Synthesis of [3<i>α</i>-<sup>3</sup>H] 17<i>α</i>-Hydroxy pregnenolone and [3<i>α</i>-<sup>3</sup>H] Pregnenolone
作者:Yuan Tian、Yang Hong、Samuel J. Bonacorsi、Aaron Balog、Sharon Gong
DOI:10.1002/jlcr.3114
日期:2014.1
For the first time, [3α-3H] 17α-hydroxy pregnenolone (1) was synthesized through a multiple step sequence. The presence of [3β-3H] isomer in RP-HPLC purified product was identified by tritium NMR. The [3β-3H] isomer was then separated from [3α-3H] 17α-hydroxy pregnenolone with chiralPAK AD-H column. [3α-3H] pregnenolone (2) was synthesized from commercial available 5-pregnen-3,20-dione in one step with an improved procedure.
首次通过多步骤合成了[3α-3H] 17α-羟基孕烯醇酮(1)。通过氚核磁共振鉴定了 RP-HPLC 纯化产物中 [3β-3H] 异构体的存在。然后用手性 PAK AD-H 色谱柱将[3β-3H]异构体与[3α-3H]17α-羟基孕烯醇酮分离。[3α-3H]孕烯醇酮(2)是采用改进的程序,一步法从市售的 5-孕烯-3,20-二酮合成的。
SteroidalΔ4-3-ketones 1, 4 and 5 react with trichloroacetic anhydride resulting in 3-trichloroacetoxy-Δ3,5-dienes 2, 6 and 7. Spectroscopic or other slightly basic methanol converts the 3-trichloroacetoxy-dienes 2 and 7 into the corresponding Δ5-3-ketones 3 and 8. The rate of its methanolysis is much faster than that of the isomerization reaction of the resulting Δ5-3-ketones 3 and 8 to the more stable