Efficient Room‐Temperature Synthesis of Tri‐ and Tetrasubstituted Imidazoles Catalyzed by ZrCl₄

An Efficient Synthesis of 2,4,5-Triaryl-1H-Imidazole Derivatives Catalyzed by Boric Acid in Aqueous Media Under Ultrasound-Irradiation

“…In Table 3, we compared our result with result obtained by a reported procedure 9 for the synthesis of 2-(4-chlorophenyl)-4,5-diphenyl-1H-imidazole (compound 3c). The data presented in this table show the promising feature of this method in terms of reaction rate and the yield of product compared with that reported in the literature.…”

Environmentally Benign Synthesis of Tetra-Substituted Imidazoles through 4-Components Strategy Mediated by (<I>S</I>)-3-Methyl-1, 1-Diphenylbutane-1, 2-Diamine

“…A lot of synthetic routes are available in the literatures to synthesize imidazoles [11] analogues including annulations of amidines and β-keto esters [12], SBA-Pr-SO 3 H [13], nanocrystalline MgAl 2 O 4 [14], Cellulose/ɤ-Fe 2 O 3 /Ag [15], urea/hydrogen peroxide (UHP) [16], N-acetyl glycine (NAG) [17] [27], 2-cyanopyridine [28], p-TsOH [29], cellulose sulfuric acid [30], ceric (iv) ammonium nitrate (CAN) [31], boric acid [32], PEG-400 [33] [43], eutectic solvents [44], iodine [45], Yb(OTf) 3 [46], ZrCl 4 [47], AcOH [48], disubstituted alkynes [49] are noteworthy. However, almost all of these methods suffer from one or more constraints such as lower yield, harsh reaction conditions, tiresome isolation technique, uses of expensive toxic metal catalysts, limited examples etc.…”

Cellulose sulfuric acid as a bio-supported and recyclable solid acid catalyst for the one-pot synthesis of 2,4,5-triarylimidazoles under microwave irradiation

“…In this approach acetophenones are oxidized in situ to R-tosyloxyacetophenones, which then condense with arylamidines to obtain the desired compounds. Very recently, a literature survey reveals several methods for synthesis of 2,4,5-triarylimidazoles using ZrCl 4 (8), zeolite HY/silica gel (9), sodium bisulfite (NaHSO 3 ) (10), sulphanilic acid (11), iodine (12), and ionic liquids (13). However, many of these methodologies suffer from one or more disadvantages, such as low yields, high temperature requirement, prolonged reaction time, highly acidic conditions, requirement of excess of catalysts, and use of solvents.…”