Example 10 Synthesis of 2-bromo-4-methylbenzonitrile: To a chloroform suspension of 2-bromo-4-methylbenzamide (14.8 g, 69.1 mmol) was added phosphorus pentoxide (24.5 g, 172.8 mmol), and the reaction mixture was refluxed for 12 hours. After completion of the reaction, it was cooled to room temperature and slowly poured into ice water with stirring. The organic layer was separated and the aqueous layer was extracted twice with chloroform (150 mL x 2). The organic phases were combined, washed with saturated brine and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure to give 2-bromo-4-methylbenzonitrile (13.3 g, 98% yield). The product was characterized by 1H NMR (400 MHz, CDCl3): δ 2.41 (s, 3H), 7.20 (d, J=8.0 Hz, 1H), 7.51-7.54 (m, 2H).
