- Cobalt-catalyzed photolytic methoxycarbonylation of bromoalkanes in the presence of a Lewis acid
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Addition of a water-stable Lewis acid, indium trichloride, improved the rate of photochemical methoxycarbonylation of bromoalkanes. Primary and secondary bromoalkanes were carbonylated in good yields. Carbonylation of tertiary substrates was somewhat more difficult and some of them reacted too slowly for the reaction to be of a preparative value.
- Cash, Daniel,Combs, Angela,Dragojlovic, Veljko
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- Palladium(II) catalyzed carbonylation of ketones
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Cyclic ketones react with PdCl2 in methanol under a CO atmosphere to give mainly diesters by a ring cleavage reaction along with some chloro- substituted monoester, 13CO labeling experiments indicate the major product is formed by a mechanism involving Pd(II)-CO2CH3 insertion across the double bond of the enol form of the ketone. Pd(II) elimination and acid- catalyzed ring cleavage form a second methyl ester group. (C) 2000 Elsevier Science Ltd.
- Hamed, Othman,El-Qisairi, Arab,Henry, Patrick M.
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- Copper-catalyzed radical ring-opening halogenation with HX
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An efficient copper-catalyzed radical ring-opening halogenation with HX (aq) is described. This protocol features redox-neutral conditions, green halogen sources, and a broad substrate scope, providing practical access to distally chlorinated, brominated and iodinated alkyl ketones and alkyl nitriles with moderate to good yields. This journal is
- Bai, Ming,Duan, Xin-Hua,Guo, Li-Na,Liu, Shuai,Sun, Qing-Xin,Xu, Peng-Fei
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supporting information
p. 8652 - 8655
(2021/09/04)
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- Practical and Selective sp3 C?H Bond Chlorination via Aminium Radicals
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The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine-tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site-selective chlorination of sp3 C?H bonds. This process exploits the ability of protonated N-chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical-chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H-atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp3 C?H chlorination.
- McMillan, Alastair J.,Sieńkowska, Martyna,Di Lorenzo, Piero,Gransbury, Gemma K.,Chilton, Nicholas F.,Salamone, Michela,Ruffoni, Alessandro,Bietti, Massimo,Leonori, Daniele
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supporting information
p. 7132 - 7139
(2021/03/03)
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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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- Palladium(II)-catalyzed oxidation of aldehydes and ketones. 1. Carbonylation of ketones with carbon monoxide catalyzed by palladium(II) chloride in methanol
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Unsubstituted or alkyl-substituted cyclic ketones react with PdCl2 in methanol under a CO atmosphere to give mainly acyclic diesters along with some acyclic chloro-substituted monoesters. The monosubstituted cyclic ketones, 2-hydroxy- and 2-methoxycyclohexanone, do not give ring cleavage but rather produce 2-(carbomethoxy)cyclohex-2-en-1-one. 13CO labeling experiments indicate one CO is inserted in forming the diester product so the second ester group must arise from the original ketone group. Two mechanisms are possible for the diester reaction. One involves initial Pd(II)-CO2CH3 insertion across the double bond of the enol form of the ketone while the second involves initial addition of Pd(II)-OCH3 followed by CO insertion into the new Pd(II) carbon bond formed. Pd(II) elimination and acid-catalyzed ring cleavage produce the second methyl ester group in both routes. The chloro-substituted monoester is formed by initial Pd(II)-Cl insertion across the double bond followed by the acid-catalyzed ring cleavage. The 2-(carbomethoxy)cyclohex-2-en-1-one must result from elimination of water or methanol from the α-ketoester product formed by the initial methoxycarbonylation of the enol form of the ketone. As expected, the acyclic ketone 2-decanone, formed methyl acetate and a mixture of methyl nonanoate and products.
