106-93-4Relevant articles and documents
Absolute Rate Constants for Bromine Abstraction from N-Bromoimides and Br2 by Alkyl Radicals
Tanko, James M.,Skell, Philip S.,Seshadri, Sri
, p. 3221 - 3225 (1988)
Imidyl radicals react with cyclopropanes solely via hydrogen abstraction.In the case of methylcyclopropane, the major product (cyclopropylcarbinyl bromide) is derived from abstraction of hydrogen from the methyl group.The resultant cyclopropylcarbinyl radical is partioned between two pathways: (1) abstraction of Br from N-bromoimide and (2) rearrangement to the allylcarbinyl radical (eventually yielding 4-bromo-1-butene).Since the absolute rate of the rearrangement is known, an absolute rate constant for the abstraction of Br from N-bromoimides by alkyl radicals can be derived (CH2Cl2 solvent, 15 deg C), k ca. (1.3-1.6)1xE10 M-1s-1.Reactions carried out in the presence of Br2 provide a third pathway for scavenging of the cyclopropylcarbinyl radical, providing kBr2=2.2x1E10 M-1s-1.Thus, trapping of primary R. by either N-bromoimides or Br2 occurs at rates that are diffusion-controlled.
Facile Preparation of Λ-Shaped Building Blocks: Hünlich Base Derivatization
Kazem-Rostami, Masoud
, p. 1641 - 1645 (2017)
Hünlich's base modification has resulted in introducing a series of versatile Λ-shaped building blocks presented in this work. The methods are optimized to provide convenient approaches in the quicker production of these new building blocks in low-cost and low-risk.
Ionic Bromination of Ethane and Other Alkanes (Cycloalkanes) with Bromine Catalyzed by the Polyhalomethane*2AlBr3 Aprotic Organic Superacids under Mild Conditions
Akhrem, Irena S.,Orlinkov, Alexander V.,Afanas'eva, Lyudmila V.,Mysov, Evgenii I.,Vol'pin, Mark E.
, p. 9365 - 9368 (1995)
The polyhalomethane*2AlBr3 aprotic organic superacids were shown to effectively catalyze low-temperature ionic bromination of (cyclo)alkanes.Ethane readily reacts with Br2 at 55-65 deg C, affording mainly 1,2-dibromoethane.Propane, butane, and C5-C6 cycloalkanes react at -40 - -20 deg C, resulting in monobromides with high yields and good selectivity.
Direct and Regioselective Transformation of α-Chloro Carbonyl Compounds into Alkenes and Deuterioalkenes
Barluenga, Jose,Yus, Miguel,Concellon, Jose M.,Bernad, Pablo
, p. 2721 - 2726 (1981)
The successive treatment ethyl chloroacetate or chloroacetyl chloride with Grignard reagents and lithium powder leads to symmetrical terminal olefins in a regioselective manner.The best results are obtained with acid chlorides.The influence of the temperature and the reaction time on overall yield of the process are studied; in general, yields are increased by working at low temperature (-60 deg C).Internally substituted olefins are obtained from α-chloro acid chlorides through a similar process.The treatment of α-chloro aldehydes, ketones and carboxylic acid derivatives (esters or acid chlorides) with lithium aluminium hydride or lithium aluminium hydride/aluminium chloride and lithium powder at low temperature (-60 deg C) leads in a regioselective manner to olefins with the same carbon skeleton as the starting carbonyl compound.Reactions with lithium aluminium deuteride lead to incorporation of deuterium at predetermined positions in the alkene.
Photolysis of 3-Bromo-3-methyldiazirine
Crespo, Maria T.,Figuera, Juan M.,Rodriguez, Juan C.,Utrilla, Roberto Martinez
, p. 5790 - 5796 (1984)
The photolysis at 354 nm of 3-bromo-3-methyldiazirine in gas phase has been studied.After a careful search of the various possibilities we have found that all available evidence points toward the intermediary formation of hot vinyl bromide, presumably via isomerization of the corresponding carbene.Its unimolecular decomposition can take place by two different paths: one is the molecular detachment of HBr and the other the radical scission of the C-Br bond.This last way of radical formation is responsible for the apparently confusing experimental data.According to our result the activation energy for the radical decomposition is closer to that of the molecular detachment than previously thought.
