Radiosynthesis of no‐carrier‐added ^75,77Br‐brombenperidol

A three‐step synthesis of the neuroleptic benperidol is presented, and the rapid no‐carrier‐added (n.c.a.) radiobromination of this compound to form brombenperidol (BBP), a radiolabelled dopaminergic receptor‐binding ligand, is described. N.c.a. radiobromination of benperidol using dichloramine‐T in trifluoroacetic acid at elevated temperatures results in bromination totally at the benzimidazolinyl ring of the neuroleptic, leaving the molecular characteristics necessary for receptor binding unaltered. Radiopharmaceutical production results in n.c.a. ^75,77Br‐brombenperidol with a corrected radiochemical yield of 30% and a specific activity exceeding 8,000 Ci/mmol.