Quaternary ethyl ammonium bromide

C2H5)3N + C2H5Br (C2H5)4NBr quaternary ethyl ammonium bromide... 

Synonyms Ammonium, ethylhexadecyidimethyl-, bromide CDA Cetyl dimethyl-ethyl ammonium bromide Cetyl ethyl dimethylammonium bromide Dimethyl ethyl hexadecyl ammonium bromide Ethyl cetab N-Ethyl-N,N-dimethyl-1-hexadecan-aminium bromide Ethylhexadecyidimethylammonium bromide Hexadecyleth-yldimethylammonium bromide Quaternium-17 Classification Quaternary ammonium salt ionic Nature Cationic Empirical C2QH44N Br Formula C.,gH33(CH3)2H5NBr... 

Cetyltrimethyl ammonium bromide (CTAB) dodecyltrimethyl ammonium bromide (DTAB) tetradecyltrimethyl ammonium bromide (TTAB) trioctyl-methyl ammonium chloride (TOMAC) N-benzyl-N-dodecyl-hf-bis(2-hy-droxy ethyl) ammonium chloride (BDBAC) cetyl pyridinimn chloride (CPC) quaternary ammonium salt with carbon atoms of R ranging from 8-10 (CHj Rj N+ CL) (Aliquat 336)... 

Jew and Park achieved a highly enantioselective synthesis of (2S)-a-(hydroxy-methyljglutamic acid, a potent metabotropic receptor ligand, through the Michael addition of 2-naphthalen-l-yl-2-oxazoline-4-carboxylic acid tert-butyl ester 72 to ethyl acrylate under phase-transfer conditions [38]. As shown in Scheme 5.36, the use of BEMP as a base at —60 °C with the catalysis of N-spiro chiral quaternary ammonium bromide le appeared to be essential for attaining an excellent selectivity. 

Phenoxy acid herbicides, sulfonyl ureas, quaternary ammonium derivatives (quats), and aryloxy propanoic acids are the main classes of compounds subjected to capillary zone electrophoresis (CZE). Triazines are also separated using nonaqueous CZE, while low pfCa characterized chlorotriazines require an ion-pair-like solubilization using cationic surfactants (tetradecylammonium bromide, dodecyltrimethyl-ammonium bromide). Chiral selectors are added in CZE for obtaining enantioselectivity. Chiral selectors used for herbicide enantiomeric discrimination are vancomycin, y-cyclodextrin, ethyl carbonate -cyclo-dextrin, cyclohexyl-alkyl-)S-D-maltoside, sulpropyl ether a-cyclodextrin, and hexakis(2,3-di-0-methyl)-a-cyclodextrin. 

The alkyl halide (ethyl bromide in the above equation) can react further with the primary amine produced to give a secondary amine and with that to form a tertiary amine and finally a quaternary ammonium salt. Quaternary ammonium hydroxides are very strong bases like sodium hydroxide. Tetramethylammonium hydroxide is a very important chemical used in the manufacture of semiconductors and other electronic industry products. 

Acids containing certain activating groups can be reduced without interference from hydrogen evolution. l-Ethyl-4-carboxypyridinium ion (I, as the bromide) is such a case, having the very strong electron-withdrawing quaternary ammonium ion as part of the... 

Alkylation of phthalimide anion can be carried out under solid-liquid phase-transfer conditions, using phosphonium salts or ammonium salts. In the reaction systems using hexadecyltributylphosphonium bromide, alkyl bromides and alkyl methanesulfonate are more reactive than alkyl chlorides. Octyl iodide is less reactive than the corresponding bromide and chloride. ( )-2-Octyl methanesulfonate was converted into (S)-2-octylamine with 92.5% inversion. Kinetic resolution of racemic ethyl 2-bromopro-pionate by the use of a chiral quaternary ammonium salt catalyst has been reported. Under liquid-liquid phase-transfer conditions, A -alkylation of phthalimide has been reported to give poor results. ... 

The asymmetric alkylation of glycine derivatives constitutes a general means of accessing a wide range of natural and unnatural oc-amino acids.111 Recently it has been established that the quaternary ammonium salt, (lS,2S,4S,5/ ,l / )-l-anthracen-9-yl)methyl-2-[benzyloxy(quinolin-4-yl)methyl]-5-ethyl-l-azoniabicyclo [2.2.2]octane bromide, is a highly effective catalyst in the asymmetric liquid-liquid phase-transfer alkylation of tert-butyl AI-(diphenylmethylene)glycinate. Subsequent hydrolysis of the imine provides access to a wide range of a-amino acid fcrt-butyl... 

