The analogs of oxytocin and D-homoarginine vasopressin with bulky substituted phenylalanine in position 2

Abstract

Solid phase technique on p-methylbenzhydrylamine resin was used for the synthesis of eight analogs of oxytocin and 8-D-homoarginine vasopressin with the non-coded amino acids L- or D-2,3,4,5,6-pentamethylphenylalanine and L- or D-4-phenylphenylalanine in position 2. The preparation of the above mentioned non-coded amino acids is described as well. All eight analogs were found to be potent inhibitors of oxytocin activity in the uterotonicin vitro test in the absence of Mg2+ ions. In the uterotonic testin vitro in the presence of Mg2+ and in the testin vivo, their potency is strongly decreased or completely abolished. The substances are also weak pressor inhibitors. The L or D configuration does not seem to influence the activity significantly.