Simple practical method for synthesis of trisubstituted imidazoles: an efficient copper catalyzed multicomponent reaction

Abstract

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.

Zn(OAc)2•2H2O-catalyzed one-pot synthesis of divergently substituted Imidazoles

“…The product was refined either by recrystallizing in hot ethanol or by column chromatography on silica gel (60-120 Mesh, 20% EtOAc/Petroleum ether mixture) after the organic layer had been concentrated under vacuum. Through the use of FT-IR, 1 H-NMR, 13 C-NMR, and mass spectrum analysis, each product was sufficiently characterized and compared with literature data [20][21][22][23][24] The mixture of aromatic aldehyde (1 mmol), aromatic primary amine (1 mmol), benzil (1 mmol), ammonium acetate (1 mmol), and Zn(OAc)2•2H2O (5 mol %) under solvent-free conditions was taken in a 10 ml round bottom flask, heated to 70 °C, and kept there while being stirred for the appropriate amount of time. TLC was used to monitor the reaction's progress.…”

“…14 In photography, photosensitive imidazole compounds are employed. 15 Keeping in view of the importance of imidazole moiety, various synthetic methodologies are being developed as a continuous process for achieving better atom economy, eco-friendly and cost-effectiveness and several recent reviews [16][17][18][19] and research articles [20][21][22][23][24] have well documented the same. Toxic transition metal catalyst, protic acids, extended reaction durations, high temperatures, low to moderate yields, volatile organic solvents, and the majority of methods of production for tri and tetraarylimidzoles have above disadvantages.…”

Molecular Iodine Mediated Synthesis of 2,4,5-Trisubstituted Imidazoles Commencing from α-Methylene Ketones and Benzylic Primary Alcohols Using a One-Pot, Two-Step Approach

“…9 2,4,5-Trisubstituted imidazoles are generally synthesized by a three-component reaction using a 1,2-diketone, aldehyde, and ammonium acetate in the presence of transition metals or acidic media. 10,11 However, most of these synthetic methods suffer from serious drawbacks such as strongly acidic conditions, very high temperatures, and elaborate, multi-step procedures. 12,13 Hence, the development of new approaches that overcome these shortcomings is of vital importance.…”

Rapid One‐Pot Aerobic Oxidative N‐α‐C(sp3)‐H Functionalization of Arylmethylamines to Access Tetrasubstituted Imidazoles

“…Previously, we have demonstrated a simple practical method for trisubstituted imidazoles synthesis. [51] Recently, the synthesis of trisubstituted imidazole reported from benzylamines and aryl ketones/2-phenylacetaldehyde by using I 2 /TBHP, I 2 /HCl and HI-mediated electrochemical method. [52][53][54] In addition, the trisubstituted imidazole synthesis achieved from benzylamines with starting material like chalcones in presence of Cu(OTf) 2 /I 2 [55] and enamides in CuBr/I 2 catalytic system.…”

“…The different synthetic methods have been reported for preparation of trisubstituted imidazoles from isocyanides, nitriles, amino acids, imines, amides, and amidines substrates. Previously, we have demonstrated a simple practical method for trisubstituted imidazoles synthesis [51] . Recently, the synthesis of trisubstituted imidazole reported from benzylamines and aryl ketones/2‐phenylacetaldehyde by using I 2 /TBHP, I 2 /HCl and HI‐mediated electrochemical method [52–54] .…”