反应详情

To a solution of 5.8 g of 1-(2,6-dichlorophenyl)indole-2,3-dione (m.p. 174°-175° C.) in 40 ml of ethanol were added 22 ml of a 1 N aqueous sodium hydroxide solution and the resulting mixture was stirred at room temperature for 1 hour. The reaction mixture was concentrated at a bath temperature of not more than 40° C. under a reduced pressure of 5 mmHg. To the residue were added 50 ml of water and the mixture was extracted with 30 ml of ether. The ether extract was separated out. The remaining aqueous layer was acidified with a 5% aqueous hydrochloric acid solution under ice-cooling and the solid thus precipitated was extracted with ether. The ether extract was washed with water and dried over sodium sulfate and concentrated at 10 mmHg without heating. The residue was recrystallized from dichloromethane-hexane to give 6.0 g of 2-(2,6-dichloroanilino)phenylglyoxylic acid as a yellow powder. m.p. 159°-159.5° C. Yield: 97% of theoretical amount

1. concentrationThe reaction mixture was concentrated at a bath temperature of not more than 40° C. under a reduced pressure of 5 mmHg
2. additionTo the residue were added 50 ml of water
3. extractionthe mixture was extracted with 30 ml of ether
4. extractionThe ether extract
5. customwas separated out
6. temperaturecooling
7. customthe solid thus precipitated
8. extractionwas extracted with ether
9. extractionThe ether extract
10. washwas washed with water
11. dry with materialdried over sodium sulfate
12. concentrationconcentrated at 10 mmHg
13. temperaturewithout heating
14. customThe residue was recrystallized from dichloromethane-hexane