N-tert-butyl-1-phenylmethanimine

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 530.85 g (5.00 mol) of benzaldehyde was placed into a 2000 mL-volume flask equipped with a stirrer, a thermometer and a dropping funnel. Subsequently, 367.50 g (5.02 mol) of t-butyl amine was dropped into the flask in a water bath, while maintaining the solution temperature at 25° C. After the completion of the dropping, the mixture was reacted while stirring at 25° C. for 15 hours. After the completion of the reaction, the reaction mixture was subjected to separation, and the organic layer obtained was refluxed under reduced pressure (25° C., 13.3 Pa) for 2 hours, to provide 788.91 g of N-benzylidene-t-butyl amine. (Isolation yield; 98%) equipped with a stirrer After the completion of the dropping, the mixture was reacted After the completion of the reaction the reaction mixture was subjected to separation the organic layer obtained was refluxed under reduced pressure (25° C., 13.3 Pa) for 2 hours

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 530.85 g (5.00 mol) of benzaldehyde was placed into a 2000 mL-volume flask equipped with a stirrer, a thermometer and a dropping funnel. Subsequently, 367.50 g (5.02 mol) of t-butyl amine was dropped into the flask in a water bath, while maintaining the solution temperature at 25° C. After the completion of the dropping, the mixture was reacted while stirring at 25° C. for 15 hours. After the completion of the reaction, the reaction mixture was subjected to separation, and the organic layer obtained was refluxed under reduced pressure (25° C., 13.3 Pa) for 2 hours, to provide 788.91 g of N-benzylidene-t-butyl amine. (Isolation yield; 98%) equipped with a stirrer After the completion of the dropping, the mixture was reacted After the completion of the reaction the reaction mixture was subjected to separation the organic layer obtained was refluxed under reduced pressure (25° C., 13.3 Pa) for 2 hours

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a three neck round bottom flask, equipped with a cold water condenser, 30 g of water and 26.5 g of benzaldehyde were added. The mixture was mixed with a magnetic stirrer at room temperature for 3 minutes. t-Butyl amine (22.1 g) was added to the reaction flask in one portion, followed by vigorous stirring for 15 hours. The agitation was stopped and the reaction mixture was allowed to stand for at least 15 minutes. The lower aqueous layer was separated from the reaction mixture. The upper layer was collected and dried over magnesium sulfate to give 35.5 g of product. 1H NMR (300 Hz, CDCl3, ppm): 8.29 (1H, s), 7.77 (2H, m), 7.40 (3H, m), 1.33 (9H, s). To a three neck round bottom flask, equipped with a cold water condenser The mixture was mixed with a magnetic stirrer at room temperature for 3 minutes to stand for at least 15 minutes The lower aqueous layer was separated from the reaction mixture The upper layer was collected dried over magnesium sulfate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a dry 3 liter, 3-necked, round bottom flask equipped with a mechanical paddle stirrer, a nitrogen gas flow, and a condenser was added 87 gm (83.5 ml; 0.82 moles) of benzaldehyde and 63 gm (90.5 ml; 0.86 moles) of t-butylamine. The mixture was stirred for about 4 hours at room temperature to allow complete formation of N-benzylidene-t-butylamine. After removal of the nitrogen gas flow and the condenser, the reaction flask was evacuated under an aspirator (about 24″ Hg vacuum) for about 15 minutes. The aspirator was detached and 288 gm (3.428 moles) of sodium bicarbonate followed by 500 ml of water and 500 ml of acetone were added to the 3-liter flask. The condenser was reattached to the flask and carefully about 600 gm (0.98 moles) of Oxone® was added portion-wise through a powder-addition funnel to the stirring reaction over a period of about 10 minutes. The reaction began to slowly foam from the evolution of carbon dioxide and turn to a bluish tinge as the temperature rose to about 35° C. The reaction was stirred for one hour after the Oxone® addition, and a GC analysis revealed a trace amount of starting imine (3.72 minutes) and a large peak representing 2-t-butyl-3-phenyl oxaziridine (4.45 minutes). The reaction was poured into a beaker containing a 2-phase solution of 3000 ml water and 300 ml toluene. Insoluble salts were filtered out and the aqueous layer separated in a separatory funnel. The upper toluene layer was placed in a 1-liter single-neck, round bottom flask and concentrated over a 30-minute period on a rotary evaporator at 50° C. under vacuum (about 24″ Hg) to remove traces of acetone and water. Several silicon carbide boiling chips were added to the concentrated oxaziridine and the oxaziridine/toluene solution was refluxed at 115° C. -125° C. for 2-3 hours to form the desired N-t-butylphenylnitrone product. The excess toluene was removed under vacuum and the resulting clear brown liquid N-t-butylphenylnitrone was poured into a crystallizing dish and placed in a fume hood. Crystallization was almost immediate, affording 113.1 gm of crude crystalline N-t-butylphenylnitrone (78% theoretical yield). To a dry 3 liter, 3-necked, round bottom flask equipped with a mechanical paddle stirrer After removal of the nitrogen gas flow the condenser, the reaction flask was evacuated under an aspirator (about 24″ Hg vacuum) for about 15 minutes were added to the 3-liter flask was added portion-wise through a powder-addition funnel to the stirring reaction over a period of about 10 minutes rose to about 35° C The reaction was stirred for one hour The reaction was poured into a beaker Insoluble salts were filtered out the aqueous layer separated in a separatory funnel The upper toluene layer was placed in a 1-liter single-neck, round bottom flask concentrated over a 30-minute period on a rotary evaporator at 50° C. under vacuum (about 24″ Hg) to remove traces of acetone and water Several silicon carbide boiling chips were added to the concentrated oxaziridine the oxaziridine/toluene solution was refluxed at 115° C. -125° C. for 2-3 hours

