Hydrogen Peroxide → 4-Piperidinol, 1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethyl-

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Reaction Conditions

Reaction Steps

Ferrous chloride tetrahydrate (0.99 g, 5.0 mmol) is added to 400 mL of tert-butyl alcohol which is heated to 40° C. The mixture is stirred for 15 minutes and 0.78 g (5.0 mmol) of 2,2'-dipyridyl is added to the tert-butyl alcohol solution. The solution is then stirred for five minutes and 17.2 g (100 mmol) of 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine is added. A solution of 49 g (0.72 mol) of 50% aqueous hydrogen peroxide mixed with 100 mL of tert-butyl alcohol is added to the reaction mixture over a 10-hour period at 40-45° C. Another 6 g (0.088 mol) of 50% aqueous hydrogen peroxide is then added while the reaction mixture is heated at 45° C. for four hours until the starting nitroxyl compound is reacted. Analysis by gas chromatography shows the reaction mixture contains 6 area % of 1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-one compared to 22 area % in Example 6. Solids are removed by filtration, and after 1.5 g of sodium borohydride is added, the filtrate is stirred for one hour. The filtrate is diluted with water, and the mixture is thoroughly extracted with ethyl acetate. The extract is concentrated to afford 24.2 g of a light tan crystalline solid which has the same gas chromatography retention time as an authenic sample of the title compound. In a similar experiment, the final product is recrystallized several times from heptane to obtain 16.9 g (69% yield) of the title compound, melting at 127-131° C.

Provenance & Evidence