Synthesis of axinastatins 2-5

Article abstract of DOI:10.1016/0040-4039(96)01105-7

The cytotoxic cyclic peptides axinastatin 2, 3, 4 and 5, isolated from the ocean marine sponges Axinella sp. and Axinella cf. cateri, were synthesized and characterized by FAB-MS and homo- and heteronuclear NMR spectroscopy. The synthetic compounds proved to be identical with the natural products. The cyclization yield of axinastatin 5 could be increased using structural information of a conformationally comparable compound. In contrast to the published biological activity very low activities were found for all compounds.