atom.

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.

The crystal structure of bis-(pyridoxylidene-L-valine)nickel(II) hydrate (referred to as nickel(II) pyridoxylidene L-valine) has been determined but the difficulty in detecting small deviations from body-centred symmetry, and in locating all solvent molecules, has precluded an accurate analysis. Octahedral coordination to the nickel atom is achieved by the attachment of two Schiff base units. The fused ring system of each unit reveals distortions from planarity.

The coordination compounds of many transition metals can exist in two form with differing magnetic moments. As the paramagnetic susceptibility arises largely from the unpaired electrons present in the molecule, this means that the two classes of compound for any metal must have differing numbers of unpaired electrons. The first satisfactory explanation of the differing magnetic moments was given by Pauling who suggested that there were two fundamentally different types of coordination compound.

The diterpene hydrocarbon rimuene has exercised over the years, the interest of a number of laboratories engaged in natural product research. As is usual with this class of compound its occurrence is confined almost entirely to the native New Zealand flora and although only two types of tree have been used as sources, it has been identified, often only in small amounts, in at least ten different species. Its co-occurrence with other diterpenes of similar chemical and physical properties has often made it hard to isolate and this, together with its geographic distribution has probably tended to limit its availability for research purposes, and hence delayed the elucidation of its structure. The awareness of the existence of this compound of undetermined structure has, therefore, caused a noticable gap in the knowledge of the diterpenoids, and this hiatus has been accentuated by Wenkert who, believing it to have a pimarane skeleton, suggested that it might be the important biogenetic precursor of a number of tetracyclic diterpenoids. Recent work, confirmed by the present investigation has, however, shown that previous structural predictions were incorrect and in actual fact rimuene has a rosane skeleton. As Ruzicka has shown for this class of compound, it has probably been formed from a pimarane diterpenoid and therefore represents a later biogenetic step than the other diterpene hydrocarbons which are always found with it in nature.

Picrotoxin is the bitter tasting convulsive poison, obtained from the cocculus berries, the fruit of the East Indian creepers, Menispermum cocculus and Anamirta paniculata. It has been used extensively in medicine as anti-barbiturate. Although picrotoxin was first isolated in 1812 by Boullay and has been the subject of exhaustive research since then, the problem of its structure is still incompletely solved.

In a survey of the secondary metabolite chemistry profiles of ten New Zealand, one Antarctic and one South African-sourced collections of Latrunculia spp. sponges, eighteen discorhabdin alkaloids have been isolated. Four of those, namely discorhabdin K, 3-dihydro discorhabdin A, 1-thiomethyl discorhabdin G*/I, and 16a,17a-dehydro discorhabdin W were fully characterized as new natural products in the series. In addition, for the first time, five enantiomeric pairs and two sets of diastereomers of the naturallyoccurring discorhabdin alkaloids were identified. The absolute configuration of all of the chiral compounds isolated, including new natural products, has been established upon comparison of the observed experimental data with the results of time dependant density functional theory calculations of the electronic circular dichroism spectra. A structure activity relationship study on discorhabdin B, the main natural product of the Wellington-sourced sponges, has identified four reactive centres on the molecule and yielded nine novel semi-synthetic derivatives. Consequently, a new discorhabdin biosynthetic tree was proposed which highlighted discorhabdin B as a crucial precursor to a number of other naturally-occurring analogues. The importance of the iminoquinone moiety and the spirodienone ring with respect to the bioactivity of the compounds in a range of naturally-occurring discorhabdins was demonstrated. A new semi-synthetic derivative, 1-discorhabdyl discorhabdin D, was identified as a potent anti-malarial agent and has opened new possibilities for the therapeutic development of the discorhabdin alkaloids.