Water → 2,5,6-trichloronicotinic acid

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence