- Generation of 'naked' fluoride ions in unprecedentedly high concentrations from a fluoropalladium complex
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An F-/Cl- ligand exchange in the stable organopalladium fluoro complex 1 generates naked fluoride ions in unusually high concentrations. The released Freadily fluorinates dichloromethane under exceedingly mild conditions and deprotonates chloroform to produce dichlorocarbene.
- Grushin, Vladimir V.
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Read Online
- Phase-transfer catalytic dichlorocyclopropanation of styrene under the influence of ultrasound conditions - A kinetic study
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The kinetics for dichlorocyclopropanation of styrene with an excess of chloroform were studied under phase-transfer catalysis and ultrasound irradiation conditions using aqueous sodium hydroxide as the base and benzyltriethylammonium bromide as a catalyst. The reaction was carried out at 35 °C under pseudo-first order conditions by keeping aqueous sodium hydroxide and chloroform in excess and was monitored by gas chromatography (GC). The effects of agitation speed, quaternary ammonium salts, amount of catalyst, amount of sodium hydroxide and temperature on the kinetics of the conversion were investigated.
- Wang, Maw-Ling,Prasad, Gandavaram Syam
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Read Online
- Synthesis of gem-Dichlorocyclopropanes Using Liquid–Liquid Slug Flow
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By analyzing the causes of precipitation and clogging in continuous flow dichlorocyclopropanation, we established that the flow reaction can be performed only with T-junctions and microtubes. Unlike tertiary amines, when quaternary ammonium salts were used as PTCs, precipitation and clogging in microchannels did not occur, and an excellent yield of up to 99% was obtained after optimizing the reaction temperature, reactant concentration, and retention time. In the scale-up experiment, the reaction yields slightly decreased as the inner diameter (ID) of the microchannel was increased, but the calculated throughput increased from 2.41 g/h (ID: 1.5 mm) to 3.46 g/h (ID: 1.9 mm) and 5.13 g/h (ID: 2.4 mm).
- Lee, Jong Won,Jang, Yea Seul,Park, Jong Min,Park, Chan Pil
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Read Online
- DIHALOMETHANES AS C-H ACIDS IN THE CATALYTIC TWO-PHASE (CTP) SYSTEM - A NEW METHOD FOR THE SYNTHESIS OF gem-DICHLOROCYCLOPROPANES
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Dihalomethanes react with carbon tetrachloride and alkenes in the CTP system affording gem-dichlorocyclopropanes.
- Jonczyk, A.,Balcerzak, P.
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Read Online
- Isotope effects and the mechanism of deoxygenation of epoxides with dichlorocarbene
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The deoxygenation of styrene oxide with dichlorocarbene is studied by a combination of isotope effects and theoretical calculations. A normal 13C isotope effect of 1.016 is observed for the α-carbon of the styrene oxide but a surprising inverse isotope effect of 0.995 is observed at the β-carbon. This is indicative of a highly asynchronous process in which the Cα-O bond is broken without any progress in the breakage of Cβ-O bond. Theoretical calculations support this interpretation. This coarctate reaction is formally concerted as it avoids involving a high-energy intermediate, but it appears uninfluenced by transition state aromaticity.
- Singleton, Daniel A.,Wang, Zhihong
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Read Online
- Synthesis and Catalytic Activity of Quaternary Ammonium Salts Containing gem-Dichlorocyclopropane and 1,3-Dioxolane Fragments
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Abstract: Quaternary ammonium salts containing gem-dichlorocyclopropane and 1,3-dioxolane groups were synthesized in high yield. The reactions of dichlorocarbonation of styrene and O-alkylation of 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane in the presence of quaternary ammonium salts were studied. It was established that in the O-alkylation reaction, compounds containing cycloacetal and allyl moieties have the maximum efficiency in the series of catalysts studied. The structures of the isolated salts were proved by 1H and 13C NMR spectroscopy.
- Raskil’dina, G. Z.,Sakhabutdinova, G. N.,Yakovenko, E. A.,Zlotskii, S. S.
