Challenges in chelating positron emitting copper isotopes: tailored synthesis of unsymmetric chelators to form ultra stable complexes
作者:Jon D. Silversides、Rachel Smith、Stephen J. Archibald
DOI:10.1039/c0dt01395a
日期:——
The synthesis of chelators that form high stability complexes with copper(II) isotopes and do not suffer from transchelation in vivo has been a goal for many chemists. Such chelators will facilitate the exploitation of the 64Cu isotope (t1/2 = 12.7 h, β+ (19%); β− (39%); EC (41%)) for positron emission tomography imaging studies, which has a longer half life relative to the more commonly used 18F (t1/2 = 109.8 min) and 11C (t1/2 = 20.4 min) isotopes. One option is the CBTE2A chelator, which has been championed by Weisman, Wong and Anderson, and, more recently, alternate bifunctional chelator (BFC) versions have been synthesised. Improved synthetic methods are required for unsymmetric derivatisation of these chelators to allow more selective biomolecule attachment. This work investigates synthetic routes to form new unsymmetric chelating ligands via stepwise reaction of the bisaminal precursor, determines their X-ray structures and demonstrates cold copper(II) isotope complex formation.
合成能与铜(II)同位素形成高稳定性络合物且在体内不会发生转切作用的螯合剂一直是许多化学家的目标。这种螯合剂将有助于利用 64Cu 同位素(t1/2 = 12.7 小时,β+ (19%);β- (39%);EC (41%))进行正电子发射断层成像研究,相对于更常用的 18F(t1/2 = 109.8 分钟)和 11C(t1/2 = 20.4 分钟)同位素,64Cu 的半衰期更长。其中一种选择是 CBTE2A 螯合剂,该螯合剂一直由 Weisman、Wong 和 Anderson 倡导使用,最近又合成了替代的双功能螯合剂 (BFC) 版本。这些螯合剂的非对称衍生化需要改进的合成方法,以实现更具选择性的生物分子附着。这项工作研究了通过双氨基前体的逐步反应形成新的不对称螯合配体的合成路线,确定了它们的 X 射线结构,并展示了冷铜(II)同位素络合物的形成。