The preparation and characterization of (±)‐[phenoxy‐³H(N)] phenoxybenzamine hydrochloride at high specific activity

Abstract

+)-Phenoxybenzamine is a ligand capable of irreversibly alkylating the alpha-1 adrenergic receptor. Previous attempts to radiolabel it have achieved only low specific activities which impeded their use in neurochemical investigations. (+)-[Phenoxy-JH(N)]Phenoxybenzamine.HC1 (1) has been prepared in our laboratory by the catalytic reductive aryl debrominatTon of an appropriate brominated precursor with tritium gas. 3H NMR showed exclusive radiolabeling on the phenoxy ring and the radioligand had a specific activity o f 32.4 Ci/mnol.