Salicylaldoxime moiety as a phenolic "A-ring" substitute in estrogen receptor ligands

The phenolic "A-ring" of natural and synthetic estrogen receptor (ER) ligan ds was effectively replaced by a planar six-member ring formed through an i ntramolecular hydrogen bond within a salicylaldoxime. Thus, oxime 1, a stru ctural analogue of a triarylethylene estrogen, showed a significant binding affinity for the ER. The OH of the oxime function appears to mimic the phe nolic OH present in more "classical" ER ligands because the binding reduced when the oxime OH is methylated (2) or absent (3).