The choice of organic solvents permits the occurrence of certain reduction reactions of alkyl halides which, if attempted in aqueous solutions, would rapidly be inhibited by the precipitation of insoluble products on the electrode. Under mildly cathodic conditions, the formation of metal alkyls occurs in high yields when alkyl halides are reduced at cathodes of low boiling metals in acetonitrile, DMF or propylene carbonate containing quaternary ammonium supporting electrolytes. " Whilst the formation of lead tetraethyl from ethyl bromide in DMF proceeds irrespective of the substitution of a sodium salt for the quaternary ammonium salt, the same change of electrolyte in propylene carbonate no longer leads to metal alkyl products. ... 

Numerous syntheses have also been reported for arabinofuranosyl nucleoside analogues, prepared either conventionally from arabinofuranosyl derivatives or via 2,2-anhydro-nucleosides obtained from appropriate ribonucleosides. 5-Aza-cytosine-D-arabinoside has been synthesized and found to show similar antiviral activity to Ara-C(arabinosyl-cytosine). 7-a-, 7-<3-, 9-0 -, and 9- 3-arabino-furanosyl derivatives of 3-deazaguanine have also been prepared, but none showed any anti-tumour activity. 9-(o -D-Arabinofuranosyl)-8-aza[2- C]-adenine, 7-(/3-D-arabinofuranosyl)-pyrrolo[2,3-d]pyrimidine-4(3//)-one (15)," l-(a-D-arabinofuranosyl)- and l-(/3-D-xylofuranosyl)-4-nitropyrazole, and Ot-arabino-nucleosides of 5-fluoro-cytosine and -uracil derivatives have also been prepared. An improved synthesis of 9-(/3-D-arabinofuranosyl)-2-fluoro-adenine has been reported. The ratio of o to 3 anomers obtained by phase-transfer reaction of 2,3,5-tri-O-benzyl-D-arabinofuranosyl bromide with 6-chloro-2-thiomethyl-7-deazapurine varied with the quaternary ammonium salt used as a catalyst, although the jU-anomer predominated in every case. 2,2-Anhydro-nucleosides have been used to prepare l-j3-D-arabinofiiranosyl derivatives of 5-alkylthio-uracils, 5-ethyl-cytosine, and 5-ethyl-uracil, 8-alkylamino-purines, and 2-aralkylamino-l,4-dihydro-4-imino-pyrimidine hydrochlorides (16). ... 

Three esters (ethyl isovalerate, ethyl r-butylacetate, and ethyl isobutyrate) do notundergo this type of condensation under normal conditions with sodium ethoxide, presumably due to the steric hindrance. However, their condensation proceeds readily when mesitylmagnesium bromide is applied as the base. In addition, the acetoacetic ester condensation has been improved to give high yields using some quaternary ammonium salts of long aliphatic chains as the phase transfer catalyst in benzene. ... 

The produced quinone makes black complexes within the original hydroquinone very easily. As shown in Figure 4.48, when the crystals of hydroquinone and quinone are placed separately, the dark-violet crystals of the complex, which are called quinhydron, appear between the two crystalline samples. We tried to stabilize hydroquinone by making complexes with various surfactant molecules containing quaternary ammonium salts, such as alkyltrimethylammonium halides, benzyl(alkyl)dimethyl-ammonium chloride, and ethyl(hexadecyl)dimethylammonium bromide (ECDAB). After many trials, complex crystals suitable for X-ray analysis were formed with benzyl(hexadecyl)dimethylammonium chloride (BCDAC) and ECDAB, as shown in Figure 4.49. 

When ethyl bromide reacts with ammonia, for example, the ethylaminium bromide that is produced initially can react with ammonia to liberate ethylamine. Ethylamine can then compete with ammonia and react with ethyl bromide to give diethylaminium bromide. Repetitions of alkylation and proton transfer reactions ultimately produce some tertiary amines and even some quaternary ammonium salts if the alkyl halide is present in excess. 

A quaternary ammonium hydroxide type of anion exchange resin, Amberlite IRA-400 (OH ), is an effective catalyst for the alkylation of ethyl malonate, ethyl cyanoacetate, or cyanoacetamide with various alkyl halides.— E Molar equivalents of 2-ethylcyanoacetamide and allyl bromide stirred 2 hrs. at room temp, with Amberlite IRA-400 (OH ) in ethanol-water 2-allyl-2-ethylcyano-acetamide. Y 82%. F. e. s. K. Shimo and S. Wakamatsu, J. Org. Ghem. 28, 504 (1963). 

Primary chlorides can be converted into bromides by the action of ethyl bromide and catalytic quantities of metal bromides, and a quaternary ammonium ion-exchange resin, in its fluoride form, has been used in the formation of alkyl fluorides from other alkyl halides (or methane sulphonates) as in equation (9). Both of these methods can be generalized to other halide interconversions. 

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