- A new, one pot synthesis of alkylated methyl tri- and tetracarboxylate derivatives by nitrolkanes
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The reaction of nitroalkanes with trimethyl trans-aconitate in acetonitrile, in the presence of DBU as base, allows the one pot formation of alkylated methyl tri- and tetralkanoate derivatives via base induced nitrous acid elimination. The title compounds can also be obtained, in one flask, starting with the reaction of methyl nitroacetate with dimethyl maleate, followed by the addition, in the same flask of the nitroalkane.
- Ballini, Roberto,Bosica, Giovanna,Fiorini, Dennis,Gil, Maria Victoria,Palmieri, Alessandro
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- Molecularly imprinted polymers and room temperature ionic liquids: Impact of template on polymer morphology
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Molecularly imprinted polymers (MIPs) were generated for trans-aconitic acid 1 and cocaine 2 in a variety of porogens (CH3CN, CHCl 3, [bmim][BF4], and [bmim][PF6]). MIP synthesis in either [bmim][BF4] or [bmim][PF6] resulted in significant acceleration of polymerization rates and, in the case of low temperature polymerizations, reactions were complete in less than 2 h, while no product was observed in the corresponding volatile organic carbon (VOC) porogen. In all instances, MIPs generated in [bmim][BF4] or [bmim][PF 6] returned imprinting selectivities (I values) on par with or better than the corresponding MIP generated in VOCs. Imprinting values ranged between I ≤ 1 and 2.9, with rebinding limited to 1 h. MIP synthesis conducted at low temperature (5°C) afforded the highest I values. Scanning electron microscopy examination of MIP morphology highlighted an unexpected template effect with MIP structure varying between discrete nanoparticles and robust monoliths. This template?monomer interaction was also observed in the rates of polymerizations with differences noted in reaction times for 1 and 2 MIPs, thus providing indirect conformation of our previously proposed use of molecular modelling?nuclear magnetic resonance titrations (the MM-NMR method) in the design phase of MIP generation. In addition, considerable batch-to-batch rebinding selectivities were observed. CSIRO 2007.
- Booker, Katherine,Bowyer, Michael C.,Lennard, Chris J.,Holdsworth, Clovia I.,McCluskey, Adam
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- A New Synthesis of Trimethyl Aconitate by Palladium-catalysed Triple Carbonylation of Propynyl Alcohol
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A two-step palladium-catalysed carbonylation, consisting of an oxidative carbonylation of propynyl alcohol, followed by a substitutive carbonylation, leads to E and Z aconitic trimethyl esters in high yield.
- Gabriele, Bartolo,Costa, Mirco,Salerno, Giuseppe,Chiusoli, Gian Paolo
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- Identification and quantification of aerosol polar oxygenated compounds bearing carboxylic or hydroxyl groups. 1. Method development
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In this study, a new analytical technique was developed for the identification and quantification of multifunctional compounds containing simultaneously at least one hydroxyl or one carboxylic group, or both. This technique is based on derivatizing first the carboxylic group(s) of the multifunctional compound using an alcohol (e.g., methanol, 1-butanol) in the presence of a relatively strong Lewis acid (BF3) as a catalyst. This esterification reaction quicldy and quantitatively converts carboxylic acids to their ester forms. The second step is based on silylation of the ester compounds using bis(trimethylsilyl) trifluoroacetamide (BSTFA) as the derivatizing agent. For compounds bearing ketone groups in addition to carboxylic and hydroxyl groups, a third step was used based on PFBHA derivatization of the carbonyls. Different parameters including temperature, reaction time, and effect due to artifacts were optimized. A GC/MS in EI and in methane-CI mode was used for the analysis of these compounds. The new approach was tested on a number of multifunctional compounds. The interpretation of their EI (70 eV) and CI mass spectra shows that critical information is gained leading to unambiguous identification of unknown compounds. For example, when derivatized only with BF3-methanol, their mass spectra comprise primary ions at m/z M .+ + 1, M.+ + 29, and M.- - 31 for compounds bearing only carboxylic groups and M.- + 1, M.+ + 29, M.+ - 31, and M+. - 17 for those bearing hydroxyl and carboxylic groups. However, when a second derivatization (BSTFA) was used, compounds bearing hydroxyl and carboxylic groups simultaneously show, in addition to the ions observed before, ions at m/z M.+ + 73, M .+ - 15, M.+ - 59, M.+ - 75, M.+ - 89, and 73. To the best of our knowledge, this technique describes systematically for the first time a method for identifying multifunctional oxygenated compounds containing simultaneously one or more hydroxyl and carboxylic acid groups.