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 13.2 gm (0.082 moles) of the N-benzylidene-t-butylamine prepared as in Example 1 was added to a 600 ml beaker containing 28.8 gm of sodium bicarbonate (0.3428 moles) in a solution consisting of 50 ml water and 50 ml acetone. The mixture was stirred vigorously with a mechanical paddle stirrer. While stirring, 60 gm (0.098 moles) of Oxone® was added portion wise over a 3 to 5 minute period. The resulting three-phase mixture was initially bluish in color and eventually faded to a pale yellow color as the reaction proceeded. The reaction was stirred at ambient temperature for one hour and followed by GC analysis as described in Example 1. The GC analysis revealed only a trace of the starting material (very tiny peak at 3.72 minutes) and predominant conversion to the oxaziridine, a peak having a retention time of 4.45 minutes. The mixture was diluted with 300 ml of water to dissolve any salts therein. The 2-phase mixture was extracted with 100 ml of hexane. The hexane layer was separated and concentrated under vacuum to remove all solvent. The resulting, almost clear liquid, 2-t-butyl-3-phenyl oxaziridine product weighed 13.74 gm (94.7% crude yield). was added to a 600 ml beaker While stirring The reaction was stirred at ambient temperature for one hour at 3.72 minutes to dissolve any salts The 2-phase mixture was extracted with 100 ml of hexane The hexane layer was separated concentrated under vacuum to remove all solvent

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The imine starting material may be commercially purchased or synthetically prepared. If desired, the imine may be prepared by a condensation reaction between an aldehyde and a primary amine. In one embodiment of the present invention, the imine precursor for α-phenyl-N-tert-butyl nitrone (PBN) is prepared by combining benzaldehyde and t-butyl amine at room temperature, in the absence of a solvent, to form the corresponding benzylidene-t-butyl amine (imine) and water. It was found that the resulting imine was sufficiently pure for use in the next step without the need for purification or removal of water by-product contained therein. Thus, the present method reduces time and cost, and improves efficiency, in comparison with traditional transformations. synthetically prepared at room temperature

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 530.85 g (5.00 mol) of benzaldehyde was placed into a 2000 mL-volume flask equipped with a stirrer, a thermometer and a dropping funnel. Subsequently, 367.50 g (5.02 mol) of t-butyl amine was dropped into the flask in a water bath, while maintaining the solution temperature at 25° C. After the completion of the dropping, the mixture was reacted while stirring at 25° C. for 15 hours. After the completion of the reaction, the reaction mixture was subjected to separation, and the organic layer obtained was refluxed under reduced pressure (25° C., 13.3 Pa) for 2 hours, to provide 788.91 g of N-benzylidene-t-butyl amine. (Isolation yield; 98%) equipped with a stirrer After the completion of the dropping, the mixture was reacted After the completion of the reaction the reaction mixture was subjected to separation the organic layer obtained was refluxed under reduced pressure (25° C., 13.3 Pa) for 2 hours