反应详情

To a solution of ethyl 4-aminobenzoate (1.65 g) in acetic acid (20 mL) is added triethylorthoformate (8 mL) and sodium azide (1.17 g) and the solution is heated at reflux for 4 h. After cooling and removing acetic acid in vacuo, water and dichloromethane are added and the organic layer is separated and dried (MgSO4) and concentrated. The crude ester is dissolved in methanol (30 mL) and 4 M aqueous NaOH solution (3 mL) is added and the solution is stirred at room temperature for 2 h. The mixture is neutralized with 6 M aqueous HCl, concentrated and then acidified with 6 M aqueous HCl. The precipitate is filtered off washing with water and dried by suction to give the title compound.

1. temperaturethe solution is heated
2. temperatureat reflux for 4 h
3. temperatureAfter cooling
4. customremoving acetic acid in vacuo, water and dichloromethane
5. additionare added
6. customthe organic layer is separated
7. dry with materialdried (MgSO4)
8. concentrationconcentrated
9. dissolutionThe crude ester is dissolved in methanol (30 mL)
10. addition4 M aqueous NaOH solution (3 mL) is added
11. concentrationconcentrated
12. filtrationThe precipitate is filtered off
13. washwashing with water
14. customdried by suction