title: Steroidal silicon side-chain analogues as potential antifertility agents.
abstract: A number of silicon-substituted analogues of ethynylestradiol that exhibit modified and enhanced biological activities have been synthesized. Particularly noteworthy are a group of [(trialkylsilyl)ethynyl]estradiol analogues that exhibit high antifertility potency and markedly reduced estrogenic activity. The best compounds synthesized are 17 alpha-[(triethylsilyl)ethynyl]estradiol (5) and 17 alpha-[(tert-butyldimethylsilyl)ethynyl]estradiol (33), which show a separation of antifertility from estrogenic activity in the rat. The results of structure-activity studies indicate a good correlation between the observed biological activities and the calculated van der Waals volumes of the three variable silicon substituents.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D003278:Contraceptives, Oral, Hormonal / Q000138:chemical synthesis* / Q000494:pharmacology; D003280:Contraceptives, Oral, Synthetic / Q000138:chemical synthesis* / Q000494:pharmacology; D004997:Ethinyl Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D051381:Rats; D012825:Silicon; D013329:Structure-Activity Relationship
chemical_list: D003278:Contraceptives, Oral, Hormonal; D003280:Contraceptives, Oral, Synthetic; D004997:Ethinyl Estradiol; D012825:Silicon