Magnesium ethoxide preparation

It is important to maintain strictly anhydrous conditions throughout this reaction. The equipment should be carefully predried and the absolute ethanol freshly prepared (preferably by the magnesium ethoxide method2) and distilled directly into the reaction flask. If the volume of ethanol is less than 2.5 1. the sodium ethoxide may not remain in solution. It is convenient to employ a three-necked flask carrying two condensers for this operation and to add the sodium through the third neck, which is otherwise kept stoppered. 

They are easily prepared from Grignard reagents, magnesium ethoxide or with the complex magnesium chloride-trialkylamine (see Section II where the generation of these reagents is discussed). The acylation of anions derived from malonates can be achieved with acyl chlorides, acyl imidazoles, aUcoxycarbonylimidazoles or mixed anhydrides. 

It is necessary to maintain strictly anhydrous conditions in this reaction. The apparatus should be carefully predried and the absolute ethanol freshly prepared either by the diethyl phtha-late method 2 or by the magnesium ethoxide method.3... 

C-Acylation. C-Acylation of active methylene compounds is usually conducted under basic conditions. Masamune et al. have developed a new method for conducting this reaction under neutral conditions that is patterned on the enzymic synthesis of fatty acids. The acylating reagent is the imidazolide of a carboxylic acid (1) prepared in situ. The substrate is the neutral magnesium salt of a mono ester or thioester of a malonic acid (2), prepared with magnesium ethoxide. The reaction of 2 with 1 is conducted in THF at 25-35° for 18-24 hours the yield of products (3) is generally >85%. ... 

Methyl /3-Iactoside monohydrate is prepared by treating hepta-O-acetyl-a-lactosyl chloride (or, preferably, the bromide) with methanol in the presence of silver carbonate (the Koenigs-Knorr reaction), followed by saponification with a trace of sodium methoxide in methanol. The unacetyl-ated glycoside can be obtained directly from the bromide derivative by the use of magnesium ethoxide in methanol. ... 

The preparation of Ru supported catalysts by sol-gel method, indeed, was extended to obtain new formulations by changing the type of support. Alkali-promoted Ru/MgO systems were prepared starting from magnesium ethoxide, Ru3(CO)i2 and a cesium compound [9]. The gels were subjected to an activation/reduction procedure to substantially obtain Ru-CsOH/MgO and then tested as catalysts in the ammonia synthesis at atmospheric pressure. It was evidenced that the sol-gel prepared Cs-promoted Ru/MgO catalysts are much more active, under similar reaction comlitions, than the analogous catalysts prepared by the impregnation procedures reported in literature [10]. 

While the majority of the syntheses discussed have been directed to the orsellinic acids and their homologues, keto and cyano analogues have also been prepared in the monocyclic series. The ketoester shown afforded the salicylate upon cyclisation with sodium ethoxide or magnesium methoxide and none of the resorcinol although an excess of magnesium ethoxide gave a mixture of both products (refe. 32, 33, and 34). 

Ethyl pentafluorobenzoylacetate (33), benzoyl(pentafluorobenzoyl)methane (34), and bis(pentafluorobenzoyl)methane (35) have been synthesized as shown in Scheme 11. The first of these is not a new compound, having been prepared in the early 1960 s by treatment of pentafluorobenzoyl chloride with diethyl malonate in the presence of magnesium ethoxide followed by hydrolysis of the diester CeF8 C0 CH(C02Et)a thus produced, and by condensation of ethyl pentafluorobenzoate with ethyl acetate in the presence... 

Ethyl phenylethylmalonate. In a dry 500 ml. round-bottomed flask, fitted with a reflux condenser and guard tube, prepare a solution of sodium ethoxide from 7 0 g. of clean sodium and 150 ml. of super dry ethyl alcohol in the usual manner add 1 5 ml. of pure ethyl acetate (dried over anhydrous calcium sulphate) to the solution at 60° and maintain this temperature for 30 minutes. Meanwhile equip a 1 litre threenecked flask with a dropping funnel, a mercury-sealed mechanical stirrer and a double surface reflux condenser the apparatus must be perfectly dry and guard tubes should be inserted in the funnel and condenser respectively. Place a mixture of 74 g. of ethyl phenylmalonate and 60 g. of ethyl iodide in the flask. Heat the apparatus in a bath at 80° and add the sodium ethoxide solution, with stirring, at such a rate that a drop of the reaction mixture when mixed with a drop of phenolphthalein indieator is never more than faintly pink. The addition occupies 2-2 -5 hoius continue the stirring for a fiuther 1 hour at 80°. Allow the flask to cool, equip it for distillation under reduced pressure (water pump) and distil off the alcohol. Add 100 ml. of water to the residue in the flask and extract the ester with three 100 ml. portions of benzene. Dry the combined extracts with anhydrous magnesium sulphate, distil off the benzene at atmospheric pressure and the residue under diminished pressure. C ollect the ethyl phenylethylmalonate at 159-160°/8 mm. The yield is 72 g. 

The method described is adapted from the procedures of Kym 3 and Engelhardt, Latschinoff, and Malyscheff.4 Thio-benzoic acid has been prepared by the reaction of benzoyl chloride with potassium sulfide,4 hydrogen sulfide in pyridine,6 6 and magnesium bromide hydrosulfide.7 It is formed from dibenzoyl disulfide with potassium hydrosulfide,4 potassium hydroxide,4 8 and ammonia.9 It is also formed from dibenzoyl sulfide, from phenyl benzoate, and from benzoic anhydride with alcoholic potassium hydrosulfide.4 It has been obtained from dibenzoyl sulfide and hydrogen sulfide,10 carbon oxysulfide and phenyl-magnesium bromide,11 12 dibenzyl disulfide and sodium ethoxide,13 benzyl chloride and sulfur in the presence of potassium hydroxide,14 and benzylthiosulfuric acid and alkali.18 16... 

Dihydrobenzo[6]thiophene-l, 1-dioxide is metallated by ethyl-magnesium bromide in the 2-position to give the Grignard compound (355). Its 2-methyl,740-742 2-bromo,718or 2-ethoxycarbonyl215 derivative may be prepared by treating 355 with methyl iodide, bromine, or ethyl chloroformate, respectively. 2-(Ethoxycarbonyl)thioindoxyl-1,1-dioxide may be methylated in the 2-position by successive treatment with sodium ethoxide and methyl iodide.215... 

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