Synthesis and biochemical characterization of a series of 17α-perfluoroalkylated estradiols as selective ligands for estrogen receptor α.

Despite intensive research efforts, the distinct biological roles of two closely related estrogen receptors, ERα and ERβ, are only partially understood. Therefore, ligands selective for either of two isotypes are useful research tools because they allow for exerting a desired subset of biological effects mediated by only one of the receptors. Here we report on the synthesis of a new class of potent and selective ligands for ERα represented by a series of 17α-substituted estradiols bearing lipophilic perfluoroalkyl chains. These 17α-perfluoroalkylated estradiols were synthesized by Ru-catalyzed cross metathesis reactions of 17α-allyl- or 17α-vinylestradiols with perfluoroalkylpropenes. Compounds were tested in both agonistic and antagonistic modes using a panel of stable steroid receptor reporter cell lines established in U2OS cells and consisting of ERα-LBD, ERβ-LBD, GR-LBD, and MR-LBD reporters. Some of the compounds are potent and selective agonists of ERα, exhibiting weak partial to no detectable agonistic activity on ERβ. Notably, 11c is the most ERα selective ligand of the prepared compounds because it activates ERα but inhibits ERβ. In addition, some compounds are pure agonists on ERα but show mixed agonistic/antagonistic profile on ERβ which is a typical pattern observed for selective estrogen receptor modulators (SERMs).