- Ethylenebis(N-methylimidazolium) ditribromide (EBMIDTB): An efficient reagent for the monobromination of 1,3-diketones and β-ketoesters
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Ethylenebis(N-methylimidazolium) ditribromide, a stable crystalline solid, is easily prepared by reaction of the corresponding dibromide salt with bromine in n-hexane. 1,3-Diketones and β-ketoesters can be brominated chemoselectively to the corresponding α-monobrominated products by using this reagent at 0-5°C. Under the same reaction conditions, diethyl malonate, ethyl cyanoacetate, and malonitrile were monobrominated at moderate yield.
- Hosseinzadeh, Rahman,Tajbakhsh, Mahmood,Mohadjerani, Maryam,Lasemi, Zahra
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- Alkyl Halides via Visible Light Mediated Dehalogenation
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Net selective bromination and chlorination of activated C-H bonds can be effected in generally high yield via a simple perhalogenation/dehalogenation sequence. The photochemical reductions require no photocatalyst, relying instead on the formation of an electron donor-acceptor complex of the substrate and reductant, or alternatively autophotocatalysis. Some reactions proceed despite any apparent photon absorption, serving as a cautionary tale for other photochemical reactions involving amines. Mechanistic experiments provide an explanation for this observation.
- Rathnayake, Manjula D.,Weaver, Jimmie D.
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supporting information
p. 9681 - 9687
(2019/11/28)
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- Selective monobromination of 1,3-diones with N-bromosaccharin/Mg(ClO 4)2 system in solution and under solvent-free conditions
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N-Bromosaccharin/Mg(ClO4)2 is an effective and regioselective system for α-monobromination of 1,3-dicarbonyl compounds. A wide variety of β-keto esters and 1,3-diketones in reaction with this system afforded a regioselectively α-mono
- Alinezhad, Heshmatollah,Tajbakhsh, Mahmood,Tehrani, Shahram Shahriari
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experimental part
p. 1543 - 1546
(2011/12/04)
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- Tetrameric DABCO-bromine: An efficient and versatile reagent for bromination of various organic compounds
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Tetrameric DABCO-bromine is a powerful brominating agent but shows reasonable selectivity with certain substrates. The selective bromination for activated aromatic compounds and alkenes is reported. Synthesis of α-bromo ketones and nitriles has also been achieved by using this reagent and the results are also reported. All products reported were obtained in good to excellent yields.
- Heravi, Majid M.,Derikvand, Fatemeh,Ghassemzadeh, Mitra
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p. 125 - 128
(2007/10/03)
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- Poly(vinylpyrrolidone)-bromine complex; a mild and efficient reagent for selective bromination of alkenes and oxidation of alcohols
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Poly(vinylpyrrolidone)-bromine complex (PVP-Br2) is easily prepared and used as a mild and convenient reagent for selective bromination of alkenes and at the position α-hydrogen of active carbonyl compounds. Selective oxidation of benzylic alcohols in the presence of aliphatic alcohols were also achieved at room temperature.
- Lakouraj, Moslem Mansour,Tajbakhsh, Mahmood,Mokhtary, Masoud
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p. 481 - 483
(2007/10/03)
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- Reaction of Li2NiBr4/THF with oxiranes: unexpected behavior of glycidic esters
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The complex Li2NiBr4/THF usually gives bromohydrins from epoxides but reacts with α-ester epoxides or α-keto epoxides to generate a carbene species which was trapped with maleimide. - Keywords: epoxides / carbenes / dilithium tetrabromonickelate
- Khamliche, Layachi,Robert, Albert,Bakkas, Salem
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p. 1031 - 1034
(2007/10/02)
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- A Convenient Synthesis of Dialkyl (E)-2,3-Dicyanobutendioates
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Dialkyl (E)-2,3-dicyanobutendioates 4, potentially useful intermediates for the synthesis of a wide variety of heterocyclic compounds, are conveniently prepared by the reaction of alkyl bromocyanoacetates 2 with potassium thiocyanate in acetonitrile followed by treatment with water.The starting alkyl bromocyanoacetates are prepared by the photochemical reaction of the appropriate alkyl cyanoacetate with bromine in carbon tetrachloride.
- Yamada, Yoichi,Yasuda, Heinosuke
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p. 768 - 770
(2007/10/02)
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- TRIBUTYLSTIBINE MEDIATED SYNTHESIS OF 1,1,2-TRI-SUBSTITUTED CYCLOPROPANES
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A novel method for the synthesis of 1,1,2-tri-substituted cyclopropanes is reported which involves the reaction of electron-deficient olefins with dibromomalonic ester, dibromocyanoacetic or dibromobenzeneacetic ester promoted by tri-n-butylstibine.The reaction was carried out under mild conditions to give the cyclopropane derivatives in moderate to good yields.Other R3M (M= As,Sb,Bi) reagents as promoter for this reaction have been studied and seem to be less effective than tributylstibine.
- Chen, Chen,Liao, Yi,Huang, Yao-Zeng
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p. 3011 - 3020
(2007/10/02)
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- Reactions of Perfluoroalkanesulfonyl Bromide
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Perfluoroalkanesulfonyl bromides were readily prepared from the reaction of the corresponding sodium sulfinates with bromine in aqueous solution in excellent yield.Several reactions of these sulfonyl bromides were reported: 1.Spontaneous addition to olefin with the loss of sulfur dioxide to give the corresponding adducts in good yield. 2.Facile bromination of compounds containing active hydrogen. 3.Reaction with alcohol, amines and alkali.
- Huang, Wei-Yuan,Chen, Jian-Long,Hu, Li-Qing
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p. 881 - 884
(2007/10/02)
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