Reaktion #220830

Reaktionsgleichung

sulfuric acid

hydrogen peroxide

sodium sulfite

picolinic acid

1-oxyl-4-benzoyloxy-2,2,6,6-tetramethylpiperidine

→

title compound

1-Cyclohexyloxy-4-benzoyloxy-2,2,6,6-tetramethylpiperidine

Lösungsmittel

pyridine

Water

cyclohexane

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.DISSOLUTIONto dissolve the metal salt
2. 2
   Temperaturmaintained at 60-64° C
3. 3
   Temperaturto cool slowly
4. 4
   workup.ADDITIONis carefully added to the reaction mixture
5. 5
   ExtraktionThe reaction mixture is extracted twice with ethyl acetate
6. 6
   WaschenThe combined organic layers are washed with dilute sodium bicarbonate solution and saturated sodium chloride solution
7. 7
   Einengenconcentrated
8. 8
   SonstigePurification by flash chromatography on silica gel with 20:1 heptane-ethyl acetate

Vorschrift

To a mixture of 3.01 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 0.153 g (0.55 mmol) of ferrous sulfate heptahydrate, 0.211 g (1.71 mmol) of picolinic acid, and 0.048 g (0.27 mmol) of ascorbic acid. Water (1 ml) is added to dissolve the metal salt. The mixture is heated to 48° C. A solution of 2.95 g (43.5 mmol) of 50% aqueous hydrogen peroxide is added dropwise over 1.25 hours to the reaction mixture while the temperature is brought to and maintained at 60-64° C. After the peroxide is added, the reaction mixture is 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 65 g of ice is carefully added to the reaction mixture to form a salt from the pyridine. The reaction mixture is extracted twice with ethyl acetate. The combined organic layers are washed with dilute sodium bicarbonate solution and saturated sodium chloride solution, then concentrated. Purification by flash chromatography on silica gel with 20:1 heptane-ethyl acetate affords 2.03 g (52% yield) of the title compound, a colorless syrup, GC assay 100%.

Quelle