50551-63-8

856357-86-3

50551-63-8

General procedure for the synthesis of 6-methoxybenzofuran from 2-(2-formyl-5-methoxyphenoxy)acetic acid: intermediate 3 (5.1 kg, 24.3 mol), acetic anhydride (10 L) and sodium acetate (3.0 kg, 36.6 mol) were added to a 50 L reactor. The reaction mixture was heated and stirred at 110-130 °C (where large amounts of gas were observed to escape) and the reaction was maintained at 130 °C for 2 hours. Upon completion of the reaction, the mixture was cooled to 60 °C, followed by batchwise addition of ethanol (10 L to quench unreacted acetic anhydride) and continued stirring at 60-80 °C for 2 hours. After cooling the reaction mixture to room temperature, water (10 L) and ethyl acetate (10 L) were added for extraction. The organic phase was separated, washed sequentially with 2N NaOH solution and water and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure to give the colorless liquid product 4 (2.98 kg in 83% yield or 77% yield corrected for purity and 99.6% purity). The structure of the product was confirmed by 1H-NMR (CDCl3, ppm): δ 7.55-7.56 (d, 1H), 7.47-7.49 (d, 1H), 7.07 (s, 1H), 6.90-6.92 (dd, 1H), 6.71-6.72 (d, 1H), 3.88 (s, 3H) [27].