Efficient synthesis of [11C]befloxatone,a selective radioligand for the in vivo imaging of MAO‐A density using PET

Carbon‐11 labelled befloxatone ((5R)‐5‐(methoxymethyl)‐3‐4‐(3R)‐4,4,4‐trifluoro‐3‐hydroxybutoxy]phenyl]‐2‐oxazolidinone) is a reversible and selective monoamine oxidase‐A (MAO‐A) inhibitor and appears to be a new potent PET tracer for the in vivo imaging of MAO‐A density. In this paper, the radiosynthesis of befloxatone was investigated and orientated towards the preparation of multi milliCuries of radiotracer. Typically, using no‐carrier‐added ¹¹C]phosgene, 150–300 mCi (5.55–11.10 GBq) of ¹¹C]befloxatone was obtained within 20 min of radiosynthesis (including HPLC purification) with specific radioactivities ranging from 500 to 2000 mCi/µmol (18.5–74.0 GBq/µmol). The high efficiency of these radiosyntheses allows for multi‐injection protocols and kinetic approaches for absolute quantification of the tracer. Copyright © 2003 John Wiley & Sons, Ltd.