Tetra-n-butylammonium iodide

Tetra-n-butylammonium iodide [311-28-4] M 369.4, m 146". Crystd from toluene/pet ether (see entry for the corresponding bromide), acetone, ethyl acetate, EtOH/diethyl ether, nitromethane, aq EtOH or water. Dried at room temperature under vac. It has also been dissolved in MeOH/acetone (1 3, lOmL/g), filtered and allowed to stand at room temperature to evaporate to ca half its original volume. Distilled water (ImL/g) was then added, and the ppte was filtered off and dried. It was also dissolved in acetone, ppted by adding ether and dried in vac at 90" for 2 days. It has also been recrystallised from CH2Cl2/pet ether or hexane, or anhydrous methanol and stored in a vacuum desiccator over H2SO4. [Chau and Espenson J Am Chem Soc 108 1962... 

In addition, NaOMe, and NaNH2, have also been employed. Applieation of phase-transfer conditions with tetra-n-butylammonium iodide showed marked improvement for the epoxide formation. Furthermore, many complex substituted sulfur ylides have been synthesized and utilized. For instance, stabilized ylide 20 was prepared and treated with a-D-a/lo-pyranoside 19 to furnish a-D-cyclopropanyl-pyranoside 21. Other examples of substituted sulfur ylides include 22-25, among which aminosulfoxonium ylide 25, sometimes known as Johnson s ylide, belongs to another category. The aminosulfoxonium ylides possess the configurational stability and thermal stability not enjoyed by the sulfonium and sulfoxonium ylides, thereby are more suitable for asymmetric synthesis. 

DME ethylene glycol dimethyl ether TBAI tetra-n-butylammonium iodide... 

Dissolve 20 g of tetra-n-butylammonium iodide in 100 mL of dry methanol and pass this solution through the column at a rate of about 5 mL min - L the effluent must be collected in a vessel fitted with a Carbosorb guard tube to protect it from atmospheric carbon dioxide. Then pass 200 mL of dry methanol through the column. Standardise the methanolic solution by carrying out a potentiometric titration of an accurately weighed portion (about 0.3 g) of benzoic acid. Calculate the molarity of the solution and add sufficient dry methanol to make it approximately 0.1M. 

As the integrity of chiral alcohols are retained in the phase-transfer catalysed O-alkylation, the procedure is valuable for the synthesis of chiral ethers under mild conditions as, for example, in the preparation of alkoxyallenes via the initial formation of chiral propargyl ethers [8]. It has been proposed that a combination of 18-crown-6 and tetra-n-butylammonium iodide provide the best conditions for the O-benzylation of diethyl tartrate with 99% retention of optical purity [9]. 

The analogous two-phase reaction of acrolein with thiolacetic acid under basic conditions in the presence of tetra-n-butylammonium iodide initially forms the Michael adduct which, upon hydrolysis, reacts further to produce l-formyl-5-thia-cyclohexene (see Scheme 4.17). In a similar manner, crotonaldehyde produces 1 -formyl-4,6-dimethyl-5-thiacyclohexene [13]. 

A phase-transfer catalysed nucleophilic displacement reaction on chloro-acetanilides by cyanate ions, followed by ring-closure (Scheme 5.10), provides a simple and viable synthesis of hydantoins [41], The formation of the hydantoins is inhibited by substituents in the orf/to-position of the aryl ring, but the addition of potassium iodide, or tetra-n-butylammonium iodide, generally increases the overall rate of formation of the cyclic compounds, presumably by facilitating the initial nucleophilic substitution step. 

Unsaturated nitriles have been obtained from the SN. reaction of 3-chloroalk-1 -enes [22] using tetra-n-butylammonium iodide as the catalyst. Under the basic reaction conditions, isomerism occurs such that not only is the 1-cyanoalk-2-ene obtained, but also the conjugated 1-cyanoalk-l-ene. Surprisingly, when tetra-n-butylammonium chloride is used, direct SN displacement of the chloro group occurs, followed by isomerization, to give the 3-cyanoalk-2-ene. 

Zirconium tetrachloride promotes a tandem nucleophilic addition and aldol-type condensation reaction of methyl propynoate, or /V,/V-dimethylpropynamidc, with aldehydes, or ketones, in the presence of tetra-n-butylammonium iodide (Scheme 6.13) [8] with a high selectivity towards the formation of Z-isomers. A similar reaction occurs between aliphatic and aromatic aldehydes and penta-3,4-dien-2-one to yield 1-substituted 2-acetyl-3-iodobut-3-enols (50-75%) [9]. 

