85573-12-2Relevant academic research and scientific papers
1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates
Foss, Frank W.,Palacios, Philip M.,Pierce, Brad S.,Thapa, Pawan,Tran, Tam
, p. 1991 - 2009 (2020/03/13)
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl and dialkyl benzimidazole precursors. N,N′-Disubstituted-OPD substrates were significantly more reactive than their N,N-disubstituted isomers, which appears to be relative to their propensity for complexation and charge transfer with Fe3+. The reaction also converted N-monosubstituted OPD substrates to 2-substituted benzimidazoles; however, electron-poor substrates produce 1,2-disubstituted benzimidazoles by intermolecular imino-transfer. Kinetic, reagent, and spectroscopic (UV-vis and EPR) studies suggest a mechanism involving metal-substrate complexation, charge transfer, and aerobic turnover, involving high-valent Fe(IV) intermediates. Overall, comparative strategies for the relatively sustainable and efficient synthesis of 1,2-disubstituted benzimidazoles are demonstrated.
Facile Synthesis of 1,2-Disubstituted Benzimidazoles Usingp-Toluenesulfonic Acid through Grinding Method
Kathing, C.,Nongkhlaw, R.,Nongrum, R.,Singh, N. G.,World Star Rani, J.
, p. 1628 - 1634 (2020/10/22)
Abstract: An efficient synthetic method for the highly selective synthesis ofpharmacologically active 1,2-disubstituted benzimidazole derivatives fromo-phenylenediamine and various aromaticaldehydes catalyzed by p-toluenesulfonic acidthrough grinding unde
Synthesis and characterization of amino glucose-functionalized silica-coated NiFe2O4 nanoparticles: A heterogeneous, new and magnetically separable catalyst for the solvent-free synthesis of 2,4,5–trisubstituted imidazoles, benzo[d]imidazoles, benzo[d] oxazoles and azo-linked benzo[d]oxazoles
Fekri, Leila Zare,Nikpassand, Mohammad,Shariati, Shahab,Aghazadeh, Behnaz,Zarkeshvari, Reza,Norouz pour, Nahid
, p. 60 - 73 (2018/07/25)
Amino glucose-functionalized silica-coated NiFe2O4 nanoparticles (NiFe2O4@SiO2@amino glucose) were chemically synthesized and characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), vibrating sample magnetometer (VSM), Zetasizer and Fourier transform infrared spectroscopy (FT-IR) instruments. NiFe2O4@SiO2@amino glucose supply an environmentally friendly procedure for the synthesis of 2,4,5-trisubstituted imidazoles through one-pot multicomponent condensation of benzil or benzoin, ammonium acetate with aryl aldehydes and for the synthesis of benzoxazoles using condensation reaction of 2-aminophenol with aryl aldehydes under solvent free condition. In the other study, this synthesized magnetically reusable catalyst was introduced as a new avenue for the synthesis of benzo[d]imidazoles using the reaction between aryl aldehydes and 1,2-diaminobenzene. These compounds were obtained in high yields and short reaction times. The catalyst could be easily recovered and reused for five cycles with almost consistent activity. Synthesized compounds were characterized by their physical constant, comparison with authentic samples, FT-IR, 1H NMR, 13C NMR spectroscopy and elemental analysis.
Natural bio-surfactant for pseudomulticomponent synthesis of 2-aryl-1-aryl methyl-1H-benzimidazoles
Morbale, Smita T.,Shinde, Sachin K.,Damate, Shashikant A.,Deshmukh, Madhukar B.,Patil, Suresh S.
supporting information, p. 57 - 63 (2018/03/06)
Green chemistry emphasizes the development of environmentally benign chemical processes and technologies. Pseudo-multicomponent synthesis of 2-aryl-1-arylmethyl-1H-benzimidazoles using o-phenylenediamine and aromatic aldehydes is carried out by Br?nsted acid type bio-surfactant as a catalyst. The green features of this method include the use of biodegradable catalyst obtained from renewable resource i.e. Citrus Limonium extract as bio-surfactant type Br?nsted acid, which provides a micellar media for effective cyclocondensation. The critical micellar concentration (cmc) of biosurfactant was determined by conductivity method and visualized by light microscopy measurement. Identity of all pure compounds was ascertained on the basis of FT-IR, 1H NMR and 13C NMR spectroscopic techniques.