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p. 967 - 972
(2020/08/24)
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- Grafted Polyethylene Glycol–Graphene Oxide as a Novel Triphase Catalyst for Carbenes and Nucleophilic Substitution Reactions
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Abstract: Separation and reusability had been main problems for the using of polyethylene glycol (PEG) as phase transfer catalysts (PTCs). To solve these problems, PEG was firstly and successfully grafted on graphene oxide (GO) using BF3·C2H5OC2H5 as Lewis acid catalyst. The solid GO-PEG composites were systemically investigated by characterization techniques (TG, FT-IR, XPS, ICP-AES etc.) and then applied to some carbenes and nucleophilic substitution reactions as novel triphase catalysts. As the results, GO-PEG showed not only equally excellent catalytic activity (≥ 93% yield of 7,7-dichlorobicyclo[4.1.0]heptane and iodooctane) but also incomparable reusability (≥ 85% yield of iodooctane after using for four times) in comparison with traditional PTCs (PEG). Graphic Abstract: [Figure not available: see fulltext.].
- Yang, Xiaohai,Zhai, Jie,Xu, Tongchun,Xue, Bing,Zhu, Jie,Li, Yongxin
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p. 2767 - 2775
(2019/06/17)
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- Catalytic Asymmetric Cycloadditions of Silyl Nitronates Bearing α-Aryl Group
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1,3-Dipolar cycloadditions of 2-alkylacroleins or atropaldehyde with triisopropylsilyl nitronates bearing an α-aryl group produced 3-aryl-2-isoxazolines having a chiral quaternary center in up to 94% ee and up to 88% yield with the aid of Corey’s oxazaborolidine catalyst. Specifically, the TIPS nitronate with an α-(p-methoxyphenyl) group gave mainly the 2-isoxazolines having an all-carbon quaternary center.
- Jiang, Minghui,Feng, Lifei,Feng, Juanjuan,Jiao, Peng
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supporting information
p. 2210 - 2213
(2017/05/12)
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- Rate Acceleration of Solid-Liquid Phase-Transfer Catalysis by Rotor-Stator Homogenizer
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A rotor-stator homogenizer was found to be an effective mixing tool that accelerated solid-liquid phase-transfer reactions. In the asymmetric alkylation under phase-transfer conditions using the homogenizer, a considerably high turnover frequency was observed. (Figure presented.).
- Kano, Taichi,Aota, Yusuke,Maruoka, Keiji
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supporting information
p. 2996 - 2999
(2016/09/16)
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- Phase-transfer and other types of catalysis with cyclopropenium ions
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Abstract This work establishes the cyclopropenium ion as a viable platform for efficient phase-transfer catalysis of a diverse range of organic transformations. The amenability of these catalysts to large-scale synthesis and structural modification is demonstrated. Evaluation of the molecular structure of an optimal catalyst reveals some unique structural features of these systems. Finally, a discussion of electronic charge distribution underscores an important consideration for catalyst design. Aromatic ions: Tris(dialkylamino)cyclopropenium ions are shown to be effective carbocationic phase-transfer catalysts for a variety of mainstay transformations. The cyclopropenium platform is shown to be modular and accessible on scale. An X-ray structure and electron-density map revealed some unique features of this architecture (see scheme).
- Bandar, Jeffrey S.,Tanaset, Anont,Lambert, Tristan H.
