Sodium sulfate, removal

The solid is separated by filtration and the filtrate is extracted with three 150-ml. portions of ether. Caution Gloves should be worn when handling this solution because of the large amount of cyanide it contains.) The solid is dissolved in ether and this solution is combined with the extracts. The combined ethereal solutions are washed with water and dried over 5 g. of sodium sulfate. Removal of the solvent by distillation leaves crude ferrocenyl-acetonitrile as a solid or as an oil that crystalli/.es on being scratched. I he nitrile is dissolved in about 200 ml. of boiling... 

A solution of cholest-4-en-3-one (139), 1 g, in diethylene glycol dimethyl ether (20 ml) is treated for 1 hr with a large excess of diborane at room temperature under nitrogen and then left for a further 40 min. Acetic anhydride (10 ml) is added and the solution refluxed for 1 hr. The mixture is concentrated to a small volume, diluted with water and extracted with ether. The extracts are washed with 10% sodium hydroxide solution, then with water and dried over sodium sulfate. Removal of the solvent leaves a brown oil (1.06 g) which is purified by chromatography on alumina (activity I). Hexane elutes the title compound (141), 0.68 g mp 76-77°. Successive crystallization from acetone-methanol yields material mp 78-79°, [a]p 66°. 

Catalysis by PhosphorousPentoxide (7) A 500-ml round-bottom flask is charged with a mixture of 1-ethynylcyclohexanol (40 g, 0.32 mole), 250 ml of dry benzene, and 10 g of phosphorous pentoxide. (The addition of the phosphorous pentoxide may be attended by considerable heating if the benzene is not well dried no particular disadvantage is found in this case, providing provision for initial cooling is made.) A condenser is attached to the flask, and the contents are refluxed gently (steam bath) for 2 hours. The cooled solution is then decanted from the phosphorous pentoxide, washed once with bicarbonate solution, and dried (anhydrous sodium sulfate). Removal of the benzene (rotary evaporator) and fractionation of the residue affords the desired product, bp 85-88°/22 mm, 1.4892, about 25 g (61 %). 

Downstream extraction. The culmre broth was diluted with ethyl acetate and the aqueous phase separated using a separation funnel. The organic layer was collected and dried over anhydrous sodium sulfate. Removal of the solvent by rotary evaporator gave (5)-7-methyl-2-oxepanone as a light yellow oil (6.5 g, 38 % yield). Chiral-phase GC showed 99 % ee and >97 % purity. EI-MS and NMR confirmed the product. Note the unconverted (R)-2-methyl cyclohexanone evaporated completely under the aeration conditions used during the overnight incubation. 

B. 2-Methoxycyclooctanone oxime. In a 500-ml., three-necked, round-bottomed flask, fitted with a mechanical stirrer, a dropping funnel, and a reflux condenser equipped with a calcium chloride tube, is placed a solution of 53.5 g. (0.252 mole) of crude 2-chlorocyclooctanone oxime hydrochloride in 250 ml. of methanol. While cooling the vessel with running water, 60.7 g. of triethyl-amine (0.60 mole) is added dropwise during 40 minutes. The reaction temperature is kept below 50° and the reaction is continued for 30 minutes with stirring. After removal of methanol under reduced pressure using an efiicient rotatory evaporator, a light brown semisolid is obtained it is treated with 200 ml. of ether and 200 ml. of water to effect complete solution. The ether layer is separated and the aqueous layer is further extracted twice with ether. The combined ether solution is washed with saturated sodium chloride and dried over sodium sulfate. Removal of ether affords 42.8 g. of crude 2-methoxycyclooctanone oxime (Note 3) as a brown oil. 

The anhydrous sodium sulfate removes water from the sample. 

Dry pigment-rich diethyl ether layer by passing through approximately 50 to 100 mg of anhydrous sodium sulfate. Remove solvent under a stream of nitrogen. 

