- Organotin-oxomolybdate coordination polymer as catalyst for synthesis of unsymmetrical organic carbonates
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Efficient and greener synthesis of unsymmetrical organic carbonates is of great importance. In this work, two organotin-oxometalates, Bu 2SnMoO4 and (Bu3Sn)2MoO4, were prepared and their catalytic performance for the transesterification of diethyl carbonate (DEC) with alcohols to synthesize unsymmetrical organic carbonates was studied. It was found that (Bu3Sn)2MoO 4 was very active and selective for the transesterification of DEC and various alcohols, including alkyl, cyclic, and aryl alcohols due to the synergetic effect between the groups of [MoO4]2- and [Bu3Sn]+ in the catalyst. The yields of the corresponding carbonates could reach 98% at the suitable conditions. The catalyst was reused five times and the activity and selectivity were not changed. We believe that the highly efficient, versatile, greener, inexpensive, selective and stable catalyst has great potential applications in the synthesis of various unsymmetrical organic carbonates from DEC and alcohols. The Royal Society of Chemistry.
- Song, Jinliang,Zhang, Binbin,Wu, Tainbin,Yang, Guanying,Han, Buxing
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- N-Heterocyclic Carbene-Phosphinidene Complexes of the Coinage Metals
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Coinage metal complexes of the N-heterocyclic carbene-phosphinidene adduct IPr·PPh (IPr=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) were prepared by its reaction with CuCl, AgCl, and [(Me2S)AuCl], which afforded the monometallic complexes [(IPr·PPh)MCl] (M=Cu, Ag, Au). The reaction with two equivalents of the metal halides gave bimetallic [(IPr·PPh)(MCl)2] (M=Cu, Au); the corresponding disilver complex could not be isolated. [(IPr·PPh)(CuOTf)2] was prepared by reaction with copper(I) trifluoromethanesulfonate. Treatment of [(IPr·PPh)(MCl)2] (M=Cu, Au) with Na(BArF) or AgSbF6 afforded the tetranuclear complexes [(IPr·PPh)2M4Cl2]X2 (X=BArF or SbF6), which contain unusual eight-membered M4Cl2P2 rings with short cuprophilic or aurophilic contacts along the chlorine-bridged M...M axes. Complete chloride abstraction from [(IPr·PPh)(AuCl)2] was achieved with two equivalents of AgSbF6 in the presence of tetrahydrothiophene (THT) to form [(IPr·PPh){Au(THT)}2][SbF6]2. The cationic tetra- and dinuclear complexes were used as catalysts for enyne cyclization and carbene transfer reactions.
- Doddi, Adinarayana,Bockfeld, Dirk,Nasr, Alexandre,Bannenberg, Thomas,Jones, Peter G.,Tamm, Matthias
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- The synthesis of organic carbonates over nanocrystalline CaO prepared via microemulsion technique
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A new method, combining microemulsion, ultrasonication and ultracentrifugation with the addition of polyethylene glycol was developed to synthesize nanocrystalline CaCO3. Calcination of the CaCO3 resulted in nanocrystalline CaO. Physical characterization by XRD indicated that the material had high purity of nanocrystalline CaCO3 and CaO particles respectively. TEM images showed that the material was composed of non-agglomerated, single nanoparticles with a size range of 10-30 nm. The CaO was used as a catalyst in the solvent free direct condensation of diethyl carbonate with benzyl alcohol. The catalytic reaction resulted in 99.7% conversion and 100% selectivity for benzyl ethyl carbonate in 3 h.
- Adam, Farook,Wong, Min-Siang
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- Electrochemical anion pool synthesis of amides with concurrent benzyl ester synthesis
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An electrosynthesis method for amide bond formation has been developed in an attempt to increase the atom economy for this class of reactions. This "anion pool" method electrochemically generates strong nucleophiles from amine substrates. The amine nucleophiles then react with acid anhydrides to generate amides, and the by-product from this reaction undergoes further chemical transformations to generate pharmaceutically relevant benzoic esters. These one-pot reactions are operationally simple, are performed at room temperature, and avoid rare transition metals and added bases. The amide synthesis is amenable to primary and secondary amines and a variety of anhydrides with yields up to 90% obtained. Atom economy and process mass index (PMI) values calculated for this procedure indicate that this process can be considered greener compared to traditional amide synthesis routes used by industry. Furthermore, this electrochemical approach showed unique selectivity when substrates that contained two inequivalent amine moieties were examined.
