Azide−Tetrazole Equilibrium of C-6 Azidopurine Nucleosides and Their Ligation Reactions with Alkynes
作者:Mahesh K. Lakshman、Manish K. Singh、Damon Parrish、Raghavan Balachandran、Billy W. Day
DOI:10.1021/jo902342z
日期:2010.4.16
nucleosides, access to the azido derivatives could be readily attained via displacement of BtO− from the O6-(benzotriazol-1-yl)inosine nucleosides by azide anion. Use of diphenylphosphoryl azide/DBU as a simple route to the acetyl-protected azido nucleosides was also evaluated, but this proved to be inferior. Since these azido nucleosides can exist in an azide·tetrazole equilibrium, the effect of solvent
已经开发了C-6叠氮嘌呤核糖核苷和2'-脱氧核糖核苷的简便合成方法。对于甲硅烷基和乙酰基保护的以及未受保护的核苷,获得了叠氮基的衍生物,可以很容易地通过BTO的位移达到-从ø 6 -叠氮阴离子(苯并三唑-1-基)肌苷核苷。还评估了使用二苯基磷酰基叠氮化物/ DBU作为获得乙酰基保护的叠氮核苷的简单途径,但事实证明这是较差的。由于这些叠氮基核苷可以在叠氮化物·四唑平衡中存在,因此研究了溶剂极性对该平衡的影响。随后,对Cu介导的叠氮化物-炔(“点击”)连接进行了详细分析。双相CH 2 Cl 2 / H事实证明,2 O介质最适合连接反应,从而抑制了竞争中不希望的叠氮化物还原。有趣的是,尽管在CD 2 Cl 2和CD 2 Cl 2 / D 2中四唑基异构体占主导(约80%)。O,Cu催化的点击反应与甲硅烷基保护的核糖核苷和2'-脱氧核糖核苷顺利进行,从而导致C-6三唑基产物的收率非常好。因此,反应