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Transfer Catalysis (transfer + catalysis)

Distribution by Scientific Domains
Chemistry88%

Kinds of Transfer Catalysis

  • phase transfer catalysis
    		•

    Selected Abstracts

    Liquid-Liquid-Liquid Phase Transfer Catalysis: A Novel and Green Concept for Selective Reduction of Substituted Nitroaromatics

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005
    Ganapati
    Abstract The selective reduction of nitroaromatics to the corresponding amines is an important transformation since many aromatic amines exhibit biological activities and find a multitude of industrial applications, being intermediates for the synthesis of dyes, pharmaceuticals and agrochemicals. A variety of nitroaromatics dissolved in organic solvents was reduced by using aqueous sodium sulfide, and tetrabutylammonium bromide (TBAB) as the phase transfer catalyst by choosing appropriate concentrations which resulted in three immiscible liquid phases. Compared to L-L PTC, the L-L-L PTC offers much higher rates of reaction, better selectivities and repeated use of catalyst. The selectivities for the desired products were 100%. [source]

    ChemInform Abstract: The Role of Phase Transfer Catalysis in the Microwave-Assisted N-Benzylation of Amides, Imides and N-Heterocycles.

    CHEMINFORM, Issue 17 2010
    Istvan Greiner
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Heterogeneous Phase Alkylation of Phenols Making Use of Phase Transfer Catalysis and Microwave Irradiation.

    CHEMINFORM, Issue 17 2010
    Gyoergy Keglevich
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: Asymmetric Aza-Henry Reaction under Phase Transfer Catalysis: An Experimental and Theoretical Study.

    CHEMINFORM, Issue 44 2008
    Enrique Gomez-Bengoa
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    ChemInform Abstract: A "One Pot" Synthesis of 2-Aryl-4H-1-benzopyran-4-ones under Coupled Microwave Phase Transfer Catalysis (PTC) and Ultrasonic Irradiation PTC.

    CHEMINFORM, Issue 29 2008
    Vijai N. Pathak
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    Asymmetric Conjugate Additions of ,-Substituted-,-cyanoacetates to Acetylenic Ketones by Chiral Phase Transfer Catalysis.

    CHEMINFORM, Issue 42 2007
    Quan Lan
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

    A Rapid and High Yield Synthesis of Aryloxyacetyl Hydrazides under Microwave Irradiation and with Phase Transfer Catalysis.

    CHEMINFORM, Issue 47 2005
    Tai-Bao Wei
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Synthesis of 3-Cyano- and 3-Cyano-4-methylcoumarins Using Phase Transfer Catalysis.

    CHEMINFORM, Issue 44 2005
    Seema Seema
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    A Novel Synthesis of Spiro 1,3-Dithiin and Spiro 1,3-Thiazine Derivatives under Phase Transfer Catalysis (PTC) Conditions.

    CHEMINFORM, Issue 51 2004
    Ahmed M. M. El-Saghier
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Phase Transfer Catalysis in the Synthesis of Diarylamines by Ullmann Reaction.

    CHEMINFORM, Issue 46 2004
    L. P. Nikitenkova
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    A Convenient Procedure for the Synthesis of O6 -Benzylguanine Derivatives by Phase Transfer Catalysis.

    CHEMINFORM, Issue 28 2003
    Qi-Huang Zheng
    No abstract is available for this article. [source]

    Synthesis of Aryl 5-(2-Chlorophenyl)-2-furoates under Phase Transfer Catalysis.

    CHEMINFORM, Issue 2 2003
    Zheng Li
    No abstract is available for this article. [source]

    Phase Transfer Catalysis in Solid,Liquid System as a Selective Method of Mono-alkylation of ,-Sulfonyl Thioesters.

    CHEMINFORM, Issue 40 2002
    Blanka Wladislaw
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Eco-friendly methodologies for the synthesis of some aromatic esters, well-known cosmetic ingredients

    INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2005
    C. Villa
    Synopsis Solid,liquid solvent-free phase transfer catalysis (PTC) and acidic catalysis in dry media were applied, with noticeable improvement and simplification over classical procedures in a Green Chemistry context, to the synthesis of some aromatic esters useful as cosmetic ingredients: 3-methylbutyl 4-methoxycinnamate, 2-ethylhexyl 4-methoxycinnamate, 2-ethylhexyl 4-(dimethylamino)benzoate and 2-ethylhexyl salicylate, well-known ultraviolet B sunscreen filters; 4-isopropylbenzyl salicylate, UV absorber and cutaneous antilipoperoxidant; propyl 4-hydroxybenzoate and butyl 4-hydroxybenzoate (parabens), antimicrobial agents. The reactions were performed under microwave (MW) activation and conventional heating. The best results for the synthesis of cinnamic, salicylic and 4-(dimethylamino)benzoic esters were achieved by in situ preformed carboxylates alkylation with alkyl bromides using PTC. The 4-hydroxybenzoates were obtained in good yields by classical esterification of the acid with alcohols using a simple heterogeneous mixture of reagents with catalytic amounts of p -toluenesulfonic acid (PTSA). The comparisons of yields and thermal profiles under either MW or conventional heating were studied and reported. Résumé La catalyse par transfert de phase (CTP) solide-liquide sans solvant et l'estérification acido-catalysée en ,,milieu sec'' ont été appliquées, dans le cadre de la ,,chimie verte'', avec des nettes améliorations et simplifications par rapport aux méthodes classiques, à la synthèse de certains esters aromatiques, ingrédients cosmétiques: 3-methylbutyl 4-méthoxycinnamate, 2-éthylhéxyl 4-méthoxycinnamate, 2-éthylhéxyl 4-(diméthylamino) benzoate et 2-éthylhéxyl salicylate, filtres solaires UVB bien connus; 4-isopropylbenzyl salicylate, filtre UV et antilipopéroxydant cutané; propyl 4-hydroxybenzoate et butyl 4-hydroxybenzoate (parabens), agents antimicrobien. Les réactions ont été procédées sous irradiation micro-onde et par chauffage classique. Pour la synthèse des esters dérivés de l'acide cinnamique, salicylique et 4-(diméthylamino)benzoïque les meilleurs résultats ont été obtenus grâce à la CTP par alkylation des carboxylates (préformés in situ) avec des bromures d'alkyle. Les esters de l'acide 4-hydroxybenzoique ont été obtenus avec de bons rendements par simple mélange hétérogène des réactifs et d'acide p-toluènesulfonique (PTSA) comme catalyseur. Les rendements et les profils de montée en température sous micro-ondes et par chauffage classique ont été comparés. [source]

