Ethyl acetate, preparation with

The hydrolysis of ethyl acetate, prepared by the reaction of ethylene with acetic acid under pressure (154), and the hydrolysis of the ethyl ester of chlorosulfonic acid (155) have been considered and found to be of Httie industrial importance. 

C) Preparation of 2-Methyl-3-(2,2,2-Trifluoroethyl)Thiomethyl-6-Chloro-7-Sulfamyl-3,4-Dihydro-1,2,4-Benzothiadiazine-1,1-Dioxide To 4.6 g (0.015 mol) of 4-amino-2-chloro-5-(methylsulfamyl)benzenesulfonamide in 30 ml of the dimethyl ether of ethylene glycol is added 4.08 g (0.02 mol) of 2,2,2-trifluoroethylmercaptoacetaldehyde dimethylacetal followed by 1 ml of ethyl acetate saturated with hydrogen chloride gas. The resulting solution is refluxed for 1.5 hours, cooled and then slowly added to cold water dropwise with stirring. The crude product is filtered, dried and recrystallized from isopropanol (3.2 g), MP 202° to 202.5°C. A second recrystallization from isopropanol raised the MP to 202°... 

The last compound was prepared as follows the hydroxyl groups of 3,4-dihydroxy-benzaldehyde was protected using t-butyldimethylsilylchloride (1). 100 mg (0.26 mmol) of 3,4-di(t-butyl-methylsiloxy)benzaldehyde was dissolved in 1 ml tetrahydrofurane under atmosphere of argon at -40°C, and 0.30 ml of metal complex from (S)-6,6 -bis(triethylsilylethynyl)-l,l-dihydroxy-2,2 -binaphtalene (2) mixed with a solution of n-butyllitium in hexane.After stirring for 30 minutes, 79.4 mg (1.3 mmol) of nitromethane was added dropwise to the mixture. After 67 hour reaction time, 2 ml of 1 N aqueous solution of hydrochloric acid added to stop the reaction. Product was extracted with 50 ml ethyl acetate, dehydrated with anhydrous sodium sulfate and concentrated within evaporator followed by silica gel chromatography (n-hexane/acetone = 10/1), after which (R)-l-(3,4-di(t-butyldimethylsiloxy) phenyl)-2-nitroethanol with an optical purity of 92% e.e. was obtained in a yield of 93%. 

R-(+)-l,2,4-butantriol (0.7 g, 6.6 mmol), prepared as described in step (a) above, was stirred for 1.5 hr in acetone (50 ml) containing 3 drops of cone, perchloric acid a satured solution of sodium bicarbonate in water (5 ml) was added and the stirring was continued for additional 10 min. The precipitate was filtered off and the filtrate evaporated under reduced pressure [2.7 kPa,(20 mm Hg), 30°C], The residue was taken up in ethyl acetate, washed with satured aqueous sodium bicarbonate (5 ml) and brine (5 ml), and dried over magnesium sulfate. Evaporation of the solvent and distillation gave the title compound as a colourless oil (0.3 g, 2.05 mmol, 31%) b.p. 104°-106°C/20 mm Hg nD2°=1.4390. 

Prepare under argon a solution of 8 g of 4-dimethylaminopyridine in 250 ml of dry methylene chloride. Cool on an ice bath and add to the stirred solution 6.0 ml of 2-furoyl chloride. Remove from the ice bath, allow the temperature to rise to room temperature and then add 11.5 g of the 21-chloro-9p,lip-epoxy-17a-hydroxy-16a-methyl-l,4-pregnadiene-3,20-dione. After 24 hours add 500 ml of ethyl acetate saturated with water. Filter off the precipitate and then evaporate off the solvent to give the crude 21-chloro-9p,lip-epoxy-17a-hydroxy-16a-methyl-l,4-pregnadiene-3,20-dione 17-(2 -furoate). 

Crude riboflavin, prepared as described above starting with 43.6 g of 2-(o-biphehylazo)-4,5-dimethyl-l-ribityl amino-benzene, is washed with 50 ml of cold ethyl acetate, slurried with 180 ml of methanol at 65°C for thirty minutes. The methanol slurry is cooled to 10°C for thirty minutes, filtered, and the filtered material washed with 40 ml of cold methanol. The methanol washed riboflavin is then slurried with 180 ml of water at 80°C for thirty minutes, the slurry is cooled to 70°C, filtered, and the filtered material is washed with 40 ml of hot (70°C) water. The hot water-washed riboflavin is... 

Kawahara [156] introduced pentafluorobenzyl esters, prepared by the following procedure. A mixture of four acids (0.8 mg of each) was dissolved in 100 ml of acetone, and 250 mg (25-fold excess) of a-bromo-2,3,4,5,6-pentafluorotoluene and 50 mg (10-fold excess of potassium carbonate were added (it can be replaced with an ethanolic solution of potassium hydroxide). After refluxing for 3 h, the mixture was diluted with 500 ml of diethyl ether and 20 ml of ethyl acetate, washed with 10 ml of water and dried with 8 g of anhydrous sodium sulphate. After filtration, the sulphate and the filter were washed with 50 ml of diethyl ether, the solvent was removed and the residue was dried at 40°C and 50 mmHg it was further dissolved in 100 ml of -hexane and, after an additional 100-fold dilution, 6 /il were injected. The ECD response to pentafluorobenzoate was almost the same as that to aldrin. A method for the preparation of p-substituted benzyl esters of lower monocarboxylic acids on the micro-scale [157] is based on the same reaction scheme. A 10-pl volume of an ethanolic solution of carboxylic acids (ca. 1 pg/pl)... 