- Mevan Dissanayake,Melville, Alex D.,Vannucci, Aaron K.
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supporting information
p. 3165 - 3171
(2019/06/18)
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- One-pot carbonyl reduction and carbonate formation using sodium borohydride in dialkyl carbonate solvents
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Preparation of mixed carbonates proceeded in one step from ketones and aldehydes via treatment with NaBH4 in dimethyl or diethyl carbonate solvent at elevated temperatures. This is an efficient and convenient alternative to the traditional two-step sequence of carbonyl reduction to alcohol and subsequent carbonate formation by treatment with an alkyl chloroformate. 25 examples are presented from 49 to 92% yield, highlighting the versatility of this reaction.
- Osumah, Abdulakeem,Magolan, Jakob,Waynant, Kristopher V.
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supporting information
(2019/10/14)
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- Carbon Dioxide Utilisation for the Synthesis of Unsymmetrical Dialkyl and Cyclic Carbonates Promoted by Basic Ionic Liquids
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An efficient and greener synthesis of unsymmetrical organic carbonates mediated by Hünig's base-appended basic ionic liquids, via carbon dioxide conversion, is described here. These ionic liquids were found to be effective bases for the fixation of carbon dioxide by various alcohols and benzyl bromide, at room temperature. When the alcohol and the halide functionalities are present within the same substrate, the reaction cleanly produces a cyclic carbonate. These functionalised basic ionic liquids were fully recyclable with no loss product yields.
- Goodrich, Peter,Gunaratne, H. Q. Nimal,Jin, Lili,Lei, Yuntao,Seddon, Kenneth R.
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p. 181 - 185
(2018/03/09)
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- Immobilization of 1,5,7-triazabicyclo[4.4.0]dec-5-ene on magnetic γ-Fe2O3 nanoparticles: A highly recyclable and efficient nanocatalyst for the synthesis of organic carbonates
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1,5,7-Triazabicyclo[4.4.0]dec-5-ene was immobilized on magnetic γ-Fe2O3 nanoparticles as a magnetic nanocatalyst. The nanoparticle reagent was obtained with good loading levels and has been successfully used for the efficient and selective synthesis of organic carbonates by the direct condensation of alcohols and diethyl carbonate. The catalyst is quantitatively recovered by an external magnet and can be reused for six cycles with almost consistent activity. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene was immobilized on magnetic γ-Fe2O3 nanoparticles as a magnetic nanocatalyst. The nanoparticle reagent was obtained with good loading levels and has been successfully used for the efficient and selective synthesis of organic carbonates by the direct condensation of alcohols and diethyl carbonate. Copyright
- Wu, Liqiang,Tian, Shuanbao
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p. 2080 - 2087
(2014/05/06)
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- Immobilization of 1,5,7-triazabicyclo[4.4.0]dec-5-ene on magnetic γ-Fe2O3 nanoparticles: A highly recyclable and efficient nanocatalyst for the synthesis of organic carbonates
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1,5,7-Triazabicyclo[4.4.0]dec-5-ene was immobilized on magnetic γ-Fe2O3 nanoparticles as a magnetic nanocatalyst. The nanoparticle reagent was obtained with good loading levels and has been successfully used for the efficient and selective synthesis of organic carbonates by the direct condensation of alcohols and diethyl carbonate. The catalyst is quantitatively recovered by an external magnet and can be reused for six cycles with almost consistent activity. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene was immobilized on magnetic γ-Fe2O3 nanoparticles as a magnetic nanocatalyst. The nanoparticle reagent was obtained with good loading levels and has been successfully used for the efficient and selective synthesis of organic carbonates by the direct condensation of alcohols and diethyl carbonate.
