Synthesis and antiplatelet evaluation of novel aryl-sulfonamide derivatives, from natural safrole1

In the scope of a research program aiming at the synthesis and pharmacological evaluation of novel possible antiplatelet prototype compounds, exploring bioisosterism principles for molecular design, we describe in this paper the synthesis of new aryl-sulfonamides derivatives, structurally similar to known thromboxane A₂ receptor antagonists. The synthetic route used to access the new compounds described herein starts from safrole, an abundant Brazilian natural product, which occurs in Sassafras oil (Ocotea pretiosa). The results from preliminary evaluation of these novel aryl-sulfonamide compounds by the platelet aggregation inhibitory test, using rabbit PRP, induced by ADP, collagen, arachidonic acid, and U46619, identified the N-[2-(4-carboxymethoxyphenyl)ethyl]-6-methyl-3,4-methylenedioxyphenyl-sulfonamido derivative as the most active among them, presenting an IC₅₀ value for the U-46619-induced platelet aggregation in rabbit platelet-rich plasma: 329 μM.