Hamigerin A and a hamigerin D decomposition product

Abstract

The sponge Hamigera tarangaensis has yielded eight new compounds and we report here the structure of one of these compounds, hamigeran A, C(20)H(25)BrO(5), or methyl 7-bromo-4beta,6-dihydroxy-1beta-isopropyl-3aalpha,8-dimethyl-5-oxo-1a,3a,4,5-tetrahydrocyclopenta[a]naphthalene-4-carboxylate, and the decomposition product of hamigeran D, C(21)H(28)BrNO(4), namely 2-(8-bromo-2beta,7-dimethyl-4-oxo-1,3alpha-benzoxazan-5-yl)-3-isopropylcyclopentylacetic acid.