Brønsted acidic reduced graphene oxide as a sustainable carbocatalyst: a selective method for the synthesis of C-2-substituted benzimidazole
作者:Murugan Karthik、Palaniswamy Suresh
DOI:10.1039/c8nj03257b
日期:——
acidic reduced graphene acts as an efficient and sustainable carbocatalyst for the selective synthesis of C-2-substituted benzimidazoles under ambient conditions. A massive influx of sulphonic acid group on reduced graphene oxide surface gives graphene sulfonic acid (G-SO3H), which acts as a Brønsted acidic catalyst for the synthesis of a series of benzimidazoles under mild conditions. The present methodology
Iron(<scp>ii</scp>) bromide-catalyzed oxidative coupling of benzylamines with ortho-substituted anilines: synthesis of 1,3-benzazoles
作者:Kovuru Gopalaiah、Sankala Naga Chandrudu
DOI:10.1039/c4ra12490a
日期:——
An iron(II) bromide-catalyzed oxidativecoupling of benzylamines with 2-amino/hydroxy/mercapto-anilines has been developed, allowing the synthesis of a diversity of substituted 1,3-benzazoles in good to excellent yields. This transformation is compatible with a wide range of functional groups. The method is practical, economical and employs molecular oxygen as an oxidant.
We show that N3-MEM-protected imidazo[4,5-b]pyridines undergo efficient C2-functionalisation via direct C–H arylation. Twenty-two substituted imidazo[4,5-b]pyridines are prepared and iterative, selective elaboration of functionalised imidazo[4,5-b]pyridines gives 2,7- and 2,6-disubstituted derivatives in good yields from common intermediates. Mechanistic observations are consistent with a concerted-metallation-deprotonation mechanism facilitated by coordination of copper(I)iodide to the imidazo[4,5-b]pyridine.
Eco-friendly and facile synthesis of 2-substituted-1H-imidazo[4,5-b]pyridine in aqueous medium by air oxidation
作者:Rajesh P. Kale、Mohammad U. Shaikh、Ganesh R. Jadhav、Charansingh H. Gill
DOI:10.1016/j.tetlet.2008.12.104
日期:2009.4
a new environmentally-benign, convenient, and facile methodology for the synthesis of 2-substituted-1H-imidazo[4,5-b]pyridine. The reaction of 2,3-diaminopyridine with substituted arylaldehydes in water under thermal conditions without the use of any oxidative reagent has been studied. The reaction has yielded 1H-imidazo[4,5-b]pyridine derivatives by an air oxidative cyclocondensation reaction in
我们报告了一种新的环境友好,方便,简便的方法合成2-取代-1 H-咪唑并[4,5- b ]吡啶。研究了2,3-二氨基吡啶与取代的芳基醛在水中在热条件下不使用任何氧化剂的反应。反应产生1 H-咪唑并[4,5- b吡啶衍生物通过空气氧化环缩合反应一步一步即可获得极佳的收率。此外,合成了一系列化合物,并通过熔点,EI-MS,NMR和IR工具对其进行了表征。为了比较,参考样品通过报道的方法制备。从经济和环境的角度来看,利用水性介质,容易的反应条件,分离和纯化使这种操作非常有趣。
Direct synthesis of benzimidazoles by Pd(II) N^N^S-pincer type complexes via acceptorless dehydrogenative coupling of alcohols with diamines
作者:Pennamuthiriyan Anandaraj、Rengan Ramesh、Jan Grzegorz Malecki
DOI:10.1016/j.jorganchem.2022.122577
日期:2023.2
geometry of the synthesized complexes 1 and 2 was confirmed by single-crystal X-ray diffraction study. A wide range of benzimidazole derivatives (32 examples) up to 94% isolated yield has been derived via acceptorlessdehydrogenative coupling of primary alcohols with derivatives of o-phenylenediamines. The present protocol operates smoothly with only 1 mol% catalyst loading. Furthermore, the mechanistic