Development of Photoswitchable Estrogen Receptor Ligands.

Photopharmacology has attracted attention as an approach for the development of novel therapeutics because it allows regulation of the bioactivity of compounds based on their conformational change by photo-irradiation. Previously, we have reported several types of selective estrogen receptor (ER) modulators based on diphenylmethane skeleton. To develop novel photopharmacological reagents, we designed and synthesized a set of ER ligands based on azobenzene skeleton, which can switch its conformation following UV irradiation. Our results showed that after UV irradiation, the Z-form of the synthesized compound 9 interacted with ER alpha, with a K-D value of 2.5 mu M, whereas the E-form of compound 9 did not bind ability to ER alpha at 10 mu M.