反应详情

393 mg (1 mmole) of 4-(2,6-dichloroanilino)-3-thiophenacetic acid benzyl ester are subjected to hydrogenolysis (in a mixture of 100 ml of ethyl acetate and 10 ml of glacial acetic acid in a circulatory hydrogenation apparatus in the presence of 50 mg of 10 percent strength palladium-on-active charcoal at room temperature and under atmospheric pressure) until the theoretical amount of hydrogen has been taken up. The catalyst is filtered off, the filtrate is concentrated in vacuo, and the residue is dissolved in 1 N sodium hydroxide solution. The aqueous solution is extracted with toluene, and the product phase is acidified with 1 N hydrochloric acid and extracted again with toluene. The organic phase is dried and concentrated. 4-(2,6-Dichloroanilino)-3-thiophenacetic acid (m. 179° to 180°) is obtained.

1. filtrationThe catalyst is filtered off
2. concentrationthe filtrate is concentrated in vacuo
3. dissolutionthe residue is dissolved in 1 N sodium hydroxide solution
4. extractionThe aqueous solution is extracted with toluene
5. extractionextracted again with toluene
6. customThe organic phase is dried
7. concentrationconcentrated