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Indoles are efficiently condensed with aromatic and aliphatic aldehydes in the absence of any catalyst in ionic liquid 1-butyl-3-methylimidazolium bromide {bmim]Br} under microwave irradiation to afford bis(indolyl)methanes in good to excellent yields and in short reaction times. Key words: catalyst-free, indole, aldehyde, ionic liquid, microwave, bis(indolyl)methane. Resume : Les indoles se condensent d'une maniere efficace avec les aldehydes aliphatiques et aromatiques, sans necessite de catalyseur, dans le liquide ionique bromure de 1-butyl-3-methylimidazolium 1 [bmim]Br} et sous irradiation par des microondes et ces reactions conduisent, en un court laps de temps, α la formation de bis(indolyl)methanes avec des rendements allant de bons α excellents. Mots-cles : sans catalyseur, indole, aldehyde, liquide ionique, micro-onde, bis(indolyl)methane. [Traduit par la Redaction], Introduction In recent years, catalyst-free reactions have attracted increasing interest due to their ease of experimental procedure as well as work-up, low cost, possibility of using acid- or base-sensitive substrates, [...]

Abstract: An efficient procedure for the synthesis of carboacyclic nucleosides via microwave-assisted Michael addition of pyrimidine and purine nucleobases to α,β-unsaturated esters in the presence of catalytic amounts of zinc [...]

We report a novel nanostructured organosalt, based on sulfonic acid functionalized pyrazinium {[H-pyrazine–SO3H]Cl2} that was synthesized and characterized by several techniques including Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG) analysis, transmission electron microscopy (TEM), mass spectrometry (MS), proton NMR (1H NMR), carbon-13 NMR (13C NMR) and also electron diffraction (ED) patterns. Results proved that the unprecedented sulfonated pyrizinium organosalt is indeed nanostructured and highly crystalline as supported by TEM, ED and XRD studies, having an average nanoparticle size of 50 nm according to TEM micrographs. The novel nano-organocatalyst was proved to be an efficient catalyst in the synthesis of 1,2,4,5-tetrasubstituted imidazoles by a one-pot multi-component condensation of benzil, a broad range of aldehydes, primary amines and ammonium acetate at 90 °C under solvent-free conditions. [ABSTRACT FROM AUTHOR]

An active and stable magnetically separable Pd nanocatalyst was prepared and characterized. The nanocatalyst exhibited excellent activities and reusabilities in aqueous phase processes including the O-arylation of phenols and Sonogashira cross-coupling reactions. The proposed protocol features mild reaction conditions and an extraordinary simplicity and efficiency using NaOH as base in water. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the ionic liquid [Et3NSO 3H]Cl as new Brønsted acidic catalyst for the synthesis of N-Sulfonylimines, imidazoles, and methanes. It states that N-sulfonylimines have been a matter of the attention for organic chemists because sufonyl moiety activates the carbon=nitrogen (C=N) bond and hence, these compounds are used as substrates in nucleophilic additions, reactions, and Diels-Alder reactions. It mentions that imidazole derivatives show several pharmacological and biological activities and also are vital factor of lots of biologically active compounds and drugs such as losartan, eprosartan, and trifenagrel. Moreover, Lewis acidic catalysts have been used to effect the condensation of indoles with carbonyl compounds.

The article focuses on the method developed for N,N-dialkylsulfonamides synthesis via aza-conjugate addition reaction by microwave irradiation with potassium fluoride as an efficient and reusable reagent. It notes the significance of the N,N-Dialkyl derivatives of sulfonamides with their potential applications being an anti-ulcer, anti-emetic analgesic, and anti-inflammatory agents. It presents a table which shows the influence of rations of KF to the microwave power and substrate in the presence of tetrabutylammonium bromide (TBAB).

KF/Al2O3 efficiently catalyzes the microwave-assisted Michael addition of sulfonamides to α,β-unsaturated esters under solvent-free conditions to afford N-alkyl derivatives of sulfonamides as biologically interesting compounds in high yields and in short reaction times. In this reaction, N,N-dialkylsulfonamides are also produced, but in very low yields. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the efficiency, generality and applicability of novel Brønsted acidic ionic liquid triethylamine-bonded sulfonic acid {[Et3N–SO3H]Cl, N,N-diethyl-N-sulfoethanammonium chloride} as homogeneous and green catalyst for organic transformations under various conditions are studied. Herein, the following one-pot multi-component reactions in the presence of {[Et3N–SO3H]Cl are investigated: (i) the synthesis of β-acetamido ketones from acetophenones, aldehydes, acetonitrile and acetyl chloride in solution and under extremely mild conditions (room temperature), (ii) the preparation of 1,8-dioxo-octahydroxanthenes from dimedone (5,5-dimethyl-1,3-cyclohexanedione) (2 equiv.) and aldehydes (1 equiv.) under solvent-free conditions at moderate temperature (80°C), and (iii) the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes from β-naphthol (2 equiv.) and aldehydes (1 equiv.) in harsh conditions (120°C) in the absence of solvent. High yields, relatively short reaction times, efficiency, generality, clean process, simple methodology, low cost, easy work-up, ease of preparation and regeneration of the catalyst and green conditions (in the synthesis of the xanthene derivatives) are advantages of the application of [Et3N–SO3H]Cl as catalyst in the above organic reactions. This work is the first report of the ionic liquid. [Copyright &y& Elsevier]

Magnetic nano-Fe3O4 was applied in the presence of atmospheric air as a green, efficient, heterogeneous and reusable catalytic system for the synthesis of benzimidazoles via the reactions of o-phenylenediamine (1 eq) with aryl aldehydes (1 eq) in excellent yields (85-97 %) and short reaction times (30-100 min) with a proposed mechanism. [ABSTRACT FROM AUTHOR]