55041-10-6

Upstream product

• 119-53-9 2-hydroxy-2-phenylacetophenone 
• 108-91-8 cyclohexylamine 
• 100-52-7 benzaldehyde 
• 134-81-6 benzil 
• 3376-25-8 N-benzylidenecyclohexylamine N-oxide 
• 16483-98-0 2,3-diphenyl-2H-azirine 

Relevant academic research and scientific papers

Ag–TiO2 nanocomposite-catalyzed one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles: a green and benign approach

Ag–TiO2 nanocomposite as an efficient catalyst was synthesized and characterized by AFM analysis. This nanocomposite acts as a heterogeneous and recyclable catalyst for the room temperature synthesis of 1,2,4,5-tetrasubstituted imidazoles from aldehydes, benzil, ammonium acetate and several anilines or aliphatic amines via one-pot four-component condensation reaction in H2O as a green solvent. Ag–TiO2 nanocomposite was simply recovered by filtration and was reused up to three times.

Acid-Catalyzed 1,3-Dipolar Cycloaddition of 2 H-Azirines with Nitrones: An Unexpected Access to 1,2,4,5-Tetrasubstituted Imidazoles

The first 1,3-dipolar cycloaddition of 2H-azirines with nitrones, a straightforward approach toward the regioselective synthesis of 1,2,4,5-tetrasubstituted imidazoles, is reported. This trifluoroacetic acid-catalyzed protocol tolerates a broad range of aliphatic and aromatic substrates, offering an efficient access to highly diverse, multisubstituted imidazoles in isolated yields up to 83% under mild conditions.

Tri(1-butyl-3-methylimidazolium) gadolinium hexachloride, ([bmim]3[GdCl6]), a magnetic ionic liquid as a green salt and reusable catalyst for the synthesis of tetrasubstituted imidazoles

The magnetic ionic liquid, tri(1-butyl-3-methylimidazolium) gadolinium hexachloride, ([bmim]3[GdCl6]), has been used as an efficient green catalyst for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles via the condensation of benzil, an aromatic aldehyde, aniline, and ammonium acetate. Good to excellent yield, mild reaction conditions, as well as ease of operation and work-up are some advantages of the protocol.

Catalytic procedures for multicomponent synthesis of imidazoles: Selectivity control during the competitive formation of tri- and tetrasubstituted imidazoles

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.

Synthesis of 1,2,4,5-tetrasubstituted imidazoles using silica-bonded propylpiperazine N-sulfamic acid as a recyclable solid acid catalyst

A simple and efficient procedure for the preparation of silica-bonded propylpiperazine-N-sulfamic acid (SBPPSA) by the reaction of 3-piperazine-N-propylsilica (3-PNPS) and chlorosulfonic acid in chloroform is described. Silica-bonded propylpiperazine-N-sulfamic acid is employed as a recyclable catalyst for the synthesis of highly substituted imidazoles from the reaction of benzil, aromatic aldehydes, ammonium acetate and amines under solvent-free conditions. The heterogeneous catalyst was recycled for five runs upon the reaction of benzil, 4-methylbenzaldehyde, benzylamine, and ammonium acetate without losing its catalytic activity.

A facile multicomponent synthesis of tetrasubstituted imidazoles using Fe3+-K10 catalyst under solvent-free microwave conditions

An efficient, microwave assisted, multi-component synthesis of 1,2,4,5-tetrasubstituted imidazoles has been achieved by the one-pot condensation of benzil, aromatic aldehyde, aliphatic/aromatic amine and ammonium acetate using Fe3+-K10 heterogeneous catalyst under solvent-free conditions. This approach offers a number of advantages such as excellent yield, solvent-free conditions, short reaction time, an eco-friendly and low loading catalyst, mild reaction temperature, and an easy work-up.

L-Proline triflate as an efficient and reusable catalyst for the one-pot synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles

L-Proline triflate has been used as an efficient catalyst for an improved and rapid one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles in good yields. The benefit of this approach is its operational simplicity and the catalyst can be easily recovered and reused without any loss of activity.

BF3·SiO2: an efficient reagent system for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles

Silica-supported boron trifluoride (BF3·SiO2) is an efficient, readily available and reusable catalyst for the synthesis of 1,2,4,5-tetrasubstituted imidazoles using benzil, an aromatic aldehyde and an amine in the presence of ammonium acetate. This one-pot procedure is very simple, affording good to excellent yields.

One-pot synthesis of tetra-substituted imidazoles on silica gel under microwave irradiation

A new procedure for synthesis of tetra-substituted imidazoles was developed. A series of imidazole derivatives including six new compounds were synthesized by this procedure via condensation of benzoin, aromatic aldehyde, amine and ammonium acetate in the presence of silica gel under solvent-free microwave irradiation.