A mixture of 4-methoxybenzyl alcohol le (5 mmol) and acetic anhydride (5 mmol) in a beaker covered with watch glass was irradiated by microwaves for 10 min (heating and cooling at the interval of 1 min). After completion of die reaction (TLC), the product was extracted with ether (3x15 mL). The ether layer was washed with 10% NaOH and then dried with anhydrous sodium sulfate. Removal of the solvent under reduced pressure gave 4-methoxybenzyl acetate 2e in excellent yield (95%). 

A mixture of ethyl l-cyclopropyl-6,7,8-trifluoro-l,4-dihydro-4-oxoquinoline-3-carboxylate (933 mg), 3-acetamidopiperidine (710 mg), triethylamine (400 mg) and dimethylsulfoxide (10 ml) was heated at 100°C for 2 hours with stirring. Thereafter the mixture was cooled down and ice water was added thereto. The resulting mixture was extracted with chloroform and the chloroform layer was washed with water three times before being dried over anhydrous sodium sulfate. Removal of the solvent in vacuum followed by purification by silica gel column chromatography (chloroform-ethanol) gave ethyl 7-(3-acetamidopiperidin-l-yl)-l-cyclopropyl-6,8-difluoro-l,4-dihydro-4-oxo quinoline-3-carboxylate (930 mg). Re-crystallization from ethanol-ether afforded a colorless crystalline substance (MP 217°-218°C). 

A solution of 4.9 g (12.8 mmol) of methyl-l-(p-nitrobenzoyl)-5-methoxy-2-methyl-3-indolylacetate in 40 ml of acetic acid containing 400 mg of p-toluene-sulfonic acid is refluxed for 20 hours and then concentrated in vacuum. The gummy residue is extracted with ethyl acetate. The extract is filtered from insoluble material, washed with water and dried over sodium sulfate. Removal of the solvent under reduced pressure affords the desired product as yellow crystals MP 185-186°C. 

Sodium selenocyanate, 2 186, 187 Sodium selenopentathionate 3-hydrate, 4 88, 89 Sodium sulfate, removal of, in... 

Ethyl 2-butyrylacetate. In a 1-L, three-necked, round-bottomed flask fitted with a mechanical stirrer, dry nitrogen inlet, and thermometer is placed 19.8 g (0.150 mol) of monoethyl malonate (Note 1), 350 mL of dry tetrahydrofuran (THF, Note 2), and 5 mg of 2,2 -bipyridyl. The solution is cooled to approximately -70°C (in an isopropyl alcohol-dry ice bath) and a 1.6M solution of n-butyllithium in hexane is added from a dropping funnel while the temperature is allowed to rise to approximately — 10°C. Sufficient n-butyllithium is added (approx. 190 mL) until a pink color persists for several minutes (Note 3). The heterogeneous solution is recooled to -65°C and 7.90 mL (7.98 g, 75 mmol) of iso-butyryl chloride (Note 4) is added dropwise over 5 min. The reaction solution is stirred for another 5 min (Note 5) and then poured into a separatory funnel containing 500 mL of ether and 300 mL of cold, 1 N hydrochloric acid (Note 6). The funnel is shaken, the layers are separated, and the organic phase is washed with two 150-mL portions of saturated aqueous sodium bicarbonate, followed by 150 mL of water, and dried over anhydrous sodium sulfate. Removal of the solvents under reduced pressure leaves 11.70 g (98%) of ethyl 2-butyrylacetate (Note 7). The crude product can be distilled at 70-74°C (7 mm) (80% yield, 96% purity by GLC). 

To the flask containing dibromocholesterol add 20 mL of ether, 5 mL of acetic acid, and 0.2 g of zinc dust and swirl. In about 3 min the dibromide dissolves after 5-10 min swirling, zinc acetate usually separates to form a white precipitate (the dilution sometimes is such thatno separation occurs). Stir for 5 min more and then add waterby drops (no more than 0.5 mL) until any solid present (zinc acetate) dissolves to make a clear solution. Decant the solution from the zinc into a separatory funnel, and wash the ethereal solution twice with water and then with 10% sodium hydroxide (to remove traces of acetic acid). Then shake the ether solution with an equal volume of saturated sodium chloride solution to reduce the water content, dry the ether with anhydrous sodium sulfate, remove the drying agent, add 10 mL of methanol (and a boiling stone), and evaporate the solution on the steam... 

