Dimethyl Sulfoxide → 1-Methoxy-2,2,6,6-tetramethyl-piperidin-4-ol

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Reaction Steps

A solution of 17.8 g (64.0 mmol) of ferrous sulfate heptahydrate in 80 ml of water is added dropwise, under nitrogen, over a 100-minute interval to a mixture of 10.0 g (58.1 mmol) of 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine, 8.3 g (73 mmol) of 30% aqueous hydrogen peroxide, and 100 ml of dimethyl sulfoxide. As the ferrous sulfate solution is added, the reaction temperature rapidly increases from 27° C. to 43° C. A cooling bath is used to regulate the temperature, which reaches 53° C. and then begins to decrease. The reaction mixture is stirred for 30 minutes after the ferrous sulfate solution is added, and then extracted with methylene chloride (3×100 ml). The crude product is purified by flash chromatography on silica gel (10:1 heptane/ethyl acetate, then 4:1 heptane/ethyl acetate) to afford 2.7 g (25% yield) of the title compound.

Provenance & Evidence