反应详情

To a solution of 2-methoxycarbonyl-6-nitrobenzoic acid (22.5 g, 0.1 mol) in methanol (100 mL) was added 10% palladium-carbon (2.0 g, 50% hydrate), and the mixture was stirred at room temperature under hydrogen atmosphere for 1 hour. The catalyst was removed by filtration, and the filtrate was concentrated under reduced pressure, and the residue was dissolved in acetone (100 mL). To the solution was added dropwise diketene (23 mL, 0.30 mol) at room temperature. After the mixture was stirred at room temperature for 16 hours, the solution was concentrated under reduced pressure. The resulting crude crystals were collected by filtration, washed with acetone and diethylether, and air dried (15.4 g). The crude crystals were suspended in a mixture of acetic anhydride (10.4 mL, 0.11 mol) and tetrahydrofuran (60 mL), and the suspension was heated under reflux for 12 hours. The suspension was allowed to cool to room temperature, and the solvents were evaporated under reduced pressure to give crude crystals. The crystals were collected by filtration, washed with diethylether, and air dried to give the title compound (8.03 g, 31% yield).

1. customThe catalyst was removed by filtration
2. concentrationthe filtrate was concentrated under reduced pressure
3. dissolutionthe residue was dissolved in acetone (100 mL)
4. stirringAfter the mixture was stirred at room temperature for 16 hours
5. concentrationthe solution was concentrated under reduced pressure
6. filtrationThe resulting crude crystals were collected by filtration
7. washwashed with acetone and diethylether, and air
8. customdried (15.4 g)
9. temperaturethe suspension was heated
10. temperatureunder reflux for 12 hours
11. temperatureto cool to room temperature
12. customthe solvents were evaporated under reduced pressure
13. customto give crude crystals
14. filtrationThe crystals were collected by filtration
15. washwashed with diethylether, and air
16. customdried