反应详情

温度

80 °C

Water (80 mL) was added to the crude crystals of 2-bromo-4,5-dimethoxybenzoic acid produced in Example 1 (20.0 g) and sodium carbonate (10.1 g). The resultant mixture was stirred under heating at 80° C., and a copper sulfate solution prepared from copper sulfate pentahydrate (1.91 g), water (20 mL), and pyridine (3.1 mL) was added to the mixture. The resultant mixture was further heated and stirred at 90 to 100° C. for one hour. The mixture was cooled to 50° C., and concentrated hydrochloric acid (16.0 g) was added dropwise thereto. After cooling of the mixture, the precipitated crystals were filtrated, and then dried under reduced pressure, to thereby produce crude crystals of 2-hydroxy-4,5-dimethoxybenzoic acid (15.08 g) (yield: 99.3%).

1. additionwas added to the mixture
2. temperatureThe mixture was cooled to 50° C.
3. temperatureAfter cooling of the mixture
4. filtrationthe precipitated crystals were filtrated
5. customdried under reduced pressure