已经开发出一种有效的直接方法来合成三唑融合的杜鹃花。提出的策略的关键步骤是磺酰胺系的5-碘-1,2,3-三唑的碱介导环化,该环化反应可通过改进的铜催化1,3-偶极环加成方案得到。在无过渡金属的条件下,在Cs 2 CO 3在二恶烷中,100°C的条件下,将杜仲片段与三唑环的环化平稳进行,并以高达99%的高收率提供稠合杂环。DFT计算支持了类似S N Ar的环化反应机理。通过制备脱氧胆酸衍生物证明了所开发方法对天然化合物的改性的适用性。
An one-pot approach to the synthesis of triazolobenzothiadiazepine 1,1-dioxide derivatives by basic alumina-supported azide–alkyne [3+2] cycloaddition
作者:K.C. Majumdar、Sintu Ganai、Biswajit Sinha
DOI:10.1016/j.tet.2012.07.040
日期:2012.9
An efficient one-pot strategy for the synthesis of triazolobenzothiadiazepine 1,1-dioxidederivatives has been developed by the reaction of 2-azido-N-substituted benzenesulfonamides and propargyl bromide in basic alumina under microwave condition via [3+2] azide–alkyne cycloaddition reaction. This protocol has synthetic advantages in terms of low environmental impact and short reaction time.