SYNTHESIS OF A NOVEL I-123 LABELED DERIVATIVE OF GBR12783, A POTENTIAL AGENT FOR SPECT IMAGING OF DOPAMINE-REUPTAKE SITES

y)ethyl]-4-[3-(m-iodophenyl)-2-propenyl]piperazine ([I-123]2), a poten tial SPECT imaging agent for dopamine reuptake sites was efficiently s ynthesized in 4 steps from 1-[2-(diphenylmethoxy)ethyl]piperazine (3). A key step in the synthesis was the selective AlH3-mediated reduction of 1-[2-(diphenylmethoxy)ethyl]-4-[m-bromocinnamoyl] piperazine (4) t o )ethyl]-4-[3-(m-bromophenyl)-2-propenyl]piperazine (5). The 1231 lab el of [I-123]2 was introduced in the final step in up to 90% radiochem ical yield by treatment of the organotin precursor 1-[2-(diphenylmetho xy)ethyl]-4-[3-[(m-(tributyl stannyl)phenyl]-2-propenyl]piperazine (6) with Na I-123 in aqueous CH3CO3H.