General procedure for the synthesis of 3-chloro-5-methylaniline from 3-chloro-5-nitrotoluene: To an ethanol solution (75 mL) containing 1-chloro-3-methyl-5-nitrobenzene (5.0 g, 29 mmol) was added tin chloride dihydrate (SnCl2-2H2O, 32.8 g, 146 mmol). The reaction mixture was heated to reflux for 3.0 hours. Upon completion of the reaction, the solution was concentrated under reduced pressure and the residue was redissolved in aqueous sodium hydroxide solution, filtered and extracted with ethyl acetate (EtOAc). The organic layers were combined, washed with saturated brine, dried over anhydrous magnesium sulfate (MgSO4) and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford 3-chloro-5-methylaniline (4.0 g, 97% yield) as a light yellow solid. The structure of the product was confirmed by 1H NMR (500 MHz, CDCl3) and ESI-MS: 1H NMR δ 6.56 (s, 1H), 6.48 (s, 1H), 6.36 (s, 1H), 3.66 (bs, 2H), 2.23 (s, 3H); ESI-MS: m/z 141.7 ([M + H]+).
