General procedure for the synthesis of 3-amino-5-chlorobenzotrifluoride from 3-chloro-5-nitrobenzotrifluoride: To a stirred mixture of 3-chloro-5-nitrobenzotrifluoride (2.90 g, 12.9 mmol) in 120 mL of ethyl acetate (EtOAc) was added stannous chloride dihydrate (SnCl2-2H2O, 12.0 g, 51.6 mmol). The reaction mixture was heated to reflux and kept for 3 hours and then cooled to room temperature. Subsequently, the reaction mixture was diluted with 100 mL of EtOAc and washed with 2.5 N sodium hydroxide (NaOH) solution (1 × 150 mL). After separation of the aqueous layer, the aqueous layer was back-extracted with EtOAc (1 × 200 mL). All EtOAc layers were combined, washed with brine (1 × 40 mL), dried over anhydrous magnesium sulfate (MgSO4), filtered, and concentrated under reduced pressure to give 2.51 g of the target product 3-amino-5-chlorobenzotrifluoride (yellow solid) in quantitative yield.HPLC analytical conditions: a Chromolith SpeedROD column (4.6 × 50 mm), a mobile phase containing Chromolith SpeedROD column (4.6×50 mm), mobile phase was 10-90% aqueous methanol containing 0.2% phosphoric acid at a flow rate of 4 mL/min, detection wavelength 220 nm, and retention time (RT) 2.57 min. Mass spectrum (electrospray ionization, ES): m/z = 196 [M + H]+.