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supporting information
p. 7365 - 7368
(2015/05/13)
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- Spectroscopic analysis of the products of the cycloaddition reaction of 1-Aryl-2-chlorocyclopropenes and cyclopentadiene
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The treatment of a series of 1-aryl-2,2-dihalocyclopropanes with t-BuOK at -10 °C produces the corresponding 1-aryl-2-halocyclopropenes, which react with cyclopentadiene to produce fairly good yield of [4+2]-cycloaddition products with more than 90% of the endo-isomer. The higher yield obtained from hexane medium then from methanol and ionic liquid demonstrates that the reaction is a nonpolar process. The treatment of a series of 1-aryl-2,2- dihalocyclopropanes with t-BuOK at -10 °C produces the corresponding 1-aryl-2-halocyclopropenes, which react with cyclopentadiene to produce fairly good yield of [4+2]-cycloaddition products with more than 90% of the endo-isomer. The higher yield obtained from hexane medium then from methanol and ionic liquid demonstrates that the reaction is a nonpolar process. Copyright
- Ding, Mei-Fang,Lee, Chuan-Chen,Lin, Lian-Chun,Lin, Shaw-Tao
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p. 285 - 289
(2014/05/06)
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- PEG400-enhanced synthesis of gem-dichloroaziridines and gem-dichlorocyclopropanes via in situ generated dichlorocarbene
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PEG400 is employed as an efficient phase transfer catalyst for the cycloaddition reaction of imines with dichlorocarbene, which is generated in situ from chloroform and sodium hydroxide, to give gem-dichloroaziridines in moderate to excellent yields at ambient temperature. This protocol is also extended to the synthesis of cyclopropanes from a variety of alkenes. In this study, PEG400 behaves as a phase transfer reagent thanks to its ability to coordinate with alkali metal cations. Notably, the one-pot synthesis of gem-dichloroaziridines from benzaldehyde and aromatic amines has also been successfully performed. The in situ generated acid, derived from CO2 and H2O, can also be effectively applied to promote the amide synthesis via the gem-dichloroaziridine pathway. The application of the gem-dichlorocyclopropane as a platform chemical is also briefly demonstrated, to afford the 2-phenylacrylaldehyde derivative via a ring-opening reaction. The Royal Society of Chemistry 2013.
- Song, Qing-Wen,Yu, Bing,Liu, An-Hua,He, Ying,Yang, Zhen-Zhen,Diao, Zhen-Feng,Song, Qing-Chuan,Li, Xue-Dong,He, Liang-Nian
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p. 19009 - 19014
(2013/10/22)
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- Nucleophilic displacements in alkylphosphonates: P-O versus P-C bond cleavage. A combined DFT and experimental study
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Potential energy surfaces for the nucleophilic displacements at phosphorus in dimethyl methyl, chloromethyl, dichloromethyl, and trichloromethyl phosphonates have been computed by DFT methods. The results reveal that sequential introduction of chlorine substituents at the methyl group in methyl phosphonates increases the stability of transition states and intermediates, which facilitates P-C bond cleavage. While nonsubstituted dimethyl methylphosphonate may undergo exclusive P-O bond cleavage, the trichlorinated analogue reacts exclusively via P-C bond dissociation to form dichlorocarbene, which was trapped by various olefins to form the corresponding gem-dichlorocyclopropanes.
- Ashkenazi, Nissan,Chen, Ravit
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p. 106 - 110
(2013/07/04)
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- Configurational stability of optically active dichloromethyl p-tolyl sulfoxide and its anionic species: Experimental and theoretical study
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Racemization of optically active dichloromethyl p-tolyl sulfoxide took place at -78°C in the presence of potassium bis(trimethylsilyl)amide (KHMDS), while the same racemization did not occur under reflux in toluene in the absence of KHMDS. Density functional theory calculations suggested that the pyramidal inversion at the sulfur center was unlikely to be involved in the racemization mechanism. An anionic species of the sulfoxide was found to be gradually converted into chlorobis(p-tolylsulfinyl)methane and dichlorocarbene. We propose a racemization mechanism mediated by achiral potassium p-toluenesulfenate and chloro(p-tolylsulfinyl)methylene. 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:131-137, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21074
- Kimura, Tsutomu,Tsuru, Takahiro,Momochi, Hitoshi,Satoh, Tsuyoshi
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p. 131 - 137
(2013/05/09)
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- An efficient recyclable polymer-supported bis-quaternary onium phase-transfer catalyst for the synthesis of dihalocyclopropyl derivatives at low alkaline concentration-comparative kinetic aspects
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In this work, a new polystyrene-bound bis-onium phase-transfer catalyst was synthesized, and their catalytic activities were investigated in the synthesis of dichlorocyclopropyl derivatives of olefins. The new polymer-anchored multi-site phase-transfer catalyst showed significant high catalytic activity as compared to single-site phase-transfer catalyst. The comparative kinetic investigation reveals that the dichlorocyclopropanation of 1-methyl-4-vinyl benzene is faster than styrene in the presence of the new catalyst. This catalyst can be used several times with consistent catalytic activity. Experimental observations support an interfacial-type mechanism. Furthermore, its catalytic utility was examined in alkylation reactions.
