The absolute structure of (+)-aplysulfurin

The spongian diterpene aplysulfurin (CHO ) is a marine natural product whose relative stereochemistry has been previously elucidated by X-ray crystallography and NMR, but its absolute structure has only been proposed on biogenetic grounds. Herein we have determined the absolute structure of (+)-aplysulfurin by anomalous dispersion effects of a highly redundant data set collected with Cu-Kα radiation. We have found that the four chirotopic centres have the absolute configuration C7(R), C10(S), C15(S) and C16(S)

Psammaplin metabolites new and old: An NMR study involving chiral sulfur chemistry

The new metabolite psammaplin N (8) that contains a sulfoxide moiety has been isolated together with psammaplins A (1), I (4a), and J (2) from a specimen of the marine sponge Aplysinella rhax (order Verongida family Aplysinidae) collected in South East Queensland. An NMR study on psammaplin J reveals its facile conversion to psammaplins A and I when exposed to methanol