A new synthesis of cyclotheonamide B via guanidination of ornithine

Article abstract of DOI:10.1016/0040-4039(96)00270-5

A macrocyclic thrombin inhibitor, cyclotheonamide B (1, R = Ac) was synthesized via a new approach: guanidination of the ornithine-containing macrocyclic peptide (2). In comparison of various coupling reagents, pentafluorophenyl diphenylphosphinate (FDPP) gave the macrocyclic peptide (2) in good yield, and the configuration of the amino acid residue has been revealed to be important for the macrolactamization.