Synthesis of H-Labeled Tetrabenazine (TBZ).

Tetrabenazine (TBZ) (1,3,4,6,7,11b-hexahydro-9,10-dimethoxy-3-(2-methylpropyl)-2H-benzo[a]quinolin-2-one), a vesicular monamine transporter 2 inhibitor, was prepared as a tritium-labeled compound with high specific activity and radiochemical purity. Catalytic hydrogenation of a precursor with the terminal double bond was used to introduce the tritium. This method provides tritium-labeled TBZ with high specific activity and radiochemical purity, which allow the further investigation of a TBZ in the neurological field.