768-66-1 2,2,6,6-Tetramethylpiperidine 13035, apiperidines compound, is more and more widely used in various fields.
768-66-1,768-66-1, 2,2,6,6-Tetramethylpiperidine is a piperidines compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated
In a 500 ml four-necked round bottom flask equipped with a mechanical stirrer, a reflux, a thermometer, a funnel and a septum are added 40 g of water, 10 g K2CO3 (99%; 7,24·10-2 mol), 5 g 2,2,6,6-tetramethylpiperidine (99%; 3,53·10-2 mol) and 50 g toluene. Then, a solution of 21,702 g of Oxone (Monopersulfate, DuPont Specialty Chemicals, USA) (3,53·10-2 mol) in 100 g water is slowly added to the 500 ml flask while stirring vigorously (with a slightly exothermic reaction) and the flask is placed in a water bath at room temperature. After the addition, the reaction medium is stirred at room temperature for 30 minutes, and the organic phase becomes progressively red due to the formation of 2,2,6,6-tetramethylpiperidine-1-oxide (TEMPO). Then, the reaction medium is heated at 40 C. for further 30 minutes. The reaction medium is then cooled at room temperature, the stirring is terminated and the water phase is removed from the reaction flask. The red organic phase is then degassed by bubbling argon for 10 minutes. 11,124 g FeSO4.7H2O (4·10-2 mol) are then slowly added under an argon atmosphere and while stirring vigorously. Then, a degassed mixture of 100 ml methanol and 36,7 g of styrene (3,53 10-1 mol) are added rapidly to the reaction flask and the temperature is increased to 40 C. Finally, a solution of 13,71 g hydrogen peroxide (35%; 0.1412 mol) in 15 g methanol is added slowly (dropwise) for 28 minutes while keeping the temperature between 30 and 40 C. (with an exothermic reaction). When the addition is complete, the reaction mixture is allowed to react while stirring vigorously by room temperature for 2 h 30 mins. [0108] The brown solution is then filtered and the residual styrene, hydrogen peroxide and methanol are then removed in vacuo at 50 C. To the viscous brown residue obtained is added 100 g of CH2Cl2 and 30 g of water, and then HCl is added until the pH is 3. The organic phase is then washed 2 times with an acidic solution (pH is 3) in order to remove the excess 2,2,6,6-tetramethylpiperidine. The organic phase is finally dried under MgSO4, filtered and dried in vacuo at 50 C. 2,79 g of a viscous light yellow oil is obtained.Synthesis of 1-phenyl-1-(2′,2′,6′,6′-tetramethyl-1′-piperidinyloxy)-2-hydroxyethane 1 using Oxone (potassium monopersulfate, DuPont Specialty Chemicals, USA) as the oxidizing agent: scale-up To a 6 l four-necked round bottom flask equipped with a mechanical stirrer, a reflux condenser a thermometer, a funnel and a septum are added 634 g of water, 158,42 g K2CO3 (99%; 1,146 mol), 79,21 g 2,2,6,6-tetramethylpiperidine (99%; 5,607·10-1 mol) and 792,1 g toluene. Then, a solution of 343,8 g of Oxone (Monopersulfate, DuPont Specialty Chemicals, USA) (5,59·10-1 mol) in 1584 g water is slowly added (over a period of 1 h 40 mins.) to the 6 l flask while stirring vigorously (slightly exothermic reaction) and the flask is placed in a water bath at room temperature. After the addition is complete, the reaction medium is stirred at room temperature for 30 minutes, and the organic phase becomes progressively red due to the formation of 2,2,6,6-tetramethylpiperidine-1-oxide (TEMPO). Then, the reaction medium is heated at 40 C. for a further 30 minutes. [0126] The reaction medium is then cooled at room temperature, the stirring is terminated and the water phase is removed from the reaction flask. The red organic phase is then degassed by bubbling argon for 10 minutes. 176,23 g FeSO4·7H2O (6,34·10-1 mol) are then slowly added in an argon atmosphere, while stirring vigorously. Then, a degassed mixture of 1584,2 g of methanol and 581,4 g of styrene (5,582 mol) is added rapidly to the reaction flask and the temperature is increased to 30 C. Finally, a solution of 217,19 g hydrogen peroxide (Merck, 35%; 2,235 mol) in 237,63 g methanol is slowly added (dropwise) for 5 h 40 minutes while keeping the temperature at between 30 and 40 C. When the addition is complete, the reaction mixture is allowed to react while stirring vigorously at room temperature for 15 h. [0127] The brown solution is then filtered and the residual styrene, hydrogen peroxide and methanol are then removed in vacuo at 50 C. To the viscous brown residue obtained is added 1500 g of CH2Cl2 and 475 g of water, and then HCl is added until the pH is 3. The organic phase is then washed twice with an acidic solution (pH=3) in order to remove the excess 2,2,6,6-tetramethylpiperidine. The organic phase is finally dried under MgSO4, filtered and dried in vacuo at 50 C. 121 g of a viscous light yellow oil is obtained. [0128] In order to remove polystyrene formed during the reaction (optional step), the product is dissolved in chloroform and then precipitated in methanol. After filtration, the methanol phase is dried in vacuo and this operation is repeated once to obtain 71,35 g of a slightly yellow oil. This oil contains 1 and very low molecular weight polystyrene. The alkoxyamine 1 may be purified by flash chromatography or by high vacuum dist…
768-66-1 2,2,6,6-Tetramethylpiperidine 13035, apiperidines compound, is more and more widely used in various fields.
Reference:
Patent; Detrembleur, Christophe; Gross, Thomas; Meyer, Rolf-Volker; US2003/236368; (2003); A1;,
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