2751-83-9Relevant academic research and scientific papers
A pentanuclear Er (III) coordination cluster as a catalyst for selective synthesis of 1,2-disubstituted benzimidazoles
Sarkar, Arijit,Jana, Sourav,Nayek, Hari Pada
, (2021/02/22)
A new tridentate ligand (H3L) was prepared from the reaction of 6-formyl-2-(hydroxymethyl)-4-tert-butylphenol and 2-amino-4-nitrophenol. The ligand H3L and acetylacetone were treated with Er (NO3)3·5H2/sub
Water extract of onion catalyst: An economical green route for the synthesis of 2-substituted and 1,2-disubstituted benzimidazole derivatives with high selectivity
Kaliyan, Prabakaran,Selvaraj, Loganathan,Muthu, Seenivasa Perumal
supporting information, p. 340 - 349 (2020/12/01)
An efficient, environmental friendly and substrate controlled method of synthesis of 2-substituted benzimidazole derivatives 3 and 1,2-disubstituted benzimidazole derivatives 4 with high selectivity has been achieved from the reaction of o-phenylenediamine 1 and aldehydes 2 in the presence of water extract of onion and selecting suitable reaction medium. This method is widely applicable for variety of aldehydes such as aromatic/aliphatic/heterocyclic aldehydes and 1,2-diamines to afford 2-substituted benzimidazole derivatives 3 and 1,2-disubstituted benzimidazole derivatives 4 in good to excellent yields (up to 96%). The developed method of water extract of onion catalysis produced 2-substituted benzimidazoles 3 from aromatic aldehydes having electron-withdrawing groups, whereas aromatic aldehydes bearing electron donating groups selectively furnished 1,2-disubstituted benzimidazole 4 derivatives. The process described here has several advantages of cheap, low energy consumption, commercially available starting materials, operational simplicity and nontoxic catalyst. The use of water extract of onion makes this present methodology green and giving a useful contribution to the existing methods available for the preparation of benzimidazole derivatives. In addition, Hammett correlation of substituent constant (σ) vs percentage (%) yield has been established.
Ruthenium(II)-catalyzed synthesis of 2-arylbenzimidazole and 2-arylbenzothiazole in water
Singh, Keisham S.,Joy, Francis,Devi, Prabha
, p. 181 - 190 (2020/11/26)
Benzimidazoles/benzothiazoles are heterocyclic compounds which contain a five membered heteroatom and a benzene ring. They constitute a crucial structural unit of numerous bioactive compounds and natural products. Since the compounds containing benzimidaz
Tandem Photocatalysis Protocol for Hydrogen Generation/Olefin Hydrogenation Using Pd-g-C3N4-Imine/TiO2Nanoparticles
Jafarpour, Maasoumeh,Feizpour, Fahimeh,Rezaeifard, Abdolreza,Pourmorteza, Narges,Breit, Bernhard
supporting information, p. 9484 - 9495 (2021/07/19)
An unprecedented visible-light-driven photocatalytic system consisting of Pd nanoparticles stabilized on g-C3N4-imine-functionalized TiO2 nanoparticles was discovered for photoassisted hydrogen generation followed by olefin hydrogenation under mild conditions. The structural integrity of the as-synthesized photocatalyst was corroborated by Fourier transform infrared spectroscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-diffuse reflectance spectroscopy, Brunauer-Emmett-Teller measurements, and thermogravimetric analysis (TGA). Transmission electron microscopy and high-resolution scanning electron microscopy revealed the nanoscopic nature of the catalyst. The photocatalyst promoted several different transformations in a one-pot reaction sequence: hydrogen evolution through photocatalytic acceptorless formation of benzimidazoles as important therapeutic agents followed by visible-light-driven photocatalytic reduction of olefins with a high hydrogen utilization efficiency of up to 92% under mild conditions. A significant volume of H2 was produced under blue light-emitting diode (LED) irradiation during the selective formation of benzimidazole, while the selectivity reduced significantly under a Xe lamp or in the dark. The in situ-generated H2 could be activated by the as-prepared Pd-C3N4-imine/TiO2 photocatalyst to effectively hydrogenate olefins under mild conditions at appropriate time exposed to blue LED irradiation. The light-dependent photocatalytic performance of the title catalyst was assessed using action spectra by calculating the apparent quantum efficiency (AQE), which exhibited the maximum AQEs at 410 and 550 nm, at which the highest performance for styrene hydrogenation was obtained. The improved photoredox activity of the title nanohybrid could be caused by the synergistic effects of the heterojunction of carbon nitride-Pd on TiO2 nanoparticles evidenced by photoluminescence spectra and catalytic reactions. The catalyst proved to be air-stable, robust, recyclable, and very active in the absence of any undesirable additives and reducing agents. Thus, this work presents a new protocol for improving the photocatalytic properties of semiconducting materials for various photocatalytic applications under environmentally friendly conditions.
