Analogues of [(triethylsilyl)ethynyl]estradiol as potential antifertility agents

Various 17 alpha-ethynylsteroids were prepared and derivatized as the corresponding triethylsilyl compounds 2-35, which were examined for a ratio of antifertility to estrogenic activity that would be more beneficial than that of the presently used agent. Among the triethylsilyl compounds evaluated, only 23 displayed this desired ratio, although two other compounds without the triethylsilyl moiety, 18 and 26, shared similar characteristics.