反应详情

To a solution of 10.26 g. of 1-[3-(4-fluorobenzoyl)propionyl]-L-proline (Example 17) in 100 ml. of acetic acid is added 3 drops of 30% hydrogen bromide in acetic acid. A solution of 5.6 g. of bromine in 20 ml. of acetic acid is then added dropwise and the mixture is stirred at room temperature overnight. The mixture is evaporated to 1/3 its volume, poured into ice and water and extracted with dichloromethane. The organic extract is washed twice with water and then with saline, dried over magnesium sulfate and evaporated to dryness in vacuo with moderate heat, giving a white glass. This glass is scraped from the flask giving 12.2 g. of white powder. This powder is dissolved in ethyl acetate-hexane-acetic acid (75:25:2), placed on a 11/2"×20" silica gel column and eluted with the same solvent system, taking 100 ml. cuts with a 300 ml. fore-cut and a 400 ml. hold back volume. Cuts 2, 5 and 6 are combined and re-columned in the same manner. Cut 2 gives the desired product as 2.0 g. of a white glass.

1. customThe mixture is evaporated to 1/3 its volume
2. additionpoured into ice and water
3. extractionextracted with dichloromethane
4. extractionThe organic extract
5. washis washed twice with water
6. dry with materialwith saline, dried over magnesium sulfate
7. customevaporated to dryness in vacuo with moderate heat
8. customgiving a white glass
9. customgiving 12.2 g
10. washeluted with the same solvent system