反应详情

The isatin from step (a) was refluxed with 150 mL of 10% potassium hydroxide under a nitrogen atmosphere. After 4 hours, the reaction was cooled to room temperature and filtered. The filtrate was diluted with water (150 mL) and ice. This solution was then acidified with concentrated HCl. A yellow precipitate separated out which was collected by filtration and rinsed with cold water and ether. After air drying, the precipitate was transferred to a round-bottom flask with methanol and evaporated to dryness. The resulting residue was evaporated to dryness twice from toluene and was obtained as a yellowish brown powder. Yield=1.15 g (26%).

1. filtrationfiltered
2. additionThe filtrate was diluted with water (150 mL) and ice
3. customA yellow precipitate separated out which
4. filtrationwas collected by filtration
5. washrinsed with cold water and ether
6. customAfter air drying
7. customthe precipitate was transferred to a round-bottom flask with methanol
8. customevaporated to dryness
9. customThe resulting residue was evaporated to dryness twice from toluene
10. customwas obtained as a yellowish brown powder