| 摘要 |
NEW MATERIAL:A compound of formula I (R is H, lower alkyl). USE:A synthetic intermediate of prednisolone, hydrocortizon or other corticoids. PREPARATION:For example, 12-hydroxypregna-1,4-diene-3-one-20-carboxylic acid of formula II (...shows alpha-configuration) is esterified with R<1>OH (R<1> is lower alkyl) to form an ester of formula III and the hydroxyl is sulfonated into OSO2R<2> (R<2> is lower alkyl). The desulfonation is effected to give a copound of formula I wherein R is R<1>, which is hydrolyzed to give a compound of formula I where R is H.
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