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 (4aR,7aS)-octahydroindole-(2S)-2-carboxamide (Choi) subunit instead of a 6-chloro-substituted core (Ccoi). Enzyme inhibitory tests against thrombin revealed an IC50 of 0.31 μM. The total synthesis of the presumed aeruginosin 205B shows that the α-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.