Hydrogen Peroxide → 3,4-Dimethylpyridine 1-oxide

温度

75 °C

The general procedure of Boekelheide1 for the preparation of hydroxymethylpyridines was used. Thus, a solution of freshly distilled 3,4-lutidine (46.0 g, 0.43 mol) in 120 mL of glacial acetic acid was cooled at 0° C. and then 64 mL of 30% H2O2 was added dropwise. The resulting solution was heated at 75° C. (oil-bath temperature) for 3 h. Another 20 mL of 30% H2O2 was then added and heating was continued for 18 h. Finally, 20 mL of 30% H2O2 was again added and the reaction was kept at 75° C. for another 3 h. The solution was then concentrated to about 100 mL under water-aspirator pressure, 50 mL of H2O was added and the mixture was concentrated to about one half volume. The resulting mixture was cooled (0°-5° C.) and basified to about pH 10 using cold 40% aqeuous NaOH. The mixture was then extracted with CH2Cl2 (5×) and the extract was dried (Na2CO3 +Na2SO4) and concentrated on the roto-vap to give a yellow solution. Dilution of this solution with hexane afforded a solid which was collected by filtration and then dried in vacuo to give 3,4-lutidine-N-oxide (48.0 g, 83%) as an off-white solid.