Abstract
Five new isocyano/isothiocyanato sesquiterpenes (1-5) with tri- or bicyclic carbon skeletons have been characterized from Australian specimens of the nudibranch Phyllidia ocellata. Spectroscopic analyses at 900 MHz were informed by DFT calculations. The 1S, 5S, 8R configuration of 2-isocyanoclovene (1) was determined by X-ray crystallographic analysis of formamide 6. A biosynthetic pathway to clovanes 1 and 2 from epicaryolane precursors is proposed. Isocyanides 1, 2, and 4 showed activity against Plasmodium falciparum (IC50 0.26-0.30 μM), while isothiocyanate 3 and formamide 6 had IC50 values of >10 μM.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antimalarials / chemistry
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Antimalarials / isolation & purification*
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Antimalarials / pharmacology*
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Australia
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Crystallography, X-Ray
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Gastropoda / chemistry*
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Isocyanates / chemistry
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Isocyanates / isolation & purification*
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Isocyanates / pharmacology*
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Isothiocyanates / chemistry
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Isothiocyanates / isolation & purification*
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Isothiocyanates / pharmacology*
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Molecular Conformation
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Molecular Structure
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Nuclear Magnetic Resonance, Biomolecular
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Plasmodium falciparum / drug effects*
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Sesquiterpenes / chemistry
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Sesquiterpenes / isolation & purification*
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Sesquiterpenes / pharmacology*
Substances
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Antimalarials
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Isocyanates
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Isothiocyanates
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Sesquiterpenes