title: Rearranged Diterpenes and Norditerpenes from Three Australian Goniobranchus Mollusks.
abstract: Three new norditerpenes (1, 6, and 7) and four diterpenes (2-5) with extensively rearranged carbon skeletons have been characterized from Australian nudibranchs. The relative configuration of the cyclopropyl-containing verrielactone (1) from Goniobranchus verrieri was suggested by spectroscopic analysis at 500 MHz informed by a combination of molecular modeling and DFT calculations. The nudibranchs G. splendidus and G. cf. splendidus provided 2-7, for which the structures and stereochemistry were deduced by 2D NMR studies at either 500 or 700 MHz. Each of the seven terpenoids exhibited a carbon skeleton modified from one of the tetrahydroaplysulphurin, spongionellin, or gracilane series of terpenes. A biosynthetic pathway to terpenes 1-7 from spongialactone is proposed.
authors.affiliation: School of Chemistry and Molecular Biosciences, ‡School of Biological Sciences, and §Centre of Advanced Imaging, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: White
authors.affiliation: School of Chemistry and Molecular Biosciences, ‡School of Biological Sciences, and §Centre of Advanced Imaging, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Pierens
authors.affiliation: School of Chemistry and Molecular Biosciences, ‡School of Biological Sciences, and §Centre of Advanced Imaging, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Louise C
authors.initials: LC
authors.lastname: Forster
authors.affiliation: School of Chemistry and Molecular Biosciences, ‡School of Biological Sciences, and §Centre of Advanced Imaging, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Winters
authors.affiliation: School of Chemistry and Molecular Biosciences, ‡School of Biological Sciences, and §Centre of Advanced Imaging, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Cheney
authors.affiliation: School of Chemistry and Molecular Biosciences, ‡School of Biological Sciences, and §Centre of Advanced Imaging, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Garson
mesh_terms: D000818:Animals; D001315:Australia; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification*; D049851:Gastropoda / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013729:Terpenes / Q000737:chemistry
chemical_list: D004224:Diterpenes; D013729:Terpenes