Brønsted acidic ionic liquid triethylamine-bonded sulfonic acid {[Et3N-SO3H]Cl} efficiently catalyzes the one-pot multi-component condensation of 2-naphthol with arylaldehydes and dimedone (5,5-dimethylcyclohexane-1,3-dione) under solvent-free conditions to afford 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in high yields and relatively short reaction times.
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, […]
