Radiosynthesis of a selective dopamine D-1 receptor antagonist: R(+)-7-chloro-8-hydroxy-3-[11C]methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine ([11C]SCH 23390)

Carbon-11 labeled SCH 23390, a selective dopamine D-1 receptor antagonist (Fig. 1b), was prepared by N-alkylation of the nor-methyl precursor with [¹¹C]iodomethane. The product was purified by semi-preparative HPLC and shown to be radiochemically pure at the end of synthesis. The synthesis was completed in approximately 22 min with an average radiochemical yield of 28% (based on [¹¹C]iodomethane) and an average specific activity of approximately 1950 mCi/μmol calculated at the end of synthesis.