DABCO catalyzed highly regioselective synthesis of fused imidazo-heterocycles in aqueous medium
作者:Vikas M. Bangade、B. Chennakesava Reddy、Pramod B. Thakur、B. Madhu Babu、H.M. Meshram
DOI:10.1016/j.tetlet.2013.06.123
日期:2013.8
efficient regioselectivesynthesis of 3-aryl imidazo[1,2-a]pyridines, 5-aryl imidazo[2,1-b]thiazoles, and 3-aryl benzo[d]imidazo[2,1-b][1,3]thiazoles is described by the reaction of phenacyl bromide with heterocyclic amine in the presence of DABCO under aqueousmedium. The method is applicable for a variety of substituted phenacyl bromides as well as 2-amino-heterocycles. An aqueous reaction medium, regioselectivity
有效的区域选择性合成3-芳基咪唑并[1,2- a ]吡啶,5-芳基咪唑并[2,1- b ]噻唑和3-芳基苯并[ d ]咪唑并[2,1- b ] [1, 3]噻唑的描述是在水介质中在DABCO存在下,苯甲酰溴与杂环胺反应。该方法适用于各种取代的苯甲酰溴以及2-氨基杂环。水性反应介质,区域选择性,温和的反应条件和高产率的产物是该方案的重要特征。
Phosphine-Free Palladium-Catalyzed Direct Arylation of Imidazo[1,2-a]pyridines with Aryl Bromides at Low Catalyst Loading
作者:Hai Yan Fu、Lu Chen、Henri Doucet
DOI:10.1021/jo300528b
日期:2012.5.4
Ligand-free Pd(OAc)2 was found to catalyze very efficiently the directarylation of imidazo[1,2-a]pyridines at C3 under very low catalyst concentration. The reaction can be performed employing as little as 0.1–0.01 mol % catalyst with electron-deficient and some electron-excessive aryl bromides.
Regioselective Synthesis of 2- and 3-Substituted Imidazo[1,2-<i>a</i>]pyridines
作者:Guoping Liu、Xuefeng Cong、Jiaheng He、Shunzhong Luo、Di Wu、Jingbo Lan
DOI:10.3184/174751912x13499663832261
日期:2012.12
A range of 2- or 3-substituted imidazo[1,2- a]pyridines were prepared from 2-aminopyridine derivatives and gem-dibromovinyl compounds by the tandem nucleophilic substitution (or nucleophilic addition)/cyclisation reaction.
Direct catalytic C–H arylation of imidazo[1,2-a]pyridine with aryl bromides using magnetically recyclable Pd–Fe3O4 nanoparticles
作者:Jaewoo Lee、Jooyoung Chung、Sang Moon Byun、B. Moon Kim、Chulbom Lee
DOI:10.1016/j.tet.2013.04.031
日期:2013.7
The direct C–H arylation of a heteroarene with aryl bromides has been achieved under the catalysis of magnetic nanoparticles. In the presence of bimetallic Pd–Fe3O4 heterodimer nanocrystals (1 mol % in palladium), the reaction of imidazo[1,2-a]pyridine with various aryl bromides gives the corresponding arylated products with exclusive C3-selectivity. The highly regioselective method is applicable to
在磁性纳米粒子的催化下,杂芳烃与芳基溴的直接C–H芳基化反应已经实现。在双金属Pd–Fe 3 O 4异质二聚体纳米晶体(在钯中为1 mol%)的存在下,咪唑并[1,2- a ]吡啶与各种芳基溴化物的反应提供了具有独占C3选择性的相应芳基化产物。高度区域选择性的方法适用于各种具有不同电子和空间特性的芳基溴化物。Pd–Fe 3 O 4纳米晶体可以通过简单的磁分离而回收,并且已经被回收了十次而没有失去催化活性。
Metal-free, base catalyzed oxidative amination and denitration reaction: Regioselective synthesis of 3-arylimidazo[1,2-a]pyridines
作者:Elango Sankari Devi、Anitha Alanthadka、Subbiah Nagarajan、Vellaisamy Sridharan、Chockalingam Uma Maheswari
DOI:10.1016/j.tetlet.2018.08.024
日期:2018.9
metal-free, regioselective strategy for the synthesis of 3-arylimidazo[1,2-a]pyridines from β-nitrostyrenes and 2-aminopyridines using triethylamine as the catalyst and H2O2 (30% aq.) as the oxidant is reported. The use of an inexpensive base and facile reaction conditions make this strategy a practical alternative for the synthesis of 3-arylimidazo[1,2-a]pyridines.
使用三乙胺作为催化剂,以H 2 O 2(30%水溶液)为氧化剂,从金属上合成β-硝基苯乙烯和2-氨基吡啶的3-芳基咪唑并[1,2- a ]吡啶的无金属区域选择性策略是报告。使用廉价的碱和容易的反应条件使该策略成为合成3-芳基咪唑并[1,2- a ]吡啶的实用替代方法。