| 摘要 |
<p>The invention relates to a new process for preparing the compounds of formula (I): <IMAGE> in which the rings A and B represent a 3-keto- DELTA <4>-6-R3, optionally in a form protected in position 3, or 3-keto- DELTA <1,4>-6-R3, R is methyl or -CH2OR' where R' is hydrogen or an ether or ester residue, R1 and R2 form a beta epoxide, a second bond, or R1 is hydrogen, ketone, or hydroxy in alpha or beta , optionally in etherified or esterified form, and R2 is hydrogen, or R1 is hydrogen and R2 is alpha -hydroxy, or R1 is beta -hydroxy optionally etherified or esterified and R2 is a fluorine or a bromine in alpha , and R3 is hydrogen, fluorine or methyl in alpha or beta , according to which a DELTA <16(17)> derivative is treated with a methylating agent, followed by intermediate hydrolysis and the enol thus obtained is oxidised by molecular oxygen in the presence of an appropriate reducing agent. The compounds (I) are known anti-inflammatory agents or possible precursors.</p> |
