Anhydrous THF

Anhydrous THF (300ml) was treated with L1A1H4 (1.7g). After reaction subsided, additional L1AIH4 (30.0 g) wa.s added carefully and the mixture was... 

In the alternative approach.the 1,3-dipolar system can be constructed in several ways. Treatment of a-chloroacylhydrazones of diaryl ketones and certain aralkyl and dialkyl ketones (382) with NaH in anhydrous THF gives l-(disubstituted methylene)-3-oxo-l,2-diazetidinium inner salts (383). Reaction of (383) with DMAD in methylene chloride gave (384), a 2 1 adduct with loss of CO. Double bond migration in (384) occurred on heating to give (385). The intermediate in the cycloaddition was found to be (386), which on heating lost CO to form a new ylide system which in turn underwent reaction with more DMAD <81JA7743). 

To a solution of 0 01 mol of lithium hexamethyldisilazide and 0 01 mol of HMPA dissolved in 50 mL of anhydrous THF at 78 °C was added 0 5 g (0 004 mol) of l-fluoro-3,3-dimethylbutanone m THF over 1 mm To the solution of the enolate was then rapidly added 0 003 mol of the aldehyde m THF After stimng an additional 2 mm, the reaction was quenched by rapid addition of a saturated ammonium chlonde soluuon Extractive workup with hexanes yielded on evaporation the product as a clear colorless oil isolated yield... 

Reduction of a perhydropyrido[l,2-c][l,4]oxazin-l-one with BH3 in anhydrous THF at room temperature yielded a perhydropyrido[l,2-c] [l,4]oxazine (OOMIPl). 

A mixture was made of L-tyrosine (18.1 g, 0.1 mol) benzoyl chloride (7.0 g, 0.05 mol) and 200 ml anhydrous THF. After stirring at reflux for 2 hours, the mixture was cooled to room temperature, and the precipitate of tyrosine hydrochloride filtered off (11 g, 46 meq. Cr). The THF was evaporated and the residue extracted with CCI4 (3 X 100 ml at reflux, discarded) and then dissolved in ethyl acetate (200 ml) filtering off insolubles. The ethyl acetate solution was evaporated to yield 13.2 g solid product, MP 159°-162°C (93%). The tyrosine was recovered (8 g) by neutralization with aqueous alkali, from the hydrochloride. 

The submitters used THF that was freshly distilled over Na/K alloy NMP was distilled over CaH2. The checkers used commercially available anhydrous THF and NMP obtained from Aldrich Chemical Co. There appears to be a slight increase in yield when THF distilled from sodium/benzophenone ketyl is used instead of the commercial THF. All other solvents used were of reagent grade quality and were used without further purification. 

Anhydrous THF was freshly distilled from sodium/benzophenone under nitrogen. 

P 55] Before synthesis, a micro-mixing tee chip micro reactor (Figure 4.85) (with two mixing tees and four reservoirs) was primed with anhydrous tetrahydrofuran (THF). A 40 gl volume of a 0.1 M solution of tetrabutylammonium fluoride trihydrate in anhydrous THF is filled into one reservoir of a micro-mixing tee chip reactor [15], 40 gl of a 0.1 M solution of 4-bromobenzaldehyde in anhydrous THF is added to a second reservoir, 40 gl of a 0.1 M solution of the silyl enol ether (masking the enolate of a carbonyl compound such as cyclohexanone) in anhydrous THF is added to a third reservoir and anhydrous TH F is filled into the fourth collection reservoir. Electrical fields of417,455,476 and 0 V cm are applied to transport the reaction species from the respective reservoirs. The reaction is carried out at room temperature. 

Treatment of the cyclometallated complexes [Au(N,N,C)Cl][PF6] [N,N,CH = 6-methylbenzyl- (a) or 6-(l,l-dimethylbenzyl)-2,2 -bipyridine (b)] [20] with KOH or Ag20 in aqueous media affords the hydroxo complexes [Au(N,N,C)(OH)][PF6] (36) in fairly good yields [45b, 101] these are air-stable white solids, quite soluble in water and in many organic solvents. When refluxed in anhydrous THF they condense to give the oxo-bridged complexes [Au2(N,N,C)2( J--0)] (37) (Equation 2.10 in Scheme 2.5) which, in turn, can be obtained by a different route [102] (see Section 3.2) the reaction can be reversed by refluxing the 0x0 complex in water. 

A related reaction process involves the use of chlorotrimethylsilane in the presence of zinc dust in anhydrous THF in which the zinc functions as both an electron donor and a chlorine scavenger. The stoichiometry and a plausible mechanism for the reaction are given in equation (9) ... 

