The discovery, synthesis and structure-activity relationships of a series of novel benzofuro [3, 2-b] pyridines as non-selective endothelin ET AET B as well as selective ETB receptor antagonists are described. The most potent non-selective inhibitor 7s displayed an IC50 of 21 nM and 41 nM for ETA and ETB receptors, respectively, whereas 7ee merely showed affinity for the ETB receptor (IC50= 3.6 nM).
