Highly efficient and metal-free synthesis of tri- and tetrasubstituted imidazole catalyzed by 3-picolinic acid

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.…”

An efficient and eco-compatible multicomponent synthesis of 2,4,5-trisubstituted imidazole derivatives using modified-silica-coated cobalt ferrite nanoparticles with tungstic acid

“…[6][7][8][9][10][11][12][13][14] The only industrial attention for the imidazole derivative construction is Debus-Radziszewski synthesis 15 via the one-pot multicomponent cyclocondensation reaction of diverse aldehydes/1,2-diketones, α-hydroxyketone/ammonium salt using classical heating/ultrasonication/microwave method accompanied with strong protic acids or Brønsted and Lewis acid catalysts. 9,16 In the last few years, many studies have been conducted to synthesize the 2,4,5-trisubstituted imidazoles with the same syn-thetic strategy by applying various practical catalysts, for example, LADES@MNP, 17 3-picolinic acid, 18 NiFe 2 O 4 /geopolymer, 19 Cu 2 O/Fe 3 O 4 @guarana, 20 (CTA) 3 PMo-MMT, 21 L-proline, 22 and Fe 3 O 4 @PVA-SO 3 H. 23 Some of the reported methods have one or more disadvantages, including long reaction times, harmful organic solvents, large volumes of catalysts, and the difficulty of removing catalysts from the reaction media. There has been an attempt to follow the green chemistry principles to avoid the drawbacks of repetition in the synthesis of antimicrobial and antibacterial active 2,4,5-trisubstituted imidazole derivatives.…”

Magnetic polyborate nanoparticles as a green and efficient catalyst for one-pot four-component synthesis of highly substituted imidazole derivatives

“…Following this goal, many catalytic systems have been investigated to facilitate the progress of organic reactions and be used in both ne and bulk chemicals production. [1][2][3][4][5][6][7][8][9][10][11] Among all of these, magnetic nanoparticles (MNPs) have attracted lots of attention by providing promising properties as supports for different catalytic systems due to their appropriate surface area and magnetic properties. The magnetic feature of such catalysts facilitates their separation from the mixture aer its completion.…”

“…[72][73][74][75] Different homogeneous or heterogeneous catalytic systems have been deployed for the multi-component synthesis of substituted imidazoles including ZSM-11 or HY zeolite, dimethylpyridinium trinitromethanide, 3-picolinic acid, silica sulfuric acid, ZrO 2 -Al 2 O 3, ZrO 2 -b-cyclodextrin, nano-Al-MCM-41, triethylammonium acetate as an ionic liquid, I 2 , Keggintype hetero polyacids, chitosan-coated Fe 3 O 4 nanoparticles, Fe 3 O 4 -PEG-Cu, Boehmite nanoparticles, silica chloride, 2,6pyromellitic diamide-diacid bridged mesoporous organosilica nanospheres, (N 2 H 5 ) 2 SiF 6 and Fe 3 O 4 /SiO 2 decorated trimesic acid-melamine. 6,40,[76][77][78][79][80][81][82] Despite of their merits, there are also some disadvantages associated with these and similar procedures. These disadvantages include the use of hazardous or expensive reagents, low stability or recyclability of the catalysts as well as yields of desired products, pollution generated during the catalyst preparation, long reaction times and difficult work-up steps.…”

“…Following this goal, many catalytic systems have been investigated to facilitate the progress of organic reactions and be used in both fine and bulk chemicals production. 1–11…”