Transition-metal-free C–C bond cleavage and formation: efficient synthesis of 2,3-diarylimidazo[1,2-α]pyridines from 2-aminopyridines and alkynoates
作者:Zhengwang Chen、Yuelu Wen、Guotian Luo、Min Ye、Qinghao Wang
DOI:10.1039/c6ra19291b
日期:——
A highly efficient transition-metal-free cyclization reaction for the synthesis of 2,3-diarylimidazo[1,2-α]pyridines is described. A variety of substituted 2-aminopyridines and alkynoates are compatible under the standard conditions. This protocol is marked by the cleavage of a C–C bond and the formation of a new Csp2–Csp2 bond under transition-metal-free conditions.
Metal-free C–H arylation of imidazoheterocycles with aryl hydrazines
作者:Sourav Jana、Sadhanendu Samanta、Avik K. Bagdi、Valerii Z. Shirinian、Alakananda Hajra
DOI:10.1039/c8ra01474d
日期:——
A simple and efficient metal-freearylation of imidazo[1,2-a]pyridines at the C-3 position with arylhydrazine has been achieved at room temperature under ambient air conditions. Various 2,3-disubstituted imidazopyridines and imidazothiazoles were synthesized with high yields. The present methodology demonstrates the usefulness of commercially available aryl hydrazine as an arylating agent.
在室温和环境空气条件下,已经实现了在 C-3 位的咪唑并[1,2- a ]吡啶与芳基肼的简单有效的无金属芳基化。以高产率合成了各种 2,3-二取代的咪唑并吡啶和咪唑噻唑。本方法证明了可商购的芳基肼作为芳基化剂的有用性。
Straightforward Synthesis of Various 2,3-Diarylimidazo[1,2-<i>a</i>]pyridines in PEG<sub>400</sub>Medium through One-Pot Condensation and C-H Arylation
PEG400 is described herein as a suitable medium for the condensation of various 2-amino pyridines with α-bromo ketones. 2-Arylimidazo[1,2-a]pyridines were synthetized in a short time through microwave irradiation in moderate to excellent yields. After optimization, a convenient one-pot process enabled access to 2,3-diarylimidazo[1,2-a]pyridines by using a reduced amount of palladium catalyst without
Copper-Catalyzed Synthesis of Imidazo[1,2-<i>a</i>]pyridines through Tandem Imine Formation-Oxidative Cyclization under Ambient Air: One-Step Synthesis of Zolimidine on a Gram-Scale
A new copper‐catalyzed oxidative cyclization via CH amination between 2‐aminopyridines and methyl aryl/heteroaryl ketones has been developed under ambient air. Imidazo[1,2‐a]pyridines containing a wide range of functional groups have been synthesized from basic and easily available starting materials. This simple, one‐pot reaction protocol is applicable for the direct preparation of zolimidine (a
一种新的铜催化的氧化环化经由Ç ħ胺化2-氨基吡啶和间甲基芳基/杂芳基酮已根据环境空气显影。含有多种官能团的咪唑并[1,2- a ]吡啶是从碱性且容易获得的起始原料合成的。这种简单的一锅法反应方案适用于大规模直接制备唑来咪定(市售的抗溃疡药)。