High molar activity [¹¹C]phosgene from [¹¹C]CO₂.
5 affiliations
- 1Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland. [email protected].
- 2Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland.
- 3Accelerator Laboratory, Åbo Akademi University, Turku, Finland.
- 4Department of Chemistry, University of Turku, Turku, Finland.
- 5NOMATEN Centre of Excellence, National Centre for Nuclear Research, Świerk, Otwock, Poland.
Abstract
Background
[¹¹C]Phosgene is a known but underutilised labelling synthon in PET-tracer development. The production of [¹¹C]phosgene faces many problems such as difficulties in achieving high molar activity, regular key component replacement and complexity of the synthesis, thereby hindering its wider use. In this paper, a robust and semi-automated synthesis route for production of [¹¹C]phosgene from [¹¹C]CO₂ was developed to solve issues restricting the use of [¹¹C]phosgene. The high molar activity [¹¹C]phosgene was then used for the labelling of biologically important molecules as a proof of concept.Results
[¹¹C]Phosgene was synthesized from [¹¹C]CO by UV-mediated photochemical chlorination with chlorine gas. [¹¹C]CO was produced by the fluoride-activated disilane reduction of cyclotron-produced [¹¹C]CO₂. [¹¹C]Phosgene was produced with satisfactory radiochemical yield (13 ± 1 GBq at EOS, 30 ± 4% dc. to SOS) based on [¹¹C]CO₂ and molar activity of 249 ± 40 GBq/µmol at EOS (n = 3). The radiosynthesis time was approximately 20 min.Conclusion
A robust synthesis route for production of high molar activity [¹¹C]phosgene from [¹¹C]CO₂ was developed. The simplicity and mild reaction conditions of the [¹¹C]CO production method used eliminate the previous issues with Zn-based reduction of [¹¹C]CO₂. Intermediate purification of [¹¹C]CO guaranteed efficient [¹¹C]phosgene production, and removal of unreacted Cl₂ minimised unwanted side reactions. This method utilises a fixed-line device with simple set up and mild conditions. With this method, it is possible to perform syntheses reliably with good radiochemical yields and high molar activities in a short synthesis time.
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BibTeX
@article{kerminen2026high,
title = {{High molar activity [¹¹C]phosgene from [¹¹C]CO₂.}},
author = {Edla Kerminen and Thomas Keller and Simo Salo and Johan Rajander and Olof Solin and Anna Krzyczmonik and Anna K Kirjavainen},
journal = {EJNMMI radiopharmacy and chemistry},
year = {2026},
month = jul,
doi = {10.1186/s41181-026-00472-w},
url = {https://europepmc.org/article/MED/42897341},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - High molar activity [¹¹C]phosgene from [¹¹C]CO₂.
AU - Edla Kerminen
AU - Thomas Keller
AU - Simo Salo
AU - Johan Rajander
AU - Olof Solin
AU - Anna Krzyczmonik
AU - Anna K Kirjavainen
PY - 2026
DA - 2026/07/01
JO - EJNMMI radiopharmacy and chemistry
DO - 10.1186/s41181-026-00472-w
UR - https://europepmc.org/article/MED/42897341
AB - Background [¹¹C]Phosgene is a known but underutilised labelling synthon in PET-tracer development. The production of [¹¹C]phosgene faces many problems such as difficulties in achieving high molar activity, regular key component replacement and complexity of the synthesis, thereby hindering its wider use. In this paper, a robust and semi-automated synthesis route for production of [¹¹C]phosgene from [¹¹C]CO₂ was developed to solve issues restricting the use of [¹¹C]phosgene. The high molar activity [¹¹C]phosgene was then used for the labelling of biologically important molecules as a proof of concept.Results [¹¹C]Phosgene was synthesized from [¹¹C]CO by UV-mediated photochemical chlorination with chlorine gas. [¹¹C]CO was produced by the fluoride-activated disilane reduction of cyclotron-produced [¹¹C]CO₂. [¹¹C]Phosgene was produced with satisfactory radiochemical yield (13 ± 1 GBq at EOS, 30 ± 4% dc. to SOS) based on [¹¹C]CO₂ and molar activity of 249 ± 40 GBq/µmol at EOS (n = 3). The radiosynthesis time was approximately 20 min.Conclusion A robust synthesis route for production of high molar activity [¹¹C]phosgene from [¹¹C]CO₂ was developed. The simplicity and mild reaction conditions of the [¹¹C]CO production method used eliminate the previous issues with Zn-based reduction of [¹¹C]CO₂. Intermediate purification of [¹¹C]CO guaranteed efficient [¹¹C]phosgene production, and removal of unreacted Cl₂ minimised unwanted side reactions. This method utilises a fixed-line device with simple set up and mild conditions. With this method, it is possible to perform syntheses reliably with good radiochemical yields and high molar activities in a short synthesis time.
SN - 2365-421X
ER -