[Ethyltriphenylethylene compounds: synthesis and estrogenic and antifertility activities; partial dissociation between these two activities].

PIP: This cis and trans isomers of Broparestrol (1-bromo-2(4-ethylphenyl)-1,2-diphenyl ethylene) and of its 1-bromo-1(4-ethylphenyl)-2,2-diphenylethylene isomer, and of the analogous 1-nitro compounds were prepared and tested for estrogenicity by the Allen-Doisy vaginal smear test in rats and for antifertility in rats. With hexanestrol-3 (dihydrodiethylstilbestrol) as a reference in the Allen-Doisy test, bromo-1-(p-ethylphenyl)-1-diphenyl-2,2-ethylene was typical estrogen, but cis (or Z) broparestrol and trans (or E) broparestrol were incomplete estrogens, producing both keratinized and nucleated cells in rat vaginal smears. Bromo-1-(p-ethylphenyl)-1-diphen yl-2,2-ethylene was 2 times more estrogenic in this test than hexanestrol, but the broparestrol isomers were over 100 times less active. For the rat antifertility test, the test compounds were administered for 5 days before and for 1 month while females were caged with males, then continued for 7 months. Nitro-1-(p-ethylphenyl)-2-diph enyl-1,2-ethylene was interesting because it inhibited fertility at 1 mg/day, a dose that was not estrogenic. Bromo-1(p-ethylphenyl)-1-diphen yl-2,2-ehtylene had antifertility activity at 10 mcg and nitro-1-(p-ethylphenyl)-1-diphenyl-2,2-ethylene at 100 mcg.^ieng