Halogenobis(N,N-dialkyldithiocarbamato)iron(III) Complexes as Potential Catalysts for Halogen Addition Reactions to Alkenes
Tsipis, Constantinos A.,Katsoulos, George A.,Vakoulis, Fotios D.
, p. 1404 - 1405 (1985)
In the presence of a catalytic amount of iron(III) halogenobisdithiocarbamates, the addition of molecular halogens to alkenes occurs rapidly to afford cis-addition products.
Reactivity of Alkaneselenyl Bromide: Conversion of Alcohols into the Corresponding Alkyl Bromides with Dialkylselenium Dibromide
Akabori, Sadatoshi,Takanohashi, Yoshinori
, p. 3482 - 3484 (1991)
The reaction of alcohols with dialkylselenium dibromide gave the corresponding bromides in moderate to high yields.Alkaneselenyl bromide, produced by the thermal decomposition from dialkylselenium dibromide, acts as a brominating agent.The reaction of alcohol with dialkylselenium dichloride afforded the corresponding chlorides, although the yields were realtively low compared with those of the bromide.
Functionalization of saturated hydrocarbons by aprotic superacids 4. Ionic bromination of ethane and other alkanes and cycloalkanes with molecular bromine in the presence of systems based on polyhalomethanes and AlBr3 under mild conditions
Akhrem,Orlinkov,Afanas'eva,Vol'pin
, p. 1148 - 1153 (1996)
Aprotic organic superacids CBr4 · 2AlBr3, CBr4 · AlBr3, · CCl4 · 2AlBr3, CCl4 · 2AlBr3, and C6F5CF3 · 2AlBr3 efficiently catalyze the bromination of alkanes and cycloalkanes with Br2. Ethane is selectively brominated at 55-65 °C to give mostly 1,2-dibromoethane (stoichiometric reaction). Propane, butane, cyclopentane, cyclohexane, and methyl-cyclopentane react with Br2 at -40 to -20 °C with good selectivity affording monobromides in high yields (catalytic reactions).
Oxidative bromination of alkenes mediated with nitrite in ionic liquids
Kuznetsova, Lidia I.,Kuznetsova, Nina I.,Zudin, Vladimir N.,Utkin, Viktor A.,Trebushat, Dmitry V.,Fedotov, Martin A.,Larina, Tatyana V.
, p. 1499 - 1506,8 (2014)
The oxidative bromination of C2-C8 alkenes with HBr-NaNO2-O2 in solutions of BMImBr, HMImBr or BMImBF 4 containing 16-28 wt% H2O was studied using volumetric method, GC-MS analysis, 14N NMR and UV-VIS spectroscopy. The optimal conditions to conduct the reaction at high selectivity for 1,2-dibromoalkanes in BMImBr were determined. The composition of ionic liquid affects the catalytic performance. Although in BMImBF4 the reaction runs with equal rate as in bromide ionic liquid, the fraction of bromohydrin in the reaction products increases to 20 %. Generated from NaNO2, NOx operated as a catalyst in the oxidation of Br- and was oxidized to catalytically inert NO3 - anions when complete conversion of HBr was attained. Graphical Abstract: Oxidative bromination of alkenes [Figure not available: see fulltext.]
1,2-Dibromotetrachloroethane: An efficient reagent for many transformations by modified Appel reaction
Essiz, Sel?uk,Da?tan, Arif
, p. 150 - 156 (2019/05/16)
An efficient and facile method has been developed for the synthesis of alkyl bromides from various alcohols under mild conditions using a triphenylphosphine (PPh 3) /1,2-dibromotetrachloroethane (DBTCE) complex in excellent yields and very short time (5 min). This method can also be applied for the transformation of chiral alcohols to their corresponding bromides in very high enantiomeric excess. The PPh 3 /DBTCE complex is also successfully applied to ring-opening reactions of cyclic ethers in mild conditions. Esterification, amidation, and formation of acid anhydrides under very mild experimental conditions are also successfully accomplished by following a modification of the Appel reaction protocol in this work.
