反应详情

The starting material is prepared as follows: A mixture of 5-phenoxysalicylaldehyde (6.52 g, 30.4 mmol), crotonaldehyde (3.2 g, 45.7 mmol) and potassium carbonate (8.41 g, 60.9 mmol) in 100 ml of 1,4-dioxane is heated at reflux for 2 hours. The mixture is cooled, diluted with water, and extracted three times with dichloromethane. The combined organic layers are dried (MgSO4) and evaporated. Purification by flash chromatography (silica gel, 7% ethyl acetate/hexane) yields 6-phenoxy-2-methyl-2H-1-benzopyran-3-carboxaldehyde which is converted to 6-phenoxy-2-methyl-3-(N-hydroxyaminomethyl)-2H-1-benzopyran as described above.

1. customThe starting material is prepared
2. temperatureis heated
3. temperatureat reflux for 2 hours
4. temperatureThe mixture is cooled
5. extractionextracted three times with dichloromethane
6. dry with materialThe combined organic layers are dried (MgSO4)
7. customevaporated
8. customPurification by flash chromatography (silica gel, 7% ethyl acetate/hexane)