Tetrabutylammonium hydrogen sulphate

Water insoluble tetrabutylammonium metaperiodate, which can be prepared from sodium metaperiodate and tetrabutylammonium hydrogen sulphate in aqueous solution, was found to be a useful reagent for the selective oxidation of sulphides in organic solvents . The reaction was generally carried out in boiling chloroform and gave dialkyl, alkyl aryl and diaryl sulphoxides in yields which are comparable with those reported for sodium metaperiodate in aqueous methanol solution (Table 4). In the case of diaryl sulphoxides, the yields decrease with prolonged reaction time. 

Cotterill [222] has developed a procedure, discussed below, in which the herbicides are extracted from soil with saturated calcium hydroxide solution. After clean-up the residues are ethylated using iodoethane and tetrabutylammonium hydrogen sulphate as counter ion. Liquid-liquid partition and the use of a macroreticular resin column were compared as clean-up steps and the reaction conditions for optimum yield of ethyl ester were evaluated. 

The preparation of alkyl methyl ethers may be readily effected under PTC conditions from the alcohol, dimethyl sulphate and 50 per cent w/w aqueous sodium hydroxide, employing tetrabutylammonium hydrogen sulphate as catalyst.95 The usefulness of this procedure has been extended, and optimum conditions have been described for the alkylation of a range of aliphatic alcohols using, for example, 1-chlorobutane or benzyl chloride.96 The PTC preparative examples described in Expt 5.73 are for the methylation, allylation, but-2-enylation and benzylation of, for example, 2-hydroxymethyl-l,4-dioxaspiro[4.5]decane (Expt 5.63), and have been developed in the editors laboratories. These methods have also been applied to the alkylation of protected monosaccharide derivatives (p. 652). 

PTC methods for the oxidation of water-insoluble acid-sensitive alcohols have been described which use an aqueous sulphuric acid solution of potassium dichromate, dichloromethane and catalytic amounts of tetrabutylammonium hydrogen sulphate.103... 

Benzylideneaniline (18.1 g, 0.1 mol) and tetrabutylammonium hydrogen sulphate (0.5 g, 1.35 mol) are dissolved in dichloromethane (100 ml) and a layer of 50 per cent aqueous sodium hydroxide introduced under this solution. Trimethylsulphonium iodide (20.4 g, 0.1 mol) is then added and the whole warmed at 50 °C with vigorous stirring for 2 hours, whereupon the originally undissolved sulphonium salt disappears. The mixture is poured on to ice, the organic phase separated, washed with water and dried. The solvent is evaporated and the residue distilled under reduced pressure to afford 1,2-diphenylaziridine (94%), b.p. 120°C/0.05mmHg. 

Iodobenzene (1.01 g, 4.9 mmol) was dissolved in dichloromethane (75 ml) and stirred vigorously with hypochlorite solution (200 ml of commercial laundry bleach adjusted to pH 8.2 and containing 200 mg of tetrabutylammonium hydrogen sulphate) at room temperature for 45 min. The reaction mixture was allowed to stand for 1 h then the precipitate was filtered to give crude iodylbenzene (0.69-0.94 g, 59-81%). Purification may be effected by crystallization from water or acetic acid. 

TBAH = tetrabutylammonium hydrogen sulphate d,l-190 P A ° - L-MenCH(Me)CH(NH2)COOH (119)... 

Consider a study, by HPLC, of the separation of three nucleotides (AMP, ADP and ATP), with a column of type RP-18. The mobile phase is a binary mixture of H2O — KH2PO4, 0.1 M (pH 6)/methanol (90/10). The compounds appear in the order ATP, ADP, AMP. If a solution of 4 mM tetrabutylammonium hydrogen sulphate is added to the mobile phase, the order of elution of these compounds is reversed (see Figure 3.15). 

Mobile phase Gradient. MeCN 10 mM pH 7.2 potassium phosphate buffer containing 5 mM tetrabutylammonium hydrogen sulphate at 25 75 for 20 min, then to 50 50 over 45 min, hold at 50 50 for 10 min. 

Fig. 8. Effect of imraunoaffinity chromatography on HPLC-fluorescence analysis of lAA in an extract from dwarf-1 Zea mays shoots. Sample A. acidic, diethylether extract B. as A but extract subjected to immunoaffinity chromatography. Column 250x5.0 mm i.d. 5 p,m ODS Hypersil. Mobile phase 25 rain, 25-75% gradient of methanol in 1% aqueous acetic acid. Flow rate 1 ml min. Detector fluorimeter, excitation 280 nm, emission 350 nm. Sample C. lAA-like peak from B. Column, flow rate and detector as A and B. Mobile phase 35% methanol in 50 mM phosphate buffer and 20 mM tetrabutylammonium hydrogen sulphate at pH 6.5 [93].

