2963-65-7Relevant academic research and scientific papers
AN EFFICIENT PREPARATION OF 4-ARYLMETHYLISOXAZOL-5-ONES BY SELECTIVE REDUCTION OF THE 4-ARYLMETHYLENEISOXAZOL-5-ONES
Risitano, Francesco,Grassi, Giovanni,Foti, Francesco
, p. 5893 - 5896 (1983)
An efficient selective reduction of the exocyclic double bond of the 4-arylmethyleneisoxazol-5-ones with o-phenylenediamines and aldehydes is described. 4-arylmethylisoxazol-5-ones are produced in high yields together with comparable quantities of benzimidazoles.
1-Methylimidazolium ionic liquid supported on Ni@zeolite-Y: fabrication and performance as a novel multi-functional nanocatalyst for one-pot synthesis of 2-aminothiazoles and 2-aryl benzimidazoles
Kalhor, Mehdi,Zarnegar, Zohre
, p. 519 - 540 (2021/12/03)
In the present study, 1-methyl-3-(3-trimethoxysilylpropyl)-1H-imidazol-3-ium chloride-supported Ni@zeolite-Y-based nanoporous materials (Ni@zeolite-Im-IL) were synthesized and their structures were confirmed using different characterization techniques such as FT-IR, FE-SEM, EDX, XRD, BET and TGA-DTG analyses. In order to synthesize this multi-functional nano-system, zeolite-NaY was modified first, with exchanged Ni2+ ions and 3-chloropropyltriethoxysilane (CPTES) as a coupling reagent and then functionalized to imidazolium chloride ionic liquid by N-methylimidazole. New multi-functional nano-material of Ni@zeolite-Im-IL demonstrated high activity in the catalytic synthesis of 2-aminothiazoles 3a–l by one-pot reaction of methylcarbonyls, thiourea and iodine at 80?°C in DMSO with good to excellent yields (85–98%). Also, the catalytic synthesis of 2-aryl benzimidazoles, 6a–m was performed by the condensational reaction of o-arylendiamine and aromatic aldehydes in EtOH at room temperature with excellent yields (90–98%). Advantages of this efficient synthetic strategy include higher purity and shorter reaction time, excellent yield, easy isolation of products, the good stability, activity and feasible reusability of the metallic ionic liquid nanocatalyst. These benefits have made this method more compatible with the principles of green chemistry. Graphical abstract: [Figure not available: see fulltext.]
One-Pot Transformation of Lignin and Lignin Model Compounds into Benzimidazoles
Guo, Tao,He, Jianghua,Liu, Tianwei,Zhang, Yuetao
, (2022/02/07)
It is a challenging task to simultaneously achieve selective depolymerization and valorization of lignin due to their complex structure and relatively stable bonds. We herein report an efficient depolymerization strategy that employs 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as oxidant/catalyst to selectively convert different oxidized lignin models to a wide variety of 2-phenylbenzimidazole-based compounds in up to 94 % yields, by reacting with o-phenylenediamines with varied substituents. This method could take full advantage of both Cβ and/or Cγ atom in lignin structure to furnish the desirable products instead of forming byproducts, thus exhibiting high atom economy. Furthermore, this strategy can effectively transform both the oxidized hardwood (birch) and softwood (pine) lignin into the corresponding degradation products in up to 45 wt% and 30 wt%, respectively. Through a “one-pot” process, we have successfully realized the oxidation/depolymerization/valorization of natural birch lignin at the same time and produced the benzimidazole derivatives in up to 67 wt% total yields.
Selective C-C bonds formation, N-alkylation and benzo[d]imidazoles synthesis by a recyclable zinc composite
Zhu, Guanxin,Duan, Zheng-Chao,Zhu, Haiyan,Ye, Dongdong,Wang, Dawei
supporting information, p. 266 - 270 (2021/08/06)
Earth abundant metals are much less expensive, promising, valuable metals and could be served as catalysts for the borrowing hydrogen reaction, dehydrogenation and heterocycles synthesis, instead of noble metals. The uniformly dispersed zinc composites were designed, synthesized and carefully characterized by means of XPS, EDS, TEM and XRD. The resulting zinc composite showed good catalytic activity for the N-alkylation of amines with amines, ketones with alcohols in water under base-free conditions, while unsaturated carbonyl compounds could also be synthesized by tuning the reaction conditions. Importantly, it was the first time to realize the synthesis of 2-aryl-1H-benzo[d]imidazole derivatives by using this zinc composite under green conditions. Meanwhile, this zinc catalyst could be easily recovered and reused for at least five times.
