organic compounds
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-tetrahydrocyclopenta[a]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.