484-47-9Relevant academic research and scientific papers
The one-pot synthesis of 2,4,5-triaryl-imidazoles using heteropolyacids as heterogeneous and recyclable catalysts
Heravi, Majid M.,Sadjadi, Samaheh,Oskooie, Hossein A.,Hekmatshoar, Rahim,Bamoharram, Fatemeh F.
, p. 1199 - 1203 (2008)
2,4,5-triaryl imidazoles were obtained in high yields with excellent purity from the condensation of benzaldehydes, NH4OAc and 1,2-diketone in the presence of a catalytic amount of various heteropolyacids (HPAs).
Bistability in an Isothermal Photochemical System. The Triphenylimidazolyl Radical Dimer in a CSTR
Lavabre, D.,Levy, G.,Laplante, J. P.,Micheau, J. C.
, p. 16 - 18 (1988)
Hysteresis and bistability were observed when a solution of triphenylimidazolyl radical dimer (TPID) is irradiated in a CSTR.The reactor is open to a flow of TPID and irradiated at 360 nm.The transition between the two stable states can be induced by changing either the flow rate or the incoming light flux.This bistability is believed to be the first experimental observation of a genuine chemical instability in an isothermal photochemical system.
Tentative mechanism for the bistability observed during irradiation of the triphenylimidazolyl radical dimer in a CSTR
Borderie,Lavabre,Levy,Micheau,Laplante
, p. 4105 - 4109 (1990)
We previously reported on the observation of a bistability when a chloroform solution of the triphenylimidazolyl radical dimer (TPID) is irradiated in a CSTR (continuous now stirred tank reactor) (J. Phys. Chem. 1988, 92, 16). In the present paper, the photochemistry of TPID in chloroform is examined in more detail and key reactions are summarized in a 6-step mechanism. Values of relevant kinetic parameters are determined and used in numerical simulations of the TPID/CHCl3 photochemistry in a CSTR. Multiple steady states are indeed observed when experimental values of the kinetic parameters arc used in the simulations. The bistability width and transition points are in good agreement with experimental results. It is suggested that the feedback mechanism responsible for the instability is of photometric origin. One of its key components is the screen effect that arises as the result of competitive absorption in multicomponent photochemical systems.
Laser flash photolysis study of triphenylimidazole
Testa
, p. 901 - 904 (2000)
Laser flash photolysis of the photocyclization of triphenylimidazole (TPI) in ethyl alcohol at 308 nm. indicates that the dihydrophenanthroimidazole (DHPI) intermediate is produced rapidly, has a lifetime of 0.25 ms, and returns predominantly back to triphenylimidazole. Analysis of the decay channels for this intermediate indicates two rate constants: (1) k1 = 3.3×103 s-1, associated with reversion back to triphenylimidazole and (2) k2 = 0.67×102 s-1 which is associated with the conversion of the dihydrophenanthroimidazole to the photoproduct, 2-phenyl-9,10-phenanthroimidazole. The photoproduct is readily observed as an increasing component in the biexponential fluorescence decay data. Fluorescence lifetimes for triphenylimidazole and 2-phenyl-9,10-phenanthroimidazole (PPI) in ethyl alcohol were determined to be 1.76 and 8.21 ns, respectively, with no additional components in the fluorescence decay as the photochemistry proceeds. An additional transient absorption observed in the 450 nm. region, with a lifetime of 0.7 μs, decaying faster than the dihydrophenanthroimidazole intermediate, is assigned to the triplet state of triphenylimidazole.
Magnetic horsetail plant ash (Fe3O4@HA): a novel, natural and highly efficient heterogeneous nanocatalyst for the green synthesis of 2,4,5-trisubstituted imidazoles
Hosseini Mohtasham, Nina,Gholizadeh, Mostafa
, p. 2507 - 2525 (2021/03/24)
Horsetail plant ash (HA), as a natural source of mesoporous silica, has been prepared from the exposure of horsetail plant (Equisetum Arvense) to high temperature. In the present study, a new magnetically separable and also recoverable Fe3O4 nanoparticles were synthesized in the presence of natural horsetail plant ash (HA) as a support to result in Fe3O4@HA. FT-IR, XRD, TEM, SEM–EDX and VSM analysis were combined to characterize the morphology and structure of this novel synthesized nanocatalyst. This magnetically solid acid nanocatalyst showed an excellent catalytic activity for the synthesis of 2,4,5-trisubstituted imidazoles at room temperature in aqueous media. The procedure led to corresponding products in high to excellent yields and appropriate times. Additionally, this nanocatalyst can be easily recovered by a magnetic field and reused for six other consecutive reaction runs without noticeable loss of its catalytic efficiency. Based on this study, Fe3O4@HA is found to be an efficient, magnetically separable, recyclable, and green catalyst with natural source. Graphic abstract: In this work, horsetail plant ash was used as a natural source of mesoporous silica for the synthesis of Fe3O4@HA as a highly powerful magnetically solid acid nanocatalyst, which was fully characterized using various techniques. The activity of the newly synthesized nanocatalyst was tested for the synthesis of 2,4,5-trisubstituted imidazole derivatives.[Figure not available: see fulltext.]
