Synthesis and application of a novel strong and stable supported ionic liquid catalyst with both Lewis and Brønsted acid sites

Recent Advances in the Synthesis of Biscoumarin Derivatives

“…With increasing amounts of AlCl 3 , the catalytic activity of P 4 VPy‐BuSO 3 H]Cl‐X(AlCl 3 ) improved. The catalyst had good efficiency after five recyclings (Scheme ) (Table , entry 34) …”

“…The catalyst had good efficiency after five recyclings (Scheme 10) ( Table 1, entry 34). 49 Nanocomposite oxides are extensively used as efficient catalysts because of good activation of the adsorbed compounds, reaction rate enhancement, selectivity, easy work-up, recyclability, and eco-friendly reaction conditions. CuO-CeO 2 nanocomposite was used as catalyst in the synthesis of biscoumarins in water under reflux condition in a short reaction time (8-60 min) in high yields.…”

Carbon Nanotube-Supported Butyl 1-Sulfonic Acid Groups as a Novel and Environmentally Compatible Catalyst for the Synthesis of 1,8-Dioxo-octahydroxanthenes

“…As can be seen in the spectrum of MWCNT-BuSO 3 H new peaks appeared at 1120, 1150, 1190, and 1230 cm -1 , which can be assigned to S=O stretching vibration. 25,26 The thermogravimetric analyses (TGA) of MWCNTs, before and after the functionalization processes, are provided in Figure 2. The TGA curves of MWCNT-OH and MWCNT-BuSO 3 H displayed a weight loss around 100 o C which is corresponding to the loss of the physically adsorbed water.…”

“…In a continuation of our recent work on synthesis and application of heterogeneous catalysts in organic reactions, [25][26][27][28] herein we now report the synthesis of multiwalled carbon nanotube-supported butyl 1-sulfonic acid groups (MWCNT-BuSO 3 H) from the reaction of the salt form hydroxyl functionalized multiwalled carbon nanotube (MWCNT-OH) with 1,4-butane sultone followed by the reaction with HCl. MWCNT-BuSO 3 H was used as a heterogeneous catalyst for one-pot Knoevenagel condensation, Michael addition, and cyclodehydration of dimedone with various aromatic aldehydes at room temperature (Scheme 1).…”

Introduction of W-doped ZnO nanocomposite as a new and efficient nanocatalyst for the synthesis of biscoumarins in water

“…In recent years and because of these important activities, several methods are reported for the synthesis of biscoumarins using a variety of catalysts and reagents [6][7][8][9][10][11][12][13][14]. These methods although useful but most of them suffer from disadvantages such as long reaction times (e.g., in the presence of piperidine [4], the reactions are performed during 3-4 h), unsatisfactory yields (e.g., when HBF 4 is used as the catalyst the products are obtained in 55-70 % yields [9] ), harsh reaction conditions, expensive reagents, hazardous and toxic solvents (e.g., refluxing toluene is used as the solvent in some of these methodologies [13]) or catalysts and tedious workup. Therefore, introduction of efficient and economical catalysts that solve these drawbacks is desirable.…”