I. An investigation of the diterpenoid chemistry of the Caribbean gorgonians Erythropodium caribaeorum and Briareum sp. II. Studies on the chemistry of the sponges Jaspis stellifera from Guam and Jaspis sp. from New Guinea. III. New bastadin-type metaboli

his dissertation focuses on the chemical investigation of five marine invertebrates: the gorgonians Erythropodium caribaeorum from the U.S. Virgin Islands and Jamaica, and Briareum sp. from Puerto Rico; the sponges Jaspis stellifera from Guam and Jaspis sp. from New Guinea; and the sponge Ianthella basta from Guam. A total of sixteen new briarane diterpenes were isolated from the two Caribbean gorgonians studied--seven from Erythropodium caribaeorum and nine from Briareum sp. The sponge Jaspis stellifera yielded five new cytotoxic but unstable triterpenes of the isomalabaricane class. Only the known compound jaspamide was obtained from the New Guinean Jaspis sp. Five new brominated tyrosine metabolites of the bastadin type were isolated from the sponge Ianthella basta. Structures for all these compounds were determined through interpretation of spectral data, especially one- and two-dimensional NMR. Some of the compounds were screened for cytotoxicity (P-388 leukemia cell line) and antiinflammatory activity (mouse ear assay).;The briaranes from Erythropodium caribaeorum, erythrolides C through I, possess structural features previously not encountered among briarein-type diterpenes. Erythrolide C, D, and H have a 2R;The briaranes from Briareum sp., briareolides A through I, are new additions to a relatively small group of briarane diterpenes that have an ;Although generally not cytotoxic, some of the new briaranes displayed marginal antiinflammatory activity.;Five new bastadins, bastadin-8 through -12, were isolated from Ianthella basta. Bastadin-8 and -9 were cytotoxic and effective antiinflammatory compounds. Complete...