Residual organic liquid saturation

Flush the saturated sodium chloride solution used during the extraction process to wash the dichloromethane down the drain. Neutralize the aqueous filtrate from isolation of 4-chlorobenzoic acid with solid sodium carbonate, and flush it down the drain. Place the dichloromethane obtained by distillation in the container for halo-genated organic liquids. Dispose of the sodium sulfate in the container for nontoxic solids after allowing residual solvent to evaporate from it in the hood. 

A mixture of phenacyl bromide (1 1.05 mmol) and amine (2 1 mmol) in [bmim]BF4 (2 mL) was added diethyl/dimethyl acetylenedicarboxylate (3 1 mmol) drop-wise and stirred at room temperature for 0.5-1 h. After completion of the reaction, as indicated by TLC, the reaction mixture was extracted with ethyl acetate (3 x 10 mL). The combined organic extracts were washed with saturated brine solution, dried over anhydrous sodium sulfate, and concentrated under vacuum the resulting crude product was purified by means of column chromatography (silica gel 60-120 mesh) using 5-10% ethylacetate/n-hexane as eluent to obtain pure product of functionalized pyrroles 4. The residual ionic liquid was reused after drying under vacuum. All the products were characterized by elemental analyses and spectral studies including H-NMR,... 

Reduction of A-nitrosomethylaniline. Into a 1 litre round-bottomed flask, fitted with a reflux condenser, place 39 g. of A-nitroso-methylaniline and 75 g. of granulated tin. Add 150 ml. of concentrated hydrochloric acid in portions of 25 ml. (compare Section IV.34) do not add the second portion until the vigorous action produced by the previous portion has subsided, etc. Heat the reaction mixture on a water bath for 45 minutes, and allow to cool. Add cautiously a solution of 135 g. of sodium hydroxide in 175 ml. of water, and steam distil (see Fig. II, 40, 1) collect about 500 ml. of distillate. Saturate the solution with salt, separate the organic layer, extract the aqueous layer with 50 ml. of ether and combine the extract with the organic layer. Dry with anhydrous potassium carbonate, remove the ether on a water bath (compare Fig. II, 13, 4), and distil the residual liquid using an air bath (Fig. II, 5, 3). Collect the pure methylaniline at 193-194° as a colourless liquid. The yield is 23 g. 

In a 2-1. flask fitted with a total-reflux, variable-take-off distillation head is placed a solution of 53 g. (0.472 mole) of dihydroresorcinol (Note 1), 2.3 g. of -toluenesulfonic acid monohydrate and 250 ml. of absolute ethanol in 900 ml. of benzene. The mixture is heated to boiling and the azeotrope composed of benzene, alcohol, and water is removed at the rate of 100 ml. per hour. When the temperature of the distilling vapor reaches 78° (Note 2), the distillation is stopped and the residual solution is washed with four 100-ml. portions of 10% aqueous sodium hydroxide which have been saturated with sodium chloride. The resulting organic solution is washed with successive 50-ml. portions of water until the aqueous washings are neutral and then concentrated under reduced pressure. The residual liquid is distilled under reduced pressure. The yield of 3-ethoxy-2-cyclohexenone (Note 3), b.p. 66-68.5°/0.4 mm. or 115-121°/11 mm., Mq 1.5015, is 46.6-49.9 g. (70-75%). 

Preparation of cholesta-5,7-diene-ia,3/3-diol a solution of 500 mg of the 1,4-cyclized adduct of cholesta-5,7-dien-3/3-ol-ia,2a-epoxideand 4-phenyl-1,2,4-triazoline-3,5-dione in 40 ml of tetrahydrofuran is added dropwise under agitation to a solution of 600 mg of lithium aluminum hydride in 30 ml of THF. Then, the reaction mixture liquid Is gently refluxed and boiled for 1 hour and cooled, and a saturated aqueous solution of sodium sulfate is added to the reaction mixture to decompose excessive lithium aluminum hydride. The organic solvent layer is separated and dried, and the solvent Is distilled. The residue Is purified by chromatography using a column packed with silica gel. Fractions eluted with ether-hexane (7 3 v/v) are collected, and recrystallization from the methanol gives 400 mg of cholesta-5,7-diene-la, 3/3-diol. 

Work-up is initiated by extracting the reaction mixture with three 50-ml. portions of aqueous ] N hydrochloric acid, three 50-ml. portions of aqueous 1AT potassium bicarbonate (Notes 7 and 8), and 50 ml. of saturated aqueous sodium chloride. The organic solution is then dried over sodium sulfate (Note 9), filtered, and concentrated on a rotary evaporator. Purification of t lie residue by bulb-to-bulb distillation (Note 10) at about 140° (5 mm.) provides 1.77-1.98 g. (85-95%) of ethyl 4-acetoxybenzoate as a colorless, viscous liquid (Note 11). 

The only accident that involves a saturated ester is the result of an attempt to extract an organic residue containing hydrogen peroxide with ethyl acetate. The latter was mixed with methanol and refluxed with the residue and hydrogen peroxide in an aqueous solution. A second extraction was carried out with acetate and the liquid was then evaporated. The small quantity of the compound that remained after the evaporation detonated violently. It was thought that this detonation was the result of the violent decomposition of methyl hydroperoxide, peracetic acid and/or ethyl peracetate. 

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