反应详情

A solution of (R)-3-amino-3-[4-(tert-butoxycarbonylamino)phenyl]-propanoic acid methyl ester [7.2 g, Reference Example 7(c)] in dimethylformamide (30 ml), was treated with acetic anhydride (2.4 ml) and diisopropylethylamine (4.6 ml). After stirring at ambient temperature for 10 minutes the mixture was poured into water (500 ml) and then extracted twice with ethyl acetate (200 ml). The combined organic extracts were washed with brine (200 ml) then dried over magnesium sulphate and then evaporated. The resulting white foam (8.5 g) was dissolved in dichloromethane (75 ml) and the solution was treated with trifluoracetic acid (17 ml). After stirring at ambient temperature for 3 hours the reaction mixture was evaporated. The residue was treated with toluene (70 ml), concentrated to dryness and the resultant material treated with dichloromethane (200 ml). The resultant suspension was treated with saturated aqueous potassium carbonate solution (20 ml) with stirring at ambient temperature for 5 minutes. The organic layer was separated, dried over magnesium sulphate, and then evaporated to give the title compound (4.1 g) as a white foam.

1. extractionextracted twice with ethyl acetate (200 ml)
2. washThe combined organic extracts were washed with brine (200 ml)
3. dry with materialthen dried over magnesium sulphate
4. customevaporated
5. dissolutionThe resulting white foam (8.5 g) was dissolved in dichloromethane (75 ml)
6. additionthe solution was treated with trifluoracetic acid (17 ml)
7. stirringAfter stirring at ambient temperature for 3 hours the reaction mixture
8. customwas evaporated
9. additionThe residue was treated with toluene (70 ml)
10. concentrationconcentrated to dryness
11. additionthe resultant material treated with dichloromethane (200 ml)
12. additionThe resultant suspension was treated with saturated aqueous potassium carbonate solution (20 ml)
13. stirringwith stirring at ambient temperature for 5 minutes
14. customThe organic layer was separated
15. dry with materialdried over magnesium sulphate
16. customevaporated