Pentane-, sodium

Chloride gas. Magnesium metal turnings, Arsenic trichloride, Tetrahydrofuran, Pentane, Sodium sulfate Diethyl ether, Dichloromethylphosphine, Ethyl alcohol, N,N-Diethylamine, 2-Diisopropylaminoethanol, Rhombic sulfur Hexachloroethane, Zinc powder... 

Solvents are distilled from sodium/benzophenone (pentane), sodium (toluene), or calcium hydride (dichloromethane) and degassed immediately prior to use. Chlorotrimethylsilane and chlorotributylstannane are distilled under argon before use. Indene (>90.0% pure) is purified by distillation... 

Mobile phase MeOH water 55 45 containing 10 mM pentane sodium sulfate and 9 mM tetramethylammonium chloride, ac usted to pH 3.4 with glacial acetic acid... 

Note 7. To a solution of 0.55 mol of sodium hydroxide in 150 ml of methanol and 40 ml of water was added a cold solution of 0.55 mol of methanethiol in 50 ml of methanol with cooling below 10°C. Subsequently 0.50 mol of propargyl chloride was added with swirling in 15 min, while keeping the temperature between 20 and 40°C. After an additional 30 min 1 1 of water was added and the product was extracted six times with small amounts of pentane. The extracts were washed with water, dried and the solvent was... 

Dimethyl carbonate is available from Aldrich Chemical Company, Inc. The checkers dried the tetrahydrofuran Immediately before use by distillation from the sodium ketyl of benzophenone under a nitrogen atmosphere. The submitters purchased sodium hydride (50% oil dispersion) from Alfa Products, Morton/Thiokol, Inc. The checkers used 12.24 g of a 50% dispersion of sodium hydride in mineral oil obtained from the same supplier. The dispersion was washed with three portions of pentane to remove the mineral oil and the remaining sodium hydride was allowed to dry under nitrogen. 

A. l-THmethyleilyloxyayalopentsne. A 1-L, two-necked, round-bottomed flask is equipped with a mechanical stirrer and a reflux condenser having a drying tube (calcium chloride). The flask is charged with 200 mL of dimethylformamide (Note 1), 45 g (0.54 mol) of cyclopentanone (Note 2), 65.5 g (0.6 mol) of chlorotrimethylsilane (Note 2) and 185 mL (1.33 mol) of triethylamine (Note 1), and the mixture is refluxed for 17 hr (Note 3). The mixture is cooled, diluted with 350 mL of pentane, and washed four times with 200-mL portions of cold saturated aqueous sodium hydrogen carbonate. The... 

The checkers dried the pentane over sodium wire prior to use. 

The general purification methods listed for xylene are applicable. p-Xylene can readily be separated from its isomers by crystn from such solvents as MeOH, EtOH, isopropanol, acetone, butanone, toluene, pentane or pentene. It can be further purified by fractional crystn by partial freezing, and stored over sodium wire or molecular sieves Linde type 4A. [Stokes and French J Chem Soc, Faraday Trans 1 76 537 1980.]... 

C. Cyclobutanone (Note 16). The residue consisting of oxaspiro-pentane (35%) and dichloromethane (about 200 ml.) is added dropwise at room temperature to a magnetically stirred solution containing about 5-10 mg. of lithium iodide in 50 ml. of dichloromethane (Notes 17, 18), at such a rate as to maintain gentle reflux of the solvent. At the end of the addition when the reaction mixture returns to room temperature, the transformation into cyclobutanone is complete. The dichloromethane solution is washed with 20 ml. of saturated aqueous sodium thiosulfate and with 20 ml. of water. After drying over magnesium sulfate and concentration by distillation of the solvent through a 15-cm., helix-packed, vacuum-insulated column, the residual liquid consists of cyclobutanone (95%) and of 3-buten-2-one and 2-methylpropenal... 

The sodium is cut under dry pentane just before introducing each sample into the flask. 

The cooled contents of the 2S0-ml. flask containing ferrous chloride (Note 6) are added to the cold sodium cyclopentadienide solution while passing a stream of nitrogen through both flasks. The combined mixture is stirred for 1.25 hours at a temperature just below reflux. Solvent is removed by distillation, and the ferrocene is extracted from the residue with several portions of refluxing petroleum ether (b.p. 40-60°). The product is obtained by evaporation of the petroleum ether solution. Ferrocene may be purified by recrystallization from pentane or cyclohexane (hexane, benzene, and methanol have also been used) or by sublimation. The 3ueld is 31-34 g. (67-73%) (Note 7), m.p. 173-174°. 

A mixture of 3.18 g (10 mmoles) of 17 -hydroxy-2-hydroxymethylene-5a-androstan-3-one, 20 ml dry dimethyl formamide and 0.3 g (13 mmoles) of sodium hydride is stirred for 0.5 hr at room temperature under nitrogen. A total of 1.51 g (12.5 mmoles) of redistilled allyl bromide is added and the mixture is stirred for 1 hr on the steam bath. Aqueous potassium hydroxide (2 g in 5 ml of water) is added and stirring is continued for 1 hr on the steam bath. The reaction mixture is diluted with 50 ml of methylene dichloride followed by careful addition of 300 ml of water. The organic phase is separated and the aqueous phase is again extracted with 50 ml of methylene dichloride. The combined extracts are washed with water, dried over sodium sulfate, filtered and chromatographed on 200 g of silica gel. Elution with pentane-ether (4 1) provides 2a-allyl-17j -hydroxy-5a-androstan-3-one 0.85 g (26%) mp 118-119° [aj 14° (CHCI3), after crystallization from ether-hexane. 

N-Cyclohex-l-enylpyrrolidine (9 g 0 06 mol) was dissolved in pentane with A -ethyldiisopropylamine (7.8 g 0.06 mol). Perfluorohexyl iodide (13.4 g, 0.03 mol) IS added to the solution. Aprecipitate of A-ethyldiisopropylamine hydroiodide IS formed instantly After 3 h, the precipitate is filtered off, and the solution is evaporated The crude liquid is hydrolyzed with 6 mL of 40% sulfuric acid The mixture is stirred for 3 h and extracted with ether. The ether layer is neutralized with aqueous sodium hydrogen carbonate, washed with water, and dried over magnesium sulfate. The solvent is evaporated, and the residue is distilled. A second distillation with a spinning-band column yields 7 9 g (63%) of pure 2-(perfluoro-hexyl)cyclohexanone (bp, 71 -73 °C at 0 4 mm of Hg). 

A mixture of 17 g of the methiodide and 32 ml of a 40 % aqueous potassium hydroxide solution is heated with stirring in a flask fitted with a condenser. The heating bath should be kept at 125-130°, and the heating should be continued for 5 hours. The cooled reaction mixture is then diluted with 30 ml of water and washed twice with 25-ml portions of ether. The aqueous layer is cautiously acidified in the cold with concentrated hydrochloric acid to a pH of about 2 and then extracted five times with 25-ml portions of ether. The combined extracts are washed twice with 10% sodium thiosulfate solution and are dried (magnesium sulfate). Removal of the solvent followed by distillation affords about 3 g of 4-cyclooctene-l-carboxylic acid, bp 125-12671-1 mm. The product may solidify and may be recrystallized by dissolution in a minimum amount of pentane followed by cooling in a Dry-Ice bath. After rapid filtration, the collected solid has mp 34-35°. 

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