Ionic Liquids Immobilized on Magnetic Nanoparticles

Ionic liquids (ILs) immobilized on supports are among the most important derivatives of ILs. The immobilization process of ILs can transfer their desired properties to substrates. The combination of the advantages of ILs with those of support materials will derive new performances while retaining the properties of both moieties. As green media in organic catalytic reactions, based on utilizing the ability of ILs to stabilize the catalysts, they have many advantages over free ILs, including avoiding the leaching of ILs, reducing their amount, and improving the recoverability and reusability of both themselves and catalysts. This has critical significance from both environmental and economical points of view. Recently, ionic liquids immobilized on magnetic nanoparticles (MNPs) have drawn increasing attention in catalytic reactions and separation technologies and achieved substantial progress. The combination of MNPs and ILs gives magnetic‐supported ionic liquids, which exhibit the unique properties of ILs as well as facile separation by an external magnetic field. The excellent efficiency of this kind of immobilized ionic liquids offers a great advantage compared with other sorts of magnetic supports. In this chapter, the green catalytic processes and recent advances in organic synthesis catalyzed by ionic liquids immobilized on magnetic nanoparticles are highlighted

Polyvinylpyrrolidone-bromine complex: An efficient polymeric reagent for selective preparation of benzyl bromides in the presence of hexamethyldisilane

Benzylic bromides were conveniently obtained in high yields via the reaction of the corresponding alcohols with crosslinked polyvinylpyrrolidone-bromine complex (PVPP-Br2)/hexamethyldisilane in chloroform at reflux condition. Selective conversion of benzyl alcohol to benzyl bromide in the presence of primary aliphatic alcohols, e.g. 2-phenylethanol was also achieved. KEY WORDS: Polyvinylpyrrolidone-bromine, Benzyl bromide, Hexamethyldisilane, Selective bromination Bull. Chem. Soc. Ethiop. 2012, 26(2), 305-309.DOI: http://dx.doi.org/10.4314/bcse.v26i2.1

Synthesis of a Biological‐Based Glycoluril with Phosphorous Acid Tags as a New Nanostructured Catalyst: Application for the Synthesis of Novel Natural Henna‐Based Compounds

A convenient multicomponent reaction towards the synthesis of natural henna‐based 3‐methyl‐1,4‐diphenyl‐1,4‐dihydrobenzo[6, 7]chromeno[2, 3‐c]pyrazole‐5,10‐dione derivatives by using a crabby nano glycoluril tetrakis(methylene phosphorous acid) (GTMPA), as an efficient and recyclable catalyst, under neat conditions is described. The major advantages of the synthetic methodology herein described are high yields, short reaction times, and the reusability of the catalyst, which has been fully characterized by Fourier Transform Infrared Spectroscopy (FT‐IR), Solid Phosphorus Nuclear Magnetic Resonance (31P NMR), Mass spectra (MS), X‐Ray Diffraction (XRD), High Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscope (SEM‐Mapp.), Energy Dispersive X‐Ray (EDX), Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTG), Differential Thermal Analysis (DTA) and X‐Ray Photoelectron Spectroscopy (XPS). The described biological‐based glycoluril with phosphorous acid pending may be applicable for the synthesis of gels, gelators, self‐healing and smart hydrogels.We thank Bu-Ali Sina University, Iran National Science Foundation (INSF) (Grant Number: 96003376), National Elites Foundation, University of Alicante (VIGROB-173, UAUSTI16-03), and the Spanish Ministerio de Economía y Competitividad (CTQ2015-66624-P) for financial support to our research groups

Nano magnetite (Fe3O4), an efficient and robust catalyst for the one-pot synthesis of 1-(aryl(piperidin-1-yl)methyl)naphthalene-2-ol and 1-(α-amido alkyl)-2-naphthol under ultrasound irradiation

The direct three component reaction via condensation of aldehydes, 2-naphthol and piperidine or acetamide to generate 1-(aryl(piperidin-1-yl)methyl)naphthalene-2-ol and N-((2-hydroxy naphthalene-1-yl)(aryl)methyl)acetamide derivatives has been carried out over Fe3O4 magnetic nanoparticle with high efficiency under ultrasound irradiation. These reactions were studied under different conditions. In terms of reaction time and yield, it was found that optimum results were obtained for the synthesis of 1-(aryl(piperidin-1-yl)methyl)naphthalene-2-ol under solvent free condition and for preparation of N-((2-hydroxynaphthalene-1-yl)(aryl)methyl)acetamide in acetic acid under ultrasound irradiation at 80 °C. Clean methodologies, easy workup procedure, and high yields are some advantages of this work