Development of novel labeled nucleosides for spect imaging of tumor tissue.

本文报道了1-α-D-（5-脱氧-5-碘阿拉伯呋喃糖基）-2-硝基咪唑（IAZA）β-异构体的合成。放射性碘标记的IAZA（123 I-IAZA）作为一种放射性药物已被广泛研究，用于诊断各种临床病理学中的局部和/或局灶性组织缺氧。以1-β-D-（5-脱氧-5-碘代阿拉伯呋喃糖基）-2-硝基咪唑（AZR）为起始原料，通过非常规路线合成了1-β-D-（5-脱氧-5-碘代阿拉伯呋喃糖基）-2-硝基咪唑（β-IAZA），改变了AZR的C-2 '位构型，得到1-β-D-（5-脱氧-5-碘代阿拉伯呋喃糖基）-2-硝基咪唑（β-AZA）。β-AZA的前体5 ′-O-甲苯磺酰基-2 ′，3 ′-二-O-乙酰基经亲核碘化后脱保护，得到β-IAZA。以β-AZA为原料，用分子碘和三苯基膦合成了β-IAZA。

The present work describes the synthesis of the β-isomer of 1-α-D-(5-deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (IAZA). Radioiodinated IAZA (123I-IAZA) has been extensively studied as a radiopharmaceutical for the diagnosis of regional and/or focal tissue hypoxia in a variety of clinical pathologies. The β-anomer of IAZA, 1-β-D-(5-deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (β-IAZA), was synthesized via an unconventional route starting from 1-f3-D-(ribofuranosyl)-2-nitroimidazole (AZR), with a change of configuration at the C-2'-position to afford 1-p-D-(arabinofuranosyl)-2-nitroimidazole (β-AZA). Nucleophilic iodination of the 5'-O-toluenesulfonyl-2',3'-di-O-acetyl precursor of β-AZA, followed by deprotection, afford β-IAZA in satisfactory yield. β-IAZA was also synthesized from (β-AZA using molecular iodine and triphenylphosphine.