反应详情

0.436 g (19 mmol) of sodium is dissolved in 20 ml of ethanol. Then 9.78 g (19 mmol) of 3-hydroxy-2,4,6-triiodobenzamide and subsequently 3.5 g (21 mmol) of ethyl bromoacetate are added thereto. The mixture is heated for one hour to reflux and, after several hours of stirring in an ice bath, the resultant 3-carbamoyl-2,4,6-triiodophenoxyacetic acid ethyl ester is vacuum-filtered, washed with a small amount of ice-cold ethanol, and suspended in 80 ml of water. The mixture is brought to pH 12 by adding concentrated sodium hydroxide solution, stirred for 30 minutes at 60° C., the solution is treated with 1 g of active carbon, filtered, and brought to pH 1 by the dropwise addition of dilute hydrochloric acid. After several hours of stirring in an ice bath, the thus-formed precipitate is vaccum-filtered, washed with water, and dried, thus obtaining 10.2 g (89% of theory) of 3-carbamoyl-2,4,6-triiodophenoxyacetic acid as a white powder, mp 211°-213° C. (decomposition).

1. temperatureThe mixture is heated for one hour
2. temperatureto reflux and, after several hours
3. filtrationthe resultant 3-carbamoyl-2,4,6-triiodophenoxyacetic acid ethyl ester is vacuum-filtered
4. washwashed with a small amount of ice-cold ethanol
5. additionby adding concentrated sodium hydroxide solution
6. stirringstirred for 30 minutes at 60° C.
7. additionthe solution is treated with 1 g of active carbon
8. filtrationfiltered
9. additionbrought to pH 1 by the dropwise addition of dilute hydrochloric acid
10. stirringAfter several hours of stirring in an ice bath
11. filtrationthe thus-formed precipitate is vaccum-filtered
12. washwashed with water
13. customdried