The design, synthesis, and in vitro biological activity of a series of 2-carboxy quinolone antagonists selective for the endothelin A receptor are presented. Introduction of a second acid group in position 3 of the quinolone ring increases dramatically the selectivity for ET A . ... Several peptidic as well as non-peptidic endothelin antagonists have been reported in the literature, being either ET A selective (ie, BQ 123, 8 BMS 182874, 9 A-127772, 10 ) ET B selective (BQ 788 11 ) ...
