Fully automated synthesis and purification of 4‐(2′‐methoxyphenyl)‐1‐[2′‐( N ‐2″‐pyridinyl)‐ p ‐[ 18 F]fluorobenzamido]ethylpiperazine

We have developed an efficient synthesis method for the rapid and high‐yield automated synthesis of 4‐(2′‐methoxyphenyl)‐1‐[2′‐( N ‐2″‐pyridinyl)‐ p ‐[ 18 F]fluorobenzamido]ethylpiperazine ( p ‐[ 18 F]MPPF). No‐carrier‐added [ 18 F]F − was trapped on a small QMA cartridge and eluted with 70% MeCN(aq) (0.4 mL) containing Kryptofix 222 (2.3 mg) and K 2 CO 3 (0.7 mg). The nucleophilic [ 18 F]fluorination was performed with 3 mg of the nitro‐precursor in DMSO (0.4 mL) at 190 °C for 20 min, followed by the preparative HPLC purification (column: COSMOSIL Cholester, Nacalai Tesque, Kyoto, Japan; mobile phase: MeCN/25 m m AcONH 4 /AcOH = 200/300/0.15; flow rate: 6.0 mL/min) to afford p ‐[ 18 F]MPPF (retention time = 9.5 min). p ‐[ 18 F]MPPF was obtained automatically with a radiochemical yield of 38.6 ± 5.0% (decay corrected, n  = 5), a specific activity of 214.3 ± 21.1 GBq/µmol, and a radiochemical purity of >99% within a total synthesis time of about 55 min. Copyright © 2012 John Wiley & Sons, Ltd.