Terpene isocyanides, isocyanates, and isothiocyanates from the Okinawan marine sponge Stylissa sp.

Seven new nitrogenous terpenoids, (1R,6R,7S,10S)-10-isothiocyanatocadin-4-ene (1), (1S,2S,5S,6S,7R,8S)-13-isothiocyanatocubebane (2), (1R,3S,4R,7S,8S,12S,13S)-7-isocyanoamphilecta-10,14-diene (3), (1S,3S,4R,7S,8S,12S,13S)-8-isocyanoamphilecta-11(20),14-diene (4), (3S,4R,7S,8S,11S,13S)-8-isocyanoamphilecta-1(12),14-diene (5), 8-isocyanatocycloamphilect-10-ene (6), and 8-isothiocyanatocycloamphilect-10-ene (7), were isolated from the Okinawan sponge Stylissasp., along with 12 known related compounds. Structural determinations of these compounds were made by spectroscopic analysis, and assessment was made of their cytotoxicity toward HeLa cells.