112 research outputs found

    Ring opening of oxiranes catalyzed by Mn-Salen immobilized mesoporous materials

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    Mn-Salen immobilized mesoporous materials were found to be efficient solid catalysts for the nucleophilic ring opening of oxiranes with TMSN3, TMSCN and aniline

    Friedel-Crafts sulfonylation of aromatics catalysed by solid acids: an eco-friendly route for sulfone synthesis

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    A mild and efficient catalytic method for Friedel-Crafts sulfonylation of arenes to the corresponding sulfones using a catalytic amount of reusable solid acid and arene- or alkanesulfonyl chlorides, sulfonic anhydrides and sulfonic acids as sulfonylating agents is described. Solid acids enable formation of a sulfone by the reaction of a sulfonic acid and an arene for the first time. In pursuit of the development of the best catalytic system, various metal-exchanged K10 montmorillonites and synthetic zeolites such as zeolite beta, zeolite Y and ZSM-5 have been screened for Friedel-Crafts sulfone synthesis. Fe3+-montmorillonite in the family of clays and zeolite beta in the family of zeolites exhibit higher activity. The activity is correlated to the presence of the right mix of Bronsted and Lewis acidic sites. The regioselective sulfonylation of toluene and naphthalene are studied in which para and beta selectivities are observed respectively

    The first example of heterogeneous oxidation of secondary amines by tungstate-exchanged Mg-Al layered double hydroxides: a green protocol

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    Tungstate exchanged Mg-Al layered double hydroxides a as recyclable heterogenised catalyst along with H2O2 as an oxidant for the oxidation of sec-amines to nitrones is developed for the first time, Reactions proceed at a fast rate in aqueous media in a single step at room temperature in good to excellent yields. The heterogenised catalyst showed higher activity (TOF) over their homogeneous analogues and other heterogeneous catalysts reported so far. The obtained catalysts were well characterised by various instrumental techniques such as FT-IR spectroscopy, thermal analysis (TGA and DTA), powder XRD and chemical analysis. The catalyst can be reused for six cycles with consistent activity and selectivity

    MgAICO3-HT catalyzed ring opening of oxiranes with TMSN3

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    1039-104

    Henry reactions catalysed by modified Mg-Al hydrotalcite: an efficient reusable solid base for selective synthesis of β-nitroalkanols

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    Henry reactions have been performed for the first time with suitably activated Mg-Al hydrotalcite as catalyst in quantitative yields in the liquid phase under mild reaction conditions and with low reaction times. Exclusive synthesis of β-nitroalkanols (3) is realised by the compatible basic Bronsted hydroxy sites of the modified hydrotalcite. Reusability with consistent activity and selectivity for a number of cycles is established indicating that the hydrated hydrotalcite employed here is a potentially eco-friendly catalyst which can replace soluble bases in commercial synthesis

    Preparation of Oxotetrachlororhenates (V) from H2ReOCl5 in Acetic Acid

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    74-7
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