Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India.
Chemistry. 2019 Feb 1;25(7):1773-1780. doi: 10.1002/chem.201805112. Epub 2019 Jan 2.
Halogenated nucleosides, such as 5-iodo-2'-deoxyuridine and 5-iodo-2'-deoxycytidine, are incorporated into the DNA of replicating cells to facilitate DNA single-strand breaks and intra- or interstrand crosslinks upon UV irradiation. In this work, it is shown that the naphthyl-based organoselenium compounds can mediate the dehalogenation of halogenated pyrimidine-based nucleosides, such as 5-X-2'-deoxyuridine and 5-X-2'-deoxycytidine (X=Br or I). The rate of deiodination was found to be significantly higher than that of the debromination for both nucleosides. Furthermore, the deiodination of iodo-cytidines was found to be faster than that of iodo-uridines. The initial rates of the deiodinations of 5-iodocytosine and 5-iodouracil indicated that the nature of the sugar moiety influences the kinetics of the deiodination. For both the nucleobases and nucleosides, the deiodination and debromination reactions follow a halogen-bond-mediated and addition/elimination pathway, respectively.
卤代核苷，如 5-碘-2'-脱氧尿苷和 5-碘-2'-脱氧胞苷，在复制细胞的 DNA 中被掺入，以促进 DNA 单链断裂和 UV 照射时的链内或链间交联。在这项工作中，表明基于萘的有机硒化合物可以介导卤代嘧啶核苷的脱卤反应，如 5-X-2'-脱氧尿苷和 5-X-2'-脱氧胞苷（X=Br 或 I）。发现脱碘反应的速率对于两种核苷都明显高于脱溴反应。此外，碘代胞嘧啶的脱碘反应速度快于碘代尿嘧啶。5-碘胞苷和 5-碘尿苷的初始脱碘速率表明糖部分的性质影响脱碘动力学。对于碱基和核苷，脱碘和脱溴反应分别遵循卤键介导的和加成/消除途径。