Preparation method of 2-substituted benzimidazole compound
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Paragraph 0079-0083, (2021/02/20)
The invention discloses a preparation method of a 2-substituted benzimidazole compound, and belongs to the field of synthesis of benzimidazole compounds. The 2-substituted benzimidazole compound is synthesized in an organic solvent by taking an o-nitroaniline compound, aromatic aldehyde, o-dinitrobenzene and aromatic aldehyde as raw materials and taking Co particles wrapped by a nitrogen-doped carbon material as a catalyst. According to the method, the 2-substituted benzimidazole compound can be prepared at room temperature, the reaction conditions are mild, the yield is as high as 95%, the selectivity is as high as 99%, and the method is economical, environmentally friendly and wide in substrate applicability. The used catalyst is easy to prepare, low in cost and good in reusability, canbe separated by utilizing magnetism, and is convenient to recover, so that the method has a relatively strong industrial application prospect.
Visible-Light Photoredox Catalyzed Double C-H Functionalization: Radical Cascade Cyclization of Ethers with Benzimidazole-Based Cyanamides
Jiang, Si,Tian, Xiao-Jing,Feng, Shu-Yao,Li, Jiang-Sheng,Li, Zhi-Wei,Lu, Cui-Hong,Li, Chao-Jun,Liu, Wei-Dong
supporting information, p. 692 - 696 (2021/02/01)
A visible-light photoredox catalyzed radical cascade cyclization of simple ethers with cyanamides is developed at room temperature. This strategy involves sequential inert Csp3-H/Csp2-H functionalizations through intermolecular addition reaction of oxyalkyl radicals to N-cyano groups followed by radical cyclization of iminyl radicals in situ generated with C-2 aryl rings. This method allows for efficient synthesis of tetracyclic benzo[4,5]imidazo[1,2-c]quinazolines. Importantly, this is the first example of an intermolecular-intramolecular radical cascade cyclization reaction of cyanamides.
Cobalt ferrite magnetic nanoparticles as highly efficient catalyst for the mechanochemical synthesis of 2-aryl benzimidazoles
Borade, Ravikumar M.,Jadhav, K. M.,Kale, Swati B.,Pawar, Rajendra P.,Tekale, Sunil U.
, (2021/08/27)
A highly efficient magnetically separable nano cobalt ferrite catalyst was synthesized via the sol-gel auto combustion method, characterized by powder XRD, SEM, TEM, UV–Visible, FT-IR, magnetic study, and BET isotherm analysis. The synthesized material was found to be an efficient heterogeneous Lewis acid catalyst for the synthesis of 2-aryl benzimidazole derivatives via solvent-free mechanochemical synthesis. The notable features of this new protocol include solvent-free reaction, cost-effectiveness, good yields, and environmental friendliness to afford the products within a short reaction time along with easy recovery and reuse of the nano catalyst.
Preparation method 2 -substituted benzimidazole derivative
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Paragraph 0083-0087, (2021/11/10)
The invention belongs to the field of fine chemical product production, and particularly relates to 2 -substituted benzimidazole derivative preparation method which comprises the following steps: (1) taking O-phenylenediamine and aldehyde as raw materials, carrying out catalytic condensation, cyclization and oxidation reaction in a eutectic solvent. (2) Water is added to the reaction system, the separated product is filtered, and the eutectic solvent is recycled. (3) After recrystallization, a target product is obtained. The method has the advantages of simple operation process, easily available raw materials, low cost, high purity of the target product and no catalyst participation, can effectively prevent isomer formation, and is beneficial to large-scale production.
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.
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.
