C(O)(=O)C.[OH:5][N:6]1[C:11]([CH3:13])([CH3:12])[CH2:10][C:9](=[O:14])[CH2:8][C:7]1([CH3:16])[CH3:15].C(#N)C.OO.[CH2:22]1[CH2:27][CH2:26][CH2:25][CH2:24][CH2:23]1>O>[CH:22]1([O:5][N:6]2[C:11]([CH3:12])([CH3:13])[CH2:10][C:9](=[O:14])[CH2:8][C:7]2([CH3:16])[CH3:15])[CH2:27][CH2:26][CH2:25][CH2:24][CH2:23]1A solution of 0.369 g (1.86 mmol) of ferrous chloride tetrahydrate and 0.327 g (5.45 mmol) of glacial acetic acid in 6 ml of water is added to a mixture of 10.97 g (64.4 mmol) of 1-oxyl-2,2,6,6-tetramethylpiperidin-4-one, 100 ml of acetonitrile, and 65 ml of cyclohexane that is heated to 50° C. A solution of 18.21 g (268 mmol) of 50% aqueous hydrogen peroxide is added to the reaction mixture dropwise over 5.25 hours as the reaction temperature is brought to and maintained at 60-62° C. A total of 0.227 g of ferrous chloride tetrahydrate, 0.267 g of glacial acid, and 5 ml of water is added to the reaction mixture in 3 portions during the peroxide addition. Work up according to the procedure of Example 44 affords 10.83 g (66% yield) of the title compound, a white solid, mp 32-36. GC assay is 98.5%.
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