- Vivekanand,Wang, Maw-Ling
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scheme or table
p. 6 - 12
(2012/05/20)
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- Ionic liquids accelerating cycloaddition between 1-aryl-2-halocyclopropenes and furan
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Treatment of a series of 1-aryl-2,2-dihalocyclopropanes with t-BuOK at-10 °C gave the corresponding 1-aryl-2-halocyclopropenes, which react with furan in a RTIL to give a fair good yield of the [4+2]-cycloadducts with more than 90% of the exo-isomer. The imidazolium type ionic liquids are able to accelerate this cycloaddition process with high steric selectivity. Neither pyrrole nor thiophene undergoes the cycloaddition with cyclopropene to form the [4+2]-cycloadduct. 1-Aryl-3,3-difluoro-2-halocyclopropenes are inert towards furan even at a temperature higher than 100 °C.
- Ding, May-Fan,Lin, Shaw-Tao,Chang, Woan-Ju
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experimental part
p. 240 - 247
(2010/09/16)
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- Is a phase transfer catalyst really needed for gem-dihalocyclopropanation of alkenes with haloforms in the presence of alkali metal hydroxide?
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Chloroform, bromoform and dibromochloromethane react with alkenes in the presence of cone. aq. sodium hydroxide, without phase-transfer catalyst, giving gem-dihalocyclopropanes. The process is particularly useful for preparation of gem-bromochlorocyclopropanes which are formed in good yields and in high selectivity.
- Karwowska,Jonczyk
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- New multi-site phase transfer catalyst for the addition of dichlorocarbene to olefins
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Three step synthesis of a new, water-soluble multi-site phase transfer catalyst (MPTC-I), viz., α,α1,α11- tris(triethyl ammonium methylene bromide) β-hydroxy ethyl benzene is described. The potentiality of MPTC-I is demonstrated by studying kinetic aspects of the reactions, viz. dichlorocarbene addition to styrene, α-methyl styrene and trans-stilbene.
- Shanmugan,Balakrishnan
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p. 1069 - 1074
(2008/02/11)
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- Triazatriangulenium cations: Highly stable carbocations for phase-transfer catalysis
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(Chemical Equation Presented) Highly stable triazatriangulenium carbocations, of pKR+ higher than 20, can be used as novel phase-transfer catalysts for several classical organic reactions, their intrinsic stability in strongly basic and nucleophilic conditions rendering this novel use feasible.
- Nicolas, Cyril,Lacour, Jerome
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p. 4343 - 4346
(2007/10/03)
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- Novel ambiphilic dichlorocarbenoid equivalent in alkene cyclopropanation and carbonyl olefination
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The Ti-Mg-dichloromethylene complexes derived from the oxidative addition of CCl4 to the Mg-TiCl4 bimetallic species serve as a novel class of ambiphilic dichlorocarbenoid equivalents. Not only is Ti-Mg-dichlorocarbenoid highly selective but also it seems highly reactive in both alkene cyclopropanations and carbonyl dichloromethylenations.
- Chien, Ching-Ting,Tsai, Chia-Chung,Tsai, Chi-Hui,Chang, Tsai-Yuan,Tsai, Ping-Kuei,Wang, Ying-Chuan,Yan, Tu-Hsin
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p. 4324 - 4327
(2007/10/03)
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- AMINE-BASED AND AMIDE-BASED INHIBITORS OF SEMICARBAZIDE-SENSITIVE AMINE OXIDASE (SSAO) ENZYME ACTIVITY AND VAP-1 MEDIATED ADHESION USEFUL FOR TREATMENT OF DISEASES
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Compositions and methods are disclosed for inhibiting semicarbazide-sensitive amine oxidase (SSAO), also known as vascular adhesion protein-1 (VAP-1). The compounds disclosed are amine-containing and amide-containing compounds. The compounds and compositions are useful for treatment of diseases, including inflammation, inflammatory diseases and autoimmune disorders.
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Page/Page column 84
(2010/02/13)
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- gem-Dihalocyclopropane formation by iron/copper activation of tetrahalomethanes in the presence of nucleophilic olefins. Evidence for a carbene pathway
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The activation of CBr4 and CCl4 by a bimetallic iron/copper couple in acetonitrile is a new, inexpensive, nontoxic and efficient procedure for gem-dibromo- and gem-dichloromethylenation of nucleophilic alkenes. This new route to gem-dihalocyclopropanes involves dihalocarbene species.
