Development of a Series of (1-Benzyl-3-(6-methoxypyrimidin-3-yl)-5-(trifluoromethoxy)-1H-indol-2-yl)methanols as Selective Protease Activated Receptor 4 (PAR4) Antagonists with in Vivo Utility and Activity Against γ-Thrombin.

Here, we describe the development of a series of highly selective PAR4 antagonists with nanomolar potency and selectivity versus PAR1, derived from the indole-based 3. Of these, 9j (PAR4 IC50 = 445 nM, PAR1 response IC50 > 30 μM) and 10h (PAR4 IC50 = 179 nM, PAR1 response IC50 > 30 μM) maintained an overall favorable in vitro DMPK profile, encouraging rat/mouse in vivo pharmacokinetics (PK) and activity against γ-thrombin.

Synthesis of indole derived protease-activated receptor 4 antagonists and characterization in human platelets.

Protease activated receptor-4 (PAR4) is one of the thrombin receptors on human platelets and is a potential target for the management of thrombotic disorders. We sought to develop potent, selective, and novel PAR4 antagonists to test the role of PAR4 in thrombosis and hemostasis. Development of an expedient three-step synthetic route to access a novel series of indole-based PAR4 antagonists also necessitated the development of a platelet based high-throughput screening assay.

Reactivity of the C2'-oxidized abasic lesion and its relevance to interactions with type I base excision repair enzymes.

The C2'-oxidized abasic lesion (C2-AP) is produced in DNA that is subjected to oxidative stress. C2-AP is incised by phosphodiesterases, but is not a substrate for endonuclease III even though a Schiff base is formed (Greenberg, M. M.