Synthesis and characterization of hydrogen peroxide activated estrogen receptor beta ligands

The development and evaluation of selective estrogen receptor modulators (SERMs) is of interest because of the complex and significant role of estrogen receptors in normal tissues as well as disease states. In neurodegenerative disorders such as Alzheimer's disease and multiple sclerosis, estrogen receptor beta (ER beta) seems to provide a protective anti-inflammatory response. Due to the increase in reactive oxygen species (ROS) in these diseases, we have masked ER beta ligands, including diarylpropionitrile (DPN), as boronate esters that release the active estrogen in the presence of H2O2. Here we demonstrate their synthesis, decreased binding affinities, kinetics of release, and selectivity toward ROS. The most promising ligand can be unmasked in the presence of pathological H2O2 to modulate ER beta transcription in cells.