Synthesis of [I-123]N ',N '-dimethyl-6-methyl-(4 '-iodophenyl)imidazo[1,2-a]pyridine-3-acetamide for the study of Peripheral Benzodiazepine Receptorsusing SPECT

The [I-123] labelled imidazo[1,2-a]pyridine [I-123]iodozolpidem 4 was found to exhibit preferential activity towards Peripheral rather than Central Be nzodiazepine receptors in vivo and was synthesised for the potential study of the Peripheral Benzodiazepine Receptors (PBR) using SPECT. [I-123]Iodozo lpidem was prepared from the corresponding tributyl tin precursor by iodode stannylation with Na[I-123] in the presence of peracetic acid or chloramine -T. Purification by semipreparative C-18 RP HPLC gave the product in radioc hemical yields of 60-85%. The product was obtained in > 97% chemical and ra diochemical puritiy with a specific activity > 80 GBq/mu mol.