反应详情

5-Chloro-2-hydroxy-3-methoxy-benzaldehyde (see J. Org. Chem. 56; 1991; 5451; 20.0 g, 107 mmol) was suspended in hydrobromic acid (100 mL of 47% in water). The mixture was refluxed for 6 h and then cooled to room temperature before dilution with water (300 mL). The formed precipitate was collected by filtration and then washed with water. After air drying, the solid material was purified by soaking with CH2Cl2 (4×150 mL). There was obtained 6.0 g (32%) of 5-chloro-2,3-dihydroxybenzaldehyde as a solid. 1H NMR (300 MHz, CDCl3): 5.7 (s, 1H), 7.1 (d, 1H), 7.2 (d, 1H), 9.8 (s, 1H), 11.0 (s, 1H).

1. temperatureThe mixture was refluxed for 6 h
2. filtrationThe formed precipitate was collected by filtration
3. washwashed with water
4. customAfter air drying
5. customthe solid material was purified