- Wu, Liqiang,Tian, Shuanbao
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p. 2080 - 2087
(2015/04/27)
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- β-aryl nitrile construction via palladium-catalyzed decarboxylative benzylation of α-cyano aliphatic carboxylate salts
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The palladium-catalyzed decarboxylative benzylation of α-cyano aliphatic carboxylate salts with benzyl electrophiles was discovered. This reaction exhibits good functional group compatibility and proceeds under relatively mild conditions. A diverse range of quaternary, tertiary and secondary β-aryl nitriles can be conveniently prepared by this method. Copyright
- Shang, Rui,Huang, Zheng,Xiao, Xiao,Lu, Xi,Fu, Yao,Liu, Lei
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supporting information
p. 2465 - 2472,8
(2020/08/31)
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- Alkali-metal ion catalysis in alkaline ethanolysis of 2-pyridyl benzoate and benzyl 2-pyridyl carbonate: Effect of modification of nonleaving group from benzoyl to benzyloxycarbonyl
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A kinetic study is reported on nucleophilic displacement reactions of benzyl 2-pyridyl carbonate 6 with alkalimetal ethoxides, EtOM (M = Li, Na, and K), in anhydrous ethanol at 25.0 ± 0.1 oC. The plots of pseudo-firstorder rate constant kobsd vs. [EtOM] curve upward, a typical phenomenon reported previously for alkaline ethanolysis of esters in which alkali-metal ions behave as a Lewis-acid catalyst. The kobsd value for the reaction of 6 with a fixed EtOK concentration decreases rapidly upon addition of 18-crown-6-ether (18C6), a complexing agent for K+ ion up to [18C6]/[EtOK] = 1.0 and then remains constant thereafter, indicating that the catalytic effect exerted by K+ ion disappears in the presence of excess 18C6. The reactivity of EtOM towards 6 increases in the order EtO- EtOLi EtONa EtOK, which is contrasting to the reactivity order reported for the corresponding reactions of 2-pyridyl benzoate 4, i.e., EtO- EtOK EtONa EtOLi. Besides, 6 is 1.7 and 3.5 times more reactive than 4 towards dissociated EtO- and ion-paired EtOK, respectively. The reactivity difference and the contrasting metal-ion selectivity are discussed in terms of electronic effects and transition-state structures.
- Um, Ik-Hwan,Kang, Ji-Sun,Kim, Chae Won,Lee, Jae-In
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p. 519 - 523
(2012/05/04)
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- Electrochemical carboxylation of benzylic carbonates: Alternative method for efficient synthesis of arylacetic acids
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Electrochemical carboxylation of benzylic carbonates was successfully performed as an alternative method for the synthesis of phenylacetic acids by using a one-compartment cell equipped with a Pt plate cathode and an Mg rod anode in CH3CN to afford the corresponding phenylacetic acids in good yields.
- Ohkoshi, Masashi,Michinishi, Jun-Ya,Hara, Shoji,Senboku, Hisanori
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experimental part
p. 7732 - 7737
(2010/10/21)
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- Environmentally friendly transesterification and transacylation reactions under libr catalysis
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A room-temperature, convenient transesterification of various esters, induced by catalytic amounts of lithium bromide and diethylamine in a solvent-free environment, is described. Products are obtained in good purity by simple filtration to remove the catalyst and evaporation of the volatile portion. The procedure has also been successfully applied to transacetylation and aminolysis of esters. Springer-Verlag 2010.
- Abaee, M. Saeed,Akbarzadeh, Elahe,Sharifi, Roholah,Mojtahedi, Mohammad M.
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experimental part
p. 757 - 761
(2011/07/08)
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- An efficient synthesis of organic carbonates using nanocrystalline magnesium oxide
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An efficient and selective synthesis of organic carbonates using nanocrystalline magnesium oxide has been realized by the direct condensation of alcohols and diethyl carbonate. The catalyst is quantitatively recovered by simple centrifugation and can be reused for four cycles with almost consistent activity.
