An efficient and environmentally benign procedure for the reactions of three components condensation of salicylaldehyde and two different CH acids to give 2‐amino‐4H‐chromenes catalyzed by a series of basic‐functionalized ionic liquids was reported. The most possible reaction pathway was proposed for the first time by performing density functional theory (DFT) calculations. Both cation and anion of [Bmim]OH have a cooperative effect on the reaction. [Bmim]+ increases the electrophilicity of salicylaldehyde via intermolecular hydrogen bonds, while OH− deprives proton of two CH acids to strengthen their nucleophilic ability.
Switchable reversible addition-fragmentation chain-transfer (RAFT) agents, so-called because they can be reversibly switched by the acid/ base stimulus to offer very good control over polymerization of both “more-activated” monomers (MAMs)...
Compared with post-grafting method, a novel and controllable strategy is applied to introduce highly dispersed ionic liquid species into mesoporous SBA-15 silica, providing simpler synthesis steps, more uniform surface coverage and higher loading of ionic liquid, with fewer raw materials. Basic task-specific ionic liquids are synthesized and characterized by X-ray diffraction, N 2 adsorption-desorption, thermogravimetry and fourier transform infrared spectroscopy. The results showed that the catalysts, prepared by co-condensation method, have better ordered mesostructure and higher loading of ionic liquid than those by post-grafting approach. Meanwhile, the catalysts exhibit much higher activity than those by post-grafting approach in Knoevenagel condensation. Furthermore, these supported catalysts are also proven to be efficient and reusable in Henry reaction under solvent-free conditions.
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