Bases Magnesium methoxide

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

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. 

One of the most widely used nonaqueous deacidification processes is that proposed by Smith (7) based on a methanol or methanol-Freon solution of magnesium methoxide. This process is very effective and leaves a good alkaline reserve, but the magnesium methoxide is very sensitive to water, and this leads to inconvenience in the handling and processing of paper as a result of premature precipitation. These inconveniences were recognized, and a better nonaqueous deacidification agent... 

From the previous discussion, it is evident that intramolecular aldol condensations are commonplace in this field. However, intramolecular Claisen-type condensations can be accomplished by the use of magnesium methoxide, as in the formation of phoroglucinol derivative 328 (70CRV553). The common intermediate 323 (undetermined ionization state) accounts for both formation of 324 through an aldol condensation (C3—C—C/C6) and formation of 328 by Claisen condensation (C3—C—C—C/C5). Further examples of directed cyclizations, depending on the base used, are gathered in the review by Money (70CRV553). 

Sodium amide, o LDA, l.illMI)S. " NaHMDS, KHMDS, ° sodium and magnesium methoxide or ethoxide, and DBU are less frequently used. The nature of the cation present in the Homer-Wadsworth-Emmons reaction depends on the chosen base and greatly influences the stereoselectivity of the reaction. The chiral lithium 2-aminoalkoxides (17 ,2S) have been used as chiral bases for the enantioselective reaction between diethyl cyanomethylphosphonate and 4-terz-butylcyclohexanone." ... 

Bases Alumina, see p-Toluenesulfonylhydrazine. Dehydroabietylamine. 1,5-Diazabicyclo [4.3.0]nonene-5. 1,4-Diazabicyclo[2.2.2]octane. l,S-Diazabicyclot5.4.0]undecene-5. 2,6-Di-/-butylpyridine. N,N,-Diethylglycine ethyl ester, see /-Amyl chloroformate. 2,6-Dimethyl-piperidine. Ethanolamine. Lithium diisopropylamide, see Diphenylsulfonium isopropylide. Lithium nitride. Magnesium methoxide. N-Methylmorpholine. Piperidine. Potassium amide. Potassium hydroxide. Potassium triethylmethoxide. Pyridine. Pyrrolidine. Sodium methoxide. Sodium 2-methyl-2-butoxide. Sodium thiophenoxide. Thallous ethoxide. Triethyla-mine. Triphenylphosphine, see l-Methyl-2-pyrrolidone. 

Synthesis of decalin-1,8-diotte systems. Magnesium methoxide has been used as the base in a one-step synthesis of the above system from cyclohexene-3-one and esters of 2-carboxyglutaric acid. The reaction involves a combined Michael addition and Dieckmann condensation.1 The diketone exists as the ra-enol... 

Fine particles of MgO were introduced in the zeolite cavities by use of magnesium methoxide in the hope that the shape selectivity is added to the basic properties of MgO[38j. The fine particles of MgO exhibit the catalytic activities for 1-butene isomerization and 1,3-butadiene hydrogenation, but their basic properties are weak as compared to MgO bulk. The charge separation between Mg and O is not sufficient to generate strong base sites for the fine particles. The shape selectivity, however, was observed in allylbenzene double bond isomerization. The MgO bulk showed activity, but the fine particles in the zeolite cavities did not show appreciable activity in a liquid phase reaction. 

Fithium tetrahydroaluminate, Fluoroamides, 0075 Lithium tetrahydroaluminate, Water, 0075 Lithium, 1,2-Diaminoethane, Tetralin, 4675 Magnesium, Barium carbonate, Water, 4685 Maleic anhydride, Bases, or Cations, 1400 Mercaptoacetonitrile, 0763 t Methanol, Hydrogen, Raney nickel catalyst, 0482 4-Methoxy-3-nitrobenzoyl chloride, 2911 Methoxyacetyl chloride, 1161 t Methyl formate, Methanol, Sodium methoxide, 0830 3-Methyl-2-penten-4-yn-l-ol, 2378 Nitric acid, 4430... 

In 1989, the concept of ethoxylating methyl esters, which do not carry a labile hydrogen, was introduced by Hoechts [2] and Henkel [3]. Hoechst demonstrated the ethoxylation of esters was chemically feasible using catalysts based on alkali and alkaline earth metals (e.g., sodium hydroxide, sodium methoxide, barium hydroxide, etc.). Henkel demonstrated the feasibility of using calcined hydrotalcite (aluminum-magnesium hydroxycarbon-ates) for the reaction. Reactivities and conversions with these catalysts, however, were found to be too low for commercial application. 

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