S1 heterocyclic thrombin inhibitors

A series of boropeptides have previously been described by Kettner et al. to be potent thrombin inhibitors. DuP 714 is a representative of this class of compounds with a Ki = 0.040 nM, but this inhibitor has undesireable side effects. New and selective boronic acid thrombin inhibitors have been developed by replacing the guanidine of the boroarginine side chain with various heterocycles ranging in size and basicity.