[11C]Carbon monoxide has been used in the
palladium-mediated synthesis of
[carbonyl-11C]ketones. Methyl iodide, vinylic and
arylic halides and trifluoromethanesulfonates (triflates) have been
coupled with tin reagents with insertion of [11C]carbon
monoxide at very low concentrations (10–100 nmol
[11C]CO in a total volume of 10 ml). The labelled products
are obtained in 36–62% isolated decay-corrected radiochemical
yields within 30 min of the end of radionuclide production. In order to
use [11C]carbon monoxide efficiently, a gas handling system
has been developed which allows the radioactive gas to recirculate
through the reaction media. The reactions are performed using a one pot
procedure. The best results are achieved with mixed tin reagents
containing an unsaturated transferable substituent and
Pd(AsPh3)4. In a typical experiment starting from
25 GBq of [11C]carbon dioxide, 4.2 GBq (47%) of
[carbonyl-11C]acetophenone 1 is obtained 30 min
after the end of radionuclide production. The specific radioactivity of
1 is 91 GBq µmol-1.
[carbonyl-13C]Benzophenone 6 has been synthesised
using the same approach to verify the position of the label.
碳 monoxide已被用于
钯催化的[carbonyl-11C]酮合成中。甲基
碘、
乙烯基和芳基卤化物以及
三氟甲磺酸盐(三
氟酸盐)已与
锡试剂耦合,在极低浓度下(10–100 nmol [11C]CO,总体积10 ml)插入[11C]carbon monoxide。标记产物在放线同位素生产结束后的30分钟内,以36–62%的独立衰变校正放射
化学产率获得。为了有效利用[11C]carbon monoxide,开发了一种气体处理系统,允许放射性气体在反应介质中循环。反应采用一步法进行。最佳结果是通过含不饱和可转移取代基的混合
锡试剂和Pd(AsPh3)4实现的。在典型实验中,从25 GBq的
[11C]二氧化碳开始,放线同位素生产结束后30分钟内可获得4.2 GBq(47%)的[carbonyl-11C]
苯乙酮1。1的特定放射性为91 GBq µmol-1。[carbonyl-13C]
二苯甲酮6已使用相同方法合成,以验证标记位置。