36755-97-2Relevant academic research and scientific papers
Steric effects of aryl aldehydes on a multicomponent one-pot synthesis of imidazoles
Li, Ruohan,Xiao, Shuzhang,Zhang, Meng,Nie, Zhaomin,Xiao, Rong,Hu, Longhai
, p. 557 - 559 (2012)
The one-pot reaction of an aryl aldehyde with 2-cyanopyridine and ammonium acetate in refluxing acetic acid produced the known 2-(2′-pyridyl) imidazole and fused imidazoles. This suggests that the steric effect of aryl rings plays an important role in these syntheses. A possible mechanism of the reaction is discussed.
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.
Simple practical method for synthesis of trisubstituted imidazoles: an efficient copper catalyzed multicomponent reaction
Kadu, Vikas D.,Khadul, Siddheshwar P.,Kothe, Gokul J.,Mali, Ganesh A.
, p. 21955 - 21963 (2021/07/02)
A rapid practical process has been developed for synthesis of 2,4,5-trisubstituted-imidazoles in excellent yields up to 95% from readily available starting materials. In this CuI catalyzed synthesis, trisubstituted imidazoles were afforded in short reaction times, wherein the substrate scope is well explored with benzoin as well as benzil reacting with different aldehydes in the presence of ammonium acetate as the nitrogen source.
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.
One-Pot Three-Component Synthesis of 2,4,5-Triaryl-1H-imidazoles Using Mn2+Complex of [7-Hydroxy-4-methyl-8-coumarinyl] Glycine as a Heterogeneous Catalyst
Aberi, Mahdi,Razavi, Seyyede Faeze,Sharghi, Hashem
, (2021/08/16)
A highly efficient and simple synthesis of 2,4,5-trisubstituted imidazoles has been developed using highly reusable support‐free Mn2+complex of [7-hydroxy-4-methyl-8-coumarinyl] glycine as a heterogeneous catalyst via a one-pot three-component reaction of benzil, aldehydes and ammonium acetate as a nitrogen source. Moreover, this catalyst was characterized by various techniques such as field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX), FT-IR spectroscopy, powder X-ray diffraction (XRD), inductively coupled plasma (ICP) and thermal gravimetric analysis (TGA). Also, the catalyst is stable and could be reused for at least six times without significant loss of activity. Graphic Abstract: [Figure not available: see fulltext.]
A mechanistic study of carbonyl activation under solvent-free conditions: Evidence drawn from the synthesis of imidazoles
Pradhan, Kiran,Tiwary, Bipransh Kumar,Hossain, Mossaraf,Chakraborty, Ranadhir,Nanda, Ashis Kumar
, p. 10743 - 10749 (2016/02/05)
Syntheses of various imidazoles and their derivatives, imidazole N-oxides and 1-hydroxyimidazole 3-oxides, from sterically different dicarbonyl moieties provided insights into the self-catalytic effect of the condensed phase reactions of carbonyl compounds. The self-catalytic activity in solvent-free multi-component syntheses was investigated using a combination of methods viz., reactivity, spectroscopy and theory. While IR spectroscopic studies revealed that reacting molecules were polarised in bulk, quantum mechanical calculations of associated HCHO monomers suggest an increase in the average dipole moment of each monomer and provide evidence for the presence of cooperative effects. A comparative study of the kinetics of un-catalysed and catalysed reactions with the help of HPLC provided insights into the mechanism.
Synthesis, structures and photophysical properties of boron-fluorine derivatives based on pyridine/1,8-naphthyridine
Li, Zhensheng,Lv, Xiaojun,Chen, Yong,Fu, Wen-Fu
, p. 157 - 162 (2014/03/21)
Three boron-fluorine complexes B1-B3 containing pyridine/1,8-naphthyridine were synthesized and structurally characterized. Compounds B1 and B2 exhibited strong fluorescence in solution and solid state. The solvent-dependent luminous properties and large
Rapid access of some trisubstituted imidazoles from benzil condensed with aldehydes and ammonium acetate catalyzed by L-cysteine
Roy,Rahman,Pramanick
, p. 153 - 159 (2013/02/25)
A simple highly versatile and efficient synthesis of 2,4,5- trisubstituted imidazole is achieved by three component cyclocondensation of benzil, substituted aromatic aldehyde and ammonium acetate by L-cysteine as organocatalyst under solvent free condition. The key advantages of this process are high yields, cost effectiveness catalyst, easy purification technique and above all environmentally benign.
One-pot synthesis of 2,4,5-trisubstituted imidazoles catalyzed by lipase
Zheng, Hui,Shi, Qiao Yue,Du, Kui,Mei, Yi Jia,Zhang, Peng Fei
, p. 118 - 121 (2013/03/28)
A simple and efficient protocol of synthesizing 2,4,5-trisubstituted imidazoles has been developed using lipase as a novel catalyst under mild conditions. A series of imidazole derivatives were synthesized with good yields. The probable enzymatic mechanism was proposed. This method expands the catalytic scope of lipase and provides a novel method to prepare imidazole derivatives. Graphical Abstract: [Figure not available: see fulltext.]
Catalytic procedures for multicomponent synthesis of imidazoles: Selectivity control during the competitive formation of tri- and tetrasubstituted imidazoles
Kumar, Dinesh,Kommi, Damodara N.,Bollineni, Narendra,Patel, Alpesh R.,Chakraborti, Asit K.
experimental part, p. 2038 - 2049 (2012/08/27)
The catalytic potential of different fluoroboric acid-derived catalyst systems viz. aq HBF4, solid supported HBF4, metal tetrafluoroborates (inorganic salts), solid supported metal tetrafluoroborates, and tetrafluoroborate based ionic liquids (organic salts) were investigated for the three component reaction (3-MCR) of 1,2-diketone, aldehyde, and ammonium salts to form 2,4,5-trisubstituted imidazoles and the four component reaction (4-MCR) involving 1,2-diketone, aldehyde, amine and ammonium acetate to form 1,2,4,5-tetrasubstituted imidazoles. The HBF4-SiO2 was found to be the stand out catalyst for both the 3-MCR and 4-MCR processes. The next most effective catalysts are LiBF4 and Zn(BF4) 2 to form 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles via the 3-MCR and 4-MCR, respectively. This is the first report on the unaddressed issue of competitive formation of 2,4,5-trisubstituted imidazole during the 4-MCR involving 1,2-diketone, aldehyde, amine and ammonium acetate and highlights the influence of the catalyst systems in controlling the selective formation of tetra substituted imidazole. The metal salt of weak protic acids drive selectivity towards tetra substituted imidazole in the order tetrafluoroborates > perchlorates > triflates. The catalytic potency of tetrafluoroborates was in the order Zn(BF4)2 > Co(BF4)2 > AgBF4 ≈ Fe(BF 4)2 > NaBF4 ≈ LiBF4 ≈ Cu(BF4)2. The developed protocols worked well for different diketones, various aryl, heteroaryl, and alkyl aldehydes and in the case of the preparation of 1,2,4,5-tetrasubstituted imidazoles different amines can be used. The effectiveness of different ammonium salts as nitrogen source has been investigated and ammonium acetate is proved to be the best. The HBF4-SiO2 is recyclable for five consecutive uses without significant loss of catalytic activity. The Royal Society of Chemistry 2012.
