Toward Continuous‐Flow Synthesis of Biologically Interesting Pyrazole Derivatives
作者:Amrita Das、Haruro Ishitani、Shū Kobayashi
DOI:10.1002/adsc.201900954
日期:2019.11.19
continuous‐flow synthesis of substituted pyrazole derivatives has been developed via the formation of vinylidene keto esters as key intermediates. Heterogeneous Ni2+‐montmorillonite was found to be an efficient catalyst for orthoester condensation of 1,3‐dicarbonyls under flow conditions. The intermediate reacted with methylhydrazine to afford pyrazole derivatives, for which suitable selection of a solvent
通过形成亚乙烯基酮基酯作为关键中间体,已开发出了一种两步连续流式合成取代吡唑衍生物的方法。发现非均相Ni2 +-蒙脱石是在流动条件下有效的1,3-二羰基原酸酯缩合催化剂。与甲基肼反应中间,得到吡唑衍生物,为此的溶剂的合适的选择在实现高产率和所需产物的优异的区域选择性发挥了关键作用。该协议的应用已通过合成生物活性吡唑的关键中间体(如Bixafen)得到了证明。