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An active imidazolium-based ionic liquid mixture was developed for efficient synthesis of some novel 4,6-diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxides (chlorosulfonyl-δ-sultones) from simple acetophenones at room temperature. The ionic liquid mixture acts as a catalyst to condense two molecules of an acetophenone derivative and as a mild sulfonating agent to convert the resulting condensate into 4,6-diaryl-1,2-oxathiine-2,2-dioxides, and finally as a chlorosulfonating reagent to deliver the desired fully unsaturated chlorosulfonyl-δ-sultones in onepot. The products were separated easily from the reaction mixture and showed valuable fluorescence properties. The structures of these products are in good agreement with their 1 H NMR, 13 C NMR, and mass spectral data. All rights reserved. [ABSTRACT FROM AUTHOR]

Addition of chlorosulfonic acid to N -methyl-2-pyrrolidone (NMP) resulted in the formation of a low-melting solid with the advantages of being reasonably stable for at least 4 months at ambient temperature and easy to handle. This solid forms homogeneous solutions with acetophenone derivatives, which on heating in the absence of any additional solvent and catalyst lead to production of the desired 1,3-dienic δ-sultones in fairly high yields and short reaction times. Beside its role as a solvent, the NMP-ClSO 3 H salt efficiently catalyzes the self-condensation of acetophenones and plays as a mild sulfonating agent in conversion of the resulting condensates into δ-sultones. The reaction protocol is simple and follows a green work-up procedure that enables to recover the reaction residues and prevent the emission of wastes into the environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new natural deep eutectic melt with a wide liquidity window was obtained. • It can exist as a supercooled liquid below its glass transition point at −42 °C. • It has a significant electric conductance and is thermally stable up to 190 °C. • It is an amphipathic solvent, making it easily separable from organic reactions. • It was tested as an efficient promoter in the synthesis of pyrano[3,2- c ]chromenes. Glassy viscous liquids were obtained by heating some mixtures of tetramethylguanidine hydrochloride and sorbitol in different molar ratios at temperatures far below the melting points of the two components. The seminatural deep eutectic melt, which was prepared in this way, showed a wide liquid window, as preserves its fluidity even by standing at −60 °C for 2 days and is thermally stable up to 190 °C. It displays a significant electric conductivity and maintains its liquid state at ambient temperature even by dissolving additional amounts of sorbitol and shows an efficient promotion effect on the three-component synthesis of pyrano[3,2- c ]chromenes. Interestingly, sorbitol preserves its chemical identity in the melt, as no signals attributable to formation of isosorbid or sorbitan are detected in the NMR spectra of the melt. [ABSTRACT FROM AUTHOR]

A class of sulfonic ionic liquids, with the supremacy of methylsulfonylimidazolium triflate hydrochloride, was found to be efficient for catalyzing the self-condensation of acetophenone derivatives and sulfonating the resulting condensates in a one-pot rapid reaction leading to the synthesis of 4,6-diaryl-1,2-oxathiine-2,2- dioxides (diaryl-δ-sultones). [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of novel 4-substituted-3,4-dihydro-6H-pyrano[3,2-c]quinoline-2,5-diones was accomplished efficiently via a three-component reaction between 4-hydroxyquinoline-2-one, Meldrum’s acid, and an alkyl or arylaldehyde under catalysis by [Bmim]HSO4. The ionic liquid catalyst offers the advantage of realizing the synthesis of the title products at ambient temperature and widens the scope of the reactants to include aliphatic aldehydes with respect to the catalysts already applied for similar syntheses. [Copyright &y& Elsevier]

Abstract: A homogeneous ionic liquid made up of 0.5mol% Mg(BF4)2 doped in [BMIm]BF4 was obtained from a mixture of MgCl2 and [BMIm]Cl subjected to anion exchange with NaBF4. The ionic liquid efficiently catalyzes the synthesis of 1,8-dioxo-octahydroxanthenes, 14-aryl-14H-dibenzo[a,j]xanthenes, and 1,8-dioxo-decahydroacridines, giving excellent yields in short periods of time at 80°C. The integrity of the ionic liquid remains reasonably unchanged when it is separated from the reaction mixture by water extraction, as it can be recycled several times without any loss of activity in each of the title syntheses. Magnesium cation, though in low concentration, appeared as an essential element of this ionic liquid catalysis, perhaps due to its non-coordinated existence giving rise to a promoted Lewis acidic characteristic. Application of this new homogeneous catalyst system offered the advantages of high yields, short reaction times, and easy workup procedure compared to the conventional methods of the syntheses. [Copyright &y& Elsevier]

