Amberlyst A-15: Reusable catalyst for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted-1H-imidazoles under MW irradiation

Abstract

One-pot multi-component condensation of benzyl, aldehydes, ammonium acetate and primary amines were used for synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted-1H -imidazole derivatives under MW radiation using amberlyst A-15 as a catalysts. This catalyst has several advantages (simple work-up, low cost and reusability).

A Facile and Green Approach for the One‐Pot Multicomponent Synthesis of 2,4,5‐Triaryl‐ and 1,2,4,5‐Tetraarylimidazoles by Using Zinc‐Proline Hybrid Material as a Catalyst

“…Similarly for the synthesis of 1,2,4,5‐tetraarylimidazole, benzil or benzoin (1mmol), appropriate aldehyde (1mmol), appropriate amine (1mmol) and ammonium acetate (1mmol) were taken in 10 ml of Water: ethanol (4:1) mixture and rest protocol is same. Unambiguously the structures of the products were established on the basis of their spectral analysis (IR, 1 H‐NMR, 13 C‐NMR data, LC‐MS data) ,,,…”

Current advances in the synthesis and biological potencies of tri- and tetra-substituted 1H-imidazoles

“…Inorganic or organic matrixsupported catalysts and nano catalysts (bioglycerol-based carbon catalysts) [102], nano-SnCl 4 ·SiO 2 [103], BF 3 -SiO 2 [104], HClO 4 -SiO 2 [105], NaHSO 4 /silica gel [106], silica sulfuric acid [107], NiCl 2 ·6H 2 O/Al 2 O 3 [108], HBF 4 -SiO 2 [109], Amberlyst A-15 [110], polymer-supported ZnCl 2 [111], SBA-15/TFE (SBA-15/2,2,2-trifluoroethanol) [112], SBA-Pr-SO 3 H [113], silica-supported tin oxide nanoparticles (SiO 2 :SnO 2 ) [114], ferric(III) nitrate supported on kieselguhr (Fe(NO 3 )3-Kie) [115], zeolite-supported reagents [116], nanocrystalline MgO [117], nano-crystalline sulfated zirconia [118], magnetic Fe 3 O 4 nanoparticles [119], heteropolyacids [120] organocatalysts, such as L-proline [121], DABCO [122], enzymes (e.g., Lipase [123], papain [124]), trichloromelamine [125]), p-toluene sulfonic acid [126], ammonium chloride (NH 4 Cl) [127], NaH 2 PO 4 [128], mercaptopropylsilica [129], sodium bisulfate [130], ceric ammonium nitrate [131], morpholinium hydrogen sulphate [132], diethyl ammonium hydrogen phosphate [133], sulfated tin oxide [134], urea/hydrogen peroxide [135], silicabound propylpiperazine N -sulfamic [136], tetrabutylammonium bromide (TBAB) [137], sodium bisulfate [128], potassium aluminum sulfate (alum) [138], l-cysteine …”

“…Thus, tetra-substituted imidazoles 213 were obtained via the four-component reaction of aldehydes, 1,2-diketones 100, amines, and ammonium acetate. A simple and green protocol (Scheme 52) via the reaction of benzyl, aldehydes, ammonium acetate, and primary amines in the presence of Amberlyst A-15 has been reported [110].…”

“…Several catalyzed reactions were published for the synthesis of 1,2,4,5-tetra-substituted imidazoles using catalysts such as Y(NO 3 [100], bioglycerol-based recyclable carbon catalyst [102], Amberlyst A-15 [110], SBA-15/TFE (SBA-15/2,2,2-trifluoroethanol) [112], SBA-Pr-SO 3 H [113], silicasupported tin oxide nanoparticles [114], magnetic Fe 3 O 4 nanoparticles [119], L-proline [121], p-toluene sulfonic acid (PTSA) [126], solvent-free conditions with sodium dihydrogen phosphate [128], microwave irradiation [141][142][143], FeCl 3 ·6H 2 O [178], fluoroboric acid adsorbed on silica-gel (HBF 4 -SiO 2 ) [179], NHC (N -Heterocyclic Carbene) [180], trifluoroacetic acid [181], a novel organometallic catalyst (PSNP-CA) [182], MCM-41 [183], nano-TiCl 4 ·SiO 2 [184], and clay-supported titanium catalyst [185]. Highly substituted imidazole derivatives can be created using a new four-component and three-step reaction from alkoxyallenes, amines, iodine and nitriles with excellent yields.…”

One-Pot Synthesis of 2,4,5-Triphenyl Imidazoles from 1,2-Diols as Key Reagents

“…The most important of these are (1) one‐pot cyclocondensation of aldehydes with benzoin or benzil and ammonium acetate, (2) one‐pot cyclocondensation of aldehydes with benzil, aromatic amine, and ammonium acetate, and (3) one‐pot cyclocondensation of aromatic nitriles . This has led to the development of new, improved methodologies involving the use of a number of catalysts such as Yb(OPf) 3 , Cu(NO 3 ) 2 /zeolite, potassium dihydrogen phosphate, ZrOCl 2 .8H 2 O, Zr(acac) 4 , NiCl 2 .6H 2 O, p ‐toluenesulfonic acid (PTSA), TiCl 4 ‐SiO 2 , MCM‐41, ZrCl 4 , sodium bisulfite, polymer‐supported zinc chloride, alum, zinc oxide, trichloroisocyanuric acid, tetrabutyl ammonium bromide, ceric ammonium nitrate, nano copper/cobalt ferrites, microwave, amberlyst, novel polymers, antimony trichloride/stannous chloride dihydrate, SbCl 3 /SiO 2 , sulfamic acid/Fe 3 O 4 , and nano aluminum nitride . Although several methodologies have been documented, most of them have their own drawbacks such as poor yields, the use of toxic catalysts, and tedious work‐up.…”