Design, Characterization and Application of N1,N1,N2,N2-Tetramethyl-N1,N2-bis(sulfo)ethane-1,2-diaminium Trifluoroacetate as a Novel Ionic-Liquid Catalyst for the Production of Polyhydroquinolines

A novel Brønsted acidic ionic liquid namely N1,N1,N2,N2-tetramethyl-N1,N2-bis(sulfo)ethane-1,2-diaminium trifluoroacetate {[TMBSED][TFA]2} was synthesized, and characterized by studying its1H NMR, 13C NMR, 19F NMR and mass spectral data. Afterward, the ionic liquid was applied ascatalyst for the production of polyhydroquinoline derivatives via the one-pot multi-componentreaction of arylaldehydes with dimedone, β-ketoesters and ammonium acetate under solvent-freeconditions. The protocol had several advantages, which include: (i) efficiency, (ii) generality, (iii)excellent yields of the products, (iv) short reaction times, (v) clean reaction profile, (vi) simplicity,(vii) usage of a few amount of the catalyst, (viii) easy preparation the catalyst from available andinexpensive starting materials, (ix) mild reaction conditions, (x) performing the reaction in solventfreeconditions, and (xi) easy work-up.