Synthesis of arginine-vasopressins, modified in positions 1 and 2, as antagonists of the vasopressor response to the parent hormone

In an attempt to determine some of the structural features in position 1 that account for antivasopressor activity, eight new 1-(beta, beta-dialkyl-substituted) analogues of 1-(3-mercaptopropanoic acid)-8-arginine-vasopressin and 1-(3-mercaptopropanoic acid)-2-O-methyltyrosine-8-arginine-vasopressin have been designed and synthesized. The protected precursors required for these peptides were obtai…