5-(4-Methylphenyl)-2-furoic acid

52939-04-5

52938-98-4

Step 3: Accurately weigh 310 mg (1.11 mmol) of the intermediate methyl 4-(4-methoxyphenyl)furan-2-carboxylate and add it slowly dropwise to a 5 mL methanol mixture containing 1 mL of 4 mol/L NaOH solution and heat to reflux for 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and concentrated to dryness under reduced pressure. The pH was adjusted to about 1 with 10% dilute hydrochloric acid and subsequently extracted three times with ethyl acetate. The organic phases were combined, washed twice with saturated sodium chloride solution, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give 290 mg of the intermediate 5-(4-methoxyphenyl)furan-2-carboxylic acid in 100% yield.