6943-23-3Relevant articles and documents
Transition-Metal-Free Transfer Hydrogenative Cascade Reaction of Nitroarenes with Amines/Alcohols: Redox-Economical Access to Benzimidazoles
Gujjarappa, Raghuram,Kabi, Arup K.,Malakar, Chandi C.,Musib, Dulal,Roy, Anupam,Sahoo, Abhishek,Singh, Virender,Vodnala, Nagaraju
, p. 14597 - 14607 (2021/11/12)
This report describes an efficient transition-metal-free process toward the transfer hydrogenative cascade reaction between nitroarenes and amines or alcohols. The developed redox-economical approach was realized using a combination of KOtBu and Et3SiH as reagents, which allows the synthesis of benzimidazole derivatives via σ-bond metathesis. The reaction conditions hold well over a wide range of substrates embedded with diverse functional groups to deliver the desired products in good to excellent yields. The mechanistic proposal has been depicted on the basis of a series of control experiments, mass spectroscopic evidence which is well supported by density functional theory (DFT) calculations with a feasible energy profile.
Graphene oxide-catalyzed CSp3–H activation of methylarenes in aqueous medium: A unified metal-free access to amides and benzimidazoles
Dandia, Anshu,Mahawar, Dinesh Kumar,Sharma, Ruchi,Badgoti, Ranveer Singh,Rathore, Kuldeep S.,Parewa, Vijay
, (2019/09/12)
Graphene oxide (GO)-catalyzed selective synthesis of amides via CSp3–H activation of methylarenes and consequent C–N bond formation with anilines under aqueous medium has been described. Oxygen functionality allied with GO surface played a dual role both as acid catalyst and oxidizing agent to some extent. However, GO has a copious effect on the reaction, shown by a high TOF value with TBHP as co-oxidant. The decisive role of carboxylic acid functional groups on GO nanosheets in this metal-free strategy has been confirmed and was monitored by various analytic techniques viz. Fourier transform-infrared, UV–Vis, Raman and XPS. A plausible mechanism was proposed by control experiments and by the isolation of the intermediate. Over-oxidation of methylarenes was not detected, and high recyclability of the carbocatalyst with its heterogeneous behavior facilitated the isolation and purification of the desired products. We have further explored the utility of this process for the chemoselective synthesis of benzimidazoles.
Efficient one-pot synthesis of 2-substituted benzimidazoles from triacyloxyborane intermediates
Cui, Wenge,Kargbo, Robert B.,Sajjadi-Hashemi, Zohreh,Ahmed, Feryan,Gauuan, Jolicia F.
experimental part, p. 247 - 250 (2012/02/15)
An efficient one-pot synthesis of 2-substituted benzim?idazoles via triacyloxyborane intermediates is reported. The mild protocol is efficient and tolerant of acid-labile functional groups. Georg Thieme Verlag Stuttgart - New York.