| Abstract: | Abstract: Novel peptide‐based endothelin (ET) receptor antagonists were designed and synthesized in our laboratory. BQ‐485, HIM‐CO‐Leu‐d ‐Trp‐d ‐Trp‐OH, was selected as the leading compound. The primary structures of these new tripeptides were ABO‐CO‐Leu‐d ‐Trp‐d ‐AA(X)‐OH. The introduction of unnatural aromatic amino acids into these tripeptides was useful in the structure–activity relationship studies. Among the 20 tripeptides, 16 of them showed high activities against the contraction of rat aortic smooth muscles induced by ET‐1. |