Fig. 4. Three inkjet printed polystyrene films. The first film (a) was printed using a butyl acetate solution. The second film (b) was printed using a 1 9 methyl ben-zoate/ethyl acetate solution with a print head speed of 6.25 mm/s. Both solutions contained 2% polystyrene and 0.05% Disperse Red 1 by weight. The third film (c) was prepared from the same film as (b) but printed at 38 mm/s. (From Ref. 16, 2004 The Royal Society of Chemistry.)...

From Ethyl Acetate.—The simplest member of this group is CH3— CO—CH2—CO—CH3 which is plainly acetyl acetone. It is best made by a reaction exactly analogous to the one used in preparing aceto acetic ester. In making the latter ethy 1 acetate is condensed with itself by means of sodium and ethyl alcohol (sodium ethylate) as described already (p. 254). If instead of condensing with another molecule of itself ethyl acetate condenses with acetone we obtain acetyl acetone, as follows ... 

In an earlier procedure for the preparation of p-nitrophenyl isocyanate a solution of the free base in ethyl acetate is added gradually to ethyl acetate saturated with phosgene while fresh phosgene is passed into the reaction mixture yield 85-95%. 

Table 10. Analysis of the terminal group in poly(vinyl acetate) prepared with AIBN at 60°C in benzene, chlorobenzene and ethyl acetate.

Sample preparation Equilibrate a Sep-Pak silica SPE cartridge with 5 mL ethyl acetate. 1 mL Serum -i- 3 mL 5% trichloroacetic acid -I- 4 mL ethyl acetate, vortex vigorously, centrifuge at 1500 g for 5 min. Remove organic layer and repeat extraction twice with 3 mL portions of ethyl acetate. Combine extracts, evaporate to about 1.5 mL, add to the SPE cartridge. Wash with 8 mL ethyl acetate, elute with 4 mL MeOH ammonium hydroxide (90 10). Evaporate the eluent to dryness under nitrogen, reconstitute in 100 jiL MeOH, inject. 

Ethyl acetate prepared in this way may contain as impurities alcohol, acetic acid, water, and ether. Alcohol is removed by shaking the ester with a saturated aqueous solution of calcium chloride, acetic acid by treatment with a solution of sodium carbonate, and water by distillation after allowing the ester to stand some hours in contact with anhydrous calcium chloride. If ether is present it must be removed by fractional distillation. 

Only Letham and Miller [68 a, 69] appear to have used TLC so far. They compared the zeatin obtained from immature fruit of Zea mays with the maize factor , isolated likewise from maize grains. The preparations, characterised through their kinetin activity, are evidently identical. They accordingly show the same Rf-values in TLC on alumina G with butanone, saturated with water (hRf 58) with ethyl acetate saturated with water IciRf 14) and with chloroform-95% ethanol (10 4- 90, hRf 86, 90 + 10, hRf 61). The compound is 6-(4-hydroxy-3-methylbut-trans-2-Giiy ) aminopurine. 

The mixed anhydride prepared from 3.2 g (10 mmoles) of Z-Gly-Leu-OH, 1.1 ml (10 mmoles) of iV-methylmorpholine and 1.34 ml (10 mmoles) of iso butyl chloroformate in 60 ml of anhydrous tetrahydrofuran at —10° to —15° is allowed to react with L-phenylalanine chloromethyl ketone hydrobromide and 1.3 ml of fV-methylmorpholine for 1.25 hr while the reaction mixture is allowed to warm to room temperature under anhydrous conditions. Work-up of the reaction mixture involves evaporation of tetrahydrofuran, extraction of the residue into ethyl acetate, washing with citric acid and sodium bicarbonate solutions, drying over magnesium sulfate, and evaporation. The product is recrystallized from ethyl acetate-cyclohexane to yield 3.41 g (68%) of product with m.p. 140.5°-143°. 

Methyl retmoate may also be prepared by refluxing retinoic acid in ethyl-acetate solution with anhydrous K2CO3 and CH3I for 2 h (ratio of methyl retmoate/ K2CO3/CH31,1/2/3, w/w/v). After allowing the solution to cool, wash It three times with water, dry it over anhydrous sodium sulfate, and evaporate the solvent. Purify the methyl retinoate product as appropriate (by TLC or HPLC or by crystallization from pentane at -20°C). 

Sample preparation Adjust pH of urine to 5.0 with acetic acid, add 1300 U/mL glusulase and 50 U/mL sulfatase, heat at 37° for 24 h, adjust pH to 9, pass through a column of Amberlite XAD-2 resin, wash with 3 vol of water, elute with MeOH. Evaporate the eluate to dryness, reconstitute the residue with water, adjust to pH 8, extract with ethyl acetate. Wash the ethyl acetate extract with one-tenth the volume of saturated NaCl, dry over anhydrous sodium sulfate, reconstitute with MeOH, inject an aliquot. Alternatively, adjust pH of urine to 5.0 with acetic acid, add glusulase/sulfatase, heat at 37°, adjust pH to 9, extract with dichloromethanedsopropanol 90 10. Evaporate the extract to dryness under reduced pressure, reconstitute, inject an aliquot. (Both the procedures are given.)... 

Internal standard 4-[5-phenyl-3-(trifluoromethyl)-lH-pyrazol-l-yl]benzenesulfonam-ide (The IS is celecoxib lacking the methyl group. Preparation is as follows. Reflux 200 mL EtOH containing 16 mmol 4,4,4-trifluoro-l-phenyl-1,3-butadiene and 17.6 mmol 4-sulfonamidophenylhydrazine hydrochloride with stirring for 22 h, evaporate under reduced pressure. Take up the residue in ethyl acetate, wash with water, wash with saline, evaporate the organic solvent, recrystallize from re-hexane ethyl acetate 50 50 to obtain the IS as white needles.) (m/z 366-302 (-30 eV)) (0.8)... 

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