Synthesis and pharmacological evaluation of peptide-mimetic protease-activated receptor-1 antagonists containing novel heterocyclic scaffolds

Protease-activated receptor-1 (PAR-1) is a G-coupled receptor activated by a-thrombin and other proteases. In this paper we describe the synthesis and the pharmacological evaluation of novel peptide-mimetic antagonists (compounds 1–16) characterized by the presence of new heterocyclic nuclei such as 2-methyl-indole (5- and 6-substituted) and 1,4-benzodiazepine moiety. The new derivatives, tested in order to evaluate their antagonist potency by using human platelet aggregation induced by PAR-1AP, resulted in some cases (compounds 1 and 4) more potent than the reference. The compounds, tested on aortic rings, confirmed the results obtained in the aggregation assay.