Lewis acidic (choline chloride.3ZnCl2) ionic liquid: A green and recyclable catalyst for the one-pot synthesis of 4-((3-indolyl)(aryl)methyl)-N,N-dimethylanilines under solvent-free conditions

Abstract

A green and convenient procedure for the one-pot multicomponent synthesis of 4-((3indolyl)(aryl)methyl)-N,N-dimethylanilines using (choline chloride.3ZnCl 2) ionic liquid as catalyst, at 100 • C and under solvent-free condition is described. Utilizing environmentally benign reagents, elimination of organic solvents, enhanced rates, reusability and moisture stability of the catalyst are the remarkable features observed in the reported reaction system. The catalyst was recycled up to four times with no noticeable drop in activity.

Choline chloride–zinc chloride ionic liquid as a green template for the sol–gel synthesis of mesoporous titania

“…This observation, in addition to the thermal behavior of ILT-B, further reiterated the fact that IL could be simply removed by washing with water and ethyl acetate. 18 The peaks at 3420 and 1629 cm À1 in the spectra of ILT-B and ILT-2 (calcined at 500 C) were due to the -OH stretching and bending vibrations of surface-adsorbed water, respectively. The interaction between IL template and titania might have been due to: (i) intermolecular hydrogen bond formation between hydroxyl hydrogen of choline cation and titania and (ii) a probable Lewis acid type interaction of Zn present in the anionic part of IL with oxygen in titania.…”

“…[13][14][15][16] However, most of the imidazolium-based ILs are highly toxic, expensive to prepare and highly sensitive to water. 17,18 Replacement of the imidazolium-based ILs by an eco-friendly alternative will be of great signicance, as it will offer a greener synthetic route. From this viewpoint, choline chloridebased ILs, possessing desirable characteristics such as nontoxicity, water solubility, air and moisture stability and reusability, offer a great potential to be explored for the green synthesis of organic chemicals and inorganic solids.…”

Brønsted Acidic Ionic Liquid Catalyzed Three-Component Friedel–Crafts Reaction for the Synthesis of Unsymmetrical Triarylmethanes

“…4,4'-((4-Chlorophenyl)methylene)bis(N,N-dimethylaniline) (6c): [23,31,32] [7] CAS Number 1477503-04-0; 72% yield (0.2468 g) as a purple solid; m.p. 122-124 °C; Rf = 0.48 (20% EtOAc/n-hexane); [23] CAS Number 3110-14-3; 6% yield (0.0203 g) as a blue oil; Rf = 0.68 (20% EtOAc/n-hexane);…”

“…To date, Bronsted acidic ionic liquids (BAILs) are gaining considerable attention as highly efficient acid-catalysts for a diversity of important synthetic reactions. 7 Several advantages of this kind of catalyst are presented such as air tolerance, moisture resistance, thermal stability, non-volatility, nontoxicity, less corrosive, cheap and reusable. However, the use of BAILs as acidic catalysts for the synthesis of triarylmethanes via Friedel-Crafts reaction are quite rare to date.…”

“…Furthermore, varying the equivalents of aniline substrate 2a and indole substrate 3a were tested (entries [7][8][9][10][11]. On reduction of substrate 2a to 1.5 equivalents, the yield of the desired product 4a decreased (70%, entry 7).…”