Anhydrous ethyl acetate

It is important to use dry ethyl acetate, but it should contain 2-3 per cent, of alcohol. The so-called absolute or anhydrous ethyl acetate of commerce is satisfactory. Experimental details for the purification of 95-97 p>er cent, ethyl acetate are given in Section 11,47,29. 

The product Is often used as the acid sulfate which is produced as follows 252.0 g (0.B5 mol) of 0 A-diphenyl-7-dlmethylamlnovaleramide was dissolved in one liter of isopropanol,and 70 ml of concentrated sulfuric acid was added as rapidly as possible. The mixture was heated until clear, then filtered and diluted with 1,500 ml of anhydrous ethyl acetate. The solution was cooled and filtered, and the white crystalline product was dried in vacuo over PjOs. 

The crude product (48.4 grams, 80.9% yield) was recrystallized from an absolute ethanol-ethyl acetate solvent system by suspending the salt in boiling anhydrous ethyl acetate and just enough absolute ethanol was gradually added to effect solution after which the solu-... 

Perchlorate as potassium perchlorate (ca 400 mg as the sodium salt in 25 mL solution). Warm the solution to 80-90 °C and treat with a slight excess of a cold saturated solution of potassium acetate. Allow to cool and after 1 hour collect the precipitate on a weighed porcelain filtering crucible. Wash twice with 0.05M potassium chloride and then with four 5 mL portions of equal volumes of anhydrous ethyl acetate and anhydrous butan-l-ol. Dry the precipitate at 110°C for 30-60 minutes and then heat at 350 °C in an electric furnace for 15 minutes. Weigh as KC104 (Section 11.68). 

These must be glycerol free. A solvent extraction procedure must be used prior to GC-MS [2, 5, 6]. If the sample is prepared with ion-exchange chromatography, the glycerol will remain in the neutral fraction and not be detected by GC-MS [2, 5]. Hydrochloric acid (5 N), pH paper, sodium sulfate (anhydrous), ethyl acetate (free of contaminants), diethyl ether (anhydrous, peroxide-free, and free of contaminants except 2,6-ditertbutylcresol, which is an antioxidant found in all ether), and malonic acid (26.25 mg/50 ml methanol). 

Chromatographic grade pentane MgS04, anhydrous Ethyl acetate (optional)... 

Flask B is separated from the apparatus but kept in the cooling bath, and 200 ml. of anhydrous ethyl acetate is added addition is slow so as to avoid excessive boiling of the dimethyl ether (Note 7). The flask, with a tube of calcium chloride attached, is gradually brought to room temperature most of the dimethyl... 

The crude product (48.4 grams, 80.9% yield) was recrystallized from an absolute ethanol-ethyl acetate solvent system by suspending the salt in boiling anhydrous ethyl acetate and just enough absolute ethanol was gradually added to effect solution after which the solution was concentrated to about two-thirds of the original volume on the steam bath, charcoal treated, and suction-filtered through Celite filter aid. The white crystals of 2-dimethylaminoethanol p-acetylaminobenzoate obtained, dried at room temperature at a pressure of 0.08 mm Hg for 15 hours, melted at 159.0°-161.5°C. 

Gaseous ammonia was passed into nicotinic acid at a temperature between 200-235°C until the conversion to nicotinamide was 85%. The reaction mixture was colored light brown. The reaction mass was cooled and grounds to a fine powder. Fifty grams of this crude nicotinamide were boiled with 500 ml of anhydrous ethyl acetate until a dark solution was. obtained. A little solid... 

Crystals of azide 1 ( 1 mmol) were dried under vacuum for a period of 24 h. The dried crystals were stored in Pyrex test tubes which were flushed with argon for 15 min and sealed. The solid samples were photolyzed for 12 h in an ice-bath. The reacted crystals were dissolved in anhydrous ethyl acetate. GC-MS analysis of the reaction mixture showed formation of 2 only and no remaining starting material. 

Monohalobenzaldehydes are converted into the derived trimeric thioaldehydes (tri-thianes) by passing hydrogen chloride and hydrogen sulfide into their solution in anhydrous ethyl acetate 402... 

Alkylation of [(methoxycarbonyl)methylene]triphenylphosphorane An alkyl halide (0.2 mole) is added to a boiling solution of [(methoxycarbonyl)methylidene]triphenylphos-phorane (0.4 mole) in anhydrous ethyl acetate, and the mixture is boiled under reflux for 2 h. The precipitated [(methoxycarbonyl)methyl]triphenylphosphonium halide is filtered off (yield 80-95%) and the filtrate is evaporated. The residue consists of the alkylated ylide it is often obtained as an oil, but this generally crystallizes when rubbed and can be recrystallized from ethyl acetate. 

Typical procedure. N-Carboxy-L-valine anhydride [894] To a solution of N-Boc-l-valine (500 mg, 2.3 mmol) and triphosgene (273 mg, 0.92 mmol) in anhydrous ethyl acetate (55 mL), distilled triethylamine (353 mL, 2.5 mmol) was added over a period of 30 s at room temperature EtaN-HCl precipitated immediately. The vessel was connected to a manometer in order to monitor CO2 evolution while maintaining vigorous stirring of the reaction mixture. The requisite amount of CO2 was generated in 3 h, whereupon the suspension was filtered. The solid EtsN HCl was washed with a small portion of ethyl acetate (10 mL), and the filtrate was concentrated to dryness. The residue obtained was crystallized from dichloromethane and petroleum ether at -20 °C to give the title compound as white crystals (330 mg, 75%). 

One of the earliest reports of graft copolymers containing polypeptide side chains involved production of a macroinitiator by modification of poly(vinyl alcohol) [23] with l,l-diethoxy-2-aminoethane [24]. Low concentrations of the aminoacetalized poly(vinyl alcohol) [25] in anhydrous ethyl acetate were used to initiate 7-methyl-D-glutamate as shown on Scheme 2. 

Reagents anhydrous oxalic acid, anhydrous ethyl acetate. 

An ozone-oxygen stream passed at 0° into a soln. of N-cyclohexylideneisobutyl-amine in anhydrous ethyl acetate until 1 molar equivalent has been absorbed -> crude cyclohexanone. Y 48%.—Gontrary to reports in the literature, carbon-nitrogen double bonds, at least in Schiff bases and nitrones, are attacked by ozone, which behaves as a nucleophilic reagent, whereas in most other cases it acts as an electrophilic reagent. F. e. s. A. H. Riebel et al.. Am. Soc. 82, 1801 (1960). 

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