Synthesis and pharmacological evaluation of 2-aryloxy/arylamino-5-cyanobenzenesulfonylureas as novel thromboxane A₂ receptor antagonists

New series of original 2-aryloxy/arylamino-5-cyanobenzenesulfonylureas were synthesized and evaluated as thromboxane A2 receptor (TP receptor) antagonists. A functional pharmacological test was used, which consisted of measuring the inhibition of intracellular calcium mobilization in a model of mammalian cell line that specifically over-expressed the individual TPα or TPβ isoforms. 2-Arylamino-5-cyanobenzenesulfonylureas exhibited virtually identical affinity and/or functional activity than 2-aryloxy-5-cyanobenzenesulfonylureas for both TPα and TPβ, but some 2-aryloxy-substituted compounds showed increased selectivity for TPβ relative to TPα. Several compounds were found to be as potent as the 2-arylamino-5-nitrobenzenesulfonylurea reference compound BM-573, supporting the view that the bioisosteric replacement of the nitro group by a cyano group was tolerated. TP receptor antagonist activity of the most promising molecules was confirmed in a platelet aggregation assay using the TP receptor agonist U-46619 as a proaggregant. Three compounds (7e, 7h and 8h) were identified as leads for further non-clinical pharmacological and toxicological studies.

2-Aryloxy/arylamino-5-cyanobenzenesulfonylureas; Antiplatelet agents; G-protein coupled receptor; GPCR; IP(3); PLC; TP receptor; TXA(2); TXS; Thromboxane receptor antagonists; inositol 1,4,5-triphosphate; phospholipase C; thromboxane A(2); thromboxane A(2) receptor; thromboxane synthase.