3,4-bis(3'-hydroxyphenyl)hexane--a new mammary tumor-inhibiting compound.

The syntheses of the hexestrol derivatives 3,4-bis-(3'-hydroxyphenyl)hexane (4a), 3,4-bis(4'-fluoro-3'-hydroxyphenyl)hexane (4b), 3,4-bis(3',4'dihydroxyphenyl)hexane (4c), and 3,4-bis(3',4'-diacetoxyphenyl)hexane (4d) are described. All compounds showed a marked, competitive inhibition of the estradiol receptor interaction (Ka4c greater than Ka4a greater than Ka4d greater than Ka4b). Evaluated in the mouse uterine weight test compounds 4c and 4d almost reached the estrone effect, whereas 4a and 4b did not produce full uterotrophic response. Compounds 4a--d antagonized the estrone stimulated uterine growth of the immature mouse. Compound 4a (NSC-297170) exhibited a specific, dose-related growth inhibition of the estrogen responsive MCF-7 human breast tumor cell line. Tested on the 9,10-dimethyl-1,2-benzanthracene-induced hormone-dependent mammary adenocarcinoma of the Sprague-Dawley rat all compounds showed marked inhibition of tumor growth. As in all experiments compounds 4a and 4b, which is resistant to hydroxylation in 4'-position exhibited an identical pattern of action, which is different from that shown by compound 4c, the effect of compound 4a cannot be explained by its possible catechol metabolite 4c.