- Hamed,El-Qisairi,Henry
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p. 180 - 185
(2007/10/03)
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- A New Oxaanalog of Myristic Acid that Suppresses Replication of Human Immunodeficiency Virus
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A series of oxaanalogs of myristic acid were synthesized and tested for antiviral activity in MT4 cells infected with human immunodeficiency virus 1 (HIV-1).The synthesized acids have no toxic effect on uninfected MT4 cells at a concentration of 100μM. 14,14,14-Trifluoro-12-oxatetradecanoic acid substantially (by 75percent) inhibits the reproduction of HIV-1.Other compounds synthesized, (7Z)-13-, (9Z)-13-, and (7Z)-11-oxatetradecenoic acids, exhibit no antiviral effect.Key words: inhibitors of retroviruses; anti-HIV agents; protein N-myristoylation; mystoylCoA: protein-N-myristoyltransferase; myristic acid; oxaanalogs; inhibitors of virus-specific protein myristoylation
- Vodovozova, E. L.,Mikhalev, I. I.,Rzhaninova, A. A.,Garaev, M. M.,Molotkovsky, Yul. G.
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p. 626 - 632
(2007/10/03)
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- MECHANISMS OF FREE-RADICAL REACTIONS. XXIV. QUANTITATIVE DESCRIPTION OF THE POLAR EFFECTS OF SUBSTITUENTS ON THE KINETICS OF THE FREE-RADICAL CHLORINATION OF ALIPHATIC COMPOUNDS BY N-CHLOROPIPERIDINE
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The free-radical chlorination of 1-substituted alkanes with electron-withdrawing substituents by N-chloropiperidine in trifluoroacetic acid was studied by the method of competing reactions, and the relative rate constants were obtained for all positions of the substrates.The data on the position selectivity can be described satisfactorily by means of an electrostatic model of the polar effect of the substituent, calculated according to the Kirkwood-Westheimer equation.The obtained characteristics of the electrostatic effect can be successfully applied to calculation of the substrate selectivity and the intermolecular relative rate constants for all the positions, beginning with the third.The Taft equation is unsuitable for description of the effect of substituents on the reaction rate.
- Dneprovskii, A. S.,Mil'tsov, S. A.,Arbuzov, P. V.
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p. 1826 - 1835
(2007/10/02)
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- Chlorination of Carboxylic Acid Derivatives. VIII. Liquid Phase Chlorination of the Aliphatic C5-Carboxylic Acids and Their Chlorides, Methyl Esters and Chloromethyl Esters with Chlorine
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The chlorination of pentanoic, 3-methylbutanoic, 2-methylbutanoic and 2,2-dimethylpropanoic acids and their derivatives with chlorine in the liquid phase have been investigated.The monochloro products formed were determined by gas-liquid chromatography (GLC) and gas-liquid chromatography-mass spectrometry (GLC-MS) as their esters through the comparison with authentic samples.The deactivation of position 2 decreases in the order COCl > CO2H > CO2CH2Cl > CO2CH3, the effect of the COCl-group in pentanoic acid derivatives being 4.3 times stronger than that of the CO2CH3-group.The deactivation is smallest in 2-methylbutanoic acid derivatives owing to the electron-donating methyl group.The EI mass spectra of the methyl and chloromethyl esters have been studied in detail.
- Kornonen, Ilpo O. O.
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p. 467 - 474
(2007/10/02)
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- MECHANISMS OF FREE-RADICAL REACTIONS. XIV. SELECTIVITY OF FREE-RADICAL CHLORINATION OF VALERIC ACID DERIVATIVES WITH ARYLCHLOROIODONIUM CHLORIDES
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The free-radical chlorination of C4H9Y compounds with arylchloroiodonium chlorides was investigated.The reaction of the secondary C-H bonds increases as they become further from the electronegative substituent.The reaction parameters were calculated from the ratio of the β- and γ-monochlorides by means of the Taft equation.The absolute value of ρ increases with the introduction of electronwithdrawing substituents into the arylchloroiodonium chloride molecule.
- Dneprovskii, A. S.,Krainyuchenko, I. V.
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p. 324 - 328
(2007/10/02)
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- Chlorination of Esters. I. Chlorination of Methyl Esters of Propanoic, Butanoic, Pentanoic and Hexanoic Acids. The Isomer Distribution of Monochloro Esters Formed
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The chlorination of methyl ester with chlorine in the liquid and vapor phase and with sulfuryl chloride in the liquid phase has been investigated.The chlorination yields all possible monochloro esters isomers with the 2-chloro isomer in the smallest amount.The products were identified by NMR and mass spectrometry.The isomer distribution and mass spectra of products were studied in detail.
- Korhonen, Ilpo O.O.,Korvola, Jorma N.J.
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p. 139 - 142
(2007/10/02)
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