In a three necked 250-ml. flask fitted with a reflux condenser stirrer and a thermometer pocket with a nitrogen inlet are placed 100 ml. of N,N-dimethylformamide, 5.6 g. (0.10 mole) of potassium hydroxide (Note 1), and 7.15 g. (0.050 mole) of freshly precipitated cuprous oxide (Note 2). 2-Bromothiophene (16.4 g., 0.10 mole) (Note 3) is then added and the apparatus flushed with nitrogen (Note 4). 2-Thiophenethiol (11.6 g., 0.10 mole) is then added slowly through the condenser an exothermic reaction sets in and the temperature may rise to 50-60°. The flask is heated in an oil bath at 130-140° for 16 hours (Note 5). The mixture is cooled to room temperature and the contents of the flask are poured into 100 ml. of 6 iV hydrochloric acid in ice and the mixture is stirred vigorously for 2 hours (Note 6). The oily black paste obtained is removed by filtration and thoroughly extracted in a Soxhlet extractor with benzene until a colorless extract is obtained. The filtrate is also extracted with two 100-ml. portions of benzene. These extracts are combined, washed with water until neutral, and finally dried over anhydrous sodium sulfate. Removal of the benzene solvent gives a yellow-colored oil which, on vacuum distillation, yields 2,2 -dithienylsulfide as a pale yellow oil, b.p. 75-78° (0.06 mm.) n j) 1.6643. The yield is 11.5-12.5 g. (58-63%). 

To a solution containing 0.25 g (0.187 mmol) of N-chlorosuccinimide in 35 mL of toluene at -25 °C was added 0.18 mL (2.45 mmol) of dimethylsulfide. The mixture was stirred at -25 °C for 30 minutes, followed by the addition of 0.35 g (0.46 mmol) of alcohol epi-44 in 18 mL of toluene over 10 minutes. Stirring continued for 3 hours, followed by the addition of 0.28 mL (2.01 mmol) of triethylamine in 18 mL of toluene dropwise. The cold bath was removed, and the contents were wanned to room temperature and maintained for an additional 30 minutes. The mixture was diluted with water and extracted with ether. The organic layer was dried over sodium sulfate. Removal of solvent and column chromatography of the yellow oil on silica gel with 10% ethyl acetate/hexanes gave 0.32 g (92%) of product epi-45 as a mixture of diastereomers. 

This is best done by diverting a portion of the main stream and cooling it to crystallize Glauber s salt, sodium sulfate decahydrate. The solubility curve of sodium sulfate in citrate liquor is similar to that in water with the solubility decreasing greatly below about 30 °C. This allows sodium sulfate removal to take place at temperatures readily attained by mechanical refrigeration. 

Bromobutyric acid (100 g) was boiled for 5-6 h with an equivalent amount (83 g) of potassium carbonate in water (500 ml). The solution was then evaporated, the residue was treated with the calculated amount of hydrochloric acid, and the viscous solution was filtered from the precipitated mixture of potassium chloride and bromide and extracted with ether. Drying of the extract over sodium sulfate, removal of the ether, and several fractionations in a vacuum gave 2-hydroxybutyric acid, m.p. 42°, b.p. 140°/12 mm. The yields were not stated. 

Sample preparation Acidify 5 mL solution with concentrated HCl, extract with two 5 mL portions of dichloromethane. Combine the organic layers and evaporate them to dryness, reconstitute the residue in 1 mL d-2-octanol toluene sulfuric acid 2 100 0.1, heat at 40°for 19 h, neutralize with 1 mL 20 mM sodium bicarbonate. Remove the organic layer and dry it over anhydrous sodium sulfate. Remove a 200 pL aliquot and evaporate it to dryness, reconstitute with 10 mL mobile phase, inject an aliquot. 

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