Azole‐Anion‐Based Aprotic Ionic Liquids: Functional Solvents for Atmospheric CO₂ Transformation into Various Heterocyclic Compounds

Abstract

The chemical transformation of atmospheric CO is of great significance yet still poses a great challenge. Herein, azole-anion-based aprotic ionic liquids (ILs) were synthesized by the deprotonation of weak proton donors (e.g., 2-methylimidazole, 4-methylimidazole, and 2,4-dimethylimidazole) with tetrabutylphosphonium hydroxide, [Bu P][OH]. We found that these ILs, such as [Bu P][2-MIm], could activate atmospheric CO through the formation of carbamates. The resultant carbamate intermediates could further react with various types of substrate, including propargylic alcohols, 2-aminobenzonitriles, ortho-phenylenediamines, and 2-aminothiophenol, thereby producing α-alkylidene cyclic carbonates, quinazoline-2,4(1 H,3 H)-diones, benzimidazolones, and benzothiazoline, respectively, in moderate-to-good yields. Thus, we have achieved the transformation of CO at atmospheric pressure, and we expect this method to open up new routes for the synthesis of various oxygen-containing heterocyclic compounds under metal-free conditions.

Cocatalyst‐Free Hybrid Ionic Liquid (IL)‐Based Porous Materials for Efficient Synthesis of Cyclic Carbonates through a Cooperative Activation Pathway

“…13 Cs ignals were referenced to glycine (C 2 H 5 NO 2 ). The N 2sorption characterization was carried out on aM icromeritics ASAP2020 volumetric adsorption analyzer.B efore the sorption measurements, samples were out-gassed at 393 Kf or 6h.T he BET surface area was calculated from the data in the relative pressure range P/P 0 of 0.04 to 0.20.…”

“…The 13 Cc ross-polarization (CP) magic-angle spinning (MAS) NMR spectrum of SBA-[V 0.15 OH 0.60 ]R 2 37 is shown in Figure 5.…”

“…Cyclic carbonates are commonly used as aproticp olar solvents, electrolytes, precursors, monomers, and intermediates for production of pharmaceuticals, fine chemicals, and agricultural chemicals, for example. [13] In view of green chemistry and sustainability,m etal-free catalysts are more desirable. To date, aw ide range of homogeneous and heterogeneous catalysts have been developed, such as alkali-metal salts, [7] metal oxides, [8] organophosphorus compounds, [9] organic bases, [10] organometallic compounds, [11] functional polymers, [12] andi onicl iquids( ILs).…”

“…To date, aw ide range of homogeneous and heterogeneous catalysts have been developed, such as alkali-metal salts, [7] metal oxides, [8] organophosphorus compounds, [9] organic bases, [10] organometallic compounds, [11] functional polymers, [12] andi onicl iquids( ILs). [13] In view of green chemistry and sustainability,m etal-free catalysts are more desirable. Imidazolium (IM)-and 1,2,4-triazolium (TR)based ionic liquids( ILs) are more attractive than other metalfree catalysts owing to their high activity and selectivity.…”

Delineating the Mechanism of Ionic Liquids in the Synthesis of Quinazoline‐2,4(1H,3H)‐dione from 2‐Aminobenzonitrile and CO2

“…[32] Thed iscovery that ILs prepared by the protonation of DBU( [HDBU][X]) [33,34] catalyze the reaction under ambient conditions led to the investigation of protic ILs, including 1,1,3,3-tetramethylguanidinium imidazolide ([HTMG][Im]), which showed similar activity. [35] Tetrabutylphosphonium 2-methylimidazolide ([TBP] ) can also catalyze the reaction at 1bar CO 2 at slightly elevated temperatures, [36] whereas tetrabutylphosphonium arginine ([TBP][Arg]) requires high CO 2 pressures and temperatures. [37] Although at 1bar CO 2 extended reaction times were required, tetrabutylammonium tungstate ([TBA] 2 [WO 4 ]) also demonstrated relevant activity.…”