N,N'-Dialkylbis(dichlorophenyl)ethylenediamines and -imidazolidines: relationship between structure and estradiol receptor affinity.

Diastereomeric N,N'-dialkylbis(dichlorophenyl)ethylenediamines and the corresponding imidazolidines with chlorine in the 2,4, 2,6, 3,4, and 3,5 positions were synthesized. Only the stereoisomers of the 2,6-dichloro-substituted compounds exhibit for N-CH3 (2e, 3e), N-C2H5 (2f, 3f), and N-C3H7 (2g, 3g) an affinity to the estradiol receptor (Ka values ranging from 9.1 X 10(4) to 9.1 X 10(6)), because the nitrogen atoms are shielded by the ortho-located chlorine atoms; therefore, a binding interaction with hydrophobic receptor areas is possible. These substances show weak uterotrophic activity and no significant effect on the growth of the DMBA-induced hormone-dependent mammary adenocarcinoma of the rat.