Analogs of an endothelin antagonist RES-701-1: substitutions of C-terminal amino acid

C-terminal substituted analogs of an ETB receptor specific antagonist RES-701-1 were prepared and evaluated of their receptor binding activities. C-terminal Trp deletion or substitutions for other aromatic amino acids, containing D-configurational ones, proved to be possible without reducing the receptor binding activity, which differs from the case of ET-1 previously reported on its Trp21 for its biological activities.