The radiosynthesis of a new potential glucose transport protein tracer: 3-[125I]iodophloretin
作者:J. Mertens、D. Terriere、R. Boumon
DOI:10.1002/jlcr.2580341103
日期:1994.11
Phloretin (2′,4′,6′-trihydroxy-3-(4-hydroxyphenyl)-propiophenone) is a glucose transport (GLUT) blocker acting at the extracellular part of the GLUT protein. Labelling this compound with radioiodine can provide a tracer for elucidating in vitro and in vivo the role of GLUT's in cells showing an increased glucose metabolism. As the inhibition of GLUT by phloretin is supposed to occur at the 2′,4′,6′-trihydroxyphenyl site, the radioiodine is substituted on the 3-position of the 4-hydroxyphenyl group. Direct electrophilic substitution on this position is not possible due to highly activated sites in the trihydroxyphenyl group. 3-Bromophloretin, the precursor for radioiodination, is prepared using a new method, a saturation substitution followed by the elimination of the unstable bromine atoms. Radioiodinated phloretin is obtained with a labelling yield of 75% by applying Cu+1-assisted radioiodo for bromo exchange at 140°C. Pure non carrier added tracer results from HPLC separation coupled to a mini-column preconcentration and recovery (± 70% overall yield).
菲洛瑞汀(2′,4′,6′-三羟基-3-(4-羟基苯基)-苯丙酮)是一种葡萄糖转运(GLUT)阻断剂,作用于 GLUT 蛋白的细胞外部分。用放射性碘对这种化合物进行标记可以提供一种示踪剂,用于在体外和体内阐明 GLUT 在葡萄糖代谢增加的细胞中的作用。由于弗罗里汀对 GLUT 的抑制作用应该发生在 2′,4′,6′-三羟基苯基部位,因此放射性碘被取代在 4-羟基苯基的 3 位上。由于三羟基苯基基团中存在高度活化的位点,因此不可能在该位点上直接进行亲电取代。3-Bromophloretin 是放射性碘化的前体,采用一种新方法进行制备,先进行饱和取代,然后消除不稳定的溴原子。通过在 140°C 温度下使用 Cu+1 辅助放射性碘进行溴交换,可获得 75% 的放射性碘化长春花苷。纯净的无载体添加示踪剂是通过 HPLC 分离和迷你柱预浓缩和回收得到的(总收率为 ± 70%)。