Acetic Acid → 4-Methoxy-3,5-dimethylpyridine 1-Oxide

Participants

Reaction Conditions

Reaction Steps

3,5-lutidine (15 kg, 140.2 moles) was dissolved in acetic acid (48 l) at 60° C. Hydrogen peroxide (8430 ml, 98 moles) was added during 3 hours. The solution was heated to 90° C. and kept at this temperature for 3 hours. The reaction mixture was cooled to 60° C. and hydrogen peroxide (3500 ml, 41 moles) was added during 1 hour. The temperature was raised to 90° C. and kept there for 16 hours. The reaction mixture was evaporated at reduced pressure (70° C. 300 mm Hg). The residue (approx 25 liters) was cooled and pH adjusted to 10 with NaOH-solution (23 liters 10M). Acetonitrile (30 liters) was added and the mixture was stirred for 30 minutes. The sodiumacetate was separated off and washed with 10 l acetonitrile. The liquid phase was evaporated at reduced pressure (55° C., 200 mm Hg). The remaining solution (approx 25 liters) was extracted with CH2Cl2 (20 liters and 3×5 liters). The combined organic layers were dried over MgSO4, filtrated and evaporated at reduced pressure (50° C. 200 mm Hg). When all CH2Cl2 had distilled off unreacted 3,5-lutidine was evaporated at 75° C., 8 mm Hg. Yield 14940 g of 3,5-dimethylpyridine-N-oxide. The identity was confirmed with 1 H and 13C NMR.

Provenance & Evidence