Steroids with 5β-configuration and acrylate 17β-side chain, namely (20E)-3β-hydroxy-5β-pregnane-21-carboxylate (XVI), its 3α-epimer XXVI, and homological ethyl ester XVIII were prepared from 3β-(2-tetrahydropyranyloxy)-21-norpregn-5-en-20-ol (I). The stereoselectivity of key steps was checked. Whereas hydrogenation of 4-en-3-one derivative IV gave exclusively 5β-derivative VI, the subsequent borohydride reduction yielded 3β- and 3α-hydroxy derivatives VII and XI in 1 : 4 ratio. The 3-hydroxy derivatives prepared (XVI, XVIII, and XXVI) were converted to the corresponding hemisuccinates (XX and XXVIII) and β-D-glucopyranosides (XXII, XVIV, and XXX) for latter use in biological studies.
具有5β构型和
丙烯酸酯17β侧链的类
固醇,即(20
E)-3β-羟基-5β孕烷-21-
羧酸酯(
XVI),其3α-表异构体
XXVI和同系物
乙酯酯XVIII均由3β-(2-
四氢呋喃氧基)-21-去甲孕-5-
烯-20-醇(
I)制备而成。关键步骤的立体选择性得到了检查。虽然4-
烯-3-
酮衍
生物IV的
氢化反应仅产生了5β-衍
生物VI,但随后的
硼氢化物还原则以1:4的比例产生了3β-和3α-羟基衍
生物VII和
XI。制备的3-羟基衍
生物(
XVI,XVIII和
XXVI)被转化为相应的半
琥珀酸酯(
XX和
XXVIII)和β-
D-葡萄糖吡喃醇(
XXII,XVIV和
XXX),以供后续的
生物学研究使用。