Twilight Zone Sponges from Guam Yield Theonellin Isocyanate and Psammaplysins I and J

From the organic extracts of two Guam sponges, Rhaphoxya sp. and Suberea sp., determined to have cytotoxic and chemopreventive activities, three new compounds, theonellin isocyanate (1) and psammaplysins I and J (5, 6), and six previously reported compounds (2–4, 7–9) were isolated and characterized spectroscopically (1H and 13C NMR, MS, IR, UV, [α]D). The two new metabolites (5 and 6) isolated from the Suberea sp. sponge are rare examples of compounds containing a bromotyramine moiety rather than the more usual dibromo analogue. For the compounds isolated from the Rhaphoxya sp., this is the first report of the known compounds 2–4 being found in a single sponge. For previously reported compounds 2–4 complete unambiguous 1H and 13C NMR data are provided.