咪唑并脱氢偶联[1,2一]吡啶衍生物已经实现首次。如果过量电子的杂环中最富电子的位置被萘-1-基取代基所阻断,则氧化芳族偶联或Scholl条件下的反应都无法使环稠合。将底物转化为相应的咪唑并[5,1,2- de ]萘[1,8- ab ]喹啉嗪的唯一方法是在无水甲苯中钾的存在下偶联。此外,我们发现了这一阴离子-自由基偶联反应的新的极好条件,该条件从一开始就在反应混合物中使用了干燥的O 2。这种方法提供了垂直熔合的咪唑并[1,2- a吡啶的产率为63%。有趣的是,而荧光量子产率(Φ FL化合物)3,尽管旋转自由,接近50%时,Φ FL平坦萘咪唑并[1,2的值一个]吡啶仅为5%。通过使用DFT计算和低温Shpol'skii矩阵对该化合物进行的详细分析揭示了磷光发射,因此表明从最低激发S 1水平到三重态歧管的有效系统间交叉是与荧光竞争的过程。
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.
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。
Synthesis of 3-Arylimidazo[1,2-a]pyridines by a Catalyst-Free Cascade Process
作者:Xiangge Zhou、Zhiqing Wu、Yinyin Pan
DOI:10.1055/s-0030-1260669
日期:2011.7
A simple and efficient protocol to synthesize 3-arylimidazo[1,2-a]pyridines by a catalyst-free cascade process from 2-aminopyridine and 1-bromo-2-phenylacetylene or 1,1-dibromo-2-phenylethene in yields up to 86% is described.
Cobalt-Catalyzed Direct Arylation of Imidazo[1,2-<i>a</i>
]pyridine with Aryl Iodides
作者:Dattatraya A. Babar、Haridas B. Rode
DOI:10.1002/ejoc.202000006
日期:2020.3.31
A practical protocol for the C‐3 arylation of imidazo[1,2‐a]pyridines with aryl/heteroaryl iodides using CoIICl2·6H2O is reported. The reaction can be performed in a Screw‐top V‐Vial® to expedite the synthesis.
报道了使用Co II Cl 2 · 6H 2 O将咪唑并[1,2- a ]吡啶与芳基/杂芳基碘化物进行C-3芳基化的实用协议。可以在Screw-topV-Vial®中进行反应,以加快合成速度。
An unprecedented Pd-catalyzed decarboxylative coupling reaction of aromatic carboxylic acids in aqueous medium under air: synthesis of 3-aryl-imidazo[1,2-a]pyridines from aryl chlorides
An efficient and practical protocol for palladium-catalyzeddecarboxylative arylation of imidazo[1,2-a]pyridine-3-carboxylic acids with aryl chlorides has been developed. Note that the reaction could proceed smoothly without an additive in aqueous medium under an ambient atmosphere, and the addition of H2O could effectively promote the decarboxylative arylation. Particularly noteworthy is that these
已开发出一种有效,实用的方案,用于钯催化的咪唑并[1,2 - a ]吡啶-3-羧酸与芳基氯化物的脱羧芳基化反应。注意,在环境气氛下在水性介质中没有添加剂的情况下反应可以顺利进行,并且H 2 O的添加可以有效地促进脱羧芳基化。特别值得注意的是,这些结果代表了Pd催化的(杂)芳香族羧酸在水性介质中在空气中的P催化脱羧偶联反应的第一个实例,以及3-芳基-咪唑并[1,2- a]合成的第一个成功实例。吡啶使用廉价的各种芳基氯化物和杂芳基氯化物作为起始原料。