Abstract: | The sponge Hamigera tarangaensis has yielded eight new compounds and we report here the structure of one of these compounds, hamigeran A, C20H25BrO5, or methyl 7‐bromo‐4β,6‐dihydroxy‐1β‐isopropyl‐3aα,8‐dimethyl‐5‐oxo‐1a,3a,4,5‐tetrahydrocyclopentaa]naphthalene‐4‐carboxylate, and the decomposition product of hamigeran D, C21H28BrNO4, namely 2‐(8‐bromo‐2β,7‐dimethyl‐4‐oxo‐1,3α‐benzoxazan‐5‐yl)‐3‐isopropylcyclopentylacetic acid. |