反应详情

To a solution of ethyl 3-hydroxy-4-nitrobenzoate (3.56 g) in ethyl acetate (100 mL) was added 10% palladium/carbon (600 mg), and the mixture was stirred under hydrogen atmosphere for 5 hr. Insoluble material was removed by filtration, and the filtrate was concentrated under reduced pressure. To a solution of the residue in methanol (100 mL) were added benzaldehyde (1.50 mL) and sodium sulfate (1.00 g), and the mixture was stirred at 45° C. for 16 hr. Insoluble material was removed by filtration, and the filtrate was concentrated under reduced pressure. To a solution of the residue in methylene chloride (100 mL) was added 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (4.21 g), and the mixture was stirred at room temperature for 30 min. Saturated aqueous sodium hydrogen carbonate solution (300 mL) was added to the reaction mixture, and the mixture was extracted with chloroform (100 mL×2). The organic layer was washed with saturated brine. After concentration under reduced pressure, the residue was purified by silica gel column chromatography to give the title compound (3.60 g) as a pale-yellow solid.

1. customInsoluble material was removed by filtration
2. concentrationthe filtrate was concentrated under reduced pressure
3. additionTo a solution of the residue in methanol (100 mL) were added benzaldehyde (1.50 mL) and sodium sulfate (1.00 g)
4. stirringthe mixture was stirred at 45° C. for 16 hr
5. customInsoluble material was removed by filtration
6. concentrationthe filtrate was concentrated under reduced pressure
7. additionTo a solution of the residue in methylene chloride (100 mL) was added 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (4.21 g)
8. stirringthe mixture was stirred at room temperature for 30 min
9. additionSaturated aqueous sodium hydrogen carbonate solution (300 mL) was added to the reaction mixture
10. extractionthe mixture was extracted with chloroform (100 mL×2)
11. washThe organic layer was washed with saturated brine
12. concentrationAfter concentration under reduced pressure
13. customthe residue was purified by silica gel column chromatography