K2S2O8-Mediated halogenation of 2-arylimidazo[1,2-a]pyridines using sodium halides as the halogen sources
作者:Praewpan Katrun、Chutima Kuhakarn
DOI:10.1016/j.tetlet.2019.03.008
日期:2019.4
halogenation of 2-arylimidazo[1,2-a]pyridines using sodium chloride/bromide/iodide as the halogen sources in the presence of K2S2O8 as an easy-to-handle oxidizing agent was developed. The present work offers an efficient and rapid access to 3-chloro-, 3-bromo- and 3-iodo-2-arylimidazo[1,2-a]pyridines which can be readily converted to C3-substituted imidazo[1,2-a]pyridines by cross-coupling reactions.
开发了在K 2 S 2 O 8作为易于处理的氧化剂存在下,使用氯化钠/溴化物/碘化物作为卤素源,方便地卤化2-芳基咪唑并[1,2- a ]吡啶的方法。本工作提供了一种快速有效地获得3-氯-,3-溴-和3-碘-2-芳基咪唑并[1,2- a ]吡啶的方法,这些吡啶基很容易转化为C 3取代的咪唑并[1,2] -一个]吡啶通过交叉偶联反应。
Ultrasound-Promoted and Base-Mediated Regioselective Bromination of Imidazo[1,2-a]pyridines with Pyridinium Tribromide
作者:Qing-Wen Gui、Hongmei Jiang、Dingyi Guo、Yixin Zhang、Qin-Peng Shen、Shiyun Tang、Junheng You、Yi Huo、Huixian Wang
DOI:10.1055/s-0040-1707856
日期:2020.9
Abstract By using pyridinium tribromide as the bromo source, an efficient and practical protocol for the synthesis of C3-brominated imidazo[1,2-a]pyridines through ultrasound-promoted and Na2CO3-mediated regioselective bromination of imidazo[1,2-a]pyridines has been developed. This method effectively avoids the use of metal catalysts and harsh reaction conditions, and shows attractive characteristics
摘要 通过使用三溴化吡啶鎓作为溴源,通过超声促进和Na 2 CO 3介导的咪唑并[1,2-]区域选择性溴化合成C3-溴化的咪唑并[1,2- a ]吡啶的有效而实用的方案。已经开发了α ]吡啶。该方法有效地避免了使用金属催化剂和苛刻的反应条件,并显示出引人注目的特性,例如操作简便,宽范围的基材范围以及良好至优异的收率,易于规模化生产和高能源效率。
Hypervalent Iodine Mediated Efficient Solvent-Free Regioselective Halogenation and Thiocyanation of Fused N-Heterocycles
作者:Divakar Reddy Indukuri、Gal Reddy Potuganti、Manjula Alla
DOI:10.1055/s-0037-1611856
日期:2019.8
2-a]pyridine/pyrimidine heterocycles has been achieved under solvent-free reaction conditions. Halogenations and thiocyanation of the heterocycles could be accomplished by simple grinding of reactants and hypervalent iodine reagents with the corresponding alkali metal or ammonium salts. The method has been extrapolated to a cleaner synthesis of brominated imidazo[1,2-a]pyridine/pyrimidine derivatives
Trihaloisocyanuric acids in ethanol: an eco-friendly system for the regioselective halogenation of imidazo-heteroarenes
作者:José S. S. Neto、Renata A. Balaguez、Marcelo S. Franco、Victor C. de Sá Machado、Sumbal Saba、Jamal Rafique、Fábio Z. Galetto、Antonio L. Braga
DOI:10.1039/d0gc00137f
日期:——
Herein, we describe an efficient, rapid and benign protocol for the direct C(sp2)–H bond halogenation (Cl, Br, I) of 2-arylimidazo[1,2-a]pyridines using trihaloisocyanuric acids in ethanol. Furthermore, this sustainable protocol was successfully extended to imidazopyrimidine, imidazothiazole and indazole heterocycles showing the broadness of this useful approach.
在这里,我们描述了使用乙醇中的三卤代异氰尿酸对2-芳基咪唑[1,2- a ]吡啶进行直接C(sp 2)-H键卤化(Cl,Br,I)的有效,快速和良性方案。此外,这种可持续的协议已成功扩展到咪唑并嘧啶,咪唑并噻唑和吲唑杂环,显示了这种有用方法的广泛性。