A process for the preparation of 17.beta.-hydroxy-20-alkoxypregnane-21-oic acid derivatives of the formula ##STR1## WHEREIN R.sub.1 is methyl or ethyl; R.sub.2 is hydrogen or methyl, either being in the .alpha.-or .beta.-position; R.sub.3 is lower alkyl of 1-4 carbon atoms; R.sub.4 is alkyl of 1-8 carbon atoms or benzyl; and St is the residue of a steroid ABC ring system; Comprises reacting (a) a 17-oxo compound of the formula ##STR2## WHEREIN R.sub.1 and R.sub.2 are as defined above and St* is said steroid ABC ring system residue, St, in a form which is chemically compatible with said reaction; With (b) an enolate ion of an alkoxyacetic acid alkyl ester of the formula ##STR3## wherein R.sub.3 and R.sub.4 are as defined above.
一种制备式为##STR1##的17-β-羟基-20-烷氧基
孕酮-21-酸衍
生物的方法,其中R1为甲基或乙基;R2为氢或甲基,可以位于α或β位置;R3为1-4个碳原子的低级烷基;R4为1-8个碳原子的烷基或苄基;ST为类
固醇ABC环系统的残基;包括将(a)式为##STR2##其中R1和R2如上定义,ST*是所述类
固醇ABC环系统残基ST的一种在
化学上与所述反应相容的形式;与(b)式为##STR3##其中R3和R4如上定义的烷氧基
乙酸烷基酯的烯醇离子反应。