- Léonel, Eric,Lejaye, Michael,Oudeyer, Sylvain,Paugam, Jean Paul,Nédélec, Jean-Yves
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p. 2635 - 2638
(2007/10/03)
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- Synthesis, characterization, and utility of trialkyl(3-sulfopropyl)ammonium betaines as new phase transfer reagents
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Synthesis of water-soluble phase transfer reagents, trialkyl(3-sulfopropyl)ammonium betaines and its utility in various hydroxide-ion initiated reactions are described.
- Jayachandran, Joseph Paul,Wang, Maw-Ling
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p. 2463 - 2468
(2007/10/03)
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- Synthesis of a poly(ethylene glycol)-supported tetrakis ammonium salt: A recyclable phase-transfer catalyst of improved catalytic efficiency
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The immobilization of four quaternary ammonium groups on a poly(ethylene glycol) support provided an efficient and recyclable phase-transfer catalyst.
- Benaglia, Maurizio,Cinquini, Mauro,Cozzi, Franco,Tocco, Graziella
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p. 3391 - 3393
(2007/10/03)
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- 1-Alkyl-4-dialkylaminopyridinium halides as phase-transfer catalysts in dichlorocarbene reactions
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A series of 1-alkyl-4-dialkylaminopyridinium halides derived from 4-dimethylamino- and 4-morpholinopyridines were synthesized and tested as phase-transfer catalysts in three typical reactions of dichlorocarbene: dehydration of benzamide, N-formylation of diphenylamine, and dichlorocyclopropanation of styrene. The catalytic performance of the above compounds was found comparable or higher than that of conventional quaternary ammonium catalysts. The influence of catalyst structure on the reactivity was evaluated.
- Kupetis, Gytis-Kazimieras,Saduikis, Gintautas,Nivinskiene, Ona,Eicher-Lorka, Olegas
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p. 313 - 321
(2007/10/03)
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- A poly(ethylene glycol)-supported quaternary ammonium salt: An efficient, recoverable, and recyclable phase-transfer catalyst
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(matrix presented) A quaternary ammonium salt readily immobilized on a soluble poly(ethylene glycol) polymer support efficiently catalyzes different reactions carried out under phase-transfer catalysis conditions; the catalyst, easily recovered by precipitation and filtration, shows no appreciable loss of activity when recycled three times.
- Annunziata, Rita,Benaglia, Maurizio,Cinquini, Mauro,Cozzi, Franco,Tocco, Graziella
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p. 1737 - 1739
(2007/10/03)
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- Solid/liquid phase-transfer catalysis. Some models and solvent influence
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The applicability of the models developed earlier for the topochemical reactions in the solid/liquid phase-transfer catalysis is discussed. Depending on the solvent and the catalyst the reaction may be inhibited by the crust of the solid inorganic product. Solvents like MeCN and THF, and catalysts such as polyethylene glycols loosen this crust, thus preventing the inhibition. The solvent influence using the E(T)(30) parameter in different reactions in the solid/liquid system is investigated.
- Sirovski, Felix,Reichardt, Christian,Gorokhova, Marina,Ruban, Sergei,Stoikova, Elena
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p. 6363 - 6374
(2007/10/03)
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- A new phase transfer reagent for the addition of dichlorocarbene to olefins under mild PTC conditions
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A three-step synthetic route to a novel water soluble phase transfer reagent, Diquat (Dq-Br), viz., 2-benzilidine-N,N,N,N',N',N'- hexaethyl propane-1,3 diammonium dibromide and its utility in various dichlorocarbenations to olefins are described.
