Magnesium ethyl carbonate

Ethyl benzoylacetate has been prepared by the condensation (by means of sodium ethylate) of ethyl acetate with ethyl benzoate,1 acetophenone with ethyl carbonate,2 and acetophenone with ethyl oxalate, with subsequent heating 3 by treatment of ethyl phenylpropiolate4 or a-bromocinnamic acid 5 with concentrated sulfuric acid, and of ethyl diazoacetate with benzalde-hyde 6 by the condensation of benzene with the monoethyl ester of malonyl monoacid chloride and aluminum chloride,7 of benzoyl chloride with the product of the reaction of magnesium and ethyl chloroacetate in ether,8 of alcohol on benzoylacetimino ethyl... 

Technical ethyl carbonate was washed successively with 10 per cent aqueous sodium carbonate and saturated calcium chloride solution. It was then dried with magnesium sulfate and distilled. The fraction boiling at 124-125° was used. 

A magnesium enolate of 99 is susceptible to aldol condensation with 4-pentenal, and the crude product can be directly protected to give its ethyl carbonate 100. a-Hydroxylation of the carbonyl group yields the hydroxyl carbonate 101. Reduction of the carbonyl group generates a triol, and this compound can be simultaneously converted to carbonate 102. Swern oxidation of 102 gives ketone 103, which can be rearranged25 to produce lactone product 104 (Scheme 7-32). 

The experimental simplicity of Method 3 has attracted the specialists in modern trends in catalysis. Thus, in Method 3 different authors used RbF (04SC4431), MgO (09EJM3805), KF/AI2O3, mixed magnesium-aluminum carbonate, or mixed magnesium-lanthanum oxide (08TL2730) in methanol. Recently, 2-aminopyran syntheses with acetylacetone 35 and ethyl acetoacetate 36 were carried out in an ionic liquid [(bmim)(BF4), 1-butyl-3-methylimidazolium borofluoride] with 1,1,3,3-tetramethylguanidine as... 

ETHYL CARBONATE (105-58-8) Forms explosive mixture with air (flash point 77°F/ 25 C). Reacts violently with strong oxidizers. Carbonates are incompatible with cerium compounds, germanium, lead diacetate, magnesium, mercurous chloride, silver nitrate. 

CONJUGATE ADDITION Alkylmethyl-magncsiocuprates. 2-Carboethoxyl-benzyl phenyl sulfoxide. Cyanodiethyl-aluminum chloride. 1-Cyclopropyl-l-tiimethylsilyloxyethylene. Lithium 1,3-butadiene-l-olate. Lithium dimethyl-cuprate. Magnesium ethyl malonate. Potassium carbonate. Tri-n-butyl-stannyllithium. Trimethylzinclithium. 

Sambri (2006) A New, Mild, General and Effident Route to Aryl Ethyl Carbonates in Solvent-Free Conditions Promoted by Magnesium Perchlorate. European Journal of Organic Chemistry, 2006,4429-4434,lSSN 1434-193X1099-0690. 

To obtain crystalline perbenzoic acid, dry the moist chloroform solution with a little anhydrous sodium or magnesium sulphate for an hour, filter, and wash the desiccant with a little dry chloroform. Remove the chloroform under reduced pressure at the ordinary temperature whilst carbon dioxide is introduced through a capillary tube. Dry the white or pale yellow residue for several hours at 30-35° under 10 mm. pressure. The yield of crystalline perbenzoic acid, m.p. about 42°, which is contaminated with a little benzoic acid, is 22 g. It is moderately stable when kept in the dark in a cold place it is very soluble in chloroform, ethyl acetate and ether, but only shghtly soluble in cold water and in cold hght petroleum. 

Decant the liquid layer into a 2 5 litre flask, and dissolve the sodium derivative of acetylacetone in 1600 ml. of ice water transfer the solution to the flask. Separate the impiue ethyl acetate layer as rapidly as possible extract the aqueous layer with two 200 ml. portions of ether and discard the ethereal extracts. Treat the aqueous layer with ice-cold dilute sulphimic acid (100 g. of concentrated sulphiu-ic acid and 270 g. of crushed ice) until it is just acid to htmus. Extract the diketone from the solution with four 200 ml. portions of ether. Leave the combined ether extracts standing over 40 g. of anhydrous sodium sulphate (or the equivalent quantity of anhydrous magnesium sulphate) for 24 hours in the ice chest. Decant the ether solution into a 1500 ml. round-bottomed flask, shake the desiccant with 100 ml. of sodium-dried ether and add the extract to the ether solution. Distil off the ether on a water bath. Transfer the residue from a Claisen flask with fractionating side arm (Figs. II, 24, 4r-5) collect the fraction boiling between 130° and 139°. Dry this over 5 g. of anhydrous potassium carbonate, remove the desiccant, and redistil from the same flask. Collect the pure acetji-acetone at 134r-136°. The yield is 85 g. 

To absolution of 1.00 mol of ethyl lithium in 800-900 ml of diethyl ether (see Chapter II, Exp. 1) was added, with cooling between -20 and -10°C, 0.50 nol of dry propargyl alcohol, dissolved in 100 ml of diethyl ether. Subsequently 1.1 mol of trimethylchlorosilane was introduced over a period of 25 min with cooling between -15 and +5°C. After stirring for an additional 2 h at about 30°C the suspension was poured into a solution of 30 g of acetic acid in 150 ml of water. After stirring for 1 h at room temperature the layers were separated and the aqueous layer v/as extracted four times with diethyl ether. The combined ethereal solutions were washed with sodium hydrogen carbonate solution in order to neutralize acetic acid, and were then dried over magnesium sulfate. The diethyl ether was removed by evaporation in a water-pump vacuum and the residue distilled... 

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