Homoselective synthesis of 5-substituted 1H-tetrazoles and one-pot synthesis of 2,4,5-trisubstuted imidazole compounds using BNPs@SiO2-TPPTSA as a stable and new reusable nanocatalyst
Khodamorady, Minoo,Ghobadi, Nazanin,Bahrami, Kiumars
, (2021/02/22)
Considering the importance of tetrazole and imidazole derivatives in pharmacy, industry, and explosives, BNPs@SiO2-TPPTSA was easily prepared and used as an effective, stable, and renewable nanocatalyst for the homoselective synthesis of different 5-substituted 1H-tetrazoles and atom economic synthesis of 2,4,5-trisubstituted-1H-imidazoles in solventless conditions. BNPs@SiO2-TPPTSA was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), thermal gravimetric-differential thermal analysis (TGA-DTA), mapping, pH analysis, and Fourier transform infrared (FT-IR) techniques. Furthermore, the catalyst recycled for at least sequential five loads without a remarkable drop-in catalytic activity.
Ultrasound-assisted synthesis of NiO nanoparticles and their catalytic application for the synthesis of trisubstituted imidazoles under solvent free conditions
Bhanage, Bhalchandra M.,Chaurasia, Shivkumar,Gajengi, Aravind L.,Monflier, Eric,Ponchel, Anne,Ternel, Jeremy
, (2021/11/12)
The present protocol reports the ultrasound assisted synthesis of NiO nanoparticles(NPs) using benzylamine as a base and different types of cyclodextrins (CDs) as capping agents. The use of α-CD, β-CD or γ-CD leads to different morphologies of NiO NPs. In particular, NiO nanosheets obtained using β-CD as the capping agent. The synthesized NPs were characterized by FEG-SEM, TEM, XRD and EDS analysis. They showed high catalytic activity towards synthesis of different trisubstituted imidazoles under solvent free conditions. In addition, NiO NPs could be recycled and reused consecutively up to four recycle runs without much loss of their catalytic activity.
TMSOTf-catalyzed synthesis of trisubstituted imidazoles using hexamethyldisilazane as a nitrogen source under neat and microwave irradiation conditions
Asressu, Kesatebrhan Haile,Chan, Chieh-Kai,Wang, Cheng-Chung
, p. 28061 - 28071 (2021/09/15)
In the process of drug discovery and development, an efficient and expedient synthetic method for imidazole-based small molecules from commercially available and cheap starting materials has great significance. Herein, we developed a TMSOTf-catalyzed synthesis of trisubstituted imidazoles through the reaction of 1,2-diketones and aldehydes using hexamethyldisilazane as a nitrogen source under microwave heating and solvent-free conditions. The chemical structures of representative trisubstituted imidazoles were confirmed using X-ray single-crystal diffraction analysis. This synthetic method has several advantages including the involvement of mild Lewis acid, being metal- and additive-free, wide substrate scope with good to excellent yields and short reaction time. Furthermore, we demonstrate the application of the methodology in the synthesis of biologically active imidazole-based drugs.
Fe3O4@THAM-Pd as a highly efficient magnetically recoverable nanocatalyst for facile one-pot assembly of substituted imidazoles under solvent-free conditions
Sanchooli Tazeh, Kazem,Heydari, Reza,Fatahpour, Maryam
, p. 1464 - 1472 (2021/09/18)
The current work has been explored an expeditious tactic toward one-pot multicomponent synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles using Fe3O4@THAM-Pd MNPs as an effective catalyst. With readily accessible benzil, ammonium acetate, anilines, and aromatic aldehydes as the simple starting materials, the condensation is run under solvent-free conditions to afford the target products in high yields. The other salient features of the present catalytic system are a simple work-up process, shorter reaction times, ease of preparation and handling of the catalyst, and cleaner reaction profiles. In addition, the sustainability of the methodology was checked by the investigation of the stability and reusability of the catalyst using an external magnet. The results showed that Fe3O4 @THAM-Pd MNPs can be reused for successive five runs without an appreciable decline in catalytic efficiency.
Catalytic conversion of 2,4,5-trisubstituted imidazole and 5-substituted 1H-tetrazole derivatives using a new series of half-sandwich (η6-p-cymene)Ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazone ligands
Vinoth, Govindasamy,Indira, Sekar,Bharathi, Madheswaran,Archana, Govindhasamy,Alves, Luis G.,Martins, Ana M.,Shanmuga Bharathi, Kuppannan
, (2020/11/16)
A new series of half-sandwich (η6-p-cymene) ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazide derivatives [Ru(η6-p-cymene)(Cl)(L)] [L = N'-(naphthalen-1-ylmethylene)thiophene-2-carbohydrazide (L1), N'-(anthracen-9-ylmethylene)thiophene-2-carbohydrazide (L2) and N'-(pyren-1-ylmethylene)thiophene-2-carbohydrazide (L3)] were synthesized. The ligand precursors and their Ru(II) complexes (1–3) were structurally characterized by spectral (IR, UV–Vis, NMR and mass spectrometry) and elemental analysis. The molecular structures of the ruthenium(II) complexes 1–3 were determined by single-crystal X-ray diffraction. All complexes were used as catalysts for the one-pot three-component syntheses of 2,4,5-trisubstitued imidazole and 5-substituted 1H-tetrazole derivatives. The catalytic studies optimized parameters as solvent, temperature and catalyst. The catalysts revealed very active for a broad range of aromatic aldehydes presenting either electron attractor or electron donor substituents and, although less active, moderate to high activities were observed for alkyl aldehydes.
