[Synthesis]
The general procedure for the synthesis of 4-chloro-2-trifluoromethylbenzaldehyde using 2-trifluoromethyl-4-chlorobenzonitrile as a starting material was as follows: 2-trifluoromethyl-4-chlorobenzonitrile (appropriate amount) was added to a mixed solution of formic acid (96%, 15 mL) and water (3 mL). Nickel-aluminum alloy (1260 mg) was then added. The reaction mixture was heated and reacted at 100 °C overnight. Upon completion of the reaction, the reaction mixture was diluted with ethyl acetate and filtered through diatomaceous earth to remove solid impurities. The filtrate was sequentially extracted with 1N sodium hydroxide solution and saturated aqueous sodium chloride solution. The organic phase was dried with anhydrous sodium sulfate, filtered and concentrated to give 4-chloro-2-trifluoromethylbenzaldehyde (555 mg, 87% yield). The product was characterized by 1HNMR (400 MHz, MeOH-d4): δ 10.29 (m, 1H), 8.10 (d, 1H, J = 8.4 Hz), 7.91 (d, 1H, J = 1.6 Hz), 7.85 (dd, 1H, J = 8.4,1.6 Hz). |