Synthesis of 1,8-Dioxo-octahydroxanthenes Catalyzed by Acidic Ionic Liquids in Aqueous Media

Abstract

Some halogen-free acyclic task-specific ionic liquids (TSILs) were synthesized as cheap and recyclable catalysts for synthesis of 1,8-dioxo-octahydroxanthenes in water. This methodology offers several advantages, such as good yields, short reaction times, simple procedure, and mild conditions. The products could simply be separated from the catalyst/water, and the catalyst could be reused at least six times without noticeably decreasing the catalytic activity.

Phosphosulfonic acid, an efficient solid acid catalyst for the one-pot preparation of 14-aryl-14H-dibenzo[a,j]xanthenes and 1,8-dioxo-octahydro-xanthenes under solvent-free conditions

“…18 In the same manner, the synthesis of 1,8-dioxooctahydroxanthenes was achieved through the dehydration of dimedone (5,5-dimethylcyclohexane-1,3--dione) and aromatic aldehydes in pseudo three-component reactions in the presence of a catalyst, such as, tetrabutylammonium hydrogen sulfate, 19 Sc 3+ -montmorillonite, 20 HClO 4 -SiO 2 and polyphosphoric acid (PPA)-SiO 2 , 21 phosphomolybdic acid (PMA)-SiO 2 , 22 acidic ionic liquids, 23 heteropoly tungstic acid (HPWA) loaded Si-mobile crystalline material (HPWA-MCM-41) mesoporous molecular sieves, 24 silica-supported Preyssler nanoparticles (SPNP), 25 MCM--41-RSO 3 H, 26 acid functionalized SBA-15 and MCM-41, 27 and silica-bonded N-propylsulfamic acid (SBNPSA). 28 Although these methods may be effective, some of them have relatively long reaction times and unsatisfactory yields.…”

Crosslinked poly(ionic liquid) as high loaded dual acidic organocatalyst

“…Among them, acid functionalized ILs have been more interested, because they are able to carry an acidic group, such SO 3 H. These acid functionalized ILs can be more acidic when accompanied with hydrogen sulfate counter anion [4][5][6][7]. These dual acidic ILs have been used as efficient catalyst for various reactions and generated higher yields and selectivity against traditional acid catalysts [8].…”

β-Cyclodextrin mediated synthesis of 1,8-dioxooctahydroxanthenes in water

“…Other methods developed for the synthesis of 1,8-dioxooctahydroxanthenes include the use of NaHSO4-SiO2 (or) silica chloride [19], Amberlyst-15 [20], Dowex50w [21], Montmorillonite [22], cyanuric chloride [23], BiCl3 [24], Fe +3 -montmorillonite [25], polyaniline-p-toluenesulfonate [26], PMA-SiO2 [27], HClO4-SiO2 & PPA-SiO2 [28], ZrOCl2 [29], H3PW12O40 [30], LiBr [31], and proline triflate [32], as catalysts. Literature survey also indicates the role of ionic liquids [33,34], and acidic ionic liquids in aqueous media [35], in the synthesis of xanthenes.…”