Water → 2,5,6-trichloronicotinic acid

Temperature

100 °C

A suspension of 2,3,6-trichloro-5-methylpyridine (Method 48, 11.8 g, 60.0 mmol) in water (400 ml) was heated to 100° C. Portionwise, KMnO4 (28.5 g, 180.2 mmol) was then added over 12 hours. The reaction was then allowed to stir for 2 days at 100° C., over which time an additional 10 g of KMnO4 was added portionwise. When no starting material remained, the hot reaction was filtered, washed with hot water (2×75 ml), and the resulting filtrate was allowed to cool to room temperature. The aqueous filtrate was then extracted with EtOAc (3×100 ml), and then concentrated to a 50 ml volume. This aqueous solution was then cooled to 0° C. and adjusted to pH 1-2 with 6.0 M HCl. The resulting solid was then collected by filtration, washed with cold water, and dried to give the title compound (2.5 g, 18%) that was used without further purification.

1. additionwas added portionwise
2. customthe hot reaction
3. filtrationwas filtered
4. washwashed with hot water (2×75 ml)
5. temperatureto cool to room temperature
6. extractionThe aqueous filtrate was then extracted with EtOAc (3×100 ml)
7. concentrationconcentrated to a 50 ml volume
8. temperatureThis aqueous solution was then cooled to 0° C.
9. filtrationThe resulting solid was then collected by filtration
10. washwashed with cold water
11. customdried

ORD record

ord-01bb3283995b42eb9b526e13967a40ec

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08835465B2