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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.

A kinetic study of the chemiluminescent (CL) reaction mechanism of lophine-derived hydroperoxides and silylperoxides induced by a base and fluoride, respectively, provided evidence for the formation of a 1,2-dioxetane as a high-energy intermediate (HEI) o

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Triphenylimidazole-based ampholytes with intramolecular charge transfer were designed with the introduction of carboxyl groups. In solution, the synergistic solvent and ionization effects on the ampholytes led to a unique pendulum-type fluorescence variation during the water content increasing process. Among them, 4-(4,5-bis(4-hydroxyphenyl)-1H-imidazol-2-yl)benzoic acid showed the most prominent three-step fluorescence switching property.

A simple, efficient and eco-friendly procedure has been developed using Cu(II) immobilized on guanidinated epibromohydrin-functionalized γ-Fe2O3@TiO2 (γ-Fe2O3@TiO2-EG-Cu(II)) for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles, via the condensation reactions of various aldehydes with benzil and ammonium acetate or ammonium acetate and amines, under solvent-free conditions. High-resolution transmission electron microscopy analysis of this catalyst clearly affirmed the formation of a γ-Fe2O3 core and a TiO2 shell, with mean sizes of about 10–20 and 5–10?nm, respectively. These data were in very good agreement with X-ray crystallographic measurements (13 and 7?nm). Moreover, magnetization measurements revealed that both γ-Fe2O3@TiO2 and γ-Fe2O3@TiO2-EG-Cu(II) had superparamagnetic behaviour with saturation magnetization of 23.79 and 22.12?emu g?1, respectively. γ-Fe2O3@TiO2-EG-Cu(II) was found to be a green and highly efficient nanocatalyst, which could be easily handled, recovered and reused several times without significant loss of its activity. The scope of the presented methodology is quite broad; a variety of aldehydes as well as amines have been shown to be viable substrates. A mechanism for the cyclocondensation reaction has also been proposed.

The present invention relates to a boronic acid-based compound and a preparation method thereof. More specifically, the present invention provides: a derivative containing boronic acid and imidazole obtained by substituting various functional groups during a synthesizing process of a boronic acid-based compound; and a preparation method of the derivative in high yield without using an oxidant.COPYRIGHT KIPO 2018

Catalytic one-pot condensation of benzil, aldehyde and ammonium acetate have been successfully carried out using 2-hydroxyethylammonium formate (HEAF) grafted on a magnetic nanoparticles as a new heterogeneous catalyst. The as-prepared catalyst was charac

An efficient and simple synthesis of 2,4,5-trisubstituted imidazoles is achieved by three-component cyclocondensation of benzil, aldehyde, and ammonium acetate by using nanosilica-supported imidazolium ionic liquid as a catalyst under solvent-free conditions. The key advantages of this process are high to excellent yields, short reaction time, easy work-up, and the reusability of the catalyst.

An efficient and eco-friendly synthesis of imidazoles, promoted by naturally occurring acids, via condensation of benzil, aldehyde and ammonium acetate using conventional and microwave heating under solvent-free condition is described. Reactions under mic

A cellulose/γ-Fe2O3/Ag nanocomposite is synthesized and used as a catalyst for the synthesis of trisubstituted imidazoles and α-aminonitriles. This catalytic protocol is simple, the reaction yield is very high, and the reaction time is very short. The remarkable magnetic properties of the nanocomposite permit easy separation of the catalyst from the reaction mixture without considerable loss of catalytic activity. In addition, antibacterial properties of the nanocomposite are investigated. For this purpose, S. aureus as the representative of Gram-positive bacteria and E. coli as the representative of Gram-negative bacteria are evaluated. To study the morphology and characterization of the prepared nanocomposite, X-ray diffraction patterns (XRD), energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscopy (FE-SEM), vibrating sample magnetometry (VSM) and thermal gravimetric analysis/differential thermal analysis (TGA/DTA) are obtained.

Isocyanurate bridging periodic mesoporous organosilica (PMO-ICS) was shown to be a highly active and efficient recyclable catalyst for the three-component synthesis of imidazole derivatives from benzoin, different aldehydes and ammonium acetate under mild reaction conditions in short reaction times and good to excellent yields in EtOH. Also, benzimidazole derivatives were efficiently prepared from o-phenylenediamine and different aldehydes in the presence of PMO-ICS. Moreover, the catalyst was also recovered and reused at least four times without a significant decrease in its activity. The PMO-ICS catalyst was characterized by Fourier transformer infrared (FTIR) spectroscopy, thermogravimetry analysis (TGA), powder X-ray diffraction (XRD) and nitrogen adsorption-desorption isotherm (NADI) techniques as well as field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Compared to the classical methodologies, this method illustrated significant advantages including low loading of the catalyst, avoiding the use of toxic transition metals or reactive reagents for modification of the catalytic activity, short reaction times, high to excellent yields, easy separation and purification of the products, and reusability of the catalyst.

In the present work, a green, rapid, convenient and eco-friendly method for the synthesis of 2,4,5-trisubstituted imidazoles is described. In this method, we used 1,2-diketone or α-hydroxy ketone, an aldehyde and ammonium acetate in the presence of graphene oxide-chitosan bionanocomposite, which acted as an efficient nanocatalyst. This protocol has many advantages such as short reaction time, high yield, easy separation of the catalyst and solvent-free condition. We used differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy (AFM) to confirm that the nanocomposite was formed, and FT-IR, 1H and 13C NMR analyses were performed for the confirmation of the synthesized products.

2,4,5-Triarylimidazoles were efficiently synthesized with excellent yields (90-96%) via the one-pot concentration of benzil, aromatic aldehyde and ammonium acetate in ionic liquid [BMIM][BF4] in the present of acetic acid. The luminescence-structure relationship of products was investigated.

In this paper, 23 multi-aryl imidazole derivatives were synthesized and identified by nuclear magnetic resonance, ultraviolet-visible and elemental analysis. At the same time, their ultraviolet-visible maximum absorption (λabmax), fluorescence emission maximum (λemmax) and quantum yields (Cyrillic capital letter eff) were measured. The relationships between the optical behaviors and structures for these compounds were assessed. The results show that the λmaxab and λmax em are red-shifted and the fluorescence Cyrillic capital letter eff are increased by the introduction of electron-withdrawing substituents and the increase in the planarity of multi-aryl imidazole molecules. The results also showed that the fluorescence quantum yields of the compounds containing two imidazole nuclei are double the corresponding mono-imidazole nucleus compounds. Copyright

2,4,5-Trisubstituted imidazoles have been synthesized by treatment of benzil with aldehydes and ammonium acetate in water under reflux in the presence of p-dodecylbenzenesulfonic acid as catalyst. The same reaction using an additional amine affords 1,2,4,

Benzotriazole is an efficient, readily available, and simple catalyst for the synthesis of 2,4,5-trisubstituted imidazoles in high yields from 1,2-diketones and aldehydes in the presence of NH4OAc via multi-components reaction. The significant features of this one-pot procedure are very simple operation, easy work-up and purification of products.

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.]

A novel organometallic catalyst (PSNP-CA) has been prepared by post synthesis grafting of COOH functionalized organosilane on porous silica nano particle by using surface hydroxyl groups as anchor point. It was characterized by using an array of sophisticated analytical techniques like 13C CP MAS NMR, 29Si MAS NMR, CHN analysis, BET, HR TEM, XRD, TGA, FTIR and pH measurement. The leaching of the active site is greatly avoided as the organic moieties are covalently attached to the inorganic support. This is the first example of organocatalysis promoted by a COOH functionalized porous silica nano particle for the chemoselective synthesis of densely substituted imidazoles. The molecular scaffolds which assimilate bio-active imidazole moiety may be worthwhile molecule from the biological point of view. All the other reported procedures led to the mixture of tri and tetra substituted imidazoles and their proportions were successfully evaluated from crude 1H NMR spectra. Greenness of the process was well instituted as water was exploited as reaction medium. This catalyst retained its activity after having it exposed to ambient atmosphere for 10 days. There was no deteriorating effect of aerial oxygen or moisture towards the activity of the catalyst.

