Magnesium methoxide

Organic compounds normally cause Htde or no corrosion of magnesium. Tanks or other containers of magnesium alloys are used for phenol [108-95-2] methyl bromide [74-96 ] and phenylethyl alcohol [60-12-8]. Most alcohols cause no more than mild attack, but anhydrous methanol attacks magnesium vigorously with the formation of magnesium methoxide [109-88-6]. This attack is inhibited by the addition of 1% ammonium sulfide [12135-76-1] or the presence ofwater. 

Magnesium Methylate. Magnesium methoxide [109-88-6] Mg(OCH2)2, mol wt, 86.3, is an almost white powder powder density 0.5 g/mL ... 

When a solution of magnesium methoxide (prepared by the reaction of magnesium with methanol) is saturated with carbon dioxide, an active carboxylating agent, MMC, is produced. The reagent carboxylates substrates capable of enolization apparently by promoting formation of the magnesium chelate of the a-adduct. The reaction has been... 

The reaction of magnesium and methanol to form magnesium methoxide and used to prepare dry methanol [1] is very vigorous, but often subject to a lengthy induction period. Sufficient methanol must be present to absorb the violent exotherm which sometimes occurs [2], Mixtures of powdered magnesium (or aluminium) and methanol are capable of detonation and are more powerful than military explosives [3],... 

The carboxylation of nitroalkanes with magnesium methyl carbonate followed by esterification gives a-nitro esters in 40-58% yield.14 Magnesium methyl carbonate is prepared by the saturation of a magnesium methoxide suspension in DMF with C02. More elegantly, sodium salt of nitroalkanes can he carboxylated by means of 1 -ethoxycarbonylbenzotriazole to give a-nitro esters in 55-80% yield (Eq. 5.7).15 Nitroacetic acids and its esters can serve as useful... 

To ensure a rapid reaction with the magnesium, the methanol should be heated to reflux over magnesium methoxide for 12 hours and then distilled and transferred to the reaction vessel with a siphon or a large pipet. If necessary, a crystal of iodine may be added to initiate the reaction of methanol with magnesium. 

Similar reaction occurs with methane forming magnesium methoxide and evolving hydrogen ... 

Anhydrous methanol is obtained by treatment with magnesium methoxide, obtained by refluxing 50 mL of methanol, 5 g of magnesium turnings, and 0.5 g of sublimed iodine together until the iodine color disappears. Then 1 L of methanol is added and the system is kept at reflux for 1 hr and distilled to yield purified methanol (bp 64.5°C). 

Preparation Bubble carbon dioxide into a solution of magnesium methoxide. Upon heating, a series of equilibrium reactions forms the reagent ... 

Compounds with acidic a-hydrogen were considered as potential nucleophilic donors for the extended 1,6-conjugate system of puupehenone. Nitromethane and nitroethane were reacted with stoichiometric amounts of magnesium methoxide and generated nucleophiles were added to a benzene solution of puupehenone (63). The addition products were then acetylated and purified to give compounds (78) and (79). 

Methanol was dried before use by distillation from magnesium methoxide under an atmosphere of nitrogen. 

Commercial absolute alcohol is dried with sodium and ethyl phthalate 1 and redistilled. The checkers obtained a considerably lower yield in a run employing alcohol dried over magnesium methoxide. 

The base-catalyzed condensation between methyl acetoacetate and methoxymethyl-eneacetoacetate (303) gives the glutaconic ester, dimethyl 2,4-diacetylpent-3-enedioate <79JCS(Pl)464). Spectroscopic studies have indicated that this compound exists predominantly in the cyclic form (304). A further base-catalyzed reaction ensues resulting in the formation of the pyran-2-one (Scheme 86). From a preparative aspect, an equimolar quantity of magnesium methoxide is the catalyst of choice (79JCS(Pl)478). The synthesis of several other pyran-2-ones by related reactions is described in the latter work. 

Other products are formed when high concentrations of sodium methoxide are present or when magnesium methoxide is used as the base. Dimethyl 5-hydroxytoluene-2,4-dicarboxylate arises from attack at the acetyl carbon atom in an aldol-like condensation, whilst reaction at the ester carbonyl leads through a Claisen condensation to methyl 5-acetyl-2,4-dihydroxybenzoate. 

Alkoxide and Hydroxide Bases Magnesium methoxide, 352 Potassium f-butoxide, 212, 252, 256, 322... 

Magnesium iodide, 171 Magnesium-Methanol, 170 Magnesium methoxide, 352 Methallylmagnesium chloride, 139 Methylmagnesium bromide, 139, 195, 203, 214, 322... 

If the condensation is effected with magnesium methoxide in methanol, y-hydroxy-a,/f-unsaturated esters (3) are obtained directly via isomerization of the double bond, u [2,3] sigmatropic rearrangementof the sulfoxide group, and cleavage of the sulfenate. The same transformation of 1 to 3 can be conducted in two steps, as formulated in cq uation (I). The overall yield is about the same as in the direct method. 

Propanol was refluxed with magnesium methoxide and fractionated. 

In another experiment, glass wool was added to the hydrolyzed magnesium methoxide gel prior to heating in the autoclave. The quartz wool coated with high-surface-area magnesium oxide was impregnated with nickel nitrate hexahydrate and activated as already described. 

On the other hand, all the organic solvents used are either flammable or toxic or expensive. Some are poisonous, or hazardous to health, and others dissolve, or cause feathering in, dyes and inks used on paper. Substances such as magnesium acetate, barium hydroxide, cyclohexylamine and its carbonate and acetate and magnesium methoxide have been tested for their safety and effectiveness. 

Magnesium methoxide has been found to be a very effective neutralizer. However, on a damp day or with a damp paper, the solution tends to precipitate prematurely and leave surface deposits on the treated paper. Methyl magnesium carbonate is also effective but much less sensitive to water. Both these products produce adequate alkaline reserves in paper. Since methanol is used as the solvent, the deacidification should be conducted in a well-ventilated hood. 

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