Synthesis of racemic [α‐¹¹C]amphetamine and [α‐¹¹C]phenethylamine from [¹¹C]nitroalkanes

Abstract

Abstract The synthesis of racemic [α‐ 11 C]amphetamine and [α‐ 11 C]‐phenethylamine from on‐line produced [ 11 C]nitroethane and [ 11 C]nitromethane, respectively, is described. The condensations of nocarrier‐added [ 11 C]nitroalkanes with benzaldehyde to form [β‐ 11 C]β‐nitrostyrenes were investigated under basic and acidic conditions. The [β‐ 11 C]β‐nitrostyrenes were reduced with lithium aluminium hydride to produce the corresponding saturated amines. Purification was performed with semi‐preparative reversed‐phase HPLC using a Suplex pKb‐100 column. The total radiochemical yields were 7‐20% (from EOB and decaycorrected) and 24‐35% (based on [ 11 C]nitroalkanes and decay‐corrected) with a total synthesis time of 40‐55 min. The specific radioactivity of [α‐ 11 C]amphetamine and [α‐ 11 C]phenethylamine at EOS was 200‐1000 Ci/mmol (7.4‐37 GBq/μmol) with a radiochemical purity >99%.