The constituents of marine sponges. VI. diterpenoid metabolites of the New Zealand sponge chelonaplysilla violacea

The sponge Chelonaplysilla violacea, collected from New Zealand coastal waters, contains as major constituents the diterpenoids aplyviolene (1a), norrisolide (2), dendrillolide A (3) aplyroseol-7 (4), spongian-16-one (5), chelonaplysin C (6), and a series of new compounds cheloviolene A-F and cheloviolin. Structures were assigned to cheloviolene A (7), [3aR-[3a, 4(1R*, 3aR*, 8aS*), 5, 6a]]-5-hydroxy-4(1, 4, 4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydrofuro [2, 3- b] furan-2(3H)-one, cheloviolene B (8), [3aR-[3a, 4a(1R*, 3aR*, 8aS*), 5, 6a]]-5-hydroxy-4-(1, 4, 4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydrofuro [2, 3-b]furan-2(3H)-one, cheloviolene C (9), [1'(1R*, 3aS*, 7aS*), 4]-4-[1-(acetyloxymethyl)-2-(4, 4, 7a-trimethyloctahydro-1H-inden-1-yl)prop-2-enyl] dihydrofuran -2(3H)-one, cheloviolene D (10), methyl [3, 4(1R*, 3aR*, 8aS*)]-5-oxo-4-(1, 4, 4-trimethyl-8-methylenedecahydroazulen-1-yl)tetrahydrofuran-3-acetate, cheloviolene E (11), methyl [3, 4-(1R*, 3aS*, 7aS*)]-5-oxo-4-[1-(4, 4, 7a-trimethyloctahydro-1H-inden-1-yl) ethenyl ]tetrahydrofuran-3-acetate, and cheloviolene F (12), [4, 5(1R*, 3R*, 8aS*)]-4-(acetyloxymethyl)-5-(1, 4, 4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydro-2H-pyran-2-one, by using spectroscopic methods; the structure (13) was deduced for cheloviolin, [1S-[1, 5, 6, 8R*(1aS*, 3aS*, 7aS*, 7b-R*)]]-6-acetyloxy-8-(4, 4, 7a-trimethyldecahydrocylopropa[a] naphthalen-la-yl)-2, 7-dioxabicyclo- [3.2.1]octan-3-one.