Triphenylethylene

Triphenylethylene (TPE) is the organic compound with the formula (C₆H₅)₂C=CH(C₆H₅). It is a colorless solid.

Triphenylethylene

Names
IUPAC name 1,1',1''-(Ethene-1,1,2-triyl)tribenzene
Identifiers
CAS Number	58-72-0
3D model (JSmol)	Interactive image
ECHA InfoCard	100.000.359
PubChem CID	6025
CompTox Dashboard (EPA)	DTXSID3022320
SMILES C1=CC=C(C=C1)C=C(C2=CC=CC=C2)C3=CC=CC=C3
Properties
Chemical formula	C20H16
Molar mass	256.348 g·mol−1
Appearance	white solid
Density	1.163 g/cm3[1]
Melting point	65–67.5 °C (149.0–153.5 °F; 338.1–340.6 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis and reactions

The compound is prepared in two steps from benzophenone via the intermediacy of 1,2,2-triphenylethanol.^[2] Triphenylethylene reacts with iodine to give 9-phenylphenanthroline.^[3] Epoxidation gives the chiral oxirane.^[4]

Bioactivity

Triphenylethylene possesses weak estrogenic activity.^[5][6] Its estrogenic effects were discovered in 1937.^[7] TPE was derived from structural modification of the more potent estrogen diethylstilbestrol, which is a member of the stilbestrol group of nonsteroidal estrogens.^[8]

TPE is the parent compound of a group of nonsteroidal estrogen receptor ligands.^[5][6][9] It includes the estrogens chlorotrianisene, desmethylchlorotrianisene, estrobin (DBE), M2613, triphenylbromoethylene, triphenylchloroethylene, triphenyliodoethylene, triphenylmethylethylene; the selective estrogen receptor modulators (SERMs) afimoxifene, brilanestrant, broparestrol, clomifene, clomifenoxide, droloxifene, endoxifen, etacstil, fispemifene, idoxifene, miproxifene, miproxifene phosphate, nafoxidine, ospemifene, panomifene, and toremifene. The antiestrogen ethamoxytriphetol (MER-25) 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.^[10]

The affinity of triphenylethylene for the rat estrogen receptor is about 0.002% relative to estradiol.^[11][12] For comparison, the relative binding affinities of derivatives of triphenylethylene were 1.6% for tamoxifen, 175% for afimoxifene (4-hydroxytamoxifen), 15% for droloxifene, 1.4% for toremifene (4-chlorotamoxifen), 0.72% for clomifene, and 0.72% for nafoxidine.^[13][11][12]

See also

• List of selective estrogen receptor modulators