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The fluorescence spectra and response characteristics of two porphyrin compounds meso -tetrakis(2-hydroxynaphthyl) porphyrin and meso -tetra (2-thiophene) porphyrin (MTHNP) to Hg 2 + were investigated. MTHNP showed preferable fluorescence response to Hg 2 + . Thereby, an efficient and selective fluorimetric optode membrane based on the fluorescence quenching of MTHNP for Hg 2 + ion determination at low concentration levels has been developed. The sensing membrane containing MTHNP reversibly responded to Hg 2 + with a working concentration range covering from 5.0 × 10 − 9 to 1.25 × 10 − 5 M with a relatively fast response time less than 3 min. In addition to high stability, reversibility and reproducibility, the sensor showed extremely high selectivity toward Hg 2 + ion with respect to some alkali, alkaline earth and heavy metal ions. The limit of detection for Hg 2 + was 5.0 × 10 − 9 M. The proposed fluorescent sensor was successfully applied to the direct determination of mercury content of biofenac eye drop, hair and different water samples. [ABSTRACT FROM AUTHOR]

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]

Highlights: [•] Introducing efficient catalysts for the synthesis of 2-amino benzo[h]chromenes. [•] Study of TGA, XRD and calculation of size and inter planer distance of the catalysts. [•] Generality of the catalysts, high yields and short reaction times. [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.

Abstract: In this work, novel Brønsted acidic ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate {[Dsim]HSO4} is synthesized, and characterized by studying its FT-IR, 1H NMR, 13C NMR, mass, TG, DTG and XRD spectra. This ionic liquid, with three acidic functional groups, is utilized as a highly efficient, homogeneous and reusable catalyst for the preparation of hexahydroquinolines via one-pot multi-component condensation of arylaldehydes, dimedone (5,5-dimethylcyclohexane-1,3-dione), β-ketoesters and ammonium acetate under solvent-free conditions. The catalyst can form dual hydrogen-bond using its SO3H groups which this subject can direct to its assembly and efficiency. [Copyright &y& Elsevier]

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]

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).

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. Les indoles se condensent d’une manière efficace avec les aldéhydes aliphatiques et aromatiques, sans nécessité de catalyseur, dans le liquide ionique bromure de 1-butyl-3-méthylimidazolium {[bmim]Br} et sous irradiation par des microondes et ces réactions conduisent, en un court laps de temps, à la formation de bis(indolyl)méthanes avec des rendements allant de bons à excellents. [ABSTRACT FROM AUTHOR]

The article presents chemical equations related to examining the catalytic properties of stable and active magnetically separable palladium (Pd) nanocatalyst in aqueous phase that was published in a 2013 issue of the journal "Green chemistry."