82326-53-2Relevant academic research and scientific papers
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.
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.
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.
K2S as Sulfur Source and DMSO as Carbon Source for the Synthesis of 2-Unsubstituted Benzothiazoles
Deng, Guobo,Kuang, Daizhi,Liang, Yun,Yang, Yuan,Yu, Jiangxi,Zhang, Fuxing,Zhu, Xiaoming
supporting information, p. 3789 - 3793 (2020/06/04)
We describe a three-component reaction of o-iodoanilines with K2S and DMSO that provides 2-unsubstituted benzothiazoles in moderate to good isolated yields with good functional group tolerance. Electron-rich aromatic amines and o-phenylenediamines instead of o-iodoanilines provided 2-unsubstituted benzothiazoles and 2-unsubstituted benzimidazoles with and without K2S under similar conditions. Notably, DMSO plays three vital roles: carbon source, solvent, and oxidant.
Synthesis method of ammonium acetate mediated benzimidazole compound
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Paragraph 0054-0056, (2020/11/23)
The invention discloses a synthesis method of a benzimidazole compound mediated by ammonium acetate. The synthesis method comprises the following steps: adding an o-phenylenediamine compound, dimethylsulfoxide, an additive 1 and an additive 2 into a reaction tube, carrying out a stirring reaction at 130-150 DEG C, cooling the reaction product to room temperature after the reaction is finished, and carrying out separation and purification on the product to obtain the benzimidazole compound. The invention develops a method for synthesizing a benzimidazole compound under the mediation of ammonium acetate by taking DMSO as a carbon source and an oxidant and an o-phenylenediamine compound as a substrate under the condition of no metal catalyst. The synthesis method does not need a metal catalyst, and the required carbon source and oxidant have the characteristics of low toxicity, low price, easiness in obtaining, stable performance and the like. The method has the advantages of easiness inoperation, few steps, mild reaction conditions, better functional group tolerance and the like, and provides a new valuable way for synthesizing benzimidazole compounds.
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.
Cobalt-catalyzed synthesis of N-containing heterocycles: Via cyclization of ortho -substituted anilines with CO2/H2
Ke, Zhengang,Yu, Bo,Wang, Huan,Xiang, Junfeng,Han, Juanjuan,Wu, Yunyan,Liu, Zhenghui,Yang, Peng,Liu, Zhimin
, p. 1695 - 1701 (2019/04/10)
The CO2-involved synthesis of chemicals is of great significance from the green and sustainable chemistry viewpoint. Herein, we report a non-noble metal catalytic system composed of CoF2, CsF and P(CH2CH2PPh2)3 (denoted as PP3) for the synthesis of N-containing heterocycles from ortho-substituted anilines and CO2/H2. Mechanism investigation indicates that [Co(PP3)H(CO2)]+ is a catalytically active intermediate under working conditions; and CsF plays important roles in activating ortho-substituted anilines via hydrogen bond interactions, thus promoting the formation of the final products. This catalytic system is highly efficient, and allows a wide scope of ortho-substituted anilines, together with excellent functional group tolerance, affording various N-containing heterocycles in good to excellent yields.
Atmospheric CO2 promoted synthesis of N-containing heterocycles over B(C6F5)3 catalyst
Gao, Xiang,Yu, Bo,Mei, Qingqing,Yang, Zhenzhen,Zhao, Yanfei,Zhang, Hongye,Hao, Leiduan,Liu, Zhimin
, p. 8282 - 8287 (2016/10/11)
B(C6F5)3 combined with atmospheric CO2 was found to be highly effective for the cyclization of ortho-substituted aniline derivatives with N,N-dimethylformamide (DMF), and a series of N-containing heterocycles including benzothiazoles, benzimidazoles, quinazolinone and benzoxazole were obtained in good to excellent yields.
Cyclization of o-phenylenediamines by CO2 in the presence of H2 for the synthesis of benzimidazoles
Yu, Bo,Zhang, Hongye,Zhao, Yanfei,Chen, Sha,Xu, Jilei,Huang, Changliang,Liu, Zhimin
supporting information, p. 95 - 99 (2013/02/25)
The cyclization of o-phenylenediamines by CO2 in the presence of H2 was presented to directly synthesize benzimidazoles, and a series of benzimidazoles were obtained in excellent yields using RuCl 2(dppe)2 as the catalyst.
