THEONELLAMIDES A-E, CYTOTOXIC BICYCLIC PEPTIDES, FROM A MARINE SPONGE THEONELLA SP

摘要

Five new cytotoxic peptides, related to theonellamide F (1), were isolated from a marine sponge Theonella sp. Theonellamide A (2) and B (3) differ from F (1) in three amino acid residues. Additionally, theonellamide A (2) bears a beta-D-galactose linked to the free imidazole nitrogen; Theonellamide C (4) is debromo 1. Theonellamide D (5) and E (6) are the beta-L-arabinoside and beta-D-galactoside of 1. Structures 2-6 were assigned on the basis of spectral data and chromatographic analyses of degradation products. [References: 16]