Keramamides E, G, H, and J, New Cyclic Peptides Containing an Oxazole or a Thiazole Ring from a Theonella Sponge

Article abstract of DOI:10.1016/0040-4020(95)00017-3

Four new cyclic peptides, keramamides E (1), G (2), H (3), and J (4), containing an oxazole or a thiazole ring have been isolated from the Okinawan marine sponge Theonella sp. and the structures elucidated by 2D NMR data and degradation experiments.The sequence of amino acid residues in 1 - 4 was determined on the basis of FAB MS/MS data.