Acidic Ionic Liquids in Ultrasonic Irradiation Conditions Promote the Nucleophilic Addition to Chalcone Derivatives

Under solvent-free conditions and with the help of ultrasonic irradiation, the synthesis of pyrano[3,2-c]chromen and pyrano[3,2-c]quinolin derivatives was promoted by four different ionic liquids. All reaction was performed at 100 °C and had good to excellent yields. 1-butyl-1-methylpyrrolidin-1-ium acetate (A), 1-butyl-1-methylpiperidin-1-ium acetate (B), N,N,N-triethylbutan-1-aminium acetate (C), and tetrabutylammonium acetate (D) as perfect ionic liquids for this reaction show remarkable catalytic activity. The work was simply developed for the reaction of chalcones with 4-hydroxy-1-methylquinolin-2(1H)-one/4-hydroxycoumarin to perform pure products of pyran heterocycles.