Synthesis of potential antiprogestins II

Alkylated derivatives of 17-acetoxyprogesterone were prepared in order to test the hypothesis that bulky groups in certain positions of the steroid molecule have the effect of transforming progestogens into antiprogestogens. These groups might exert binding influence outside the area occupied by progesterone itself. The compounds were tested for competitive affinity against tritiated progesterone and receptor from rabbit uterus cytosol. The low affinity of all derivatives makes it unlikely that they would be active as antiprogestational agents.