ZnBr₂ Functionalized Ionic Liquid: An Efficient Solvent and Catalyst for the Facile Synthesis of 1-Benzamino-1,4-Dihydropyridine ^†

Ionic liquids (ILs) are mostly composed of organic cations and organic/inorganic anions. One of the most important class of ILs are imidazolium ILs. The hydrophilicity and hydrophobicity of ILs are regularly influenced by length of alkyl side chain of cation. According to this effect, better hydrophilicity comes from a shorter alkyl side chain and on the contrary, better hydrophobicity comes from a lengthier alkyl side chain of cation. Typical ILs have exceptional properties. Most ILs are stable at about 300 °C in the liquid state at normal conditions. Due to the exceptional properties of ILs, they have been used in diverse industries including batteries and fuels. As solvents, ILs have been employed in many chemical fields. Solubilities of ILs with organic/inorganic species are completely satisfactory. Here, by N-methyl imidazole (Im), 1,3-dibromopropane, triethanolamine (TEA), and ZnBr₂, new ionic liquid (TEA-Im-Zn) was synthesized and used as catalyst and solvent in the synthesis of functionalized 1-benzamino-1,4-dihydropyridine using aromatic aldehydes, malononitrile, triethylamine, arylamine and dialkyl acetylenedicarboxylate.