Synthesis of dibenzoxanthene and acridine derivatives catalyzed by 1,3-disulfonic acid imidazolium carboxylate ionic liquids

Abstract

New members of 1,3-disulfonic acid imidazolium carboxylate ionic liquids [DSIM][X] (where X = [CH₃COO]⁻, [CCl₃COO]⁻, [CF₃COO]⁻) were prepared and characterized by ¹H NMR,¹³C NMR, FT-IR, TGA,UV-vis and elemental analysis. The more acidic ILs [DISM][CCl₃COO] and [DSIM][CF₃COO] were efficiently utilized as recyclable catalysts for the preparation of 14H-dibenzo[a,j]xanthene and 1,8-dioxo-decahydroacridine derivatives in short times under solvent-free conditions at 80–100 °C with excellent yields. The above two ILs could be effectively utilized as catalysts for the synthesis of 1,8-dioxo-decahydroacridine in water at the same temperature.