Nucleophilic 18F-Fluorination of heteroaromatic iodonium salts with no-carrier-added [18F]Fluoride
Nucleophilic 18F-Fluorination of heteroaromatic iodonium salts with no-carrier-added [18F]Fluoride
复制标题
DOI：
10.1021/ja066850h
复制
发表时间：
2007-06-27
影响因子：
15
通讯作者：
Coenen, Heinz H.
中科院分区：
文献类型：
--
作者：
Ross, Tobias L.;Ermert, Johannes;Coenen, Heinz H.
含2-噻吩基的二芳基碘鎓盐作为富电子芳香杂环的一个例子，被证明是各种芳烃的亲核、区域选择性无载体（nca）放射性取代的非常有效的前体。它甚至允许nca [F-18]氟化物亲核引入富电子芳烃化合物中。研究了取代方式、抗衡阴离子和不同反应条件对反应的影响。反离子的作用可以通过溶剂对前体盐离子对分离的影响来解释。不同的芳基（2-噻吩基）碘鎓盐被用作前体，其中同芳族基团系统地从承载缺电子到富电子取代基变化。交换动力学的相对速率与相应取代基的Hammett常数呈线性相关，证实了高反应性和低选择性的亲核芳香取代反应。
Diaryliodonium salts containing the 2-thienyl group as an example of an electron-rich heteroaromatic moiety proved to be very potent precursors for the nucleophilic, regioselective no-carrier-added (nca) radiofluorination of various arenes. It even allowed the nucleophilic introduction of nca [F-18]fluoride into electron-rich arene compounds in one step. The influences of the substitution pattern, of counteranions, and of different reaction conditions were studied. Effects of counterions could be explained by the influence of solvent on ion pair separation of precursor salts. Different aryl(2-thienyl)iodonium salts were used as precursors, where the homoaromatic group systematically varied from bearing electron-deficient to electron-rich substituents. Relative rates of exchange kinetics correlated linearly with Hammett constants of the appropriate substituents confirming a nucleophilic aromatic substitution reaction of high reactivity and low selectivity.