- Kantam, M. Lakshmi,Pal, Ujjwal,Sreedhar,Choudary
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p. 1671 - 1675
(2008/02/11)
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- A new, mild, general and efficient route to aryl ethyl carbonates in solvent-free conditions promoted by magnesium perchlorate
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A new, general and mild method for the direct synthesis of aryl and alkyl ethyl carbonates promoted by a Lewis acid is reported. The reaction proceeds smoothly with diethyl dicarbonate in the presence of Mg(ClO4) 2, a specific activator of 1,3-dicarbonyl compounds, and shows general applicability. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Locatelli, Manuela,Marcantoni, Enrico,Melchiorre, Paolo,Palazzi, Paolo,Sambri, Letizia
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p. 4429 - 4434
(2007/10/03)
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- New highly active and selective heterogeneous catalytic system for the synthesis of unsymmetrical organic carbonates: A green protocol
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A green, efficient, and selective synthesis of unsymmetrical organic carbonates is realised in the liquid phase by direct condensation of an alcohol and diethyl carbonate, in an ecocompatible route, in the presence of a recyclable heterogeneous solid-base CsF/α-Al2O3 catalyst. The catalyst displayed unprecedented activity after activation at 393 K for 4 h and produced quantitative yields with a greater rate compared with solid bases reported so far. The present process is a potential alternative to replace soluble bases in commercial synthesis. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Veldurthy, Bhaskar,Clacens, Jean-Marc,Figueras, Francois
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p. 1972 - 1976
(2007/10/03)
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- Method for producing symmetrical and asymmetrical carbonates
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Process for the preparation of symmetrical and asymmetrical carbonates of the general formula I by reaction of alcohols of the general formula II and alkyl or aryl halides of the general formula III,R—OH??IIR′—HAL??IIIwith carbon dioxide and caesium carbonate at room temperature in dipolar aprotic solvents.
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Page column 3
(2010/02/06)
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- An efficient synthesis of organic carbonates: Atom economic protocol with a new catalytic system
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Selective and solvent free synthesis of unsymmetrical organic carbonates catalysed by a reusable MgLa mixed oxide is achieved for the first time via direct condensation of an alcohol and diethyl carbonate in economic route with excellent yields.
- Veldurthy, Bhaskar,Figueras, Francois
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p. 734 - 735
(2007/10/03)
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- Method for the production of dibenzyl carbonates
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Dibenzyl carbonates are prepared by reacting a dialkyl carbonate with a benzyl alcohol in the presence of a basic catalyst and removing the highly volatile components and the catalyst from the reaction mixture. This process permits the preparation of benzyl carbonates in a simple manner, in good yields and without any particular technical safety arrangements.
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- A safe and mild synthesis of organic carbonates from alkyl halides and tetrabutylammonium alkyl carbonates
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A safe and mild procedure for the synthesis of mixed organic carbonates is described. Reaction of commercially available tetrabutylammonium methoxide and ethoxide with carbon dioxide yields the corresponding methyl and ethyl tetrabutylammonium carbonates (TBAMC and TBAEC). The reactions of these new compounds with several different alkyl halides give methyl and ethyl carbonates in high yields. The use of classic toxic and harmful chemicals such as phosgene and carbon monoxide is avoided.
- Verdecchia, Mirella,Feroci, Marta,Palombi, Laura,Rossi, Leucio
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p. 8287 - 8289
(2007/10/03)
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- Catalytic activity of MCM-41-TBD in the selective preparation of carbamates and unsymmetrical alkyl carbonates from diethyl carbonate
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The synthesis of carbamates 3 and unsymmetrical alkyl carbonates 5 by reaction of diethyl carbonate with aliphatic amines or alcohols has been realized by using as heterogeneous catalyst a hybrid organic-inorganic material prepared by anchoring TBD to MCM-41 silica. Products are obtained in high yield and very good selectivity and the solid catalyst can be recovered simply by filtration and reused for different cycles without apparent lowering of activity. A supported N -carbethoxyguanidinium active intermediate is proposed, and some spectroscopic data are shown to support the mechanistic hypothesis.
