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51-17-2Relevant academic research and scientific papers
Synthesis of a conformationally constrained analogue of BW A78U, an anticonvulsant adenine derivative
Desaubry, Laurent,Wermuth, Camille Georges,Bourguignon, Jean-Jacques
, p. 4249 - 4252 (1995)
The synthesis of a conformationally constrained analogue of the anticonvulsant BW A78U, a 9-benzyl-adenine derivative, has been devised, using silicon tetrachloride in a new cyclodehydration.
Synthesis, Structure, and Luminescent Property of One Zinc(II) Coordination Polymer Constructed from 1H-Benzoimidazole
Zhang, Shu Hua,Zhao, Ru Xia,Li, Gui,Zhang, Hai Yang,Li, He Ping
, p. 804 - 808 (2016)
A new metal-organic coordination polymer [Zn(bm)(AcO)]n (1), where Hbm is 1H-benzoimidazole), has been prepared and structurally characterized by IR, elemental analysis and single-crystal X-ray diffraction. Single-crystal X-ray analysis shows that it crystallizes in the monoclinic space group of P21/c with a = 10.8231(5) ?, b = 9.8329(4) ?, c = 8.8665(4) ?, β = 99.298(4)°, V = 931.20(7) ?3, and X = 4. The bm ligand bridges two adjacent Zn(II) with its two nitrogen atoms to form a one-dimensional chain, which further constructed 2D network through a bridge bidentate AcO- ligand. Furthermore, luminescent property of 1 was investigated.
UV monitoring of microwave-heated reactions - A feasibility study
Getvoldsen, Gareth S.,Elander, Nils,Stone-Elander, Sharon A.
, p. 2255 - 2260 (2002)
UV/Visible spectroscopy has been used to monitor the progress of the formation of benzimidazole from the reaction between 1,2-diaminobenzene and formic acid. The reaction was performed at three concentration levels, each becoming more dilute so that at the most dilute level direct UV monitoring from the reaction sample was possible. At each level the reaction was conducted by conventional and by microwave heating. The success of the microwave reaction at the most dilute levels encourages the construction of a microwave reactor/UV/Vis spectrometer hybrid instrument for the monitoring of this and other reactions.
Haloacetylated enol ethers. 13 [19]. Synthesis of N-[1-aryl(alkyl)-3- oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines and 2-trichloromethyl- 4-aryl-3H-1,5-benzodiazepines
Bonacorso, Helio Gauze,Bittencourt, Sandra R. T.,Wastowski, Arci D.,Wentz, Alexandre P.,Zanatta, Nilo,Martins, Marcos A. P.
, p. 45 - 48 (1999)
The synthesis and isolation of the intermediates N-[1-aryl(alkyl)-3- oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines 2a-f and the corresponding 2-trichloromethyl-4-aryl-3H-1,5-benzodiazepines 3c-g or benzimidazoles 4a-b derivatives obtained from the intramolecular cyclization of 2a-f or from direct cyclocondensation reaction of β-alkoxyvinyl trichloromethyl ketones 1a-g with o-phenylenediamine, is reported. Depending of the structure of the β-alkoxyvinyl trichloromethyl ketones or the N-[1- aryl(alkyl)-3-oxo-4,4,4-trichloro-buten-1-yl]-o-phenylenediamines and the reactions conditions, benzimidazoles or 3H-1,5-benzodiazepines were obtained.
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.
Sulfoxylate Anion Radical-Induced Aryl Radical Generation and Intramolecular Arylation for the Synthesis of Biarylsultams
Laha, Joydev K.,Gupta, Pankaj
supporting information, p. 4204 - 4214 (2022/03/16)
Aryl radical generation from the corresponding aryl halides using an electron donor and subsequent intramolecular cyclization with arenes could be an important advancement in contemporary biaryl synthesis. A green and practically useful synthetic protocol to access diverse six- and seven-membered biarylsultams especially with a free NH group including demonstration of a gram-scale synthesis is reported herein. The sulfoxylate anion radical (SO2-?), generated in situ from the reagents rongalite or sodium dithionite (Na2S2O4), was found to be the key single electron transfer agent forming aryl radicals from aryl halides, which upon intramolecular arylation gives biarylsultams with good to excellent yields. The approach features generation of aryl radicals that remained underexplored, use of a cheap and readily available industrial reagents, and transition metal-free, mild, and green reaction conditions.
Highly efficient one pot synthesis of benzimidazoles from 2-nitroaniline and PhSiH3 as reducing agent catalyzed by Pd/C as a heterogeneous catalyst
Phatake, Vishal V.,Bhanage, Bhalchandra M.
, (2021/03/15)
This work reports an efficient route for the synthesis of benzimidazole from o-nitroaniline in the presence of carbon dioxide atmosphere, PhSiH3 as a reducing agent catalyzed by Pd/C as a catalyst. Benzimidazoles have become the focus of organic chemists, as benzimidazole is an important intermediate in medicinal chemistry. We have developed more efficient route for the synthesis benzimidazole and various substituted benzimidazoles have been synthesized in good to excellent yield. The TBD (1,5,7-Triazabicyclo [4.4.0] dec-5-ene) is selected as a base as it promotes the CO2 insertion. Benzimidazoles were synthesized through reduction of nitro group followed by cyclization of amine using CO2 as a carbon source. Moreover, the Pd/C catalyst can be recycled up to five recycle run without significant changes in the yield of the product.
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.
CO2 improved synthesis of benzimidazole with the catalysis of a new calcium 4-amino-3-hydroxybenzoate
Gao, Ruo-Xuan,Gao, Yuan-Yuan,Han, Li-Min,Zhu, Ning
, p. 205 - 211 (2021/06/07)
In this paper, we explored the synthesis of benzimidazole by the reaction of DMF and o-phenylenediamine. In the process of catalyst screening, we found that 4-amino-3-hydroxybenzoic acid, benzoic acid, and benzene-1,3,5-tricarboxylic acid could catalyze the reaction. Moreover, the calcium 4-amino-3-hydroxybenzoate and CO2 could more effectively catalyze the reaction, the synergistic effect of CO2 and 4-amino-3-hydroxybenzoic acid calcium salt can increase the yield of benzimidazole from 28% to 94%.
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.