Electrochemical Synthesis of Benzo[ d]imidazole via Intramolecular C(sp3)-H Amination
Li, An,Li, Caohui,Li, Lijun,Liu, Yu,Tang, Kewen,Yang, Tao,Yang, Zan,Zhou, Congshan
, (2022/01/03)
An electrochemical dehydrogenative amination for the synthesis of benzimidazoles was developed. This electrosynthesis method could address the limitations of the C(sp3)-H intramolecular amination synthesis reaction and provide novel access to obtain 1,2-disubstituted benzimidazoles without transition metals and oxidants. Under undivided electrolytic conditions, various benzimidazole derivatives could be synthesized, exhibiting functional group tolerance.
Nickel catalyzed sustainable synthesis of benzazoles and purines: Via acceptorless dehydrogenative coupling and borrowing hydrogen approach
Chakraborty, Gargi,Guin, Amit Kumar,Mondal, Rakesh,Paul, Nanda
, p. 7217 - 7233 (2021/08/30)
Herein we report nickel-catalyzed sustainable synthesis of a few chosen five-membered fused nitrogen heterocycles such as benzimidazole, purine, benzothiazole, and benzoxazole via acceptorless dehydrogenative functionalization of alcohols. Using a bench stable, easy to prepare, and inexpensive Ni(ii)-catalyst, [Ni(MeTAA)] (1a), featuring a tetraaza macrocyclic ligand (tetramethyltetraaza[14]annulene (MeTAA)), a wide variety of polysubstituted benzimidazole, purine, benzothiazole, and benzoxazole derivatives were prepared via dehydrogenative coupling of alcohols with 1,2-diaminobenzene, 4,5-diaminopyrimidine, 2-aminothiphenol, and 2-aminophenol, respectively. A wide array of benzimidazoles were also prepared via a borrowing hydrogen approach involving alcohols as hydrogen donors and 2-nitroanilines as hydrogen acceptors. A few control experiments were performed to understand the reaction mechanism.
Nitroarenes as versatile building blocks for the synthesis of unsymmetrical urea derivatives and N-Arylmethyl-2-substituted benzimidazoles
Rodríguez-Huerto, Paula A.,Pe?a-Solórzano, Diana,Ochoa-Puentes, Cristian
, p. 6275 - 6283 (2021/07/29)
In this contribution, a fast and simple method for the synthesis of unsymmetrical urea derivatives and N-arylmethyl-2-substituted benzimidazoles was developed starting from nitroarenes. The reaction of nitroarenes and phenyl isocyanate or phenyl isothiocyanate in tin (II) chloride dihydrate/choline chloride eutectic mixture afforded the expected urea and thiourea derivatives, while the reaction of different aldehydes with o-nitroaniline or 4-methoxy-2-nitroaniline shows a markedly high preference for the obtention of N-arylmethyl-2-substituted benzimidazoles over the 2-substituted analogues. This method offers a straightforward alternative to obtain the target compounds in good to excellent yields with short reaction times employing an operationally simple experimental set-up. Graphic abstract: [Figure not available: see fulltext.] A series of unsymmetrical urea and thiourea derivatives together with 1,2-disubstituted benzimidazoles are easily obtained in good yields starting from nitroarenes employing the eutectic mixture tin (II) chloride dihydrate/choline chloride as reductive reaction media.
Heterogenizing a Homogeneous Nickel Catalyst Using Nanoconfined Strategy for Selective Synthesis of Mono- And 1,2-Disubstituted Benzimidazoles
Shadab,Dey, Gargi,Sk, Motahar,Banerjee, Debasis,Aijaz, Arshad
supporting information, p. 16042 - 16047 (2021/11/04)
A homogeneous Ni-phenanthroline catalyst was successfully immobilized into the cavities of a metal-organic framework, ZIF-8. The as-synthesized heterogeneous catalyst, Ni-Phen@ZIF, represents the first MOF based catalyst that enables dehydrogenative coupling of alcohols with aromatic diamines for selective synthesis of both mono- and 1,2-disubstituted benzimidazoles. The catalyst survived under harsh basic conditions, characterized by SEM, TEM, BET, PXRD, and EDX elemental mappings. The presence of the nanoconfined Ni-phenanthroline complex and the formation of extra Lewis acid sites during catalysis in the Ni-Phen@ZIF structure, confirmed by TPD analysis and kinetic experiments, might be responsible for higher activity and selectivity.
Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation
Godugu, Kumar,Gundala, Trivikram Reddy,Mohinuddin Pinjari, Mohammad Khaja,Reddy Nallagondu, Chinna Gangi,Sanapareddy, Lakshmi Reddy,Sri Yadala, Venkata Divya
supporting information, p. 1881 - 1900 (2020/10/02)
Natural dolomitic limestone (NDL) is employed as a heterogeneous green catalyst for the synthesis of medicinally valuable benzimidazoles, dihydropyrimidinones, and highly functionalized pyridines via C–N, C–C, and C–S bond formations in a mixture of ethan
Highly efficient chemoselective synthesis of 2-aryl-1-arylmethyl-1H-benzimidazoles by using TiCp2Cl2 catalyst
Halder, Samiran,Datta, Arup
, p. 1173 - 1178 (2021/02/09)
One pot highly efficient chemoselective N-arylmethyl benzimidazole has been prepared by using catalyst TiCp2Cl2 in tetrahydrofuran solvent smoothly. This method is very much effective for the condensation between different aldehydes
