Physical properties
6-Trifluoromethylnicotinic acid is a white powder with a melting point
of 193-197 °C. It has a boiling point of 259.3℃ at 760 mmHg. Its
density is 1.484 g/cm3. Its flash point, refractive index and vapor
pressure are 110.6℃, 1.475 and 0.007mmHg at 25°C, respectively.
Uses
6-(Trifluoromethyl)nicotinic acid can be used to prepare Raf inhibitors to treat cancer.
Application
6-(Trifluoromethyl)nicotinic acid is a key intermediate of many fluorine-containing drugs.
Hazard
6-(Trifluoromethyl)nicotinic acid causes skin irritation and serious eye irritation.
Synthesis
To a 10L three-necked flask were added 1420 g of water, 2440 g of sulfuric acid, and 150 mL of glacial acetic acid, and 870 g (5 mol) of 6-(trifluoromethyl)nicotinonitrile was added slowly. The mixture was heated to reflux and kept overnight. Upon completion of the reaction, the reaction mixture was cooled, ice was added and the mixture was cooled using ice brine to precipitate a white solid. After filtration, the filtrate was extracted with ethyl acetate. The organic phases were combined and washed twice with water, followed by drying the organic phase to acidity. After washing, 930 g of 6-(trifluoromethyl)-3-pyridinecarboxylic acid was obtained as a beige solid in 97.3% yield.
References
[1] Patent: CN107298677, 2017, A. Location in patent: Paragraph 0036-0038
[2] Patent: CN107337638, 2017, A. Location in patent: Paragraph 0031; 0032; 0033
[3] Patent: EP1122242, 2001, A1
[4] Patent: US6673799, 2004, B1. Location in patent: Page column 16
