Design, synthesis and biological evaluation of novel estrogen-derived steroid metal complexes

A new series of estrogen-derived metal complexes were synthesized and characterized. The functionalized estrogen receptor ligands were prepared by a four-step synthetic strategy, and then three transition metal Pd, Ni, Zn were introduced readily to give the title metal complexes, in which the squaramide was introduced as ion acceptor for the first time in the development of estrogen-derived metal complexes for estrogen receptor. Upon binding to estrogen receptors, all of the estrogen conjugates exhibited acceptable binding affinity (up to 4.04% relative to estradiol), and in transcription assays, all the compounds are agonists on ERα. Molecular modeling studies suggest a structural basis for the agonist activity of these compounds.