- Aromatic cation activation: Nucleophilic substitution of alcohols and carboxylic acids
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A new method for the nucleophilic substitution of alcohols and carboxylic acids using aromatic tropylium cation activation has been developed. This article reports the use of chloro tropylium chloride for the rapid generation of alkyl halides and acyl chlorides under very mild reaction conditions. It demonstrates, for the first time, the synthetic potential of tropylium cations in promoting chemical transformations.
- Nguyen, Thanh V.,Bekensir, Alp
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supporting information
p. 1720 - 1723
(2014/04/17)
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- Solid-state chlorodecarboxylation of mono- and dicarboxylic acids with the Pb(OAc)4-MCl system
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Solid state reactions of acids RCOOH (R = n-C7H15, BuC(Et)H, n-C9H19, PhCH2, PhCH 2CH2, H2C=CH(CH2)8, or MeOOC(CH2)3) with Pb(OAc)4 combined with KCl, NaCl, CdCl2, or NH4Cl in the absence of a solvent and without mechanical activation afford chlorohydrocarbons RCl. The corresponding reactions of acids HOOC(CH2)nCOOH (n = 3-6) give dichloroalkanes Cl(CH2)nCl and γ-butyrolactone (n = 3).
- Nikishin,Sokova,Chizhov,Makhaev,Kapustina
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p. 2200 - 2204
(2007/10/03)
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- Ionic liquids as reagents and solvents in conjunction with microwave heating: Rapid synthesis of alkyl halides from alcohols and nitriles from aryl halides
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We show that using ionic liquids as reagents in conjunction with microwave heating it is possible to prepare primary alkyl halides from the corresponding alcohols rapidly. Using ionic liquids as solvents in conjunction with microwave heating it is possible to prepare aryl nitriles from the corresponding aryl bromides or iodides. The scope and limitations of using microwave-promotion as a tool in these reactions is discussed.
- Leadbeater, Nicholas E.,Torenius, Hanna M.,Tye, Heather
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p. 2253 - 2258
(2007/10/03)
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- Cu-catalyzed alkylation of Grignard reagents: A new efficient procedure
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The presence of NMP (4-9 equiv.) clearly improves the yield and the chemoselectivity of the Cu-catalyzed alkylation of organomagnesium reagents. Thus, secondary and tertiary alkylmagnesium chlorides were used successfully for the first time in such a reaction and ester, amide, nitrile or keto groups are tolerated. The procedure is cheap, environmentally friendly and very easy to carry out (1-3% Li2CuCl4 or CuCl, THF, 20°C). It is an interesting alternative to the classical alkylation of organocuprates reagents. (C) 2000 Published by Elsevier Science Ltd.
- Cahiez, Gérard,Chaboche, Christophe,Jézéquel, Michelle
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p. 2733 - 2737
(2007/10/03)
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- Influence of Haloalkanes on the Selectivity of Radical Chlorination of Saturated Hydrocarbons
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The selectivity of radical chlorination of alkanes with molecular chlorine increases when the reaction is carried out in halogenated hydrocarbons. The relations of the observed selectivity to the concentrations of the solvent and the substrate suggest formation of a complex between chlorine atom and haloalkane molecule.
- Dneprovskii,Eliseenkov,Kuznetsov
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p. 637 - 641
(2007/10/03)
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- Halogen-exchange reactions between alkyl fluorides and boron trihalides or tetrahalides. A convenient synthesis of alkyl halides from alkyl fluorides
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A simple and effective method for converting fluoroalkanes to their corresponding chloro-, bromo- and iodo-alkanes using commercially available boron trihalides and titanium tetrahalides is described. - Keywords: Halogen-exchange reactions; Alkyl fluorides; Boron trihalides; Titanium tetrahalides; NMR spectroscopy; Mass spectrometry
- Namavari, Mohammad,Satyamurthy, N.,Barrio, Jorge R.
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- THE PHOTOCHEMICAL CHLOROSULFONATION OF HEPTANE BY SULFURYL CHLORIDE. THE ROLE OF SOLVENT AND CATALYST. A REINVESTIGATION.
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Sulfuryl chloride has been tested as a chlorosulfonation reagent of n-heptane under various conditions.Pyridine was confirmed as the best catalyst for the reaction and the sulfochlorination yield was found to be enhanced by the use of benzene as solvent.The distribution of all the isomeric chlorinated and sulfochlorinated products has been measured.This information is used in order to understand the mechanism of this rather complex reaction.The catalyzed photoinitiation leads to the in situ formation of a low concentration of molecular chlorine.The observed selectivity is the result of a delicate balance between the photoinitiation leading the chlorine atoms and the rather short chain propagations leading to the formation of the chlorosulfonyl radical.
- Tazerouti, A.,Rahal, S.,Soumillion, J. Ph.
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p. 101 - 119
(2007/10/02)
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- Cobalt(II)-Porphyrin Catalyzed Selective Functionalization of Alkanes with sulfurylchloride: A Remarkable Substituent Effect
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Cobalt(II)-porphyrin complex 1 and 2 catalyses the chlorination and sulfochlorination respectively of n-alkanes and cycloalkanes with sulfuryl chloride in benzene.The p-substituent of the benzene ring in the porphyrin complex 1 and 2 shows a remarkable chemoselectivity in these reactions.
