The syntheses and estrogen receptor affinities of meso- and (~)-N,N’-dialkyl-1,2-bis(2,6-dichloro-4-hydroxypheny1)
ethylenediamines (2) are described. They show high binding affinities in both diastereomeric forms but
with a preference for the meso isomer, reaching a RBA value of 8.6 (meso-2b; 17@-estradiol=1 00). Both stereoisomers
of 2b exhibit a strong inhibitory effect on the 7,12-dimethylbenz[a]anthracene( DMBA) induced hormone-dependent
mammary carcinoma of the Sprague-Dawley rat, reducing the tumor area by 74 (meso-2b) and 24% [(*)-2b],
respectively, after 4 weeks administration of 6 X 6 (mg/kg)/week. The high uterotrophic potency makes a mode
of action likely which corresponds to the effect of high doses of estrogens.