Pd-catalyzed reaction of the androst-16-ene derivative 6 with alkyl diazoacetates producing the respective cyclopropane derivatives 5, and lithium in liquid ammonia reduction of 5 leading to 17α-pregnane-20-carboxylic acid derivatives 9. The side chain was attached to ester 19 in a known manner.
第一个合成方法来17-外延-calcidiol 4和同类物呈现。合成的关键步骤包括Androst-16-ene衍
生物6与重氮烷基
乙酸酯的Pd催化反应,生成相应的
环丙烷衍
生物5,以及液
氨中的
锂还原5生成17α-孕烷20-
羧酸衍
生物9。侧链以已知方式连接至酯19。