| 摘要 |
The invention relates to a process for the preparation of the compounds (I): <IMAGE> where R1 is especially hydrogen or alkyl, R2 is alkyl and the rings A, B, C and D optionally carry one or more double bonds, one or more hydroxyl or ketone functional groups which are optionally protected, one or more halogen atoms or one or more alkyl, alkyloxy, alkenyl or alkynyl radicals, process consisting in oxidising a corresponding compound 20-formamido-21-hydroxy-17(20)-ene, in the presence of water, and then in hydrolysing the 21-formate obtained. The invention also relates to the new intermediates thus obtained.
|
