117519-09-2

117519-08-1

General procedure for the synthesis of 2-chloro-3-nitro-6-trifluoromethylpyridine from 2-chloro-6-trifluoromethyl-3-amino-pyridine: To a mixture of fuming sulfuric acid (3.2 mL) and aqueous hydrogen peroxide (50%, 1.6 mL) was slowly added a solution of 3-amino-2-chloro-6-(trifluoromethyl)pyridine in concentrated sulfuric acid (4 mL) at 0°C (304 mg. 1.55 mmol). The reaction mixture was slowly warmed to 25 °C and stirred at this temperature for 20 hours. After completion of the reaction, the mixture was carefully poured into ice water. The reaction mixture was neutralized with aqueous ammonium hydroxide and subsequently extracted with ethyl acetate (5 x 10 mL). The organic layers were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure to afford the target compound 2-chloro-3-nitro-6-trifluoromethylpyridine (126 mg, 36% yield) as a yellow solid, which could be used in subsequent reactions without further purification.