(Diethylamino)sulfur trifluoride (DAST) was used for the preparation of 3α-fluorides (e.g., 3α-fluoro-5α-pregnane-12,20-dione, 3α-fluoro-16α-[(methoxycarbonyl)methyl]-5α-pregnan-20-one, methyl 3α-fluoro-5α-androstane-17β-carboxylate, 3α-fluoro-5β-pregnan-20-one) from the corresponding 3β-alcohols and for the preparation of 3,3-difluorides from 3-ketones (e.g., 3,3-difluoro-5α-pregnan-20-one). Boron trifluoride etherate was used for the conversion of an epoxide into 3α-fluoro-2β-hydroxy-5α-pregnan-20-one. Thein vitrobinding of the 3α-fluorides and the corresponding 3α-alcohols to the GABAAreceptor was established using [3H]muscimol and [35S]-tert-butylbicyclo[2.2.2]phosphorothionate as ligands.
(Diethylamino)sulfur trifluoride(DAST)被用于从相应的3β-醇制备3α-氟化物(例如,3α-氟-5α-孕酮-12,20-二酮,3α-氟-16α-[(甲氧羰基)甲基]-5α-孕酮-20-酮,甲基3α-氟-5α-雄烷-17β-羧酸酯,3α-氟-5β-孕酮-20-酮),并用于从3-酮制备3,3-二氟化物(例如,3,3-二氟-5α-孕酮-20-酮)。三氟化硼醚酯用于将环氧化物转化为3α-氟-2β-羟基-5α-孕酮-20-酮。使用[3H]肌肽酒石酸盐和[35S]-tert-丁基双环[2.2.2]磷酸酯作为配体,建立了3α-氟化物和相应的3α-醇对GABAA受体的in vitro结合。