Yield: 99%

Reaction Conditions:

with dihydrogen peroxide;acetic acid in water at 90;

Steps:

111.1
Step 1 In a round-bottomed flask, 4-tert-butylpyridine (1.5 g, 11.1 mmol) was dissolved in acetic acid (9 mL) and hydrogen peroxide (30 wt. % solution in water, 6.0 mL, 58.7 mmol) was added. The colorless solution was stirred at 90° C. overnight. The reaction mixture was cooled to room temperature and concentrated. The residue was poured onto ~40 mL saturated Na₂CO₃ solution and extracted with 100 mL dichloromethane (2*). The organic layers were combined, dried over sodium sulfate, filtered and concentrated to afford 1.75 g (99%) of 4-tert-butylpyridine N-oxide as light yellow solid.

References:

Hendricks, Robert Than;Hermann, Johannes;Kondru, Rama;Lou, Yan;Lynch, Stephen M.;Owens, Timothy D.;Soth, Michael US2011/230462, 2011, A1 Location in patent:Page/Page column 97