Progestins contraceptive trials with

Progestins A synthetic progestin, medroxyprogesterone acetate (Provera), has been used for male contraceptive trials alone or in combination with nandrolone (a synthetic androgen). When given once monthly for 2-3 months, the combined treatment caused azoospermia in about one-half of the subjects. 

Clinical trials of these orally active progestins showed that they were effective as contraceptives with a success rate that exceeded 99%. These compounds were then marketed as obtained from the reaction sequence after appropriate purification. As the analytical methodology improved it became apparent that a small amount of an impurity was present in all active samples. An examination of the reaction scheme allowed ready identification of that by-product. Any unreduced estradiol methyl ether (13-1) will go to estrone methyl ether on oxidation this will then afford the potent orally active estrogen mestranol (9-1) on ethynylation. Subsequent... 

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