Preparation and application of triphenyl(propyl-3-hydrogen sulfate)phosphonium bromide as new efficient ionic liquid catalyst for synthesis of 5-arylidene barbituric acids and pyrano[2,3- d ]pyrimidine derivatives

We report synthesis of triphenyl(propyl-3-hydrogen sulfate)phosphonium bromide ([TPPHSP]Br) as a reusable green Brønsted-acidic ionic liquid catalyst and its application for synthesis of 5-arylidene barbituric acids and pyrano[2,3- d ]pyrimidine derivatives by condensation reaction between aromatic aldehydes and barbituric acid or aromatic aldehydes, malononitrile, and barbituric acid in EtOH–H 2 O in reflux condition with good to excellent yield. The [TPPHSP]Br IL catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, 1 H and 13 C nuclear magnetic resonance (NMR), and thermogravimetric (TG) analysis and showed good catalytic activity and reusability.