Step 1: Preparation of 2-iodo-4-methylaniline
To a solution of 4-methylaniline (53.5 g, 500 mmol) in dichloromethane (DCM, 200 mL) was added a solution of sodium bicarbonate (NaHCO3, 50.4 g) in water (500 mL) at room temperature, followed by iodine (I2, 127 g). The reaction mixture was stirred at room temperature overnight. After completion of the reaction, the mixture was treated with aqueous sodium bisulfite (NaHSO3) and extracted with dichloromethane (DCM). The organic layers were combined, washed with brine, dried over anhydrous sodium sulfate (Na2SO4) and concentrated under reduced pressure to give the brown oily product 2-iodo-4-methylaniline (110 g, 95% yield). The product was characterized by 1H NMR (300 MHz, CDCl3): δ 7.48 (dd, J = 1.8 and 0.6 Hz, 1H), 6.96 (dd, J = 8.1 and 1.8 Hz, 1H), 6.67 (d, J = 8.1 Hz, 1H), 3.98 (broad peak, 2H), 2.22 (s, 3H) ppm.
