542-11-0Relevant articles and documents
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Snyder,Heckert
, p. 2006,2008 (1952)
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Selective catalytic Hofmann: N -alkylation of poor nucleophilic amines and amides with catalytic amounts of alkyl halides
Xu, Qing,Xie, Huamei,Zhang, Er-Lei,Ma, Xiantao,Chen, Jianhui,Yu, Xiao-Chun,Li, Huan
supporting information, p. 3940 - 3944 (2016/07/21)
Using only catalytic amounts of alkyl halides in the reactions of poor nucleophilic amines/amides and alcohols led to a selective Hofmann N-alkylation reaction catalytic in alkyl halides, providing a practical and efficient method for the practical synthesis of mono- or di-alkylated amines/amides in high selectivities. This new method avoids the use of large amounts of bases, alkyl halides, and solvents, and generates water as the only byproduct. Preliminary mechanistic studies showed that alkyl halides are key intermediates/catalysts regeneratable in the reaction cycle.
Stabilities of complexes of Br- with substituted benzenes (SB) based on determinations of the gas-phase equilibria Br- + SB = (BrSB)-
Paul, Gary J. C.,Kebarle, Paul
, p. 1148 - 1154 (2007/10/02)
Equilibria involving some forty substituted benzenes (SB) and the bromide ion (SB + Br- = SBBr-) in the gas phase were determined with a pulsed electron, high-pressure mass spectrometer (PHPMS). The resulting -ΔG°1 provide information on the stabilities of the SBBr- complexes. Previous work, involving gas-phase thermochemical data for. X- (CH3O-, F-, C1-, Br-, I-) and quantum chemical calculations, indicate that the most stable SB·X- complexes might have a variety of structures, depending on X- and the nature of the substituents. Thus X- may engage in hydrogen bonding to an aromatic hydrogen atom, or lead to a σ-bonded (Meisenheimer) complex, or form a complex where X- is on an axis perpendicular to the benzene plane. A Taft substituent analysis of the δΔG°1 indicates that Br- and Cl- form aromatic C-H hydrogen-bonded complexes with all singly substituted benzenes. The field effects of the substituents provide the dominant contribution to the bonding in these complexes. Similar conclusions are reached also for the singly substituted nitrobenzenes and Br-. A clearcut analysis of the bonding to Br- when triply substituted benzenes with strongly electron withdrawing substituents like CF3, CN, and NO2 are present could not be obtained. In these cases all three bonding structures mentioned above may have similar stabilities.