Preparation of 4-acetamido-TEMPO
70.0 g, (0.686 mol) of acetic anhydride was added, dropwise, to a solution of 34.6 g (0.221 mol) of 4-amino-2,2,6,6-tetramethylpiperidine dissolved in 100 mL of anhydrous ether that had been cooled to 0 ºC. After addition was complete (about 1 hours), the solution was stirred for 30 min at room temperature. The precipitate was removed by filtration and washed with 20 mL of ether to give 55.6 g (98%) of 4-(acetylamino)-2,2,6,6-tetramethylpiperidinium acetate, mp 175 ºC subl. The acetate was dissolved in 400 mL of water and basified with 50.0 g of potassium carbonate (0.303 mol). To this solution was added 80 mL of 30% hydrogen peroxide, 4.00 g of sodium tungstate, and 4.00 g of ethylenediaminetetracetic acid, tetrasodium salt. The mixture was stirred at room temperature for 72 hours. The red precipitate was removed by filtration and washed with 20 mL of distilled water to give 38.6 g of 4-acetamido-TEMPO, which melted at 146-147 ºC, lit. The filtrate was saturated with solid potassium carbonate and extracted several times with two 100-mL portions of dichloromethane. The organic phase was washed with saturated aqueous sodium chloride, dried over sodium sulfate, and evaporated to give 7.1 g more of product, mp 145-147 ºC. The combined yield was 45.7 g (overall yield for the two steps, 97%).
Heterocycles 1988,27, 509
J. Org. Chem., 1991, 56 (21), 6110–6114
4-Acetamido-TEMPO, 4-Acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-Acetamido-TEMPO, free radical, ST51005987, 4-Acetylamino-2,2,6,6-tetramethylpiperidin-1-oxyl, PubChem9193, AA-TEMPO, AC1LARIB, UNII-G7ABJ73L6S, G7ABJ73L6S, 390380_ALDRICH, 00375_FLUKA, MolPort-003-925-053, C11H21N2O2, AKOS015910523, LS41075, ST24043173, X4276, B-7279, 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl, W-201301, 201863-94-7
Tempace, C7H2F2N2O2, 14691-89-5, 3,4-Difluoro-5-nitrobenzonitrile, CID518988, A1348, N-(1-, V0041, 4-Acetamido-2,2,6,6-tetramethylpiperidinyloxy, 4-Acetamido-2,2,6,6-tetramethylpiperidino-1-oxyl, 1-Piperidinyloxy, 4-(acetylamino)-2,2,6,6-tetramethyl-, N-(1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl)acetamide, 1119454-07-7