4887-82-5Relevant academic research and scientific papers
Rhodium(I) N-Heterocyclic Carbene Bioorganometallics as in Vitro Antiproliferative Agents with Distinct Effects on Cellular Signaling
Oehninger, Luciano,Spreckelmeyer, Sarah,Holenya, Pavlo,Meier, Samuel M.,Can, Suzan,Alborzinia, Hamed,Schur, Julia,Keppler, Bernhard K.,W?lfl, Stefan,Ott, Ingo
, p. 9591 - 9600 (2015)
Organometallics with N-heterocyclic carbene (NHC) ligands have triggered major interest in inorganic medicinal chemistry. Complexes of the type Rh(I)(NHC)(COD)X (where X is Cl or I, COD is cyclooctadiene, and NHC is a dimethylbenzimidazolylidene) represent a promising type of new metallodrugs that have been explored by advanced biomedical methods only recently. In this work, we have synthesized and characterized several complexes of this type. As observed by mass spectrometry, these complexes remained stable over at least 3 h in aqueous solution, after which hydrolysis of the halido ligands occurred and release of the NHC ligand was evident. Effects against mitochondria and general cell tumor metabolism were noted at higher concentrations, whereas phosphorylation of HSP27, p38, ERK1/2, FAK, and p70S6K was induced substantially already at lower exposure levels. Regarding the antiproliferative activity in tumor cells, a clear preference for iodido over chlorido secondary ligands was noted, as well as effects of the substituents of the NHC ligand.
One-Pot Transformation of Lignin and Lignin Model Compounds into Benzimidazoles
Guo, Tao,He, Jianghua,Liu, Tianwei,Zhang, Yuetao
supporting information, (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.
Methanol as the C1source: Redox coupling of nitrobenzenes and alcohols for the synthesis of benzimidazoles
An, Jie,Lai, Zemin,Li, Hengzhao,Peng, Mengqi,Sun, Yanhao,Yan, Zihan,Yang, Ruoyan,Zhang, Yuntong
supporting information, p. 748 - 753 (2022/02/02)
We present an operationally simple redox coupling for the synthesis of N-1 substituted benzimidazoles using feedstock building block 2-nitroaniline derivatives as the precursors and methanol as the C1 source. Higher atom, step, and redox economies and exc
Sustainable Synthesis of 2-Hydroxymethylbenzimidazoles using D-Fructose as a C2 Synthon
Raja, Dineshkumar,Philips, Abigail,Sundaramurthy, Devikala,Chandru Senadi, Gopal
supporting information, p. 3754 - 3759 (2021/10/14)
D-fructose, a biomass-derived carbohydrate has been identified as an environmentally benign C2 synthon in the preparation of synthetically useful 2-hydroxymethylbenzimidazole derivatives by coupling with 1,2-phenylenediamines. Proof of concept was established by synthesizing 23 examples using BF3.OEt2 (20 mol%), TBHP (5.5 M, decane) (1.0 equiv.) in CH3CN at 90 °C for 1 h. The pivotal features of this method include metal-free conditions, short time, good functional group tolerance, gram scale feasibility and the synthesis of benzimidazole fused 1,4-oxazine. Control studies with conventional C2 synthons did not produce the desired product, thus suggesting a new reaction pathway from D-fructose.
Method for synthesizing benzimidazole from carbon dioxide and o-phenylenediamine compound
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Paragraph 0029-0032, (2021/06/06)
The invention discloses a method for synthesizing benzimidazole from carbon dioxide and an o-phenylenediamine compound, the method is characterized in that an amino-containing functionalized ordered mesoporous polymer is used as a catalyst, o-phenylenediamine and carbon dioxide are used as raw materials, dimethylaminoborane is used as a hydrogen reduction reagent, carbon dioxide and the o-phenylenediamine compound are catalyzed to react in an NMP solvent to generate a benzimidazole compound, wherein the dosage of a catalyst is 0.01-1mol% based on the nitrogen content of the o-phenylenediamine compound; the filling pressure of the carbon dioxide is 0.1-2MPa; the reaction temperature is 60-180DEG C; the molar ratio of the catalyst to the NMP is 1:50-100. Compared with the prior art, the catalyst has the advantages of simple preparation, high catalytic activity, capability of catalyzing the reaction of carbon dioxide and the o-phenylenediamine compound under mild conditions to generate benzimidazole and derivatives thereof, and the like.
