(1) 2-Chloro-5-(trifluoromethyl)pyridine (25 g) was mixed with 100% hydrazine hydrate (100 mL) in ethanol (60 mL) in a reactor. The reaction was stirred at 100 °C for 3 hours. After completion of the reaction, the reaction solution was concentrated under reduced pressure. Chloroform and water were added to the residue for liquid-liquid separation, and the organic layer was collected and dried over anhydrous sodium sulfate. The organic solvent was removed by evaporation under reduced pressure to give the crude product. The crude product was dissolved in ethanol solution of 4N hydrochloric acid to give 2-hydrazino-5-(trifluoromethyl)pyridine hydrochloride (15.4 g).
