反应详情

7-Methoxybenzofuran-4-carboxylic acid (0.50 g) was dissolved in methanol (10 ml), and sulfuric acid (0.6 ml) was dropwise added thereto under ice-cooling, followed by heating under reflux for one hour. Sulfuric acid (0.2 ml) was further added to the mixture followed by heating under reflux for 30 minutes. After being allowed to stand for cooling, the solvent was distilled off, and the residue was poured into a 1N aqueous solution of sodium hydroxide. The precipitate was collected by filtration and dried to give Compound IIw-a (0.53 g, 99%) as a white solid.

1. temperatureunder ice-cooling
2. temperatureby heating
3. temperatureunder reflux for one hour
4. temperatureby heating
5. temperatureunder reflux for 30 minutes
6. temperaturefor cooling
7. distillationthe solvent was distilled off
8. additionthe residue was poured into a 1N aqueous solution of sodium hydroxide
9. filtrationThe precipitate was collected by filtration
10. customdried
11. customto give Compound IIw-a (0.53 g, 99%) as a white solid