Mesoporous silica supported ytterbium as catalyst for synthesis of 1,2-disubstituted benzimidazoles and 2-substituted benzimidazoles
Samanta, Partha Kumar,Banerjee, Rumeli,Richards, Ryan M.,Biswas, Papu
, (2018/08/06)
The benzimidazole ring is an important pharmacophore in contemporary drug discovery. Thus, effort to identifying new compounds containing benzimidazole scaffolds have gained much attention in recent years. In the present study, MCM-41 type mesoporous silica with large pore (l-MSN) supported ytterbium was successfully prepared by wet impregnation method. Among rare earth metal salts, ytterbium triflate has already been widely investigated as a catalyst in organic synthesis but less toxic ytterbium oxide has yet to be explored. Relatively high abundance and low cost of ytterbium with respect to many catalytically active metals (e.g. Pd, Au, Ru, Ir, Pt) offer an opportunity to develop sustainable catalysts for organic conversions. The catalyst has been characterized by various techniques including nitrogen adsorption, FT-IR, TEM, SEM, EDX technique and elemental mapping. The obtained materials exhibit high surface area and a narrow distribution of mesoporosity. The catalytic performance of the Yb@l–MSNs was tested by synthesis of 1,2-disubstituted benzimidazoles and 2-substituted benzimidazoles through the coupling of aldehydes with o-phenylenediamine. The catalyst resulted in excellent yields in short reaction times and the reaction showed tolerance toward both electron-donating and electron-withdrawing functional groups at room temperature. A particularly interesting finding was the solvent selectivity of this reaction; namely, 1,2-disubstituted benzimidazoles generated as major product in water-ethanol, while the 2-substituted benzimidazoles was generated exclusively in non-polar solvents like toluene.
KIT-6 Mesoporous Silica-coated Magnetite Nanoparticles: A Highly Efficient and Easily Reusable Catalyst for the Synthesis of Benzo[d]imidazole Derivatives
Fekri, Leila Zare,Maleki, Roghayeh
, p. 1167 - 1171 (2017/03/27)
KIT-6 mesoporous silica-coated magnetite nanoparticles as highly ordered large-pore nanoparticles supply an environmentally friendly procedure for the synthesis of benzo[d]imidazoles through condensation of 1,2-diaminobenzene with aryl aldehydes. These co
1,4-Diazabicyclo [2.2.2] octanium diacetate: As an effective, new and reusable catalyst for the synthesis of benzo[d]imidazole
Fekri, Leila Zare,Nikpassand, Mohammad,Maleki, Roghayeh
, p. 77 - 81 (2016/07/19)
A general synthetic route to benzo[d]imidazoles has been developed using 1,4-diazabicyclo [2.2.2] octanium diacetate as a new bis ionic liquid under thermal and solvent free condition. The union of two fragments including one equivalent of various aldehydes and one equivalent of 1,2-phenylenediamine was accomplished by an efficient and convenient protocol enabling the synthesis of benzo[d]imidazoles in excellent yields. The major advantages of the present method are: less reaction times, high yields, and easy purification of the products, solvent-free conditions, environmental friendliness, and convenient operation.
Synergetic catalytic effect of ionic liquids and ZnO nanoparticles on the selective synthesis of 1,2-disubstituted benzimidazoles using a ball-milling technique
Sharma, Hemant,Kaur, Navneet,Singh, Narinder,Jang, Doo Ok
, p. 4263 - 4270 (2015/08/11)
A solvent-free selective green synthesis of 1,2-disubstituted benzimidazoles was developed using a ball-milling technique. Recyclable ionic liquid-coated ZnO-nanoparticles (ZnO-NPs, catalyst 5) were employed as a catalyst, which produced high yields, turn
Ultrasound promoted and SiO2/CCl3COOH mediated synthesis of 2-aryl-1-arylmethyl-1H-benzimidazole derivatives in aqueous media: An eco-friendly approach
Kumar, Brajesh,Smita, Kumari,Kumar, Brajendra,Cumbal, Luis
, p. 1831 - 1840 (2015/02/05)
Ultrasonic irradiation is an efficient and innocuous technique of reagent activation for synthesizing organic compounds. First one-pot synthesis of 2-aryl-1-arylmethyl-1H- benzimidazole derivatives from o- phenylenediamine and an aromatic aldehyde in the presence of silica gel supported trichloroacetic acid (SiTCA) was carried out with excellent yields at 50°C by sonication. This method provided several advantages such as green solvent, inexpensive catalyst, simple experimental methodology, shorter reaction time and higher yield.
A simple and efficient mechanochemical route for the synthesis of 2-aryl benzothiazoles and substituted benzimidazoles
Banerjee, Mainak,Chatterjee, Amrita,Kumar, Vikash,Bhutia, Zigmee T.,Khandare, Dipratn G.,Majik, Mahesh S.,Roy, Biswajit Gopal
, p. 39606 - 39611 (2014/11/07)
An efficient and versatile mechanochemical route to 2-aryl benzothiazoles and both 2-substituted and 1,2-disubstituted benzimidazole derivatives has been developed via a simple mortar-pestle grinding method. The mechanochemical agitation was found to be sufficient for smooth condensation between a variety of aromatic aldehydes and o-aminothiophenol/o-phenylenediamine followed by cyclization leading to the formation of the corresponding 1,3-benzazoles. The salient features of this new protocol are catalyst-free reaction, cleaner reaction profiles, absence of a work-up step, high yields, and short reaction times.
