One-pot four-component synthesis of N-aryl-1,8-dioxo-decahydroacridines, N-arylquinolines and spiro[indoline-3,4′-quinolines] catalyzed by a new ionic liquid immobilized on nonporous SiO2

In this research, a new heterogeneous catalyst formulated as SiO2-[bip]-NH2+ HSO4- was obtained from the immobilization of bis-3-(trimethoxysilylpropyl)-ammonium hydrogen sulfate ionic liquid bridge on nonporous SiO2 and different techniques including FT-IR, XRD, FESEM and TGA were used for its identification. In continuation, the promoting ability of this reagent was investigated in the synthesis of N-aryl-1,8-dioxo-decahydroacridines, N-arylquinolines and spiro[indoline-3,4'-quinolines] via the one-pot four-component condensation reactions. Using this method, all products were obtained during suitable times with high isolated yields without the formation of any by-products. Solvent-free nature of the reaction conditions or use of the green solvents (H2O and EtOH), ease of the preparation of the catalyst and also its reusability are the other important features of this method.

Automated summary

A new heterogeneous catalyst SiO2-[bip]-NH2+HSO4- was obtained by immobilizing bis-3-(trimethoxysilylpropyl)-ammonium hydrogen sulfate ionic liquid bridge on nonporous SiO2. The catalyst was characterized using FT-IR, XRD, FESEM and TGA. The catalyst showed promoting ability in the one-pot four-component condensation reactions, leading to high yields of the desired products without any by-products. The reaction can be carried out without solvents or using green solvents (H2O and EtOH), and the catalyst is easily prepared and reusable.