    Syntheses and Properties of Fluorous Quaternary Phosphonium Salts that Bear Four Ponytails; New Candidates for Phase Transfer Catalysts and Ionic Liquids

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 12-13 2006
    Charlotte Emnet
    Abstract The fluorous tertiary phosphine [Rf6(CH2)2]3P [Rfn=CF3(CF2)n,1] and excess PhCH2Br, CH3(CH2)3OSO2CF3, or Rf6(CH2)2OSO2CF3 react (CF3C6H5, 45,110,°C) to give the phosphonium salts (PhCH2)[Rf6(CH2)2]3P+ Br, (2, 71,%), [CH3(CH2)3][Rf6(CH2)2]3P+ CF3SO3, (3, 65,%), or [Rf6(CH2)2]4P+ CF3SO3, (4, 83,%). The phosphines [Rf6(CH2)2]2[Rf8(CH2)2]P and [Rf8(CH2)2]3P are similarly elaborated with Rf6(CH2)2I, Rf8(CH2)2I, or Rf8(CH2)2Br (DMF, 115,°C) to [Rf8(CH2)2]4- x[Rf6(CH2)2]xP+ I, (x=3, 7; 2, 8; 1, 9; 0, 10) or [Rf8(CH2)2]4P+ Br, (80,60,%). The salts exhibit melting points between 110,°C and 43,°C, with lower values favored by less symmetrical cations, Rf6 segments, and triflate and bromide anions. Solubilities decrease in the solvent sequence CF3C6F5 (all salts at least moderately soluble, room temperature)>acetone>THF>CF3C6H5>CF3C6F11>CH3C6H5, Et2O, CH2Cl2, hexane (all salts insoluble at elevated temperatures); some appreciably increase upon heating. Partition coefficients are very biased towards fluorous phases (>93:<7). The salts can be quite efficient at extracting picrate from water into CF3C6F5 (97,86,% for 2, 4, 9, 10) or CF3C6H5 (85,66,% for 2 - 4), demonstrating their potential for phase transfer catalysis. A CF3C6F5 solution of Rf8(CH2)3I and aqueous NaCl react at 100,°C in the presence (but not the absence) of 9 to give Rf8(CH2)3Cl. [source]

    N1'-(p -[18F]Fluorobenzyl)naltrindole (p -[18F]BNTI) as a potential PET imaging agent for DOP receptors

    JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 10 2006
    Eyup Akgün
    Abstract The N1'-(p -fluorobenzyl)naltrindole 5 has been synthesized by reaction of 3- O -benzyl NTI 3 with p -fluorobenzylbromide under phase transfer catalysis. The subsequent 3- O -benzyldeprotection of 4 in HBr/CH3COOH gave the target compound 5 in three steps from naltrindole 2. p -FBNTI 5 is a novel delta opioid receptor antagonist (Ki=0.00312 nM) and antagonizes the delta opioid (DOP) agonist, DPDPE, with a Ke=1.55 nM in the mouse vas deferens preparation. Using the same synthetic strategy the synthesis of p -[18F]BNTI 10 was undertaken. The final yield was 4% and the specific activity varied in a range of 250,400 mCi/µmol. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Polyrotaxanes based on polyethers and ,-cyclodextrin

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2009
    Saloua Chelli
    Abstract A polyrotaxane in which ,-cyclodextrins (,-CDs) are threaded onto a polyether chain was prepared by polycondensation of a ,-CD/bisphenol A (BPA) inclusion complex with aromatic dihalides. Two dihalides, with and without a side chain, were used. This polycondensation results in a polyrotaxane (or pseudopolyrotaxane for polymers without stoppers) with a 1:1 threading ratio when the side chain is present and 2:3 when there is none. The long side chain prevents dethreading of the macrocycles. The best yield and a good threading ratio were obtained when the polycondensation was performed by liquid,solid phase transfer catalysis without solvent (L/S PTC) using 2,5-bi(iodomethyl)-4-methoxy-(1-octyloxy)benzene as dihalide. The 1H NMR and FTIR spectra show that the products consist of ,-CD and polyether. The 2D NOESY NMR spectrum shows that the polyether chains are included in the ,-CD cavity. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4391,4399, 2009 [source]