We report herein an effective method for the halogenation of imidazo-fused heterocycles using readily available sodiumsalts (NaCl/NaBr/NaI) as halogen source and K2S2O8 (or) oxone as promoter. A variety of C-3 halogenated imidazo[1,2-a]pyridines and benzo[d]imidazo[2,1-b]thiazoles were obtained in good to excellent yields. The present method of halogenation has been also extended to 2-aminopyridines
我们在此报告了一种使用容易获得的钠盐(NaCl / NaBr / NaI)作为卤素源和K 2 S 2 O 8(或)oxone作为促进剂的咪唑基稠合杂环卤化的有效方法。以良好或优异的产率获得了各种C-3卤代咪唑并[1,2- a ]吡啶和苯并[d]咪唑并[2,1- b ]噻唑。本发明的卤化方法还以中等至优异的产率扩展到2-氨基吡啶,2-氨基嘧啶,吲哚和异喹啉。
Base-Promoted Transition-Metal-Free Arylation of Imidazo-Fused Heterocycles with Diaryliodonium Salts
The arylation of imidazo[1,2‐a]pyridine and benzo[d]imidazo[2,1‐b]thiazoles by using diaryliodonium salts has been developed. Potassium tert‐butoxide was used to promote this transition‐metal‐free reaction, which afforded the corresponding products in good to excellent yields.
咪唑的芳基化[1,2一]吡啶和苯并[ d ]咪唑并[2,1- b ]通过使用二芳基碘盐已经开发噻唑。钾叔丁醇是用来促进此过渡金属无反应,得到相应的产品以良好至优异的产量。
Hypervalent iodine mediated synthesis of imidazo[1,2-<i>a</i>]pyridine ethers: consecutive methylene linkage and insertion of ethylene glycol
Hypervalent iodine mediated selective synthesis of imidazo[1,2-a]pyridine ethers using ethylene glycol as a methoxy ethanol source as well as solvent under metal-free conditions is described. The method is also applicable to other fused heterocycles such as benzo[d]imidazo[2,1-b]thiazoles, 2-(thiophen-2-yl)benzo[d]imidazo [2,1-b]thiazole and indazole. Control experiments suggest that, when the C-3
描述了在无金属条件下使用乙二醇作为甲氧基乙醇源以及溶剂的高价碘介导的咪唑并[1,2- a ]吡啶醚的选择性合成。该方法还适用于其他稠合杂环,例如苯并[ d ]咪唑并[ 2,1- b ]噻唑,2-(噻吩-2-基)苯并[ d ]咪唑并[ 2,1- b ]噻唑和吲唑。对照实验表明,当咪唑并[1,2- a ]吡啶的C-3位被封闭时,该反应不会在显示本方案区域选择性的任何其他位置发生。
Palladium-catalyzed regioselective direct C–H bond alkoxycarbonylation of 2-arylimidazo[1,2-<i>a</i>]pyridines
作者:Arezoo Tanbakouchian、Ebrahim Kianmehr
DOI:10.1039/d1nj00605c
日期:——
A palladium-catalyzed practical and efficient method to access alkoxycarbonylated imidazo[1,2-a]pyridines at the C-3 position has been developed based on the association of W(CO)6 as a safe and easy-to-handle CO surrogate and related alcohols. Through this synthetic strategy, a wide range of alkoxycarbonylated imidazo[1,2-a]pyridines with moderate to high yields have been prepared, which are important
基于 W(CO) 6作为安全且易于处理的 CO 替代物的结合,开发了一种钯催化的实用且有效的方法来获取C-3 位的烷氧基羰基化咪唑并 [1,2- a ] 吡啶和相关的酒精。通过这种合成策略,已经制备了多种具有中等至高产率的烷氧基羰基化咪唑并[1,2- a ]吡啶,它们是医药产品中的重要结构基序。
Polyethylene Glycol (PEG-400) as Methylene Spacer and Green Solvent for the Synthesis of Heterodiarylmethanes under Metal-Free Conditions
作者:Rahul Kumar、Deepa Rawat、Subbarayappa Adimurthy
DOI:10.1002/ejoc.202000467
日期:2020.6.23
protocol for the direct synthesis of heterodiarylmethanes employing polyethylene glycol (PEG‐400) as methylene spacer under metal‐free conditions. The method is applicable to heterocycles such as imidazopyridines, imidazothioazoles, imidazobenzothiozoles, indolizines, indole, 1‐methyl‐1H‐indole, N,N‐dimethylaniline, and trimethoxybenzene; (diacetoxyiodo)benzene (PIDA) is used as oxidant.