The Constituents of Marine Sponges. IV. The Isolation of Degraded Spongian Diterpenoids From Aplysilla tango (sp. nov.) (Dendroceratida)

Abstract

From the orange encrusting marine sponge Aplysilla tango (sp. nov .) five degraded spongian diterpenes were isolated: gracilin A, aplytandiene-1, aplytandiene-2, aplytangene-1 and aplytangene-2. Gracilin A was confirmed by spectroscopic methods to be (4Z, 1R*, 1′S*, 3S*, 3aR*, 7aR*)-4-ethylidene-5-(1′,3′,3′-trimethylcyclohexyl)-1,3,3a,4,7,7a- hexahydroisobenzofuran-1,3-diyl diacetate (31, and related diterpenes aplytandiene-1 and -2 were confirmed to be (4) and (5) respectively. Aplytangene-1 was shown to be (1′Z, 1R*, 1″S*, 5S*,6R*, 8R*)-8-[1′-ethenyl-2′-(1′,3″,3″-trimethoxycyclohexyl) ethenyl ]-3-oxo-2,7-dioxabicyclo [3.2.1]oct-6-yl acetate (6) and aplytangene-2 to be methyl (4E, 1′S*, 3R*, 3aR*, 5R*,6aS*)-5-methyl-2-oxo-4-(1′,3′,3′-trimethylcyclohexylmethylene ) hexahydrofuro [2,3-b]furan-3-acetate (7). A steroid fraction was also isolated.