High-affinity, non-nucleotide-derived competitive antagonists of platelet P2Y12 receptors

Abstract

Anthraquinone derivatives related to the moderately potent, nonselective P2Y12 receptor antagonist reactive blue 2 (6) have been synthesized and optimized with respect to P2Y12 receptor affinity. A radioligand binding assay utilizing human blood platelet membranes and the P2Y12 receptor-selective antagonist radioligand [3H]2-propylthioadenosine- 5′-adenylic acid (1,1-dichloro-1-phosphonomethyl-1-phosphonyl) anhydride ([3H]PSB-0413) was applied for compound testing. 1-Amino-2- sulfoanthraquinone derivatives bearing a (p-phenylamino) anilino substitution in the 4-position and an additional acidic function in the meta-position of the aniline ring showed high P2Y12 receptor affinity. These new anthraquinone derivatives became accessible by a recently developed copper(0)-catalyzed Ullmann coupling reaction of 1-amino-4-bromoanthraquinone derivatives with anilines in phosphate buffer under microwave irradiation. The most potent compounds exhibited Ki values of 24.9 nM (1-amino-4-[4-phenylamino-3-sulfophenylamino]-9,10-dioxo-9,10-dihydroanthracene- 2-sulfonate, PSB-0739, 39), and 21.0 nM (1-amino-4-[4-phenylamino-3- carboxyphenylamino]-9,10-dioxo-9,10-dihydroanthracene-2-sulfonate, PSB-0702, 41), respectively. 1-Amino-2-sulfo-4-anilinoanthraquinone derivatives appeared to be noncytotoxic, as shown for selected derivatives at two human cell lines (melanoma and astrocytoma). Compounds 39 and 41 represent new lead structures for the development of antithrombotic drugs. © 2009 American Chemical Society.