Structural diversity in nudibranch chemistry: elucidation of norditerpenes with a dendrillane scaffold from the Australian nudibranch Goniobranchus coi.

Autor: Forster, Louise C., Pierens, Gregory K., De Voss, James J., Garson, Mary J.
Zdroj: Australian Journal of Chemistry; 2024, Vol. 77 Issue 7, p1-8, 8p
Abstrakt: In addition to three known compounds (1 – 3), two new rearranged spongian diterpenes (4 and 5) with perhydroazulene and dioxabicyclooctane ring systems were isolated from the mantle and viscera of the Australian nudibranch G oniobranchus coi. The relative configuration of the major spiroepoxide 4 was explored by comparison with those of m -chloroperbenzoic acid oxidation products derived from dendrillolide A (1). Aldehydes 6 and 7 were identified as the ring-opened artefacts of the spiroepoxides 5 and 4 respectively, and yielded ketone 3 on storage. The relative configurations of lactols 8 and 9 , isolated as an inseparable mixture of diastereomers, were deduced by molecular modelling and computational studies. Acetylation of the lactol mixture provided dendrillolide A (1), further confirming the structural assignments of 8 and 9. Dissection of animal tissue established that the norditerpenoid metabolites were present in both mantle and viscera tissues. The nudibranch Goniobranchus coi sequesters and concentrates antifeedant oxygenated diterpenes into its mantle dermal formations to utilise as a chemical weapon when attacked by predators. Through chemical correlation, high-field NMR spectroscopy and molecular modelling new oxygenated metabolites were identified and elucidated. (Image credit: Louise C. Forster.) This article belongs to the collection 10th Anniversary Collection of RACI and AAS Award papers. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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