- Jayachandran, J. Paul,Wang, Maw-Ling
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p. 4101 - 4112
(2007/10/03)
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- Photochemical activation of metalloporphyrin carbene complexes
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While the photochemistry of simple metalloporphyrin complexes has been explored to some extent, the photoactivation of multiple-bonded axial ligands coordinated to metalloporphyrins has not been previously examined. We report here the photochemistry of several iron porphyrin carbene and vinylidene complexes. Irradiation of these complexes with visible light cleaves the iron-carbon double bond and produces a four coordinate iron(II) porphyrin and a free carbene, which can be trapped in high yield with a variety of alkenes. This photochemistry is unique among organo transition metal complexes of carbenes or alkylidenes. For these metalloporphyrin carbene complexes, the presence of the porphyrin ring alters the photoreactivity of the metal-carbon bond. This is probably due to the mixing between the π * orbitals of the porphyrin ring and the iron-carbon orbitals, which is also responsible for the hypso-type spectrum (i.e. blue-shifted) seen in these complexes. Hypso spectra are a common trait in other photodissociative porphyrin complexes, most notably CO complexes.
- Ziegler, Christopher J.,Suslick, Kenneth S.
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- Synthesis and in vitro reactivity of 3-carbamoyl-2- phenylpropionaldehyde and 2-phenylpropenal: Putative reactive metabolites of felbamate
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We propose that 3-carbamoyl-2-phenylpropionaldehyde is an intermediate in the metabolism of felbamate, an anti-epileptic drug with a unique profile of therapeutic activity, and undergoes a cascade of chemical reactions responsible for the toxic properties of the parent drug. To test this hypothesis, we have synthesized 3-carbamoyl-2-phenylpropionaldehyde and evaluated its in vitro reactivity. This molecule was found to be highly unstable at physiological pH (t(1/2) ≤ 30 s) and to undergo facile elimination to 2-phenylpropenal, an α, β-unsaturated aldehyde commonly termed atropaldehyde. However, the predominant reaction pathway for 3- carbamoyl-2-phenylpropionaldehyde was reversible cyclization to generate 4- hydroxy-5-phenyltetrahydro-1,3-oxazin-2-one, a urethane that has a considerably longer half-life at physiological pH (t(1/2) ≤ 5 h) and may serve as a stable reservoir of the reactive aldehyde both in vitro and in vivo. Atropaldehyde is a potent electrophile and was found to exhibit cytotoxicity to cultured fibroblasts (50% growth inhibition (GI50) = 4.1 ± 1.1 μM) comparable to the known unsaturated aldehyde toxins, 4-hydroxy-2- nonenal and acrolein. 3-Carbamoyl-2-phenylpropionaldehyde also exhibited significant cytotoxicity (GI50 = 53 ± 8 μM), whereas 2-phenyl-1, 3- propanediol monocarbamate (GI50 > 500 μM) and 3-carbamoyl-2- phenylpropionic acid (GI50 > 500 μM) were nontoxic. We have additionally demonstrated the formation of a glutathione-atropaldehyde conjugate from the in vitro incubation of 3-carbamoyl-2-phenylpropionaldehyde with glutathione. Thus, the potent cytotoxicity and potential allergenicity of atropaldehyde implicate this unsaturated aldehyde as a possible causative agent in the toxicities observed with felbamate treatment.
- Thompson, Charles D.,Kinter, Michael T.,Macdonald, Timothy L.
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p. 1225 - 1229
(2007/10/03)
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- Preparation of zirconium (benzyldiethylammoniomethylphosphonate chloride) and PTC reactions
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Zirconium (benzyldiethylammoniomethylphosphonate chloride)phosphate Zr(HPO4)2-x (O2PCH2N+Et2CH2ph·Cl-)x·H2O, (0.25 x 0.75, ZBEPC-ZP) were prepared for the first time and characterized by IR and elemental analyses. ZBEPC-ZP catalyzed some typical PTC reactions in L/S/L phases were carried out to give good results. ZBEPC-ZP can be easily separated from the reaction mixture and recovered about 70-100%, and can be reused and did not show any change in activity after 10 cycles.
- Fu,Wen
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p. 2435 - 2442
(2007/10/02)
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- New 'multi-site' phase transfer catalyst for the addition of dichlorocarbene to styrene
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The kinetics of dichlorocarbene addition to styrene has been studied under phase transfer catalytic conditions using aqueous sodium hydroxide as the base and 2-benzylidine-N,N,N,N'N'N'-hexaethylpropane-1,3-diammonium dichloride as a new 'multi-site' phase transfer catalyst.The reaction was carried out at 40 deg C under pseudo-first order conditions by keeping aqueous sodium hydroxide and chloroform in excess and was monitored by GC.The effect of various experimental parameters on the rate of the reaction has been studied and based on the results obtained, a suitable mechanism is proposed.
