- Electrooxidative coupling of salts of nitro compounds with halide, nitrite, cyanide, and phenylsulfinate anions
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Electrolysis of salts of primary and secondary nitro compounds (nitroethane, 1- and 2-nitropropanes, nitrocyclohexane, and nitrocycloheptane) in the presence of excess halide, nitrite, cyanide, and phenylsulfinate anions under undivided and divided amperostatic electrolysis conditions in a two-phase medium (CH2Cl2/H2O) produces geminal nitrohalides (35-85% yields), dinitro compounds (15-51%), nitronitriles (6-27%), and nitrosulfones (50-70%). The salts of secondary nitro compounds form the products of oxidative coupling with halide and phenylsulfinate anions under the undivided electrolysis conditions. In all other cases, divided electrolysis is required.
- Ilovaisky,Merkulova,Ogibin,Nikishin
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p. 1585 - 1592
(2007/10/03)
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- N,N-Dibromobenzenesulfonamide: A useful regenrable reagent for bromination of various carbanionic substrates
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N,N-Dibromobenzenesulfonamide(dibromoamine-B), which is prepared easily in high yield, has been employed as effective brominating agent for carbanionic substrates under mild conditions. β-Diketones and β-ketoesters were brominated by this reagent without using any bases. The reagent can be recovered, rebrominated, and reused several times.
- Tajbakhsh, Mahmood,Khazaei, Ardeshir,Mahalli, Majid Shabani,Vaghi, Ramin Ghorbani
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p. 1159 - 1163
(2007/10/03)
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- UNUSUAL REACTION OF NITROSO COMPOUNDS WITH THE BIS(AMINOOXY)METHANE/DIBROMOISOCYANURATE SYSTEM
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The reaction of nitroso compounds with bis(aminooxy)methane in the presence of dibromoisocyanurate gives the products of the formal replacement of the nitroso group by bromine.
- Smirnov, G. A.,Vasil'ev, A. M.,Luk'yanov, O. A.
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p. 2523 - 2524
(2007/10/02)
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- Polynitro-Substituted Strained-Ring Compounds. Synthesis, Mechanism of Formation, and Structure of trans-Dinitrocyclopropanes
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1,2-Dinitrocyclopropane, 1,2-dimethyl-1,2-dinitrocyclopropane, and 1,2-diethyl-1,2-dinitrocyclopropane have been prepared in 23-36percent yield by oxidative cyclization of the corresponding open-chain 1,3-dinitronate dianions with iodide in DMSO.In each case only the trans isomer of the dinitrocyclopropane was obtained.Treatment of 2,4-dibromo-2,4-dinitropentane with the lithium salt of 2-nitropropane gave trans-1,2-dimethyl-1,2-dinitrocyclopropane, suggesting the intermediacy of a halonitro nitronate intermediate in the oxidative cyclization process.Further mechanistic studies using m-dinitrobenzene suggest either an internal single-electron transfer, nonchain pathway or an internal SN2 process leading to the dinitrocyclopropanes.An X-ray crystallographic study performed on trans-1,2-dinitrocyclopropane indicates substantially shortened distal C-C bonds (1.47 Angstroem) and bisected conformations for each nitro group.Ab initio calculations using a 4-31G basis set are in agreement with the X-ray data, except longer distal C-C bonds (1.49 Angstroem) are calculated.Ab initio calculations using a variety of basis sets were performed on nitrocyclopropane as a model.
- Wade, Peter A.,Dailey, William P.,Carroll, Patrick J.
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p. 5452 - 5456
(2007/10/02)
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- A Convenient Method For The Preparation of gem-Halonitro Compounds
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Aliphatic nitro compounds are easily halogenated by N-chloro- or N-bromosuccinimide in protic solvents to give the practically pure gem-halonitro compounds.
- Amrollah-Madjdabadi, A.,Beugelmans, R.,Lechevallier, A.
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p. 828 - 830
(2007/10/02)
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- Reactions of Carbanions with Electron Acceptors
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Second-order rate constants for reactions of families of 9-substituted fluorenide ions, 9-R-Fl(-), and related carbanions in Me2SO solution with the electron acceptors PhSO2CH2Br, PhSO2CH(Ph)Br, PhSO2C(Me)(Ph)Br, Me2CBr2, Me2C(NO2)X, PhS(O)CH2Cl, Me2C(SO2Ph)2, and Ph2I(+)Cl(-) have been measured.The carbanions used varied in basicity over a range of about 20pKHA units.For a given family, Broensted plots of log k vs. pKHA were linear, with slopes usually near unity.The relative order of rate constants correlated for the most part with the order of reduction potentials of the electron acceptors.The carbanions were converted by the electron acceptors to dimers, i.e., 9-R-Fl- -> (9-R-Fl)2, by way of a single electron transfer (e-T) mechanism.The Broensted lines for the e-T reactions of the GC6H4C(Me)CN- ion family (G = p-Cl, H, and p-Me) and the 9-t-BuFl- ion family were displaced below that of the 9-MeFl- ion family (slower rates); the kinetic points for PhC(Me)SO2Ph- and Ph2CSO2Ph- ions fell near the 9-t-BuFl- ion family line.It is demonstrated that carbanions too weakly basic to undergo thermal e-T with a given electron acceptor can be made to undergo comparable e-T reactions under photostimulation.
- Bordwell, Frederick G.,Clemens, Anthony H.,Smith, Donald E.,Begemann, John
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p. 1151 - 1156
(2007/10/02)
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