A. Synthesis of 4-methyl-3-nitrobenzonitrile. Nitric acid (20 mL) was slowly added dropwise to a mixture of 4-methylbenzonitrile (11 g, 0.098 mol) with concentrated sulfuric acid (20 mL) over a period of 1 hour at 0°C. After the dropwise addition was completed, the reaction mixture was continued to be stirred at 0°C for 1 hour. Subsequently, the reaction mixture was carefully poured into crushed ice to quench the reaction. The precipitate precipitated was collected by filtration to afford 4-methyl-3-nitrobenzonitrile (15.2 g, 95% yield) as a white solid. The product was characterized by 1H NMR (500 MHz, CDCl3): δ 8.27 (d, J = 1.6 Hz, 1H), 7.78 (dd, J = 8.0,1.7 Hz, 1H), 7.51 (d, J = 8.0 Hz, 1H), 2.69 (s, 3H).
