Preparation, characterization and testing the catalytic activity of a new acidic ionic liquid in multicomponent reactions

In this study, N1,N1,N2,N2-tetramethylethane-1,2-diamine was reacted with chlorosulfonic acid to afford N1,N1,N2,N2-tetramethyl-N1,N2-bis(sulfo)ethane-1,2-diaminium chloride ([TMBSED][Cl]2) as a new acidic ionic liquid. [TMBSED][Cl]2 was identified by 1H and 13C NMR, mass and FT-IR spectra. Then, its catalytic activity was examined to promote the following multicomponent reactions: (i) the production of 4,4´-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s from arylaldehydes and 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one in ethanol, and (ii) the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones from arylaldehydes, dimedone and 2-naphthol in solvent-free conditions. The ionic liquid was highly efficient and general catalyst for these reactions.