Metabolites of Three Marine Sponges of the Genus Plakortis

Article abstract of DOI:10.1021/jo01305a005

One sample of Plakortis halichondrioides contained the cyclic peroxides 3-epiplakortin (9) and 9,10-dihydro-3-epiplakortin (10).A second sample of P. halichondrioides that had been stored in ethanol gave an α,β-unsaturated ester 16 as the major secondary metabolite.A portion of the same sponge that had been frozen and then lyophilized contained the ester 16 and the lactone 19 together with the two peroxides 20 and 21 having a different, but closely related, carbon skeleton.A sample identified as Plakortis sp. contained two unstable peroxides (26 and 27) and a related aromatic hydrocarbon (25).All structures were elucidated by interpretation of spectral data and limited chemical-degradation reactions.The chemotaxonomic implications of these results are discussed.structure