Amino and Deamino Analogs of 8-D-Homoarginin-vasopressin with Modified Tyrosine in Position 2: Synthesis and Some Biological Properties

Abstract

Solid phase methodology on benzhydrylamine or p-methylbenzhydrylamine resin was used for the synthesis of seven analogs of amino or deamino vasopressin with non-coded amino acid, D-homoarginine, in position 8 and D- or L- O-methyl or O-ethyl tyrosine in position 2. [L-Tyr-(Me)2, D-Har8]vasopressin (I), [D-Tyr(Me)2, D-Har8]vasopressin (II), [L-Tyr(Et)2, D-Har8]vasopressin (III), [D-Tyr(Et)2, D-Har8]vasopressin (IV), [Mpr1, L-Tyr(Me)2, D-Har8]vasopressin (V), [Mpr1, D-Tyr(Me)2, D-Har8]vasopressin (VI) and [Mpr1, D-Tyr(Et)2, D-Har8]vasopressin (VII) were synthesized. All analogs have very low antidiuretic activity. Analogs containing O-methyltyrosine of D-configuration or O-ethyltyrosine of both D- and L-configuration are low pressor inhibitors. All analogs were found to be uterotonic inhibitors, the most potent one in vitro being [Mpr1, D-Tyr(Me)2, D-Har8]vasopressin (VI) with pA2 = 9.0 and [Mpr1, D-Tyr(Et)2, D-Har8]vasopressin (VII) with pA2 = 8.8.