New scaffolds for the design of selective estrogen receptor modulators

In the present work we report the synthesis of four new ER ligands which can be used as scaffolds for the introduction of the basic side chains necessary for antiestrogenic activity. Affinities and agonist/antagonist characterization of the ligands for both ERα and ERβ have been determined in a competitive radioligand assay, and in an in vitro coactivator recruitment functional assay, respectively. Molecular modelling techniques have been used in order to rationalize the experimental results. Compound 2 is reported as a novel ERβ-agonist/ERα-antagonist. Two compounds show an interesting antitumour profile towards two pancreatic cancer cell lines and have been selected for in vivo assays.