- Balakrishnan, Thayilekannu,Jayachandran, J. Paul
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p. 2081 - 2086
(2007/10/03)
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- Synthesis and utility of α,α'-bis (triethyl ammonium methylene chloride) β-phenyl ethene in hydroxide ion initiated reactions - A new multi-site phase transfer catalyst
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A three step synthesis of novel 'multi-site' water soluble phase transfer catalyst viz, α,α'-bis(triethyl ammonium methylene chloride) β-phenyl ethene and its utility in various organic biphase reactions are described.
- Balakrishnan,Jayachandran
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p. 3821 - 3830
(2007/10/03)
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- Calixarene-Catalyzed Generation of Dichlorocarbene and Its Application to Organic Reactions: The Catalytic Action of Octopus-Type Calixarene
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The dichlorocarbene generation reaction from CHCl3 and solid KOH in CH2Cl2 was catalyzed by the p-t-butylcalixarene derivative 1 which bears six 3,6,9-trioxadecyl substituents on the phenolic oxygens.Dichlorocarbene generated by this method reacted efficiently with alkenes and amides to give dichlorocyclopropane derivatives and nitriles, respectively, in high yields.The reaction with alkadiene having isolated double bonds gave mixtures of the mono- and bis-dichlorocarbene adducts, but the monoadduct formation always predominated.The catalytic action of the calixarene and the reactivity features of dichlorocarbene generated by the above procedure are discussed on the basis of kinetic measurements.They are also compared with those of the 18-crown-6-catalyzed reactions.
- Nomura, Eisaku,Taniguchi, Hisaji,Otsuji, Yoshio
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p. 792 - 799
(2007/10/02)
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- A CONVENIENT METHOD FOR SYNTHESIS OF GEM-BROMOCHLOROCYCLOPROPANES
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Gem-bromochlorocyclopropanes can be prepared by a convenient method based on the reactions of the mixtures of haloforms and tetrahalomethanes or hexahaloethane with powdered sodium hydroxide.
- Xu, Linxiao,Tao, Fenggang
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p. 2117 - 2122
(2007/10/02)
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- Cationic Complexes of Transition Metals as a New Type of Phase-transfer Catalyst
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Cationic complexes of the type (+)Cl(-) (M = Rh, Ir, Fe; L = 2,2'-bipyridyl or 1,10-phenanthroline) were found to act as phase-transfer catalysts that can be used as bifunctional catalysts in consecutive reactions of metal-complex and phase-transfer catalysis.
- Goldberg, Yuri Sh.,Iovel, Irina G.,Shymanska, Mariya V.
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p. 286 - 287
(2007/10/02)
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- Carbon Tetrachloride-Dimethyl Sulphone-Potassium Hydroxide-t-Butyl Alcohol: a Convenient New Reagent for gem-Dichloromethylenation of Alkenes
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The action of dimethyl sulphone-potassium hydroxide-t-butyl alcohol on carbon tetrachloride readily affords dichlorocarbene.In the presence of alkenes, gem-dichlorocyclopropanes are formed in moderate to high yields.The dichlorocarbene generated by this procedure adds stereospecifically to alkenes with retention of geometric configuration about the carbon-carbon double bond.Relative reactivities of alkenes towards the CCl4-derived dichlorocarbene parallel the nucleophilicities of the alkenes and indicate that free dichlorocarbene is probably involved.
- Poon, Chi-Duen,Yuen, Po-Wai,Man, Tim-On,Li, Chun-Sing,Chan, Tze-Lock
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p. 1561 - 1563
(2007/10/02)
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- THE REACTION OF TERTIARY AMINES WITH DICHLOROCARBENE
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Reaction of dichlorocarbene with phenethyl tertiary amines gives conjugated unsaturated compounds which are the result of a β-elimination.A similar reaction occurs with β-tertiary amino esters.
- Castedo, Luis,Castro, Jose L.,Riguera, Ricardo
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p. 209 - 212
(2007/10/02)
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