Example 12 Preparation of 4-bromo-3-(trifluoromethyl)benzaldehyde (C70): to a solution of (4-bromo-3-(trifluoromethyl)phenyl)methanol (C72) (12.0 g, 47.1 mmol) in dichloromethane (100 mL) was added manganese dioxide (25.6 g, 294 mmol). The reaction mixture was stirred at room temperature for 12 hours before being filtered through a Celite pad to remove solid impurities. The filtrate was concentrated under reduced pressure to afford 3-trifluoromethyl-4-bromobenzaldehyde as a light yellow solid (10.0 g, 82% yield). The product was characterized by the following data: 1H NMR (300 MHz, CDCl3) δ10.05 (s, 1H), 8.19 (s, 1H), 7.94-7.88 (m, 2H); IR (thin film) 1704, 1123 cm-1; EIMS m/z 219 ([M]+).
