Utility of boron clusters for drug design. Relation between estrogen receptor binding affinity and hydrophobicity of phenols bearing various types of carboranyl groups

High binding affinity for estrogen receptor and the appearance of estrogenic activity require a phenolic ring and an appropriate hydrophobic group adjacent to the phenolic ring. A quantitative structure–activity relationship analysis based on the values of logP and the pKa of the phenolic group showed that the hydrophobicity of these compounds is highly correlated to the estrogen receptor α (ERα)-binding affinity. These results should be useful for application of these spherical boron clusters (dicarba-closo-dodecaboranes; carboranes) as hydrophobic pharmacophores in drug design, as well as for microscopic analysis of ER–ligand interactions.