Richard C. Cambie

Fatty acid composition and the classification of the Porifera

Abstract The fatty acid content of 30 species of Porifera, including samples of Hexactinellida and Lithistida for which no fatty acid data previously existed, have been examined. The sponges are unique among animal phyla in diversity of fatty acids with generally high levels of long chain fatty acids (LCFAs; C 24–30 , high unsaturation (mainly polyunsaturation), high incidence of branched and odd chain fatty acids. Further, peculiarities in proportions of individual acids of particular chain lengths distinguish the phylum. Hexactinellid fatty acid traits corresponded closely to those of Demospongiae while the calcareous species was atypical in exhibiting low levels of LCFAs and unsaturation. Seasonal and geographical influences on components of the fatty acid profile limit the extent to which this information can be utilized in a chemotaxonomic sense.

132,173-cyclopheophorbide enol, the first porphyrin isolated from a sponge

Abstract 132,173-Cyclopheophorbide enol (1) a non-metalated chlorophyll A derivative has been isolated from Darwinella oxeata (Bergquist) and its structure determined by physical and X-ray measurements.

Sterol composition and classification of the Porifera

Abstract The sterols of 27 species of Porifera have been examined by GC-MS; this study includes 23 members of the class Demospongiae and four species of the hitherto uninvestigated class Calcarea. The trends observed earlier for the Demospongiae are supported by the results of the present survey. Sterols of the Calcarea have not proved diverse but, of those present, the majority are of the C 27 type.

The taxonomic distribution of some hydrocarbons in gymnosperms

Abstract The alkanes of thirty-two Podocarpaceae and other related species have been analysed by gas-liquid chromatography and their taxonomic significance is discussed.

The taxonomic distribution of some diterpene hydrocarbons

Abstract A survey of twenty-eight species of the Podocarpaceae and of nine related gymnosperms for diterpene hydrocarbons has been carried out by gas-liquid chromatography. The results have been used to clarify previously reported occurrences of diterpenes and to assess their taxonomic value.

A chemotaxonomic division of Murraya based on the distribution of the alkaloids yuehchukene and girinimbine

Abstract An examination of the roots of eight species and one variety of Murraya for the presence of the dimeric indole yuehchukene has revealed a dichotomy in the genus between species producing this alkaloid and those producing the carbazole alkaloid girinimbine, with no apparent overlap between the two groups of species.

Chemistry of the podocarpaceae: LXX. Synthesis and cyclopentaannulation of a diterpenoid chromium carbene complex

A pentacarbonylcarbene chromium complex of the diterpenoid methyl O-methylpodocarpate has been prepared and its reactions with some alkynes have been studied with the aim fo synthesising ring-C aromatic steroids. The use of diphenylacetylene resulted in cyclisation to give steroidal derivatives in moderate yield.

Chemistry of the podocarpaceae—VI : Constituents of the heartwood of Podocorpus totara g. benn.

Abstract Totarol (I, R = H), 16-hydroxytotarol (I, R = OH), sugiol (II), podocarpic acid (III, R = H), methyl podocarpate (III, R = CH 3 ), pododacric acid, β-sitosterol, and two unidentified compounds, the major one of which has been named podototarin, have been isolated from the heart-wood of Podocarpus totara . The absolute configuration of 16-hydroxytotarol has been determined by the conversion to (+)-totarol.

Ent-atisane diterpenes from Euphorbia fidjiana

Abstract The heartwood of the Fijian species Euphorbia fidjiana has yielded seven new ent-14-oxo-atisenes, four ent- atisane-16,17-diols, a 4,5-seco-atisene, and a 3,4-seco- atisene-ent-13[S]-hydroxy-14-oxo-3,4-seco-atis-16-en- 3,4-olide, as well as two chlorinated ent-atisanes which were identified as artifacts. Their structures and relative stereochemistry have been determined by detailed high field NMR studies and from an X-ray structure analysis of ent-13-[S]- hydroxyatis-16-ene-3,14-dione. Their absolute configuration is inferred from an X-ray structure of ent-17-p- bromobenzoyloxy-16α-hydroxyatisan-3-one.

Chemistry of the podocarpaceae: LXXI. Preparation, structure, and reactions of some (arene)tricarbonylchromium(0) complexes. Crystal structure of α-tricarbonyl[8,9,11,12,13,14-η)-methyl podocarpa-8,11,13-trien-19-oate]chromium(0)☆

Abstract Tricarbonyl[8,9,11,12,13,14-η)methyl podocarpa-8,11,13-trien-19-oate]chromium(0) ( 7 ), tricarbonyl[4a,5,6,7,8,8a-η)-1,2,3,4-tetrahydronaphthalene]chromium(0) ( 11 ) and (benzene)tricarbonylchromium(0) ( 10 ) were prepared and examined. Complex 7 was obtained as a mixture of diastereomers, an X-ray structural determination showing that the α-isomer possesses a near eclipsed conformation, in agreement with the conformation in solution deduced from 400 MHz 1 H NMR analysis. Carbonions derived from 1,3-dithiane, 2-methyl-1,3-dithiane and 2-(2,2-dimethoxyethyl)-1,3-dithiane ( 24 ), and the dianion derived from 2,2′-methylenebis-1,3-dithiane ( 27 ) were prepared and brought into reaction with the complexes. Compounds 23 and 33 resulted from regioselective attack on 7 at the site predicted. Treatment with methyl electrophiles of the dithianyl η 5 -intermediate leading to 22 did not give products of acetyl incorporation. Arene lithiation-electrophilic quenching of 7 gave a mixture of compound 6 and its C(14) regioisomer along with the novel ketone 39 and its C(14) regioisomer.