Alternative synthesis for the preparation of 16<i>α</i>-[<sup>18</sup>F]fluoroestradiol
作者:Hee Seup Kil、Han Yang Cho、Sang Ju Lee、Seung Jun Oh、Dae Yoon Chi
DOI:10.1002/jlcr.3076
日期:2013.10
We have developed a new precursor, 3,17β-O-bis(methoxymethyl)-16β-O-p-nitrobenzenesulfonylestriol (14c) of 16α-[18F]fluoroestradiol ([18F]FES). Although we could not selectively protect the C17 alcohol in the presence of the C16 alcohol, we were able to prepare and chromatographically isolate the desired C16 TBDMS, C17,C3-dimethoxymethyl (diMOM) protected estriol derivative and convert into the ultimate fluorination precursor. The MOM protective group proved to be more quickly removed than the cyclic sulfate group. The di-MOM protective precursor at the C3 and C17 alcohols instead of a cyclic sulfate group shortened hydrolysis time. We prepared three different sulfonate precursors at C16 alcohol. After checking their reactivity in the [18F]fluorination step and considering the stability of the precursors, we obtained the best results with nosylate precursor 14c.
我们开发了一种新的前体,16α-[18F]氟雌二醇([18F]FES)的3,17β-O-双(甲氧基甲基)-16β-O-对硝基苯磺酰雌三醇(14c)。尽管我们无法在 C16 醇存在的情况下选择性地保护 C17 醇,但我们能够制备并通过色谱分离所需的 C16 TBDMS、C17,C3-二甲氧基甲基 (diMOM) 保护的雌三醇衍生物,并将其转化为最终的氟化前体。 MOM 保护基团被证明比环状硫酸基团更容易被去除。 C3和C17醇上的二-MOM保护前体代替环状硫酸基团缩短了水解时间。我们在 C16 醇中制备了三种不同的磺酸盐前体。在检查了它们在[18F]氟化步骤中的反应性并考虑了前体的稳定性后,我们用苯磺酸盐前体14c获得了最好的结果。