[Synthesis]
(Step 1) To a 25 mL round-bottomed flask was added 1.0 g (4.85 mmol) of 5-(trifluoromethoxy)salicylaldehyde, 8 mL of dimethylformamide (DMF), and 738 mg (5.34 mmol) of potassium carbonate, and the mixture was stirred at room temperature for 30 min. Subsequently, 758 mg (5.34 mmol) of iodomethane dissolved in 2 mL of DMF was slowly added dropwise to the reaction system under ice bath cooling conditions. After the dropwise addition, stirring was continued under ice bath conditions for 1 h. The ice bath was then withdrawn and the reaction mixture was allowed to stir for 19 h at room temperature. Upon completion of the reaction, 20 mL of ethyl acetate and 20 mL of water were added to the mixture and the organic layer was separated by shaking thoroughly. The aqueous layer was extracted again with 20 mL of ethyl acetate and all organic layers were combined. The organic phase was sequentially washed twice with 20 mL of water and then twice with 20 mL of saturated saline. Finally, the organic layer was dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give 1.0 g of 2-methoxy-5-(trifluoromethoxy)benzaldehyde in 93% yield. The product was characterized by 1H-NMR (CDCl3): δ 3.96 (s, 3H), 7.02 (d, 1H, J = 8.8 Hz), 7.41 (d, 1H, J = 9.2 Hz), 7.69 (s, 1H), 10.44 (s, 1H). |