| 摘要 |
DELTA 4-Steroid-20-carboxylic acids (BNC compounds) which may optionally contain at least one other double bond in the 1(2)- and/or 9(11)-position and which may also contain an oxygen function, particularly a hydroxyl group or a keto group, in the 11-position, are degraded in the 20-carboxyl group by carboxy inversion degradation. To achieve this, the BNC-carboxylic acids are first transformed into their acid halides which are reacted with peracids to form mixed acid anhydrides, followed by hydrolysis. The reaction product obtained is a mixture of 20-hydroxy- and 20(21)-ene-steroid compounds which contain one carbon atom less than the starting material used. New and known C21-steroid compounds can be produced by the process. The C21-steroid compounds having an oxygenated function in the 11-position may be processed to prednisolone and prednisone by known procedures. |
