Hydrochloric Acid → 2-Chloro-3-methyl-1-oxo-1lambda~5~-pyridine

To a mixture of 2-chloro-3-methylpyridine (12.8 g, 100 mmol), urea hydrogen peroxide (19.8 g, 210 mmol) and dichloromethane (130 mL) was added dropwise anhydrous trifluoroacetic acid (28.2 mL, 200 mmol) at 0° C. The reaction was stirred for a further 1.5 hours, warmed to room temperature and then treated with 9% w/w aqueous sodium hydrosulfite (200 mL). The mixture was stirred for a further 15 minutes then 2N hydrochloric acid (50 ml) was added and the mixture was extracted with dichloromethane (2×120 mL). The combined extracts were washed with saturated aqueous sodium hydrogen carbonate (2×100 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to yield 2-chloro-3-methylpyridine 1-oxide as a yellow solid (11.45 g; 89% purity by UV).

1. stirringThe mixture was stirred for a further 15 minutes
2. extractionthe mixture was extracted with dichloromethane (2×120 mL)
3. washThe combined extracts were washed with saturated aqueous sodium hydrogen carbonate (2×100 mL)
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure

ORD record

ord-63f5e9bba6c646e5aecab37b93ce9212

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08501770B2