An improved synthesis of α-AZA, α-AZP and α-AZG, the precursors to clinical markers of tissue hypoxia

α-[123I]-IAZA and α-[123I]-IAZP are experimental diagnostic radiopharmaceuticals which have been used clinically to diagnose hypoxia in a number of pathologies, including cancer, peripheral vascular disease, rheumatoid arthritis and brain trauma. These nitroimidazole nucleosides are synthesized from the non-iodinated nucleosides AZA, AZP and AZG, respectively. Earlier methods report low chemical yields for the synthesis of these precursors. The modified procedures now reported provide nearly quantitative yields of these compounds, thereby substantially reducing the cost and effort of synthesis.