反应详情

温度

70 °C

The starting material is prepared as follows: 4-Phenoxyphenol (20.0 g, 107 mmol) and sodium hydroxide (3.8 g, 845 mmol) are dissolved in a water/ethanol (130 ml/26 ml) mixture and heated at 70° C. To this reaction mixture is added chloroform (24.6 g, 215 mmol) dropwise over 45 minutes, and heating is continued for 3 hours. The mixture is cooled to room temperature, and then evaporated. The aqueous phase is acidified with conc. HCl to pH 1-3, and extracted twice with ether. The extracts are dried (MgSO4) and evaporated. Silica gel chromatography (10% ethyl acetate/hexane) of the residual oil yields 5-phenoxy-2-hydroxybenzaldehyde as a yellow solid, m.p. 54°-55° C., which is converted to 3-(N-hydroxyaminomethyl)-6-phenoxy-2H-1-benzopyran as described under (a).

1. customThe starting material is prepared
2. temperatureheating
3. temperatureThe mixture is cooled to room temperature
4. customevaporated
5. extractionextracted twice with ether
6. dry with materialThe extracts are dried (MgSO4)
7. customevaporated