Design and synthesis of ring-constrained boropeptide thrombin inhibitors

Ring-constrained boropeptide thrombin inhibitors were designed using information from the X-ray crystal structure of 1 (3-Phenylpropionyl-Pro-boroLys-OH •HCl) bound to thrombin. The constraints utilized cyclohexane and pyrrolidine rings to preorganize an aromatic ring in an orientation allowing optimum edge-to-face interaction with the tryptophan 215 side chain located in the S3 specificity pocket of thrombin.