Tetra-n-butylammonium triborono-octahydride, which can be obtained by metathesis from the sodium salt and tetra-n-butylammonium iodide, is a mild reducing agent with a selectivity similar to that of the tetrahydride, but with a much lower overall activity [l]. For example, acid chlorides are reduced five-times more readily than are aldehydes, which are ten-times more susceptible to reduction than acyclic... 

A stereoselective tandem iodination and aldol-type condensation has been described for the reaction of methyl propiolate and carbonyl compounds in the presence of a stoichiometric amount of tetra-n-butylammonium iodide and zirconium chloride to yield Z-3-iodo-2-(l-hydroxyalkyl)propenoates, as the major products [48]. No reaction occurs in the absence of the Lewis acid. There does not appear to be any control on the chirality of the hydroxyl centre. 

Fig. 12 Relative rates of debromination of v/c/na/-dibromides 27-30 with di-n-hexyl-telluride (26) and tetra-n-butylammonium iodide.

Monoetherification of polyols.12 Monobenzylation and monoallylation of polyols can be conducted conveniently under mild conditions by conversion to the stannylene derivative (dimeric) by di-n-butyltin oxide (5, 189 9, 141). The stannylene is then treated with benzyl bromide or allyl bromide and tetra-n-butylammonium iodide (1 equiv.) in benzene. The same conditions can be used to prepare monomethoxymethyl ethers. Quaternary ammonium bromides are less efficient catalysts than the iodides. These salts also accelerate reaction of stannylenes with acid anhydrides. The mechanism for this activation is not clear it may involve coordination of I" to tin. 

Tetra-n-butylammonium Iodide Solution Transfer 1.250 g of tetra-w-butylammonium iodide into a 500-mL volumetric flask, dilute to volume with water, and mix. 

Procedure Pipet 10.0 mL of the Sample Solution into a 250-mL flask, and add 40 mL of chloroform, 50 mL of Salt Solution, and 10 drops of bromophenol blue TS. Titrate with Tetra-n-butylammonium Iodide Solution to the first appearance of a blue color in the chloroform layer after vigorous shaking. Calculate the percent C2oH37Na07S by the formula... 

Phase-transfer catalysis can effectively promote the substitution of group 6 metal carbonyls by nitrogen, phosphorus, and arsenic ligands. Reaction of M(CO) [M = Cr, Mo, W] with a group 5 ligand and tetra-n-butylammonium iodide in benzene-sodium hydroxide (50%), at 25-80°C... 

This monomer is prepared by the substitution reaction of 2-chloroethyl vinyl ether (CEVE) with sodium acetate in the presence of a phase-transfer catalyst (tetra-n-butylammonium iodide) [17]. All reagents are of commercial sources and employed without further purification except for vacuum drying when necessary. 

In a 500-mL, three-necked, round-bottomed flask equipped with a reflux condenser, a Teflon paddle stirrer, and a drying tube (calcium chloride), and a thermometer are placed CEVE (240 mL, 2.4 mol), sodium acetate (82 g, 1.0 mol), and tetra-n-butylammonium iodide (ca. 2 g). The mixture is stirred for 8 hr at 80-90° C in a water bath and cooled to room temperature. The resulting sodium chloride is filtered off and extracted with 200 mL diethyl ether. The ether extract is combined with the reaction mixture, and the ether and unreacted CEVE are removed by evaporation. 

Deoxylodo sugars. Preparation of these compounds by displacement reactions usually has limitations because of the vigorous conditions commonly required. Replacement of a triflate group (4, 533) by iodine using tetra-n-butylammonium iodide, however, proceeds under relatively mild conditions (refluxing benzene, 15 hours). In six reported examples, overall yields were 85-95%. ... 

Lithium iso -amyl, LiCgH, reacts with triethyl-n-butylammonium bromide to give diethyl-n-butylamine and lithium n-heptyl, with tetra-n-butylammonium iodide to form tri-n-butylamine, a trace of a hydrocarbon and possibly n-heptane. 

Extraction of the cadmium-iodide complex from iodide-H2S04 solutions with oxygen-containing solvents (e.g., mesityl oxide, 2-ethyl-1-butanol) is a selective recommended separation method (e.g., from zinc) [1-3]. The iodide complex of cadmium can also be extracted with high molecular weight amines in xylene [4], TBP in benzene [5], and with tetra-n-butylammonium iodide in CHCI3 [6]. 

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