Abstract We have synthesized a novel Bronsted acidic ionic liquid, 1-(2-hydroxyethyl)-1-(4-sulfobutyl)piperidin-1-ium hydrogen sulfate, [HEPiPYBSA]+HSO4− and explored its catalytic efficiency for synthesis of indenoquinoxalone tethered spiro-1,2,4-triazolidine-5-thiones from reaction of 11H-[1,2-b]quinoxalin-11-one and… Click to show full abstract
Abstract We have synthesized a novel Bronsted acidic ionic liquid, 1-(2-hydroxyethyl)-1-(4-sulfobutyl)piperidin-1-ium hydrogen sulfate, [HEPiPYBSA]+HSO4− and explored its catalytic efficiency for synthesis of indenoquinoxalone tethered spiro-1,2,4-triazolidine-5-thiones from reaction of 11H-[1,2-b]quinoxalin-11-one and thiosemicarbazide. The most stable geometries of synthesized ionic liquid (IL) [HEPiPYBSA]+ HSO4− were obtained through systematically optimization by the DFT theory at B3LYP/6-31G* level. A photoluminescence study of the synthesized spiro-1,2,4-triazolidine-5-thiones revealed a remarkable fluorescent activity. The advantages of the present method are a reusable hydrophilic green catalyst, mild reaction conditions, use of benign solvent system, short reaction span, high atom economy and wide substrate scope.
               
Click one of the above tabs to view related content.