发明授权
EP0589034B1 METHOD FOR MAKING 3-ALPHA-HYDROXY,3-BETA-SUBSTITUTED-PREGNANES 失效
VERFARHREN为3-α-羟基的制剂,3-β取代的孕烷衍生物

METHOD FOR MAKING 3-ALPHA-HYDROXY,3-BETA-SUBSTITUTED-PREGNANES
摘要:
This invention provides a simplified method for converting pregnan-3,20-dione compounds to 3α-hydroxy,3β-substituted-pregnanes. By selective use of reagents the unprotected dione is converted chemoselectively and diastereoselectively into a 3(R)-pregnan-3-spiro-2'oxirane-20-one intermediate. This intermediate can then be converted regioselectively by a second set of reactions to the 3α-hydroxy,3β-substituted-20-one form, which can be further modified at the 20-keto position. Through this method, each ketone group is independently treated. By modifying the ketones one at a time, one can obtain the desired stereo-specificity at each site.
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