Chemical synthesis and biological activity of the neopetrosiamides and their analogues: revision of disulfide bond connectivity

Chemically synthesize of two diastereomeric tricyclci peptides, neopetrosiamides A and B from the marine sponge Neopetrosia sp. that have ability to inhibit tumor cell invasion associated with metastasis is reported. The chemical synthesis method which used solid-phase peptide synthesis and sequential stepwise disulfide bond formation in solution could also be used to generate analogues containing methionine or norleucine instead of the methionine sulfoxide at position 24.