85148-26-1

light yellow crystalline

3-Chloro-5-(trifluoromethyl)pyridine (3CTFP) is a pyridinium salt that is a byproduct of the production of chlorofluorocarbons. It is used to reduce the level of chlorine in water, and it can be used as a pesticide. 3CTFP is also an anion that can be reduced to form the chloride ion. 3CTFP reacts with nucleophiles such as ammonia or amines, which leads to nucleophilic substitution reactions. This reaction can be reversed by adding acid. The product from this reaction is ammonia gas. 

The general procedure for the synthesis of 3-chloro-5-trifluoromethylpyridine using 2,3-dichloro-5-trifluoromethylpyridine as starting material was as follows: zinc powder (1.18 g, 18.0 mmol) was added to a suspension of 2,3-dichloro-5-trifluoromethylpyridine (2.0 g, 9.30 mmol) in a solvent mixture of 80:20 (v/v) water and acetic acid (5 mL) at 90° C with stirring for 1 hour. Subsequently, zinc powder (1 g, 15.3 mmol) was made up and stirring was continued at 90°C for 15 minutes. After completion of the reaction, the mixture was cooled to room temperature, filtered and the filtrate was washed with dichloromethane. The filtrate was carefully concentrated and the residue was purified by silica gel column chromatography with an elution gradient of 100:0 to 0:100 (v/v) hexane:dichloromethane, resulting in 3-chloro-5-trifluoromethylpyridine as a colorless oil (0.120 g, 7% yield). The product was characterized by 1H NMR (300 MHz, CDCl3): δ 7.93 (s, 1H), 8.78 (s, 2H); GC-MS (EI) analysis showed m/z = 181.0, 183.0 [M].

[1] Patent: WO2005/94822, 2005, A1. Location in patent: Page/Page column 28
[2] Bioorganic and Medicinal Chemistry, 2010, vol. 18, # 20, p. 7150 - 7163