Quaternary ammonium ions can externally block voltage-gated K+ channels. Establishing a theoretical and experimental model that predicts KDs and the selectivity of K+ over Na+ ions
摘要:
The physicochemical basis for the high ion selectivity of potassium channels is poorly understood. In the present studies, external blockade of cloned voltage-gated potassium channels with alkyl quaternary ammonium ions are analyzed from a model derived from theory and experimental data. Atomic mass units, electrostatic potential residing on the nitrogen atom, the COSMO van der Waals solvent accessible surface, the Onsager solvation model, and the isodensity PCM solvation model are computed at the semi-empirical and the ab initio levels of theory. A structure-activity relationship (SAR) exists between the calculated values and the experimentally obtained K-D (mM). The SAR model gives us K-D predictions and when K+ and Na+ are incorporated into the model, it dramatically predicts the selectivity of K+ over Na+ ions. (C) 2001 Elsevier Science B.V. All rights reserved.
Disclosed is a hydrocarboxylation process for the production of carboxylic acid from olefins wherein an olefin, water, a Group VIII metal hydrocarboxylation catalyst, an onium salt compound are combined in a reaction zone and contacted with carbon monoxide under hydrocarboxylation conditions of pressure and temperature The process does not require or utilize the addition of a hydrogen halide or an alkyl halide exogenous or extraneous to the hydrocarboxylation process.
On the electrochemical fluorination of quaternary ammonium compounds. Part 1. Tetraalkyl ammonium salts
作者:A. Dimitrov、W. Radeck、St. Rüdiger、O. Bechstein
DOI:10.1016/s0022-1139(00)82195-8
日期:1993.1
Tetraalkylated ammonium compounds, which are known to be very stable towards oxidative attack, can be electrofluorinated readily to yield perfluoro tertiary amines. Other than the enhanced formation of gaseous cleavage products, the electrofluorination proceeds similarly to that of other tertiary amines.
An improved process is provided for the production of thioalkyl aniline compounds, which are known and useful as intermediates for producing anthelmintic, antibacterial and fungicidal benzimidazole compounds. According to the process a thiocyano aniline compound, an alcohol and an alkali metal cyanide are reacted, with the additional presence of an alkyl halide, and also with a dipolar aprotic solvent, or in the preence of an immiscible solvent and a phase transfer catalyst. A further improvement consists of providing said phase transfer catalyst as a polymer-bound catalyst.
A process is disclosed for producing 1-hydrocarbyl mercaptans which comprises reacting a 1-hydrocarbyl halide with an alkali hydrogen sulfide or an ammonium hydrogen sulfide in the presence of a quaternary ammonium halide, which serves as a phase transfer catalyst.