| 摘要 |
The invention comprises a process for preparing compounds of partial formulae <FORM:1078724/C2/1> wherein each of R2 and R3 is a C1- 5 saturated hydrocarbon radical or the group -NR2R3 forms a heterocyclic ring which may contain a second nitrogen atom optionally substituted by a C1- 6 alkyl or hydroxyalkyl group, by treatment with an aqueous acid medium containing-no additional water-miscible organic solvent to obtain a D 17(20)-20-hydroxy-21-oxo compound, or with an aqueous acid medium in the presence of a water-miscible organic solvent to obtain a 20-oxo-21,21-dihydroxy compound, followed if desired by (a) dehydration of the 21,21,diol to a 20,21-dioxo compound or (b) reaction of any of the products with an alkanol to form a 21,21-dialkyl acetal. |
