Novel DABCO Based Ionic Liquids: Green and Efficient Catalysts with Dual Catalytic Roles for Aqueous Knoevenagel Condensation

Four novel basic ionic liquids (ILs), based on 1,4-diazobicyclo[2.2.2]­octane (DABCO) and 3-chloro-1,2-propanediol, have been introduced as catalysts for Knoevenagel condensation. These catalysts are applicable to a wide range of aromatic/heteroaromatic aldehydes with α-aromatic (heteroaromatic or polyaromatic)-substituted methylene compounds in water at room temperature, and they afford the products in excellent yields within short times. These reactions are operationally simple, and the desired products can be separated directly from the reaction mixture without further purification. A possible reaction mechanism was proposed, and the relevant evidence was given. In addition, the ionic liquids used can be regenerated and recycled several times without significant loss of activity. Furthermore, the novel ILs could be efficiently used in a step of atorvastatin synthesis

Novel Multiple-Acidic Ionic Liquids: Catalysts for Environmentally Friendly Benign Synthesis of <i>trans</i>-β-Nitrostyrenes under Solvent-Free Conditions

A series of novel multiple-acidic ionic liquids, sulfated from the low-cost starting material 2-aminoethanol, were introduced as catalysts for the Henry reaction of versatile aldehydes and nitroalkane under solvent-free conditions. The ionic liquid with hydrogen sulfate as a counteranion showed the best catalytic efficiency and gave the corresponding <i>trans</i>-β-nitrostyrenes in good to excellent yields. More importantly, the ionic liquid catalyst could be readily recovered and reused six times without considerable loss of its catalytic activity

Ionic Modified TBD Supported on Magnetic Nanoparticles: A Highly Efficient and Recoverable Catalyst for Organic Transformations

1,5,7-Triazabicyclo­[4.4.0]­dec-5-ene (TBD) with ionic modification supported on magnetic nanoparticles was prepared and characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TG), vibrating sample magnetometer (VSM) and elemental analysis. The supported ionic specie was certified as a highly active and magnetically recoverable catalyst for the synthesis of various substituted ureas and structurally diverse <i>N</i>-heterocyclic compounds. The catalyst can be readily recovered by external magnetie and be reused for 6 times without significant loss in catalytic activity. Ionic tagged catalyst performs much better than its ionic-free counterpart in organic transformations

DABCO-Based Ionic Liquids: Recyclable Catalysts for Aza-Michael Addition of α,β-Unsaturated Amides under Solvent-Free Conditions

An array of novel 1,4-diazobicyclo[2.2.2]­octane (DABCO) based ionic liquids were developed and used as recyclable catalysts for the aza-Michael addition at room temperature without any organic solvent. [DABCO–PDO]­[OAc] was found to be the most efficient catalyst, and the amount of catalyst was only 10 mol %. Various amines reacted with a wide range of α,β-unsaturated amides, smoothly affording target products in good to excellent yields within hours. Moreover, the catalyst could be reused up to eight times, still maintaining a high catalytic activity. Finally, a plausible mechanism was proposed. FTIR and computational chemistry were used to verify the catalytic mechanism