General procedure for the synthesis of 2,4-dichloro-5-methoxyaniline from N-(2,4-dichloro-5-methoxyphenyl)acetamide: N-(2,4-dichloro-5-methoxyphenyl)acetamide (100.7 g, 0.43 mol) was suspended in a mixture of ethanol (500 g), water (500 g), and concentrated hydrochloric acid (300 g, 3 mol), stirred and heated to 70 °C and the reaction lasted for 12 h to obtain a brown solution. After completion of the reaction, ethanol (about 200 g) was evaporated under reduced pressure and the remaining mixture was stirred and cooled to room temperature. After standing for 2 h, the precipitated solid was collected by filtration, washed with water (2 x 200 g) and dried under vacuum at 35 °C to afford 2,4-dichloro-5-methoxyaniline (69.4 g, 84% yield) as a light tan solid with a melting point of 49.5-51.1 °C (literature value 50.5-51.5 °C). The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6) and mass spectrometry (EI): 1H NMR δ= 3.76 (s, 3H), 5.13 (br s, 2H), 6.58 (s, 1H), 7.23 (s, 1H); mass spectrum (EI) m/z (relative abundance) = 191 (100).
