Electrochemical Oxidative Regioselective C–H Cyanation of Imidazo[1,2-<i>a</i>]pyridines
作者:Ting Cui、Yanling Zhan、Changhui Dai、Jun Lin、Ping Liu、Peipei Sun
DOI:10.1021/acs.joc.0c03026
日期:2021.11.19
Electrochemical oxidative regioselective C–H cyanation of imidazo[1,2-a]pyridines was developed using readily available TMSCN as the cyano source. The KH2PO4/K2HPO4 buffer was essential for this transformation. This protocol was compatible with a broad range of substituted imidazo[1,2-a]pyridines and provided the C3 cyanated products in moderate to excellent yields.
咪唑并[1,2- a ]吡啶的电化学氧化区域选择性C-H氰化是使用现成的TMSCN作为氰基源开发的。KH 2 PO 4 /K 2 HPO 4缓冲液对于这种转化是必不可少的。该方案与多种取代的咪唑并[1,2- a ]吡啶兼容,并以中等至优异的产率提供C3氰化产物。
Heterogeneous copper-catalyzed three-component reaction of 2-aminopyridines, acetophenones and benzyl cyanide towards 3-cyanoimidazo[1,2-a]pyridines
作者:Bingbo Niu、Chongren You、Bin Huang、Mingzhong Cai
DOI:10.1016/j.catcom.2019.01.025
日期:2019.4
The heterogeneous three-componentreaction of 2-aminopyridines, acetophenones and benzyl cyanide was achieved in NMP at 120 °C by using an MCM-41-anchored L-proline‑copper(I) complex [MCM-41-L-Proline-CuI] as catalyst under air, yielding a wide variety of 3-cyanoimidazo[1,2-a]pyridines in moderate to high yields. The new heterogeneous copper catalyst exhibited higher catalytic activity than CuI, and
的2-氨基吡啶,苯乙酮和苄基氰的非均相三组分反应在NMP中在120℃下通过使用MCM-41锚定实现大号-脯氨酸-铜(I)配合物[MCM-41-大号-脯氨酸翠在空气中作为催化剂,以中等至高收率产生了多种3-氰基咪唑并[1,2- a ]吡啶。新的非均相铜催化剂显示出比CuI更高的催化活性,并且可以以几乎恒定的活性循环至少八次。
Synthesis of Imidazo[1,2-a]pyridines by the Bis(acetyloxy)(phenyl)-λ³-iodane-Mediated Oxidative Coupling of 2-Aminopyridines with β-Keto Esters and 1,3-Diones
作者:Wei Yu、Xianpei Wang、Lijuan Ma
DOI:10.1055/s-0030-1260106
日期:2011.8
2-aminopyridines and β-keto esters by using bis(acetyloxy)(phenyl)-λ³-iodane as an oxidant and borontrifluoride etherate as a catalyst. The amount of catalyst plays a key role in determining the course of the reaction. Whereas the use of 0.2 equivalents of catalyst ensures the generation of imidazo[1,2-a]pyridines, raising the amount of catalyst to 1.0 equivalents results in exclusive α-acetoxylation of
咪唑并[1,2一]吡啶-3-羧酸盐,可直接由2-氨基吡啶和β酮酯通过使用双(乙酰基氧基)制备(苯基)-λ ³ -iodane作为氧化剂和三氟化硼醚作为催化剂。催化剂的量在确定反应过程中起关键作用。尽管使用0.2当量的催化剂可确保生成咪唑并[1,2- a ]吡啶,但将催化剂的量提高至1.0当量可导致β-酮酯的独家α-乙酰氧基化。2-氨基吡啶也可以与1,3-二酮反应,得到3-酰基咪唑并[1,2- a ]吡啶。 杂环-多环-环化-氧化-偶联
Copper- and DMF-mediated switchable oxidative C–H cyanation and formylation of imidazo[1,2-<i>a</i>]pyridines using ammonium iodide
作者:Xuan Li、Shoucai Wang、Jiawang Zang、Meichen Liu、Guangbin Jiang、Fanghua Ji
DOI:10.1039/d0ob01838d
日期:——
The cyanation and formylation of imidazo[1,2-a]pyridines were developed under copper-mediated oxidative conditions using ammonium iodide and DMF as a nontoxic combined cyano-group source and DMF as a formylation reagent. Mechanistic studies indicate that the cyanation of imidazo[1,2-a]pyridines proceeds through a two-step sequence: initial iodination and then cyanation. The cyanation has a broad substrate
咪唑并[1,2 - a ]吡啶的氰化和甲酰化是在铜介导的氧化条件下开发的,使用碘化铵和 DMF 作为无毒的组合氰基源,DMF 作为甲酰化试剂。机理研究表明,咪唑并[1,2 - a ]吡啶的氰化过程分为两步:初始碘化,然后是氰化。氰化具有广泛的底物范围和高官能团耐受性,并且可以在克级安全地进行。使用广泛可用的 DMF 作为甲酰化试剂和环境友好的分子氧作为氧化剂的新型铜介导的甲酰化也已被开发出来。该协议还为临床使用的沙利吡坦的合成提供了一种方便的方法。