2-Aryloxycarbonylthiophene-3-sulfonamides: Highly potent and etA selective endothelin receptor antagonists

A series of 2-aryloxycarbonylthiophene-3-sulfonamides were synthesized and evaluated to determine their antagonistic activity at the endothelin receptors. N-(4-chloro-3-methyl-5-isoxazolyl)-2-[(3,4-methylenedioxy)phenoxycarbonyl]thiophene-3-sulfonamide was identified as a highly selective, potent (IC50 = 8.3 nM) and low molecular weight nonpeptide antagonist.