反应详情

温度

65 °C

2-Chloro-4,5-dimethoxybenzaldehyde (5.00 g, 24.9 mmol; commercially available from Akos Consulting) is dissolved at room temperature in conc. H2SO4 (23 mL; Riedel) at room temperature. The deeply colored mixture is heated at 65° C. overnight with stirring, and after cooling is poured with caution into ice-water containing 38 g of solid NaOH (pH 14). The water phase is washed twice with AcOEt, and then is adjusted to pH 1 by addition of HCl 37% with ice-cooling to form a white suspension. Extraction with AcOEt, drying of the organics over MgSO4 and evaporation gives the crude product in a mixture with unreacted starting material. The title compound is obtained after silica gel chromatography (hexane/AcOEt gradient from 3:1 to 1:1) as white solid. TLC, Rf (hexane/AcOEt 1:1)=0.35. MS: 187.0 [M+H]+. ]+. 1H-NMR (DMSO-d6): δ 3.41 (s, 3H), 7.14 (s, 1H), 7.45 (s, 1H), 9.83 (s, 1H), 10.2 (s, 1H) ppm.

1. temperatureafter cooling
2. washThe water phase is washed twice with AcOEt
3. additionis adjusted to pH 1 by addition of HCl 37% with ice-
4. temperaturecooling
5. customto form a white suspension
6. extractionExtraction with AcOEt
7. customdrying of the
8. customorganics over MgSO4 and evaporation
9. customgives the crude product in a mixture