Triphenylethylene
Triphenylethylene is the organic compound with the formula. It is a colorless solid.
Synthesis and reactions
The compound is prepared in two steps from benzophenone via the intermediacy of 1,2,2-triphenylethanol. Triphenylethylene reacts with iodine to give 9-phenylphenanthroline. Epoxidation gives the chiral oxirane.Bioactivity
Triphenylethylene possesses weak estrogenic activity. Its estrogenic effects were discovered in 1937. TPE was derived from structural modification of the more potent estrogen diethylstilbestrol, which is a member of the stilbestrol group of nonsteroidal estrogens.TPE is the parent compound of a group of nonsteroidal estrogen receptor ligands. It includes the estrogens chlorotrianisene, desmethylchlorotrianisene, estrobin, M2613, triphenylbromoethylene, triphenylchloroethylene, triphenyliodoethylene, triphenylmethylethylene; the selective estrogen receptor modulators afimoxifene, brilanestrant, broparestrol, clomifene, clomifenoxide, droloxifene, endoxifen, etacstil, fispemifene, idoxifene, miproxifene, miproxifene phosphate, nafoxidine, ospemifene, panomifene, and toremifene. The antiestrogen ethamoxytriphetol is also closely related, but is technically not a derivative of TPE and is instead a triphenylethanol derivative. The tamoxifen metabolite and aromatase inhibitor norendoxifen is also a TPE derivative. In addition to their estrogenic activity, various TPE derivatives like tamoxifen and clomifene have been found to act as protein kinase C inhibitors.
The affinity of triphenylethylene for the rat estrogen receptor is about 0.002% relative to estradiol. For comparison, the relative binding affinities of derivatives of triphenylethylene were 1.6% for tamoxifen, 175% for afimoxifene, 15% for droloxifene, 1.4% for toremifene, 0.72% for clomifene, and 0.72% for nafoxidine.