Synthesis and antiestrogenic activity of 2,4-bis(bromomethyl)-estrone methyl ether1: A bifunctional alkylating steroid

The synthesis of 2,4-bis(bromomethyl)estrone methyl ether was accomplished by reacting estrone methyl ether with formaldehyde and hydrogen bromide in s-tetrachloroethane. The compound readily reacts with cysteine, tryptophan and histidine in 0.05 $\text{M}$ phosphate buffer pH 7.0. It also reacts with compounds containing sulfhydryl groups, such as 2-mercaptoethanol and the reduced form of 5,5'dithiobis(2-nitrobenzoic acid). Structural analysis and stoichiometry of the reaction of the bromomethylsteroid with cysteine indicates that the title compound contains two reactive bromomethyl groups. The biological activity of the bromomethylsteroid was evaluated by analysis of its effect on uterine glucose-6-phosphate dehydrogenase activity after administration into the uterine lumen of ovariectomized rats. While it lacked estrogenic activity, the compound did display an antiestrogenic effect that was both greater and more persistent than that of an equimolar quantity of estrone methyl ether.