Acetic Acid → 1-Cyclohexyloxy-4-benzoyloxy-2,2,6,6-tetramethylpiperidine

Participants

Reaction Conditions

Reaction Steps

To a mixture of 3.00 g (10.9 mmol) of 1-oxyl-4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 20 ml of pyridine, and 12 ml of cyclohexane are added 2.2 ml (38.4 mmol, 3.5 equivalents) of glacial acetic acid, 1 ml of water, 0.124 g (0.446 mmol) of ferrous sulfate heptahydrate, and finally, 0.57 g (8.7 mmol, 0.80 equivalents) of zinc powder. A slight exothermic reaction occurs upon the addition of zinc. The reaction mixture is heated to 45° C. A solution of 3.0 g (44 mmol) of 50% aqueous hydrogen peroxide is added dropwise over 1.5 hours to the reaction mixture while the temperature is brought to and maintained at 60-64° C. After the peroxide is added, the mixture is heated at 62° C. for 15 minutes, then allowed to cool slowly. After the reaction mixture is stirred overnight at room temperature, residual peroxide is decomposed by the addition of aqueous sodium sulfite solution. A mixture of 15 ml of concentrated sulfuric acid and 76 g of ice is carefully added to the reaction mixture to form a salt from the pyridine. Work-up and purification according to the procedure of Example 40A afford 2.07 g (53% yield) of the title compound, a white solid, GC assay 100%.

Provenance & Evidence