Dahl Kenneth, Itsenko Oleksiy, Rahman Obaidur, Ulin Johan, Sjöberg Carl-Olof, Sandblom Peter, Larsson Lars-Anders, Schou Magnus, Halldin Christer
Centre for Psychiatric Research and Education, Department of Clinical Neuroscience, Karolinska Institutet, S-171 76, Stockholm, Sweden.
J Labelled Comp Radiopharm. 2015 May 15;58(5):220-5. doi: 10.1002/jlcr.3280. Epub 2015 Mar 27.
[(11)C]Carbon monoxide ((11)CO) is a versatile building block for the synthesis of Positron Emission Tomography (PET) radioligands. However, the difficulty of trapping (11)CO in a small solvent volume has limited its utility. We here report an evaluation of a simple, fully automated high-pressure synthesizer prototype for the use in (11)C-carbonylation reactions. [(11)C]Carbon monoxide was easily prepared by online reduction of [(11)C]carbon dioxide using either Mo(s) or Zn(s) as the reducing agent. The conversion yield of (11)CO was >99% when zinc was used as the reducing agent, and the corresponding value for Mo was approximately 71%. When the Zn or Mo column was constantly kept under inert atmosphere, no significant decrease in reducing properties was observed for more than 100 (11)CO productions. However, in our hands, Mo reductant was much easier to service. A total of nine functional groups were successfully radiolabeled using the (11)CO synthesizer prototype. All measured radiochemical yields exceeded 37%, and the (11)CO trapping efficiency was generally above 90%, except for the Suzuki coupling where the trapping efficiency was 80%. This high-pressure synthesizer using [(11)C]carbon monoxide as the labeling precursor is easy to operate allowing for (11)C-carbonylation reactions to be performed in a high yield and in a routinely fashion.
[¹¹C]一氧化碳（¹¹CO）是用于合成正电子发射断层扫描（PET）放射性配体的通用构建模块。然而，在小溶剂体积中捕获¹¹CO的困难限制了其应用。我们在此报告了一种用于¹¹C羰基化反应的简单、全自动高压合成器原型的评估。通过使用Mo(s)或Zn(s)作为还原剂在线还原[¹¹C]二氧化碳可轻松制备[¹¹C]一氧化碳。当使用锌作为还原剂时，¹¹CO的转化率>99%，而Mo的相应值约为71%。当Zn或Mo柱持续保持在惰性气氛下时，在超过100次¹¹CO制备过程中未观察到还原性能的显著下降。然而，在我们手中，Mo还原剂更易于操作。使用¹¹CO合成器原型成功对总共九个官能团进行了放射性标记。所有测得的放射化学产率均超过37%，除了铃木偶联反应中捕获效率为80%外，¹¹CO捕获效率一般高于90%。这种以[¹¹C]一氧化碳作为标记前体的高压合成器易于操作，能够以高产率和常规方式进行¹¹C羰基化反应。
