分子碘使肟能够生成亚氨基自由基:从简单的吡啶制备咪唑并[1,2- a ]吡啶及其区域选择性C-3亚磺化产物的简便途径
摘要:
已经开发了碘促进的简单且环境友好的方案,以从未官能化的吡啶和肟酯中获得咪唑并[1,2- a ]吡啶。这种简单的方法可以有效地将底物转化为相应的产品,从而提供中等到良好的产率以及较大的官能团耐受性。另外,广泛的研究表明,在DMSO溶剂中,吡啶和肟酯类也可以首次获得区域选择性多米诺C-3甲基亚磺酰咪唑并[1,2- a ]吡啶。该反应通过容易获得的肟酯的无金属生成亚胺基进行,从而在吡啶上建立第二个杂环。
A transition-metal-free protocol for the difluoroalkylation of imidazopyridines with bromodifluoroaryl ketones promoted by visible light irradiation is presented. This protocol is distinguished by simple, mild, and catalyst-free reaction conditions with a wide reaction scope, which is complementary to existing difluoroalkylation strategies by photoredox scenarios. Additionally, this protocol potentially
imidazoheterocycles has been developed through sp2 C–Hbondfunctionalization with molecular iodine in water at room temperature. The reaction is catalyzed by an imidazole-based zwitterion-type molten salt. A library of iodo-substituted imidazo[1,2-a]pyridines with broad functionality have been synthesized. This methodology is also applicable to imidazo[2,1-b]thiazole and imidazole scaffolds. An environmentally
摘要 通过室温下水中的分子碘与sp 2 C–H键的官能化作用,开发了咪唑杂环杂环碘化的环境友好方案。该反应由基于咪唑的两性离子型熔融盐催化。已经合成了具有广泛功能的碘取代的咪唑并[1,2- a ]吡啶的文库。该方法学也适用于咪唑并[2,1- b ]噻唑和咪唑支架。 通过室温下水中的分子碘与sp 2 C–H键的官能化作用,开发了咪唑杂环杂环碘化的环境友好方案。该反应由基于咪唑的两性离子型熔融盐催化。已经合成了具有广泛功能的碘取代的咪唑并[1,2- a ]吡啶的文库。该方法学也适用于咪唑并[2,1- b ]噻唑和咪唑支架。
Copper-catalyzed C–H ethoxycarbonyldifluoromethylation of imidazoheterocycles
ethoxycarbonyl-difluoromethylation of imidazo[1,2-a]pyridines has been developed through sp2 C–Hbondfunctionalization with BrCF2CO2Et under ambient air. A series of ethoxycarbonyldifluoromethylated imidazo[1,2-a]pyridines with broad functionalities have been synthesized. This methodology is also applicable to imidazo[2,1-b]thiazole and benzo[d]imidazo[2,1-b]thiazole.
咪唑并[1,2- a ]吡啶在铜上的区域选择性铜催化的乙氧基羰基-二氟甲基化反应是通过在环境空气中用BrCF 2 CO 2 Et进行sp 2 C–H键官能化而开发的。合成了一系列具有广泛功能的乙氧基羰基二氟甲基化咪唑并[1,2- a ]吡啶。该方法也适用于咪唑并[2,1- b ]噻唑和苯并[ d ]咪唑并[2,1- b ]噻唑。
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。
Electrochemical Oxidative C—H Sulfenylation of Imidazopyridines with Hydrogen Evolution
作者:Yong Yuan、Yangmin Cao、Jin Qiao、Yueping Lin、Xiaomei Jiang、Yaqing Weng、Shan Tang、Aiwen Lei
DOI:10.1002/cjoc.201800405
日期:2019.1
Selective oxidativeC—H sulfenylation of imidazopyridine heterocycles is achieved using an undivided electrolytic cell. The reaction avoids the use of stoichiometric amount of external chemical oxidant and produces hydrogen gas as the only byproduct. Both aryl and aliphatic thiols demonstrate good reactivity for C—S bond formation.