A substituent- And temperature-controllable NHC-derived zwitterionic catalyst enables CO2upgrading for high-efficiency construction of formamides and benzimidazoles
Li, Hu,Li, Zhengyi,Wu, Hongguo,Yang, Song,Yu, Zhaozhuo,Zhang, Lilong,Zhu, Kaixun
supporting information, p. 5759 - 5765 (2021/08/23)
Chemocatalytic upgrading of the greenhouse gas CO2 to valuable chemicals and biofuels has attracted broad attention in recent years. Among the reported approaches, N-formylation of CO2 with an amine is of great significance due to its versatility in the construction of N-containing linear and cyclic skeletons. Herein, a stable N-heterocyclic carbene-carboxyl adduct (NHC-CO2) was facilely prepared and could be used as a recyclable zwitterionic catalyst for efficient CO2 reductive upgrading via either N-formylation or further coupling with cyclization under mild conditions (25 °C, 1 atm CO2) using hydrosilane as a hydrogen source. More than 30 different alkyl and aromatic amines could be transformed into the corresponding formamides or benzimidazoles with remarkable yields (74%-98%). The electronic effect of the introduced substituent on NHC-CO2 was found to evidently affect the thermostability and nucleophilicity of the zwitterionic catalyst, which is directly correlated with its catalytic activity. Moreover, NHC-CO2 could supply CO2 by in situ decarboxylation at a specific temperature that is dependent on the introduced substituent type. Experimental and computational studies showed that the carboxyl species on NHC-CO2 was not only a nucleophilic center, but also a C1 source which rapidly captures or substitutes ambient CO2 during hydrosilylation. In addition, a simple and green conceptual process was designed for the product purification and catalyst recycling, with a good feasibility for small-scale production.
Reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to synthesize 1H-benzoimidazole derivatives
Han, Limin,Hong, Hailong,Li, Xiao,Yang, Yue,Zhang, Junhua,Zhu, Ning
supporting information, (2021/09/28)
A simple and green protocol was developed for the reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to yield 1H-benzimidazole. The desired 1H-benzimidazole derivatives were produced under mild conditions. Mechanism investigation indicated that the coordination of o-phenylenediamine with the boron atom of BH3NH3 promoted the transfer of the formyl group to form a stable intermediate, which facilitated the intramolecular nucleophilic addition-elimination for the formation of target product. In this process, BH3NH3 served multifunctional roles, acting as a reducing agent and a formylation catalyst.
Metal-Free Synthesis of Benzimidazoles via Oxidative Cyclization of d -Glucose with o-Phenylenediamines in Water
Raja, Dineshkumar,Philips, Abigail,Palani, Pushbaraj,Lin, Wei-Yu,Devikala, Sundaramurthy,Senadi, Gopal Chandru
, p. 11531 - 11540 (2020/10/12)
d-Glucose has been identified as an efficient C1 synthon in the synthesis of benzimidazoles from o-phenylenediamines via an oxidative cyclization strategy. Isotopic studies with 13C6-d-glucose and D2O unambiguously confirmed the source of methine. The notable features of this method include the following: broad functional group tolerance, a biorenewable methine source, excellent reaction yields, a short reaction time, water as an environmentally benign solvent, and the synthesis of vitamin B12 component on the gram scale.
Visible-light-induced aerobic oxidative desulfurization of 2-mercaptobenzimidazolesviaa sulfinyl radical
Deng, Guo-Jun,Fu, Mei,Huang, Huawen,Ji, Xiaochen,Li, Yongtong
supporting information, p. 5594 - 5598 (2020/09/21)
A mild transition-metal-free non-toxic aerobic photoredox system was found to enable highly efficient desulfurization of 2-mercaptobenzimidazoles. This viable catalytic system includes Rose Bengal in a low catalyst loading as a photosensitizer and cheap, non-toxic NaCl in a catalytic amount as an additive, combined with an oxygen atmosphere. This protocol provides an important alternative access to a broad range of benzimidazole and deuterated benzimidazole products in generally high yields with good tolerance of various synthetically and pharmaceutically useful functionalities. The mechanistic studies reveal that both single electron transfer and energy transfer probably occur in the initial step and a sulfinyl radical intermediate is involved in the key desulfurization process.
Accelerated microdroplet synthesis of benzimidazoles by nucleophilic addition to protonated carboxylic acids
Basuri, Pallab,Gonzalez, L. Edwin,Morato, Nicolás M.,Pradeep, Thalappil,Cooks, R. Graham
, p. 12686 - 12694 (2020/12/29)
We report a metal-free novel route for the accelerated synthesis of benzimidazole and its derivatives in the ambient atmosphere. The synthetic procedure involves 1,2-aromatic diamines and alkyl or aryl carboxylic acids reacting in electrostatically charged microdroplets generated using a nano-electrospray (nESI) ion source. The reactions are accelerated by orders of magnitude in comparison to the bulk. No other acid, base or catalyst is used. Online analysis of the microdroplet accelerated reaction products is performed by mass spectrometry. We provide evidence for an acid catalyzed reaction mechanism based on identification of the intermediate arylamides. Their dehydration to give benzimidazoles occurs in a subsequent thermally enhanced step. It is suggested that the extraordinary acidity at the droplet surface allows the carboxylic acid to function as a C-centered electrophile. Comparisons of this methodology with data from thin film and bulk synthesis lead to the proposal of three key steps in the reaction: (i) formation of an unusual reagent (protonated carboxylic acid) because of the extraordinary conditions at the droplet interface, (ii) accelerated bimolecular reaction because of limited solvation at the interface and (iii) thermally assisted elimination of water. Eleven examples are shown as evidence of the scope of this chemistry. The accelerated synthesis has been scaled-up to establish the substituent-dependence and to isolate products for NMR characterization.
