Intermediates for preparing octapeptide vasopressin antagonists

摘要

Certain octapeptides, which have structures characterized by being a six unit cyclic peptide ring with a dipeptide tail which lacks a glycine unit at position 9, have potent vasopressin antagonist activity. The compounds here claimed are in general characterized by having an amino acid unit at position 4 which is other than valine. An important species of the group is [1-( beta -mercapto- beta , beta -cyclopentamethylenepropionic acid)-2-(O-ethyl-D-tyrosine)-4- alpha -aminobutyric acid-8-arginine-9-desglycine]vasopressin.