- Khanna, Vibha,Tamilselvan, Pitchiah,Kalra, Swinder Jeet Singh,Iqbal, Javed
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p. 5935 - 5938
(2007/10/02)
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- Intramolecular H-Transfer Reactions During the Decomposition of Alkylhydroperoxides in Hydrocarbons as the Solvents
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Eight defined primary and secondary alkylhydroperoxides were decomposed in n-alkanes as the solvent, mostly in the presence of manganese stearate.In all cases the corresponding alcohols and carbonyl compounds were formed as the main products with yields of 60-90percent.Besides, difunctional products were formed by an intramolecular H-transfer in the alkoxy radicals corresponding to the starting hydroperoxides.Products possibly formed by an intramolecular H-transfer in the corresponding alkylperoxy radical could be found only in the case of 4-methyl-2-hydroperoxy pentane.The amount of products formed by intramolecular H-transfer depended on the nature of the C-H bond in δ-position to the original hydroperoxy group and lay between 4percent (primary C-H in the case of 4-hydroperoxy heptane) and 13percent (tertiary C-H in the case of 2-hydroperoxy-5-methyl hexane) with respect to the starting hydroperoxide.The amount of products formed by oxidative attack of the alkoxy and alkylperoxy radicals at the normal paraffins used as the solvents was unexpectedly low (always less than 10percent with respect to the starting hydroperoxide).An increment system is proposed for the calculation of 13C-nmr shifts in alkyl hydroperoxides.
- Jinsheng, Li,Pritzkow, Wilhelm,Voerckel, Volkmar
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- Halogen exchange reactions between alkyl halides and aqueous hydrogen halides. A new method for preparation of alkyl halides
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Alkyl fluorides and chlorides are efficiently converted to their corresponding alkyl bromides and iodides by using readily available aqueous HBr and HI. The application of the same method for the conversion of some alkyl fluorides to the corresponding alkyl chlorides with cone. HCl is also described.
- Namavari, Mohammad,Satyamurthy,Phelps, Michael E.,Barrio, Jorge R.
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p. 4973 - 4976
(2007/10/02)
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- Derivatives of 2', 5'-oligoadenylate and antiviral uses thereof
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Synthetic analogs of 2',5'-oligoadenylate wherein the aglycon, ribosyl moiety and/or terminal nucleoside have been modified are effective antiviral agents for pharmaceutical and agricultural use. They are particularly useful in inhibiting replication of tobacco mosaic virus. Novel synthetic analogs have the following formulae wherein m=0, 1, 2 and 3 and n=0, 1, 2, 3 or 4: STR1 The invention described herein was supported by National Institutes of Health Grant GM-26134 and National Science Foundation Grant PCM-8111752.
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- HOMOLOGATION DES DERIVES HALOGENES
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The halide R-X is converted, in two steps, to its homologous R-CH2-X.
- Yankep, Emmanuel,Charles, Georges
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p. 427 - 430
(2007/10/02)
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- Direct Oxidation of Alkanoic Acids and their Amides to γ-Lactones by Peroxydisulphate-containing Systems
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The reaction of one-electron oxidation of alkanoic acids (I) and their amides (VI) on treatment with Na2S2O8-containing systems has been studied.As a result of the direct one-pot reaction acids (I) and amides (VI) are converted into γ and δ-lactones, the reaction being regioselective and leading mainly to γ-lactones in up to 35percent yield.The regioselectivity of the oxidative lactonisation depends greatly on the nature of alkyl substituents.The results obtained are presented in terms of a mechanism suggesting the generation of acyloxyl and amidyl radicals from (I) and (VI), respectively, followed by a rearrangement via a 1,5- or 1,6-H shift into the corresponding 3- and 4-carboxy- or -carboxamido-alkyl ra The latter undergo oxidative cyclisation to produce γ and δ lactones.The system Na2S2O8-NaCl-NaOH converts carboxamides (VI) into amines with loss of one carbon atom as a result of a Hoffmann type rearrangement.
- Nikishin, Gennady I.,Svitanko, Igor V.,Troyansky, Emmanuil I.
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p. 595 - 602
(2007/10/02)
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- TRANSFORMATIONS OF 1,1-DIALKOXYETHANES IN CHLOROFORM UNDER THE INFLUENCE OF FREE RADICALS
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The radical transformations of 1,1-dialkoxyethanes in a chloroform medium lead to the formation of the corresponding alkyl acetates, alkanes, 1-chloroalkanes, alkanals, and 1-chloro-1-alkoxyethanes.A scheme is proposed, and the relative rate constants for the free radical transformations of 1,1-dialkoxyethanes in chloroform are determined.The reactivity of the various C-H bonds in the acetal molecule is evaluated; the most active is the bond adjacent to the two oxygen atoms.
- Rol'nik, L. Z.,Kalashnikov, S. M.,Pastushenko, E. V.,Zlot-skii, S. S.,Rakhmankulov, D. L.
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p. 1415 - 1419
(2007/10/02)
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