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

本文报道了1-α- d -（5-脱氧-5-碘阿拉糖呋喃基）-2-硝基咪唑(IAZA) β-异构体的合成。放射性碘化IAZA （123I-IAZA）作为一种放射性药物被广泛研究，用于诊断各种临床病理中的局部和/或局灶性组织缺氧。IAZA的β-异位化合物，1-β- d -（5-脱氧-5-碘阿拉比诺呋喃基）-2-硝基咪唑（β-IAZA），以1-f3- d -（核呋喃基）-2-硝基咪唑（AZR）为起始点，在C-2'位置改变构型，合成了1-p- d -（阿拉比诺呋喃基）-2-硝基咪唑（β-AZA）。β-AZA的5′- o -甲苯磺酰-2′，3′-二- o -乙酰基前体亲核碘化，然后去保护，得到了令人满意的β-IAZA产率。以分子碘和三苯基膦为原料，由（β-AZA）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.