Fig. 11.1.4. Separation of uracil and 5-fluorouracil bases, nucleosides and nucleotides by reversed phase ion-pair HPLC. Chromatographic conditions column, Bondapak Cig (300 x 4 mm) mobile phase, (from 0-30 min) 0.1 mM tetrabutylammonium hydrogen sulphate (Cjg), 2.5 mM tetraethylammonium bromide (Cg) and 2% methanol in 2 mM sodium acetate, 1.5 mM phosphate buffer, pH 6.0 (Buffer A) (from 30-50 min) Buffer A-i-30 mM phosphate detection, UV at 254 nm. Peaks FU, fluorouracil FUR, fluorouracU riboside/ FUdR, fluorouracil deoxyriboside FUMP, fluorouridine 5 -monophosphate 5 dFUR, 5 -deoxyfluorouracil riboside FdUMP, deoxyfluorouri-dine monophosphate UDPG, uridine diphosphoglucose UDP, uridine diphosphate dUDP, deoxyuridine monophosphate UTP, uridine triphosphate. Reproduced from Au et al. (1982), with permission.

Secondary nitroaUcanes are oxidized to ketones by 3-chloro- or 4-nitrobenzoyl peroxide by way of their anions thus MePhCHN02 gives acetophenone in 92% yield. The same reaction can be carried out with sodium chlorite in methylene chloride/aqueous sodium hydroxide/tetrabutylammonium hydrogen sulphate under phase-transfer conditions. Nitrones 382 (R = H or Me = Me, C02Me, CONHMe or CONMe2 R = t-Bu or Ph) are formed when the sodium salts 381 of nitroaUcanes are treated with the appropriate nitroso compounds 24 ... 

Phase-transfer selective benzoylation of methyl 4,6-(9-benzylidene-Q -D-gluco-pyranoside using tetrabutylammonium hydrogen sulphate, benzoyl chloride, and 5% aqueous sodium hydroxide during 15 min gave 50% 2-O-benzoyl derivative. The yields were increased to 85 % by using benzene, benzoyl chloride, tetrabutylammonium iodide, and potassium carbonate for 48 h. ... 

As an alternative to the potassium salt, tertiary amines and tetra-alkylammonium salts have been used instead. The acids, e.g. the dried residue from a serum extraction, are treated with an acetonitrile solution of pentafluorobenzyl chloride and di-isopropylethylamine, in a 3 1 molar ratio, at 40 °C for 5 minutes. The reaction mixture is blown dry with nitrogen if necessary the esterification may be repeated (96). lndole-3-acetic acid was similarly esterified, but using acetone as solvent and N-ethylpiperidine as the cation and reaction for 45 minutes at 60 °C [97). Tetrabutylammonium hydrogen sulphate (0.1 mmol) was converted to the hydroxide with sodium hydroxide (0.2 mmol) and added to the dried acids in a serum extract with 1 ml of methylene chloride and 20 pi of pentafluorobenzyl bromide. The mixture was vigorously shaken for 30 minutes and blown down to dryness with nitrogen, and the esters were extracted into hexane for HPLC [98,99). 

A column (250 x 4.6 mm i.d.) of Zorbax CIS (10 micron) with an ion-pair (0.1 M tetrabutylammonium hydrogen sulphate (pH 5))/water/ acetonitrile gradient system and both diode array and fast atom bombardment MS was used to determine the hydrophobe distribution of the LAS [17]. 

Sodium salts of alkyl (C10-C14) sulphosuccinates are separated on a 250 X 4.6 mm i.d. column of 10 micron Nucleosil C8 with aqueous 0.01 M tetrabutylammonium hydrogen sulphate/methanol (23 77) at pH 3 as mobile phase. Detection is by refractive index [26]. 

Phase transfer catalysis by tetrabutylammonium hydrogen sulphate (TBAH), dicyclohexyl-18-crown-16, and Kryptofix [222], has also been employed to treat 4-chloromethylstyrene polymers (both linear and cross-linked) and epichloro-hydrin polymers with various amines. This modification (Scheme 6) yields poly-... 

In the first example of the application of phase-transfer catalysis to early-transition metal organometallic chemistry, reaction of (q -cyclopentadienyOtetracarbonylvanadium with 5 N sodium hydroxide, in benzene and in the presence of tetrabutylammonium hydrogen sulphate as a phase-transfer catalyst, afforded the (q -cyclopentadienyl)tricarbonylhydridovanadate anion (Scheme 8) [75] ... 

II) solvent A 50 mM potassium phosphate, pH 5.9, 2 mM tetrabutylammonium hydrogen sulphate,... 

Figure 4. Analytical revetsed-phase ion-pair HPLC of oligofrA) on a C, g column. Sample, 10 oligofrA) column, LiChrosorb RP-18 (4.0 x 250 mm) apparatus, Bruker LC 21 B with a Shimadzu SPD-6A spearophotometer set at 260 nm with 0.16 AUFS elution, linear gradiem from 0 to 60% (v/v) acetonitrile in SO mM potassium phosfdiate, pH S.S, 2 mM tetrabutylammonium hydrogen sulphate in 120 min flow-rate, 0.8 ml/min.

Tetrabutylammonium hydrogen sulphate Triethylammonium acetate puriss. Fluka 86868... 

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