Synthesis of Polyethylene-tethered Phthalonitrile. Polyethylene monoalcohol ( 700 Daltons, 80% functionalized) in pellet form (6.0 g, 8.0 mmol) and anhydrous THF (62 mL) were added to a flask equipped with a magnetic stirring bar. This was allowed to stir for 2 hours before 4-nitrophthalonitrile (2.25 g, 13.0 mmol) was added to the mixture and the suspension heated to reflux. After the polymer had dissolved the CS2CO3 (4.22 g, 13.0 mmol) was added in three equal portions over 3 hours. After 24 hours the reaction was cooled to 60°C then poured into 500 mL of water with stirring. The precipitate was filtered and washed thoroughly with water until pH neutral. The product was then rinsed with A, V-DMF, THF and then dried under vacuum to yield 5.03 g of material. H NMR (toluene-dg, 100°C, 71% conversion) 5 6.86 (d), 6.59 (s), 6.41 (m), 3.41 (t), 3.37 (t), 1.31 (s), 0.88 (t). 

Later, Araki et al. found that the allylation of aldehydes and ketones can be carried out by using catalytic amounts of indium(III) chloride in combination with aluminum or zinc metal.109 This reaction was typically performed in a THF-water (5 2) mixture at room temperature, although the conversion was much slower compared to the same reaction mediated by use of a stoichiometric amount of indium and it required days to complete. When the reaction was carried out in anhydrous THF alone, the yield dropped considerably and side-reactions such as reduction to alcohol increased. The combinations of Al-InCL or Zn-InCl3 gave comparable results. 

Ethyl cinnamate[7] To 2.96 g (20.0 mmol) of cinnamic acid in 25 mL of anhydrous THF 3.24 g (20.0 mmol) of CDI was added. When C02 evolution had ceased, 5 mL of ethanol was added and the mixture was refluxed for 30 min. After concentration in a rotary evaporator the residue was taken up in 100 mL of diethylether and extracted three times each with 50 mL of water. After drying of the ethereal solution and concentration in vacuo the residue was distilled to give ethyl cinnamate (b.p. 145-147 °C/17 mm) in 80% yield. 

The presence of water is essential for the success of these reductions. In anhydrous THF, for example, treatment of iV-benzoylimidazole with NaBH4 leads to benzyl benzoate as the main product (73%), along with 19% benzyl alcohol.[33] Other reports, however, describe the conversion of carboxylic acid imidazolides to the corresponding alcohols by complex hydrides in organic solvents. Further alcohols have been synthesized via imidazolides ... 

General Considerations. The following chemicals were commercially available and used as received 3,3,3-Triphenylpropionic acid (Acros), 1.0 M LiAlH4 in tetrahydrofuran (THF) (Aldrich), pyridinium dichromate (Acros), 2,6 di-tert-butylpyridine (Acros), dichlorodimethylsilane (Acros), tetraethyl orthosilicate (Aldrich), 3-aminopropyltrimethoxy silane (Aldrich), hexamethyldisilazane (Aldrich), tetrakis (diethylamino) titanium (Aldrich), trimethyl silyl chloride (Aldrich), terephthaloyl chloride (Acros), anhydrous toluene (Acros), and n-butyllithium in hexanes (Aldrich). Anhydrous ether, anhydrous THF, anhydrous dichloromethane, and anhydrous hexanes were obtained from a packed bed solvent purification system utilizing columns of copper oxide catalyst and alumina (ether, hexanes) or dual alumina columns (tetrahydrofuran, dichloromethane) (9). Tetramethylcyclopentadiene (Aldrich) was distilled over sodium metal prior to use. p-Aminophenyltrimethoxysilane (Gelest) was purified by recrystallization from methanol. Anhydrous methanol (Acros) was... 

Solvent exchange pHEMA particles into anhydrous THF using centrifugation and resuspension with sequential exchange into greater percentages of THF in water until the particles... 

Wash the activated particles 3 times with anhydrous THF to remove excess CDI and reaction by-products. After the final wash, remove the solvent and perform a quick wash with ice-cold water to remove most traces of solvent in the particle pellet. Finally, resuspend the particles at 10 mg/ml in cold 0.1 M sodium phosphate, pH 8.2, or 0.1 M sodium carbonate, pH 9.5 (coupling buffer). The higher pH coupling buffer will result in greater reactivity of the imidazole carbamate and greater coupling yields for proteins. 

Ketones - in sharp contrast to enols - are electron acceptors in a wide variety of organic transformations that occur at the carbonyl carbon. For example, the familiar dark-blue benzophenone anion radical is produced via one-electron reduction of benzophenone with sodium in anhydrous THF (equation 21). 

The substrate is taken up in anhydrous THF (5 mL) under argon. This solution is then added to 1.5—2.0 equiv. of Cp2Zr(H)Cl at room temperature under argon, which elicits the desired conversion within 15—30 min. Subsequent work-up of the concentrated mixture by short-path silica gel chromatography (hexanes/ethyl acetate) affords the desired aldehydes in near quantitative yields. 

Transformation of 2-deoxysugar derivatives into glycosyl xanthates can be performed by the treatment of O-benzyl-protected hemiacetal derivative with diphe-nylphosphoryl chloride, followed by the reaction with O-ethyl potassium xanthate in the presence of a base (NaOH, PTC reaction or NaH in appropriate organic solvent). High yields and selectivities in such reactions were observed when using sodium hydride in anhydrous THF [401],... 

