Synthesis of 4,4’-(Arylmethylene)bis(1H-pyrazol-5-ols) Using Silica-bonded Ionic Liquid as Recyclable Catalyst

AN ECO-FRIENDLY ONE-POT SYNTHESIS OF 4,4'-(ARYLMETHYLENE)BIS(1H-PYRAZOL-5-OLS) USING [Et3NH][HSO4] AS A RECYCLABLE CATALYST

“…The results showed that reactions in solvents take more time and also the yields are low compared to the solvent-free conditions (Table 1, entries [13][14][15][16][17][18]. Water has been identified as an ideal solvent because it is abundant, inexpensive, non-flammable and environmentally benign 40,41 .…”

Design, characterization and application of silica-bonded imidazolium-sulfonic acid chloride as a novel, active and efficient nanostructured catalyst in the synthesis of hexahydroquinolines

“…In this work, in continuation of our previous studies on the preparation and applications of acidic ILs and solid salts in organic transformations [30][31][32][33][34][35][36][37][38][39][40][41][42], and also previous works on the synthesis of silica-bonded imidazolium compounds [43][44][45][46], we have synthesized silica-bonded imidazolium-sulfonic acid chloride (SBISAC) (Figure 1) in which SAFIS have been immobilized on silica gel, and characterized it by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG), scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX). Then, we have utilized SBISAC as a highly efficient, stable, reusable and heterogeneous nanocatalyst for the preparation of hexahydroquinolines at 50 °C under solvent-free conditions (Scheme 1).…”

Application of silica-bonded imidazolium-sulfonic acid chloride (SBISAC) as a heterogeneous nanocatalyst for the domino condensation of arylaldehydes with 2-naphthol and dimedone

“…According to the previous works on the synthesis of silica-bonded imidazolium compounds [36][37][38][39], initially, imidazole was reacted with (3-chloropropyl) trimethoxysilane under reflux conditions to afford I, which transformed to II as s white precipitate by releasing of one molecule of HCl. In the next step, II was reacted with silica in refluxed ethyl acetate to give III.…”