1,3-Disulfonic Acid Imidazolium Trifluoroacetate as a Highly Efficient and Dual-Functional Catalyst for the Pseudo Five-Component Reaction of Phenylhydrazine with Ethyl Acetoacetate and Arylaldehydes

Ionic liquid 1,3-disulfonic acid imidazolium trifluoroacetate ([Dsim][TFA]) has been used as a highly efficient catalyst for the one-pot pseudo five-component reaction of phenylhydrazine (2 eq) with ethyl acetoacetate (2 eq) and arylaldehydes (1 eq) in ethanol (reflux conditions). In this reaction, 4,4′‐(arylmethylene)‐bis(3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐ol)s have been obtained in high yields and relatively short reaction times. High efficacy of [Dsim][TFA] can be attributed to dual-functionality (possessing three acidic and one basic sites). A plausible and attractive mechanism based on dual-functionality of the catalyst has been proposed.