A facile strategy for the synthesis of highly substituted imidazole using tetrabutyl ammoniumbromide as catalyst

Abstract

A simple and facile strategy for the synthesis of highly substituted imidazoles has been developed by multi-component condensation of 1,2-diketone, aldehyde, amine, and ammonium acetate in presence of tetrabutyl ammonium bromide as catalyst.

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 …”

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.…”

One-pot synthesis of multisubstituted imidazoles catalyzed by Dendrimer-PWAn nanoparticles under solvent-free conditions and ultrasonic irradiation

“…Generally, trisubstituted imidazoles are synthesized by the condensation of 1,2-diketones, an aldehyde and ammonium acetate by using various catalysts such as: InCl 3 Á3H 2 O [6], Yb(OTf) 3 [7], TBAB [8], Fe 3 O 4 @SiO 2 -Imid-PMA n [9], Nanocrystalline MgAl 2 O 4 [10], Ferric(III) nitrate supported on kieselguhr [11], SBA-15/2,2,2-trifluoroethanol [12], and HOAc [13]. 1,2,4,5-tetrasubstituted imidazoles are synthesized by the condensation of 1,2-diketones, an aldehyde, ammonium acetate and primary amine in the presence of various catalysts such as silica gel or silica gel/NaHSO 4 [14], K 5 CoW 12 O 40 .3H 2 O [15], HY zeolite [16], Fe 3 O 4 @SiO 2 -Imid-PMA n [9], trifluoroethanol [12], HClO 4 -SiO 2 [17], heteropolyacids [18], FeCl 3 .6H 2 O [19], 1-Butyl-3-methylimidazolium bromide [20], trityl chloride [21], tetrabutyl ammonium bromide [22], alumina [23], 1,4-diazabicyclo [2,2,2]octane (DABCO) [24], nano-TiCl 4 ÁSiO 2 [25], PPA-SiO 2 [26], nanocrystalline sulfated zirconia (SZ) [27] and silica-bonded propylpiperazine N-sulfamic acid (SBPPSA) [28]. However, some of these synthetic methods have limitations such as harsh reaction conditions, use of hazardous chemicals with often expensive acid catalysts, complex working and purification procedures, long reaction times, and moderate yields.…”