Tetra-ethyl ammonium

Another facet of striatal LTP is that potentiation is reliably induced by HFS in the presence of the potassium-channel blocker, tetra-ethyl ammonium (Walsh, 1991 Wickens et al., 1998). By analogy with other systems, this result might be interpreted as an increased influx of calcium into the postsynaptic neuron. However, this does not appear to be the case. Intracellular application of potassium-channel blockers does not facilitate LTP (Wickens et al., 1998), as would be predicted, if these effects were mediated by greater depolarization of the postsynaptic neuron. The facilitation of LTP by extracellular potassium-channel blockers is therefore more likely to be due to presynaptic effects, such as facilitation of dopamine release by prolongation of the action potential in dopaminergic axon terminals. 

Solubility of Tetra Ethyl AMMONIUM BROMIDE N(CsHj)4Br, and of Tetra Methyl Ammonium Bromide N(CH 4Br in Acetonitril. 

Solubility op Uranyl Ammonium Chloride, U. Tetra Methyl Ammonium Chloride, U. Tetra Ethyl Ammonium Chloride, U. Caesium Chloride, U. Rubidium Chloride, and U. Potassium Chloride in Water. 

Recorded in CH3CN solution with 0.1 M tetra ethyl ammonium perchlorate (TEAR) as supporting electrolyte. 

The Heck reaction is a C-C coupling reaction where an unsaturated hydrocarbon or arene halide/triflate/sulfonate reacts with an alkene in presence of a base and Pd(0) catalyst so as to form a substituted alkene. Kaufmann et al. showed that the Heck reaction carried out in presence of ILs such as tetra-alkyl ammonium and phosphonium salts without the phosphine ligands, resulted in high yields of product. They attributed the activity to the stabilizing effect of ammonium and phosphonium salts on Pd(0) species. Carmichael et al. used ionic liquids containing either A,A -dialkylimidazolium and A-alkylpyridinium cations with anions such as halide, hexafluorophosphate or tetrafiuoroborate to carry out reactions of aryl halide and benzoic anhydride with ethyl and butyl acrylates in presence of Pd catalyst. An example of iodobenzene reacting with ethyl acrylate to give trans-et vy cinnamate is shown in Scheme 14. 

Ionic liquids [e.g. l-ethyl-3-methylimidazolium triflate (mp. —9 C) l-n-butyl-3-methyl-pyridinium chloride (mp. 98 °C) tetra- -butyl-ammonium bromide (mp. 130 °C)]... 

TMA = tetra-methyl ammonium, TPA = tetra-propyl ammonium, Et-Py- = N-ethyl pyridinium, DIQ-6 = 1,6 hexa-methylene bis (trimethyl ammonium bromide), DIQ-6 = 1,6 hexa-methylene bis (benzyldimethyl ammonium bromide) and DIQ-6 = 1,6 hexa-methylene bis (triethyl ammonium bromide). 

Cl-, Tetra-ethylammonium chloride, - bromide (Cfl,),N-F-, (n-C,H,UNn-Stearyltrimethyl-ammonium chloride Benzyltrimethyl-ammonium chloride, Benzyltri ethyl-ammonium -Girard reagent T Pyridinium ethiodide (CH )JS Br-Br ... 

GTP was employed for the synthesis of block copolymers with the first block PDMAEMA and the second PDEAEMA, poly[2-(diisopropylamino)e-thyl methacrylate], PDIPAEMA or poly[2-(N-morpholino)ethyl methacrylate], PM EM A (Scheme 33) [87]. The reactions took place under an inert atmosphere in THF at room temperature with l-methoxy-l-trimethylsiloxy-2-methyl-1-propane, MTS, as the initiator and tetra-n-butyl ammonium bibenzoate, TBABB, as the catalyst. Little or no homopolymer contamination was evidenced by SEC analysis. Copolymers in high yields with controlled molecular weights and narrow molecular weight distributions were obtained in all cases. The micellar properties of these materials were studied in aqueous solutions. 

The highly hydrophilic alcohols, pentaerythritol and 2-ethyl-2-hydroxymethyl-propan-l,3-diol, can be converted into their corresponding ethers in good yields under phase-transfer catalytic conditions [12]. Etherification of pentaerythritol tends to yield the trialkoxy derivative and kinetics of the reaction have been shown to be controlled by the solubility of the ammonium salt of the tris-ether in the organic phase and the equilibrium between the tris-ether and its sodium salt [13]. Total etherification of the tetra-ol is attained in good yield when reactive haloalkanes are used, and tetra-rt-octylammonium, in preference to tetra-n-butylammonium, bromide [12, 13]. 

