Acetaldehyde → 1-Methoxy-2,2,6,6-tetramethylpiperidin-4-one

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Reaction Steps

The intermediate, 1-oxy-2,2,6,6-tetramethyl-piperidin-4-one, can be produced by reacting 2,2,6,6-tetramethyl-piperidin-4-one with 1.75 equivalents of hydrogen peroxide in 2M sodium chloride solution, with 1 mol % sodium tungstate added, for 12 h at 50°. When the reaction is complete, the solution is slightly acidified with 2 N hydrochloric acid to pH 5, then 3 equivalents of acetaldehyde and two equivalents of 30% hydrogen peroxide are added slowly at 50°. The mixture is stirred at 90° for 2 h, and then cooled. The work-up, as above in example E, gives 64% of liquid product, crystallizes slowly.

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