Technologies of CLST
Rapid C-[11C]methylation
To acquire more accurate PET image, it is important that the PET probe should be stable, both chemically and metabolically, in the imaging time window. Aiming to introduce 11C into carbon frameworks of target compounds, RIKEN radiochemistry group is developing rapid C-[11C]methylation reaction based on carbon-carbon bond formation, focusing on the methyl group as the minimum carbon substituent. Indeed, we have succeeded in developing several cross-coupling reactions between organostannane or organoborane compounds and [11C]methyl iodide in the presence of palladium catalysts (Figure 1).
These reactions are attracting worldwide attention as groundbreaking synthesis for introducing the [11C]methyl group into a carbon framework in the very short time of 5 minutes. Figure 2 shows representative PET probes developed by RIKNE.
The human PET studies with the 11C-labeled PET probes, synthesized by the Pd-mediated rapid C-[11C]methylations, have been conducted so far in Osaka City University Hospital (Osaka, Japan) and Uppsala University PET Centre (Sweden) under the supervision of RIKEN CLST Director, Prof. Dr. Yasuyoshi Watanabe.