Nanosized MCM-41-SO3H based on ordered mesoporous silica material with a covalent sulfonic acid group was synthesized and used as acid catalyst for the new, simple, convenient and green synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetra-substituted imidazoles. Also some of synthesis products are new. Echo-friendly protocol, short reaction times, easy and quick isolation of the products and excellent yields are the main advantages of this procedure.

A series of nine metal chloride hydrates (ZnCl2.2H2O, SnCl2.2H2O, CdCl2.2H2O, MnCl 2.4H2O, CoCl2.6H2O, SrCl 2.6H2O, NiCl2.6H2O, CrCl 3.6H2O and CeCl3.7H2O) was investigated as mild and inexpensive Lewis acid catalysts to promote the multicomponent synthesis of triarylimidazoles. Reactions starting from benzil showed the best results when SnCl2.2H2O was used, while for benzoin as the starting material, CeCl3.7H2O was more efficient. All reactions were performed in EtOH as solvent. These catalysts were also successfully employed in the synthesis of triaryloxazoles.

One-pot, three-component condensation of benzil/benzoin, substituted aromatic aldehydes, and ammonium acetate in an ethanol-water (1:1, v/v) solvent system using sulfated tin oxide catalyst under reflux condition afforded corresponding 2,4,5-triaryl-1H-imidazoles in excellent yield. The remarkable advantages offered by this method include green and reusable catalyst, mild reaction conditions, fast reaction rate, and excellent yield of products. This novel methodology maintains atom economy and an environmentally friendly approach. Copyright Taylor & Francis Group, LLC.

Ammonium formate and silica gel have been found to be efficient reagent combination for an improved and very rapid one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles in excellent yields. Multicomponent condensation in the presence of solid support with operational simplicity, inexpensive reagents, high yield of products, tolerance of sensitive functionalities, use of non-hazardous and non-toxic reagents combination under solvent-less condition makes this synthetic protocol, an attractive one. Moreover, trisubstituted imidazole, 2-(4,5-diphenyl-1H-imidazol- 2-yl)-4-phenylazo-phenol or tetrasubstituted imidazole, 2-(4,5-diphenyl-1- thiazol-2-yl)-1H-imidazol-2-yl)-4-phenylazophenol have been found to be naked eye and colorimetric sensor for anions like F-, Cl-, CH3COO-, H2PO4- offering very high binding constant with F- ion (K = 1.39 × 10 4 M-1).

A series of 2,4,5-triarylimidazoles was synthesized from a new, highly efficient and green method. The reaction is performed in water, without the presence of any catalyst, and under microwave irradiation. This provides new opportunities for the rapid scr

Lophine (2,4,5-triphenylimidazole) derivatives were synthesized and their physicochemical properties were determined. Spectroscopic and fluorescence behavior of lophine derivatives in methanol at different pH and various solvents were presented. The observed spectroscopic features in the solution are determined by specific interactions of the NH hydrogen. These kinds of interactions are manifested both in the solid state and in solution. The crystal and molecular structures of lophine derivatives with different solvents of crystallization are presented and discussed. In all solvates the solvent molecules link host molecules through hydrogen bonds.

An efficient and green procedure for the synthesis of 2,4,5-trisubstituted imidazoles with various aldehydes using a catalytic amount of 1-methylimidazolium hydrogenesulfate as an active and low cost Broensted acidic room temperature ionic liquid has been developed. The ionic liquid was easily separated from the reaction mixture and was recycled five times without any loss in activity.

A simple, high-yielding synthesis of 2,4,5-trisubstituted imidazoles from 1,2-diketones and aldehydes in the presence of NH4OAc is described. Under microwave irradiation, alkyl-, aryl-, and heteroaryl-substituted imidazoles are formed in yields ranging from 80 to 99%. Short syntheses of lepidiline B and trifenagrel illustrate the utility of this approach.