- Jaoui,Kleindienst,Lewandowski,Edney
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p. 4765 - 4778
(2007/10/03)
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- A facile access to natural and unnatural dialkylsubstituted maleic anhydrides
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A facile new route to the potential building blocks 2-bromomethyl-3-alkylmaleic anhydrides 15a/b for the synthesis of natural and unnatural dialkylsubstituted maleic anhydrides has been demonstrated, starting from dimethyl citraconate (9) via NBS-bromination, SN2′ Grignard coupling reactions, hydrolysis, molecular bromine addition and dehydrative ring closure reactions pathway with 49-51% overall yield in 5-steps. Chemoselective allylic substitution of bromoatom in 15a/b with Grignard reagents has been described to obtain the unsymmetrical maleic anhydride 16 and symmetrically dialkylsubstituted maleic anhydrides 25a/b in 55% yield. The naturally occurring 2-carboxymethyl-3-hexylmaleic anhydride (1) has been synthesized from 16 via esterification, ozonolysis and an oxidation route. The synthesis of two naturally occurring 2-(β-carboxyethyl)-3-alkylmaleic anhydrides 2a/b have been completed via a chemoselective diethylmalonate coupling reaction followed by acid induced hydrolysis. In our hands the SN2 or SN2′ coupling of Grignard reagent with 21 to obtain 1 and Reformatsky reaction with 15a/b to obtain 2c/d met with failure.
- Kar, Anirban,Argade, Narshinha P.
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p. 2991 - 2998
(2007/10/03)
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- Synthesis of β-functionalized α,β-unsaturated oximes via silylation of nitro compounds
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A general method for the synthesis of conjugated enoximes 2 via silylation of functionalized aliphatic nitro compounds 1 has been elaborated. The configuration of obtained products has been determined by NMR spectroscopy.
- Danilenko, Vitaly M.,Tishkov, Alexander A.,Ioffe, Sema L.,Lyapkalo, Ilya M.,Strelenko, Yury A.,Tartakovsky, Vladimir A.
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p. 635 - 647
(2007/10/03)
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- Reaction of phenyl- and alkoxycarbonylmethanesulfonyl fluoride with activated haloalkanes
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Arylmethanesulfonyl fluorides condense with α-bromoketones by attacking at the methylenyl carbon instead of the carbonyl bond to give α,β-conjugated ketones.They also condense with other activated haloalkanes in a similar manner.The preparation of FSO2CH2R (R = CO2Me, CO2Et, CN) is described.Fluorosulfonyl acetate reacts with the carbonyl bonds of aldehydes to give alkenes, whereas it attacks the phenacyl bromide exclusively at the α-carbon.The reaction mode of these sulfonyl fluorides is discussed on the basis of kinetic data. Key words: α-Fluorosulfonylcarbanions; α,β-conjugated ketone; α,β-conjugated ester; alkene formations.
- Kagabu, S.,Shimizu, C.,Takahashi, J.,Hara, K.,Koketsu, M.,Ishida, M.
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p. 435 - 439
(2007/10/02)
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- CONVENIENT APPROACHES TO HETEROCYCLES VIA COPPER-CATALYSED ADDITIONS OF ORGANIC POLYHALIDES TO ACTIVATED OLEFINS
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An efficient method for the synthesis of 2,3-dichloro-5-substituted (Cl, CF3, alkyl) pyridines 29 starting from the 1:1 adducts of the copper-catalysed addition of chloral or the corresponding 2,2-dichloroaldehydes to acrylonitrile is presented.Proper choice of experimental conditions allows the preparation of 29 in one-pot process.Similarly, the CuCl-catalysed reaction of methyl itaconate with several trichloromethyl compounds R-CCl3 gives 6-R-substituted 2-pyrone derivatives 40 via dehalogenation and subsequent thermal ring closure of the primary 1:1-adducts. The new electrophilic 2-pyrone 40b undergoes-cycloaddition reactions with inverse electron demand with a number of olefins and acetylenes, allowing thereby regioselective transfer of a trifluoromethyl group from a simple Freon derivative (1,1,1-trichloro-2,2,2-trifluoroethane) into more complex organic molecules.Finally, the 1:1-adduct of trichloroacetylchloride with methyl acrylate allows a very covenient synthesis of novel N-substituted derivatives 66 of pyroglutamic acid as well as of proline.
- Martin, Pierre,Steiner, Eginhard,Streith, Jacques,Winkler, Tammo,Bellus, Daniel
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p. 4057 - 4078
(2007/10/02)
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- Citric acid derivatives
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Epoxyaconitic acid and esters thereof are useful for the control of lipogenesis.
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