An evaluation of a high‐pressure 11CO carbonylation apparatus. (27th March 2015)

• Record Type: Journal Article
• Authors: Dahl, Kenneth; Itsenko, Oleksiy; Rahman, Obaidur; Ulin, Johan; Sjöberg, Carl‐Olof; Sandblom, Peter; Larsson, Lars‐Anders; Schou, Magnus; Halldin, Christer
• Is Part Of: Journal of labelled compounds & radiopharmaceuticals. Volume 58:Number 5(2015)
• Page Start: 220
• Page End: 225
• Publication Date: 2015-03-27
• Subjects: Tracers (Chemistry) -- Periodicals; Radiopharmaceuticals -- Periodicals; 615.8424
• DOI: 10.1002/jlcr.3280
• Languages: English
• ISSNs: 0362-4803

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>[<sup>11</sup>C]Carbon monoxide (<sup>11</sup>CO) is a versatile building block for the synthesis of Positron Emission Tomography (PET) radioligands. However, the difficulty of trapping <sup>11</sup>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 <sup>11</sup>C‐carbonylation reactions. [<sup>11</sup>C]Carbon monoxide was easily prepared by online reduction of [<sup>11</sup>C]carbon dioxide using either Mo(s) or Zn(s) as the reducing agent. The conversion yield of <sup>11</sup>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 <sup>11</sup>CO productions. However, in our hands, Mo reductant was much easier to service. A total of nine functional groups were successfully radiolabeled using the <sup>11</sup>CO synthesizer prototype. All measured radiochemical yields exceeded 37%, and the <sup>11</sup>CO trapping efficiency was generally above 90%, except for the Suzuki coupling where the trapping efficiency was 80%. This high‐pressure synthesizer using [<sup>11</sup>C]carbon monoxide as the labeling precursor is easy to operate allowing for <sup>11</sup>C‐carbonylation reactions to be performed in a high yield and in a routinely fashion.</p> </abstract>