反应详情

three-necked flask, equipped with a mechanical stirrer, a thermometer and a dropping funnel was charged with 159.5 g (0.56 mol) of crude alpha-acetamido-6-methylindole-3-acrylic acid ethylester and 475 ml of methanol. The mixture was heated in an oil bath to 50°. A solution of 66.8 g (1.67 mol) of sodium hydroxide in 320 ml of water was added over 3 minutes and the resulting brown solution was stirred at 50° for 45 minutes. The reaction mixture was cooled with an ice bath to 25° and 600 ml of 4-N hydrochloric acid was added over 20 minutes at 25°. The precipitate was collected on a Buchner funnel, washed with 900 ml of water and dried at 50° overnight and at 60°/0.5 mm for 3 hours. The beige solid (146 g) was dissolved in 1 1 of methanol and 175 ml of dimethylformamide at reflux. 10 g of charcoal was added and reflux was continued for 10 minutes. The mixture was filtered through a bed of Celite and the clear brown solution was brought again to reflux. 425 ml of water was added over a 20 minute period, while reflux was maintained. The mixture was refrigerated for 3 hours. The product was collected by suction filtration, washed with 750 ml of 1:1 methanol - water and dried at 50° for 24 hours (const. weight) to yield 119.9 g (69%, based on 6-methylindole-3-carboxaldehyde of product as yellow crystals, m.p. 229° (dec.).

1. customthree-necked flask, equipped with a mechanical stirrer
2. temperatureThe mixture was heated in an oil bath to 50°
3. temperatureThe reaction mixture was cooled with an ice bath to 25°
4. customThe precipitate was collected on a Buchner funnel
5. washwashed with 900 ml of water
6. customdried at 50° overnight and at 60°/0.5 mm for 3 hours
7. dissolutionThe beige solid (146 g) was dissolved in 1 1 of methanol and 175 ml of dimethylformamide
8. temperatureat reflux
9. addition10 g of charcoal was added
10. temperaturereflux
11. waitwas continued for 10 minutes
12. filtrationThe mixture was filtered through a bed of Celite
13. temperatureto reflux
14. addition425 ml of water was added over a 20 minute period
15. temperaturewhile reflux
16. temperaturewas maintained
17. waitThe mixture was refrigerated for 3 hours
18. filtrationThe product was collected by suction filtration
19. washwashed with 750 ml of 1:1 methanol - water
20. customdried at 50° for 24 hours (const. weight)
21. customto yield 119.9 g (69%