Known pregnane derivatives are prepared by esterificiation of known androstane derivatives to give new ester of Formula III ##STR1## wherein in each case symbolizes a single bond or a double bond, n is 1 or 2, R.sub.1 is hydrogen or methyl, R.sub.2 is hydrogen or formyl, and R.sub.3 is chlorine, hydroxy or an alkanoyloxy group of up to 6 carbon atoms, and reaction of the latter with Ag(I) and formic acid.
已知的孕烷衍
生物是通过将已知的雄烷衍
生物酯化制备出新的化合物III的
酯来制备的##
STR1##其中在每种情况下,符号表示单键或双键,n为1或2,R.sub.1为
氢或
甲基,R.sub.2为
氢或甲酰基,R.sub.3为
氯、羟基或最多含有6个
碳原子的烷酰
氧基团,并与Ag(I)和
甲酸反应。