To the Wang resin (100 mg, 0.070 mmol) in a 3-mL polypropylene filtration tube with polyethylene frit was added 1 mL 0.4 N CDI in anhydrous THF (note 1), capped with a yellow polyethylene cap, and shaken at room temperature for 6 h (note 2). The resin was thoroughly washed with CH2C12 (3x1 mL) and THF (3x1 mL) to remove the excess CDI and then treated with 1 mL 0.4 N piperazine in THF at room temperature for 15 h. The resulting resin was washed with DMF (3x1 mL), MeOH (4x1 mL),... 

In situ formation of allenylindium bromide in the presence of (+)- or (-)-cinchoni-dine and subsequent addition of various aldehydes provides a direct route to homo-propargylic alcohols of modest enantiopurity (Table 9.58) [121]. The additions were conducted in strictly anhydrous THF-hexanes as traces of water resulted in diminished product yields. Allenylcarbinols were not detected in these reactions. 

A. (R)-(-)-1 -Amino-1 -phenyl-2-methoxyethane (2).2 A solution of (R)-(-)-2-phenylglycinol (1) (25.0 g, 182.2 mmol) (Note 1) in anhydrous tetrahydrofuran (THF) (370 mL) (Note 2) is added dropwise via an oven-dried, 500-mL, pressure-equalizing addition funnel to an oven-dried, 2-L, round-bottomed flask containing a stirred (Note 3) suspension of potassium hydride (7.82 g, 195 mmol) (Note 4) in anhydrous THF (150 mL) at 25°C under an argon atmosphere. The resultant pale yellow mixture is stirred overnight and then treated dropwise with a solution of methyl iodide (25.2 g, 177.6 mmol) (Note 5) in THF (220 mL) over 2 hr at room temperature. The resultant mixture is stirred for an additional 3 hr, poured into cold ( 5°C) saturated aqueous sodium chloride solution (1.5 L) and extracted with anhydrous diethyl ether (4 x 250 mL) the combined organic extracts are dried over anhydrous sodium sulfate (Note 6). Filtration and rotary evaporation gives 39.2 g of yellow oil that is purified by vacuum distillation (bp 47-50°C, 0.2 mm) to yield 25.3 g (94%) of 2 as a colorless oil (Note 7). 

Dialkyl ditellurides (general procedure A mixture of powdered Te (3.58 g, 28 mmol), Na chips (0.65 g, 28 mmol) and naphthalene (0.36 g, 2.8 mmol) in anhydrous THF (25 mL) is refluxed under Nj and stirred for 1 h. During this time all the sodium is consumed and the mixture turns a light brown colour. The solution is stirred for an additional 3 h to ensure the complete reduction of Te, the temperature is then lowered to 10°C and the alkyl hahde (28 mmol) is added dropwise for 30 min with stirring. After an additional hour of stirring at room temperature, the reaction mixture is filtered, the solvent evaporated and the residue distilled under vacuum, giving the pure ditelluride (R=Et (85%), n-Pr (90%), n-Bu (90%), MeOCHjCHj (60%)). 

Diphenyl ditelluride (typical procedure) To a suspension of powdered Te (25.5 g, 0.2 mol) in anhydrous THF (300 mL), 2.0 M phenyllithium (100 mL, 0.2 mol) is added dropwise, with stirring and under argon. The resultant mixture is stirred at room temperature for 2 h and under reflux for 1 h. The reaction mixture, which should contain only a small amount of unreacted Te, is allowed to cool to 20°C, and is poured into 1 L of H2O. Oxygen (or air) is bubbled for 1 h through the mixture, which is then extracted with benzene (100 mL). The benzene solution is washed three times with H2O, dried (Na2S04) and evaporated. The residue is recrystallized from EtOH (77% m.p. 63.8-65.0°C). 

Di[o-(l-buten-3-ynyl)phenyl] ditellurides (generalprocedure). A teri-butyUithium hexane solution (1.5 M, 14.7 mL, 22 mmol) was added dropwise over a 15-min period to a stirred solution of the above-obtained butenine (10 mmol) in anhydrous THF (50 ml.) at - 80°C... 

Solvent was anhydrous THF. 100% excess of the salt of the psuedo acid used (no sodium acetate). Solvent was ferf-butanol. Equivalent amounts of reactants and sodium acetate used unless otherwise stated. Reactions conducted in aqueous methanol unless otherwise stated. 

Reaction of the chloro ester 1-Me with the enol silyl ether 23 a in the presence of dimethylaluminum chloride afforded the [2-1-2] cycloadduct 20 (67% yield) (Scheme 6). Deprotection of the alcohol moiety with uBu4NF in THF gave an 83% yield of a mixture of the 5-keto ester 21a and the spiropentane derivative 22 (ratio 1 90). Upon running the reaction in a mixture of THF/water (ratio 1 1) instead of anhydrous THF, the 5-keto ester 21a was isolated exclusively [331. 

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