作者:Frank Seela、Khalil?I. Shaikh、Thomas Wiglenda、Peter Leonard
DOI:10.1002/hlca.200490224
日期:2004.10
The syntheses of N7-glycosylated 9-deazaguanine 1a as well as of its 9-bromo and 9-iodo derivatives 1b,c are described. The regioselective 9-halogenation with N-bromosuccinimide (NBS) and N-iodosuccinimide (NIS) was accomplished at the protected nucleobase 4a (2-[(dimethylamino)methylidene]amino}-3,5-dihydro-3-[(pivaloyloxy)methyl]-4H-pyrrolo[3,2-d]pyrimidin-4-one). Nucleobase-anion glycosylation
描述了N 7-糖基化的9-脱氮鸟嘌呤1a以及其9-溴和9-碘衍生物1b,c的合成。区域选择性9-卤化用Ñ溴代琥珀酰亚胺(NBS)和Ñ碘代丁二酰亚胺(NIS)的混合物在所述保护的核碱基完成4A [(二甲基氨基)亚甲基]氨基} -3,5-二氢-3 - - [(新戊酰氧基(2- )甲基] -4 H-吡咯并[3,2- d ]嘧啶-4-一)。4a – c的碱基碱基阴离子糖基化与2-deoxy-3,5- di - O-(p -toluoyl)-α-D- erythro-戊呋喃糖基氯(5)提供了受完全保护的中间体6a – c(方案2)。将它们用0.01M NaOMe脱保护,得到糖去保护的衍生物8a – c(方案3)。在较高浓度(0.1M NaOMe)下,新戊酰氧基甲基基团也被除去,得到7a – c,同时浓。水 NH 3溶液提供了核苷1a – c。在D 2 O中,糖的构象总是偏向S(67-61%)。