Methyl esters undergo trans-esterification with the quaternary ammonium salts at high temperature and the reaction has been used with some effect for the preparation of, for example, n-butyl esters by heating the methyl ester with tetra-n-butylammo-nium chloride at 140°C [31]. Optimum yields (>75%) are obtained in HMPA or in the absence of a solvent. A two-step (one-pot) trans-esterification under phase-transfer catalysed conditions in which the carboxylate anion generated by initially hydrolysis of the ester is alkylated has been reported for Schiff s bases of a-amino acids [32] and for A-alkoxycarbonylmethyl [1-lactams [33]. Direct trans-esterification of methyl and ethyl esters with alcohols under basic catalytic conditions occurs in good yield in the presence of Aliquat [34, 35]. 

The final analytical method for the simultaneous determination of A9-THC and its metabolites consists of the following sequence the cannabinoids are extracted from plasma with toluene they are then back extracted from toluene into Claisen s alkali the Claisen s alkali is diluted with water, tetrahexyl ammonium hydroxide is added and the alkaline solution is extracted with methylene chloride containing ethyl iodide. The overall recoveries were 45% for A9-THC and 83% for 11-hydroxy-A9-THC. External standards (l-0-ethyl-A9-THC and l-0-ethyl-ll-hydroxy-A9-THC) were added to the methylene chloride phase followed by a small amount of Florosil, which absorbed the tetra-hexylammonium hydroxide and tetrahexylammonium iodide. The methylene chloride was decanted and evaporated. 

Ac, acetyl AIBN, azobis(isobutanonitrile) All, allyl AR, aryl Bn, benzyl f-BOC, ferf-butoxycarbonyl Bu, Butyl Bz, benzoyl CAN, ceric ammonium nitrate Cbz, benzyloxycarbonyl m-CPBA, m-chloroperoxybenzoic acid DAST, diethylaminosulfur trifluoride DBU, l,8-diazabicyclo[5.4.0]undec-7-ene DCC, /V. /V - d i eye I oh e x y I c ar bo -diimide DCM, dichloromethyl DCMME, dichloromethyl methyl ether DDQ, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DEAD, diethyl azodicarboxylate l-(+)-DET, L-(+)-diethyl tartrate l-DIPT, L-diisopropyl tartrate d-DIPT, D-diisopropyl tartrate DMAP, 4-dimethylaminopyridine DME, 1,2-dimethoxyethane DMF, /V./V-dimethylformamide DMP, 2,2-dimethoxypropane Et, ethyl Im, imidazole KHMDS, potassium hexamethyldisilazane Me, methyl Me2SO, dimethyl sulfoxide MOM, methoxymethyl MOMC1, methoxymethyl chloride Ms, methylsulfonyl MS, molecular sieves NBS, N-bromosuccinimide NIS, /V-iodosuccinimide NMO, /V-methylmorpho-line N-oxide PCC, pyridinium chlorochromate Ph, phenyl PMB, / -methoxvbenzyl PPTs, pyridiniump-toluenesulfonate i-Pr, isopropyl Py, pyridine rt, room temperature TBAF, tetrabutylammonium fluoride TBS, ferf-butyl dimethylsilyl TBDMSC1, f-butylchlorodimethylsilane Tf, trifhioromethylsulfonyl Tf20, trifluoromethylsulfonic anhydride TFA, trifluoroacetic acid THF, tetrahydrofuran TMS, trimethylsilyl TPAP, tetra-n-propylammonium perruthenate / -TsOH. / -toluenesulfonic acid... 

Viscose Silk.—III. From Cellulose Xanthate. We have referred to the solvent action of xanthic acid, which is the ethyl ether of di-thio-carbonic acid, viz., HS-CS-OC2H5. When sodium cellulose is dissolved in xanthic acid the cellulose is in the form of sodium cellulose xanthate. A solution properly prepared by treating cellulose with sodimn hydroxide and carbon di-sulphide in the presence of benzene or carbon tetra-chloride, in which polymerization of the cellulose compound is effected, is decomposed by forcing capillary streams of the solution into a solution of ammonium sulphate. The cellulose is thus obtained as in the other processes in the form of fine filaments of a hydrated cellulose possessing silk-like properties. Artificial silk of this type is known as viscose silk and is made in large quantities. In 1914 about 20,000,000 pounds of artificial silk were made, of which about 3,000,000 pounds were made in the United States. Most of this product was viscose silk. 

N2Cl4CrC4Hi8, Ammonium, ethyl-, tetra-chlorochromate(ll) (2 1), ferromagnets, 24 188... 

Next, process chemistry for the practical synthesis of 7b (MGS0028) is discussed (Schemes 3.5-3.7) [42-45]. First, the synthesis of key intermediate (+)-29 from racemic acetoxycyclopentene (34) is shown in Scheme 3.5 [43]. The key reaction in this approach was Trost s asymmetric ally lie alkylation reaction of ethyl 2-fluoroacetoacetate with 34, which afforded 35 in high yield and high enantioselectivity, especially when a bulky tetra-n-hexyl ammonium bromide was used as a phase-transfer reagent (89% yield, 94-96%... 

---