More Peptides and Other Diverse Constituents of the Marine Mollusk Philinopsis speciosa

In addition to five new depsipeptides related to kulolide-1 (1), further examination of the mollusk Philinopsis speciosa has yielded a linear peptide, pupukeamide (14), and an unprecedented macrolide, tolytoxin-23-acetate (7). Chemical makeup suggested that the compounds originate from blue-green algae and are transmitted via herbivorous mollusks to P. speciosa. This could be verified by laboratory experiment. The structures were determined largely by spectroscopic techniques and the stereochemistry by hydrolysis of the peptides followed by chiral chromatography.