Synthesis of 2′-Deoxy-2′-[18F]Fluoro-9-β-D-Arabinofuranosylguanine: a Novel Agent for Imaging T-Cell Activation with PET

M Namavari, YF Chang, B Kusler, S Yaghoubi… - Molecular imaging and …, 2011 - Springer
M Namavari, YF Chang, B Kusler, S Yaghoubi, BS Mitchell, SS Gambhir
Molecular imaging and biology, 2011Springer
Abstract Purpose 9-(β-D-Arabinofuranosyl) guanine (AraG) is a guanosine analog that has a
proven efficacy in the treatment of T-cell lymphoblastic disease. To test the possibility of
using a radiofluorinated AraG as an imaging agent, we have synthesized 2′-deoxy-2′-[18
F] fluoro-9-β-D-arabinofuranosylguanine ([18 F] F-AraG) and investigated its uptake in T
cells. Procedure We have synthesized [18 F] F-AraG via a direct fluorination of 2-N-acetyl-6-
O-((4-nitrophenyl) ethyl)-9-(3′, 5′-di-O-trityl-2′-O-trifyl-β-D-ribofuranosyl) guanine with …
Purpose
9-(β-D-Arabinofuranosyl)guanine (AraG) is a guanosine analog that has a proven efficacy in the treatment of T-cell lymphoblastic disease. To test the possibility of using a radiofluorinated AraG as an imaging agent, we have synthesized 2′-deoxy-2′-[18F]fluoro-9-β-D-arabinofuranosylguanine ([18F]F-AraG) and investigated its uptake in T cells.
Procedure
We have synthesized [18F]F-AraG via a direct fluorination of 2-N-acetyl-6-O-((4-nitrophenyl)ethyl)-9-(3′,5′-di-O-trityl-2′-O-trifyl-β-D-ribofuranosyl)guanine with [18F]KF/K.2.2.2 in DMSO at 85°C for 45 min. [18F]F-AraG uptake in both a CCRF-CEM leukemia cell line (unactivated) and activated primary thymocytes was evaluated.
Results
We have successfully prepared [18F]F-AraG in 7–10% radiochemical yield (decay corrected) with a specific activity of 0.8–1.3 Ci/μmol. Preliminary cell uptake experiments showed that both a CCRF-CEM leukemia cell line and activated primary thymocytes take up the [18F]F-AraG.
Conclusion
For the first time to the best of our knowledge, [18F]F-AraG has been successfully synthesized by direct fluorination of an appropriate precursor of a guanosine nucleoside. This approach maybe also useful for the synthesis of other important positron emission tomography (PET) probes such as [18F]FEAU, [18F]FMAU, and [18F]FBAU which are currently synthesized by multiple steps and involve lengthy purification. The cell uptake studies support future studies to investigate the use of [18F]F-AraG as a PET imaging agent of T cells.
Springer