Tetrabutylammonium hydrogensulfate

In a 50 mL three-necked flask with a magnetic stirrer bar was dissolved (E)-stilbene (181 mg) in acetonitrile-dimethoxymethane (15mL, 1/2, v/v). Buffer (10 mL), tetrabutylammonium hydrogensulfate (15 mg) and ketone catalyst (77.4mg) were added with stirring. 

At ambient temperature a mixture consisting of the step 1 product (1.45 mol), 2,2-dimethyl-l,3-dioxolane-4-methanol (2.90mol), tetrabutylammonium hydrogensulfate (0.290 mol), and dimethylacetamide (2.11 kg) were treated with sodium hydroxide (3.63 mol). The mixture was then heated at 60°C for 3 hours and then recooled to ambient temperature and treated with hydroxylamine hydrochloride (2.32 mol). The mixture was stirred at 80°C for 2 hours and then cooled to 50°C. Thereafter, it was treated with butyl acetate (1.45 kg) and 1.45 liters of water and the organic layer... 

The Fischer method7 for preparation of sugar isothiocyanates is general however, many modifications have been introduced, using, for example, nonpolar solvents and silver thiocyanate,29 33 lead thiocyanate,33 or ammonium thiocyanate,34 and potassium thiocyanate in acetonitrile in the presence of tetrabutylammonium hydrogensulfate.34 ... 

Benzyltriethylammonium chloride, 239 Methyltrioctylammonium chloride, 192, 240, 258, 281 Polyethylene glycol, 235 Tetrabutylammonium hydrogensulfate, 94... 

TBA tetrabutylammonium hydrogensulfate. b Prior derivatization with phenacylbromide. 

An alternative method for preparing 1-alkylisatins consists in the reaction of isatin and alkyl halides in a benzene-chloroform/50% aq. KOH biphasic system, employing tetrabutylammonium hydrogensulfate as the phase transfer catalyst. ... 

Hansson and Rosengren135 reported the first application of the ion-pair alkylation procedure136 to the formation of a glycosidic bond in the preparation of 45. Alkylation of tetrabutylammonium 2-(benzyl-oxy)-4-formylphenolate (prepared in situ from the aldehyde plus tetrabutylammonium hydrogensulfate, followed by extraction of the ion pair with dichloromethane) with the bromide 1 gave a mixture of 45 and methyl 3,4,5-tri-0-acetyl-2,6-anhydro-D-Zj/xo-hex-5-enonate (6) in 28 and 37% yield, respectively the former was obtained pure by chro-... 

Tetrabutylammonium hydrogensulfate, KF-2H20, RX, THF rt, 3-24h, 51-99% yield.Trialkylsilyl esters can be converted similarly. ... 

Although isomerization of alkenes occurs simultaneously with the oxidation, rhodium and ruthenium complexes can also be used instead of palladium for the oxidation of terminal alkene [15]. With these catalysts, symmetrical quaternary ammonium salts such as tetrabutylammonium hydrogensulfate are effective. Interestingly, the rate of palladium-catalyzed oxidation of terminal alkenes can be improved by using poly(ethylene glycol) (PEG) instead of quaternary ammonium salts [16]. Thus, the rates of PEG-400-induced oxidation of 1-decene are up three times faster than those observed with cetyltrimethylammonium bromide under the same conditions. Interestingly, internal alkenes can be efficiently oxidized in this polyethylene glycol/water mixture. 

In addition, the application of Jeffery s conditions by Sinou and co-workers, with extra triphenylphosphine and tetrabutylammonium hydrogensulfate, confirmed that Cul is not essential to success in alkyne coupling reactions [24], Moreover, they reported the most efficient coupling of bromoanisole with propargyl alcohol in 81% yield. These results prompted the authors to apply these conditions in a cascade reaction, consisting of an intermolecular Heck reaction followed by cyclization of the intermediate cr-complex (Eq. 9). The product, which is a mixture of (E) and (Z) stereomers (approximately 1 1), was sometimes contaminated with a by-product resulting from aromatization, especially for longer reaction times. 

A series of nine alkyl and alkylphenol ether carboxylates were separated on a Cig column (A = 276 nm or RI detector) using a 75/15/10 methanol/water/acetonitrile mobile phase containing 4 mM tetrabutylammonium hydrogensulfate and 1 mM tetrabutylammonium hydroxide [137]. A linear range of 0.01-10 mg/mL for UV detection and 0.1-10 mg/mL for RI detection was reported. Although baseline resolution was not achieved for all analytes, various mixtures used to create surfactant formulations could be readily identified and characterized using this method. Elution for the longest-retained analyte, oleth-6-carboxylic acid, occurred in <25 min. 

Fig. 6-43. Separation of fatty alcohol sulfosuccinates of different carbon chain length. - Separator column Nucleosil 10 Cg eluant lOmmol/L tetrabutylammonium hydrogensulfate (pH 3.0) / methanol (23 77 v/v) flow rate 2 mL/min detection Rl injection 50 pL of a Rewopol-SBF-12 solution with C,o-sulfosuccinate (1), Ci2-sulfosuccinatE (2), and C,4-sulfosuccinate (3) (taken from (43)).

Tetrabutylammonium hydrogensulfate (0.10 g, 0.29 mmol, 7 mol %), potassium hydroxide (50 % aq. solution 5 mL), and a solution of p-toluenesulfonyl chloride (0.97 g, 4.99 mmol, 1.2 equiv) in toluene (7 mL) were added to a solution of 3-iodo-l//-indole[194] (1.11 g, 4.16 mmol, 1 equiv) in toluene (4 mL). After stirring for 4 h, water was added, then the aqueous phase was washed 2 times with EtOAc. Finally, the organic phases were washed with brine, dried over MgS04 and concentrated to afford 1.43 g of 3-iodo-l-tosyl-l//-indole (87 %), which weas used in the next step without further purification [251]. 

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