Total synthesis and structural revision of the presumed aeruginosins 205A and B.

A stereoselective synthesis of enantiopure aeruginosin 205B aglycon confirms the presence of a (3R,2S)-3-chloroleucine amide residue and a (6R)-hydroxy (3aS,7aS)-octahydroindole-(2S)-2-carboxamide [corrected] (Choi) subunit instead of a 6-chloro-substituted core (Ccoi). Enzyme inhibitory tests against thrombin revealed an IC(50) of 0.31 microM. The total synthesis of the presumed aeruginosin 205B shows that the alpha-d-xylopyranosyl unit carries a sulfate group at C-4' (and not at C-3'). Comparison of NMR data leads to the same revision of aeruginosin 205A.