A facile and practical one-pot synthesis of multisubstituted 2-aminothiophenes via imidazole-catalyzed Gewald reaction

Easy single-step preparation of ZnO nano-particles by sedimentation method and studying their catalytic performance in the synthesis of 2-aminothiophenes via Gewald reaction

“…ZnO nano-particles were prepared by sedimentation method and were used as catalyst in the reactions. All products were identified by comparison of their spectral and physical data with those previously reported [22][23][24][25][26][27]. Infrared spectra were recorded (KBr pellets) on a 8400 Shimadzu Fourier transform spectrophotometer.…”

“…A number of protocols have been announced for the synthesis of substituted 2-aminothiophenes [20][21][22][23][24]. However, most of these methods are generally unsuitable because they involve difficult preparation of the starting materials, multistep synthesis, and low yields.…”

“…However, most of these methods are generally unsuitable because they involve difficult preparation of the starting materials, multistep synthesis, and low yields. Although, the Gewald reaction represents the best way to the multi-component preparation of substituted 2-aminothiophenes, however, it needs specific expensive organic bases such as secondary or tertiary amines (diethylamine, morpholine, triethylamine, pyridine, and proline) [22] in stoichiometric amounts which produce wastes and increase production expenses because of corrosion and environmental impacts. Moreover, polar solvents like DMF, alcohols, and 1,4-dioxane is essential in the Gewald method for enhancing condensation of intermediates.…”

A facile and environmentally benign polyethylene glycol 600-mediated method for the synthesis of densely functionalized 2-aminothiophene derivatives under ultrasonication

“…Recently, some modifications to the Gewald reaction have been reported in the literature. For example, some basic compounds such as imidazole (28), Mg/La mixed oxide (29), silica-supported piperazine (30), bovine serum albumin (31), ZnO nano-particles (32), saturated NaHCO 3 solution in PEG 600 (13) and ionic liquids can be mentioned (33). Furthermore, techniques such as solid phase synthesis (34), microwave irradiation combined with insoluble polymer support (35) or soluble polymer support (36), and electrochemical activation (37) have also been reported.…”

Uses of Cyclohexan-1,4-dione for the Synthesis of 2-Amino-4,5-dihydrobenzo[<i>b</i>]thiophen-6(7<i>H</i>)-one Derivatives with Anti-proliferative and Pim-1 Kinase Activities

“…In recent drugs investigations, they acquired a particular importance due to the innovations in their synthesis (Gewald reaction), availability, stability, and structural simplicity that allow them to be important scaffolds in chemical and therapeutic products; like the top selling drugs olanzepine and tinoridine. [16][17][18] In addition, they present a large spectrum of biological properties that include antimicrobial, 19,20) anti-inflammatory, 21) anxiolytic, 22) antileishmanial, 23) anti-diabetes, 24) antifungal, 25) antioxidant 26) and antiplatelet activities. 27) The antitumor evaluation of the 2-aminothiophenes has already been addressed through different reports.…”