4′-Substituted analogues of idoxifene: Antiestrogens and calmodulin antagonists

4′-substituted analogues of the antiestrogen idoxifene have been prepared. All the compounds were assayed for antagonism of calmodulin dependent c-AMP phosphodiesterase and for binding to rat uterine estrogen receptor. The 4′-amino compound was the most potent antiestrogen (RBA = 47) whilst retaining a similar calmodulin antagonism to idoxifene.