- Carloni, Silvia,De Vos, Dirk E.,Jacobs, Pierre A.,Maggi, Raimondo,Sartori, Giovanni,Sartorio, Raffaella
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p. 199 - 204
(2007/10/03)
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- Reactivity of the electrogenerated O2·-/CO2 system towards alcohols
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The reactivity towards alcohols of the system obtained from the reduction of dioxygen carried out in aprotic dipolar solvents and in the presence of carbon dioxide has been investigated. This reagent is able to convert primary and secondary alcohols into the corresponding aldehydes and ketones. The optimization of the experimental conditions as well as the advantages and the limitations of the method are reported. Wiley-VCH Verlag GmbH, 2001.
- Casadei, Maria Antonietta
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p. 1689 - 1693
(2007/10/03)
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- Electrogenerated base-promoted synthesis of organic carbonates from alcohols and carbon dioxide
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Electrogenerated bases promote the reaction between primary alcohols and carbon dioxide to give organic carbonates in excellent yields. Secondary alcohols are converted in moderate yields, whereas tertiary alcohols and phenols are unreactive. 1,2-Diols give a mixture of both cyclic and linear diand monocarbonates. These latter are intermediates in the reaction pathway leading to the cyclic derivatives.
- Casadei, Maria Antonietta,Cesa, Stefania,Rossi, Leucio
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p. 2445 - 2448
(2007/10/03)
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- Rate and product studies with benzyl and p-nitrobenzyl chloroformates under solvolytic conditions
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The specific rates of solvolysis of p-nitrobenzyl chloroformate are well correlated using the extended Grunwald-Winstein equation, with a high sensitivity (l) to changes in solvent nucleophilicity (N(T)) and a moderate sensitivity (m) to changes in solvent ionizing power (Y(Cl)). The values are consistent with a rate-determining association within an association-dissociation pathway. The selectivity values (S) for the attack at the acyl carbon show a modest preference for ethanol over water and a relatively high preference for ethanol over 2,2,2-trifluoroethanol (TFE). The solvolyses of benzyl chloroformate show similar characteristics in solvents of relatively high nucleophilicity and/or low ionizing power. In solvents with considerable fluoro alcohol content, an ionization mechanism, accompanied by loss of carbon dioxide, leads to benzyl chloride, benzyl alcohol, and benzyl alkyl ether. A new correlation now applies, with a much lower l value and somewhat higher m value. The S values for this pathway are close to unity, even in TFE-ethanol mixtures, consistent with the components of the binary solvent capturing a highly reactive carbocation.
- Kyong,Park,Kim,Kevill
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p. 8051 - 8058
(2007/10/03)
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- Transfer of Alkoxycarbonyl from Alkyl Imidazolium-2-carboxylates to Benzyl Alcohol, a Cyclohexanone Enamine and Diethylamine
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Alkylimidazole-2-carboxylates may be alkylated with methyl triflate to give the corresponding N-methylimidazolium salts.These salts react with benzyl alcohol in the presence of 1,4-diazabicyclooctane, with 1-(pyrrolidin-1-yl)cyclohexene and with diethylamine to give benzyl alkyl carbonates, an enamino ester and a urethane respectively; in one case a tetrahedral intermediate is observed.The corresponding phenyl ester was consumed without attack by benzyl alcohol at the carbonyl group.A 2-cyanoimidazolium salt underwent similar ill-defined consumption whereas a 2-dimethylaminocarbonyl derivative remained unchanged. 2-Methylsulfonylimidazolium salts suffered attack by benzyl alcohol at the ring C-2.
- Bakhtiar, Cuross,Smith, Edward H.
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p. 239 - 244
(2007/10/02)
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- KINETIC RELATIONSHIPS GOVERNING THE ETHANOLYSIS OF HALOGENOFORMATES
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The kinetics of the ethanolysis of a series of halogenoformates at various temperatures were investigated by titrimetric and conductometric methods.It is suggested that the conformational composition of the chloroformates has an effect on the solvolysis rate.A parameter which takes account of the conformational factor is proposed, and the quantitative relation of the Taft type relating the solvolysis rate constant to the parameters of the substituents is obtained.The effect of the leaving group and the effect of substitution of the ether oxygen by sulfur in the chloroformate were investigated.The obtained data are interpreted in terms of an addition-elimination mechanism.
- Orlov, S. I.,Chimishkyan, A. L.,Grabarnik, M. S.
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p. 1981 - 1987
(2007/10/02)
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