合成了一个新的腙修饰的胞苷亚磷酰胺结构单元,并将其整合到寡脱氧核苷酸中以构建光开关 DNA 链。在核苷和寡脱氧核苷酸的背景下,通过1 H NMR 光谱和 HPLC研究和证实了由波长为 450 nm 的蓝光照射引发的EZ异构化。在使用Bst的引物延伸模型中,发现该腙-胞苷的光活化Z型异构体具有六元分子内氢键,可抑制 DNA 合成DNA聚合酶。此外,腙修饰导致 dATP 与 dGTP 以相似的选择性错误结合到正在生长的 DNA 链中,突出了潜在的 G 到 A 突变。这项工作提供了一种新的功能性 DNA 构建块和一种额外的分子工具,具有潜在的化学生物学和生物医学应用,可使用细胞友好的蓝光照射来控制 DNA 合成和 DNA-酶相互作用。
Electrophilic glycosidation employing 3,5-O-(di-tert-butylsilylene)-erythro-furanoid glycal leads to exclusive formation of the β-anomer: synthesis of 2′-deoxynucleosides and its 1′-branched analogues
摘要:
Stereoselectivity in N-iodosuccimide (NIS)-mediated electrophilic glycosidation was examined by employing 2,4-bis-O-(trimethylsilyl)thymine and three different silyl-protected erythro-furanoid glycals 12, 16, and 18. As a result, it was found that 3,5-O-(di-t-butylsilylene)-protected 18 gave only the beta-anomer (21). The remarkable stereoselectivity observed by employing 18 is discussed on the basis of its X-ray crystallographic analysis. 1-Substituted glycals gave the corresponding beta-anomer, again exclusively, to provide access to 1'-branched 2'-deoxynucleosides. (C) 2010 Elsevier Ltd. All rights reserved.