Regioselective C(sp<sup>2</sup>)–H halogenation of pyrazolo[1,5-<i>a</i>]pyrimidines facilitated by hypervalent iodine(<scp>iii</scp>) under aqueous and ambient conditions
作者:Abhinay S. Chillal、Rajesh T. Bhawale、Umesh A. Kshirsagar
DOI:10.1039/d4ra02090a
日期:2024.4.22
An efficient and mild approach has been developed for the regio-selective direct C3 halogenation of pyrazolo[1,5-a]pyrimidines employing readily available potassium halide salts and a hypervalent iodine(III) reagent at ambient temperature. The protocol is both practical and environmentally friendly, utilizing water as a green solvent, potassium halides as an inexpensive and bench stable halogen source
开发了一种有效且温和的方法,使用易于获得的卤化钾盐和高价碘( III )试剂在环境温度下对吡唑并[1,5- a ]嘧啶进行区域选择性直接C3卤化。该方案既实用又环保,利用水作为绿色溶剂,卤化钾作为廉价且稳定的卤素源,PIDA作为无毒试剂,可在室温下实现清洁高效的卤化。该程序以良好至优异的产率产生一系列 C3 卤代吡唑并[1,5- a ]嘧啶。机理研究表明亲电取代机制参与卤化过程。