Abstract: The mildly basic ionic liquid N,N,N,N-tetramethylguanidinium triflate (TMGTf) was found to be a very effective solvent for the reaction between 4-hydroxy-6-methyl-2H-pyran-2-one, Meldrum''s acid, and aldehydes to afford some novel pyrano[4,3-b]pyran-2,5-diones in high yields at room temperature. The stages, through which these reactions might proceed, depend largely on the nature of the aldehyde substrates. The reaction of aliphatic aldehydes has given access to some novel carboxylated products. [Copyright &y& Elsevier]

Abstract: Synthesis of spiro[1H-indeno[1,2-b]benzoquinolin-13,3′-indoline]-7,13-dihydro-12,2′-dione derivatives was achieved expediently through three-component reactions between 2H-indene-1,3-dione, 1- or 2-naphthalenamine, and isatin derivatives under catalysis of the ionic liquid N,N,N,N-tetramethylguanidinium triflate. The ionic liquid appeared as a task-specific catalyst solvent being amenable to successive recycling without appreciable decrease in activity. This synthetic method similarly works well when acenaphthylene-1,2-dione or 1H-indene-1,2,3-trione is employed in place of isatin and likewise when 2-aminouracil is used instead of naphthalenamine to furnish the structurally related spirocyclic products. A convergent mechanism was suggested for the reactions to account for the selective formation of the spiro-compounds corresponding to the employed components. [Copyright &y& Elsevier]

Abstract: A simple and efficient one-pot approach for assembling some fused spiro[4H-pyran-oxindole] heterocycles by means of three-component reactions between isatins, malononitrile or ethyl cyano-acetate, and 1,3-dicarbonyl compounds is reported. The combinatorial syntheses were achieved for the first time without applying extra activation energy at ambient temperature while making use of [BMIm]BF4 as an ionic liquid catalyst. Good functional group tolerance and broad scope of usable substrates are other prominent features of the present methodology. [Copyright &y& Elsevier]

Abstract: Three ionic liquids, [BMIM][BF4] doped with 60mol% of LiCl ([BMIM][BF4]–LiCl), N,N,N,N-tetramethylguanidinium trifluoroacetate (TMGT), and N,N,N,N-tetramethylguanidinium triflate (TMGTf) were found useful as catalyst solvents for controlled 3-indolylation of isatins. Our investigation revealed that the reaction between isatin and indoles in [BMIM][BF4]–LiCl or TMGTf media stops at the step of addition of the two components providing 3-indolyl-3-hydroxyindolin-2-ones while the ionic liquid TMGT runs the reaction further through accompanying Friedel–Crafts substitution to afford symmetrical 3,3-di(indol-3-yl)indolin-2-ones. To take advantage of the difference between the effects of these ionic liquids on the reaction progress, we planned a two-step protocol for the efficient synthesis of unsymmetrical 3,3-di(indol-3-yl)indolin-2-ones. [Copyright &y& Elsevier]

Abstract: Two ionic liquids, N,N,N,N-tetramethylguanidinium trifluoroacetate (TMGT) and the unprecedented N,N,N,N-tetramethylguanidinium triflate (TMGTf), were used as catalyst solvents in condensations between indoles and arylaldehydes or 1,3-diketones providing a simple and efficient method for synthesis of bis(3-indolyl)methanes or casually 3-alkenylindoles due to stereoelectronic concerns of reactants. The ionic liquids are easily separated and reused for several times. [Copyright &y& Elsevier]

Abstract: An unexpected condensation profile was observed for the three-component reaction of 5,5-dimethyl-1,3-cyclohexadione (dimedone), various anilines, and isatin leading to the synthesis of novel 2-arylpyrrolo[2,3,4-kl]acridin-1(2H)-ones in the ionic liquid [HMIm]HSO4. Regeneration of the enamine group after the initial condensation reaction associated with participation of the restored amine group in translactonization with the pyrrolidone ring are suggested as the main differentiating events being favored over addition of the second dimedone molecule, with respect to similar reported reactions. [Copyright &y& Elsevier]