Novel bicyclic lactam inhibitors of thrombin: potency and selectivity optimization through P1 residues.

Peptidomimetic inhibitors of thrombin lacking the important Ser195-carbonyl interaction have been prepared. The binding energy lost after the removal of the activated carbonyl was recaptured through a series of modifications of the P1 residues of the bicyclic lactam inhibitors. Selected substituted compounds displayed useful pharmacological profiles both in vitro and in vivo.