m-Carborane bisphenol structure as a pharmacophore for selective estrogen receptor modulators

A series of m-carborane derivatives was prepared based upon the structures of antiestrogenic drugs and their activities were evaluated by estrogen receptor alpha (ERα) binding assay and transactivation assay using human breast cancer cell line, MCF-7 cells. The m-carborane bisphenol 5 exhibited about a thousand times more potent ER agonistic activity than the o-carborane bisphenol 11. The m-carborane bisphenol structure appears to be a favorable hydrophobic pharmacophore for the development of novel selective estrogen receptor modulators (SERMs).