Synthesis of a Ring-oxygenated Variant of the 2-carboxy-6-hydroxyoctahydroindole Core of Aeruginosin 298-A from Glucose

[reaction: see text] The design and synthesis of a new core structure, a ring-oxygenated variant of 2-carboxy-6-hydroxyoctahydroindole (Choi) from D-glucose, is reported. Choi, a rigid bicyclic unnatural amino acid, is the core structure of about 15 aeruginosins natural compounds. These compounds are thrombin, trypsin, and factor VIIa inhibitors and Choi is important for their biological activity. The ring-oxygenated variant of 2-carboxy-6-hydroxyoctahydroindole can potentially be used as a surrogate of Choi in the design and synthesis of aeruginosin-based thrombin inhibitors.