Alkyl complexes metal hydroxides

The yV-alkyl-substituted azadiol was treated with an equimolar amount of tosyl chloride and excess alkali metal hydroxide in an aprotic solvent (powdered NaOH, dioxane, room temperature, 3 hr) to give a 60% yield of the monoaza-crown (Kuo et al., 1978). Template effects are important in this cyclization reaction, so sodium hydroxide was used for aza-15-crown-5 and potassium hydroxide for aza-18-crown-6. The intramolecular ring-closure process is the result of the initial formation of a tosylate by the reaction of one alkoxide anion with tosyl chloride followed by displacement of the tosylate leaving group by the second alkoxide anion. The pure monoaza-crowns were isolated from their metal ion complexes by thermolysis under reduced pressure (Kuo et al., 1980). 

Heterocyclic structures analogous to the intermediate complex result from azinium derivatives and amines, hydroxide or alkoxides, or Grignard reagents from quinazoline and orgahometallics, cyanide, bisulfite, etc. from various heterocycles with amide ion, metal hydrides,or lithium alkyls from A-acylazinium compounds and cyanide ion (Reissert compounds) many other examples are known. Factors favorable to nucleophilic addition rather than substitution reactions have been discussed by Albert, who has studied examples of easy covalent hydration of heterocycles. 

In the autoxidation of neat hydrocarbons, catalyst deactivation is often due to the formation of insoluble salts of the catalyst with certain carboxylic acids that are formed as secondary products. For example, in the cobalt stearate-catalyzed oxidation of cyclohexane, an insoluble precipitate of cobalt adipate is formed. 18fl c Separation of the rates of oxidation into macroscopic stages is not usually observed in acetic acid, which is a better solvent for metal complexes. Furthermore, carboxylate ligands may be destroyed by oxidative decarboxylation or by reaction with alkyl hydroperoxides. The result is often a precipitation of the catalyst as insoluble hydroxides or oxides. The latter are neutralized by acetic acid and the reactions remain homogeneous. 

Carbon dioxide readily undergoes insertion reactions probably via initial C02 complexing, with metal alkoxides, hydroxides, oxides, dialkylamides, and metal hydrides and alkyls 103... 

The original Bader and Sunder process was simplified considerably by the discovery of Morton Sundour Fabrics that the sulphuric ester can be formed as a metal complex by the action of fuming sulphuric acid, or an alkyl ester of chlorosulphonic acid, on the oxidized vat pigment in the presence of pyridine. The complex is finally converted into the sodium salt by the action of sodium hydroxide as shown in the series of reactions below ... 

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