反应详情

(RS)-2-amino-2-phenylpropanoic acid (20 g, 0.12 mol) in 88% formic acid (220 mL) was reacted with acetic anhydride (100 mL) at such rate as to keep the internal temperature at 60-65° C. After the final addition, the reaction was stirred until the internal temperature dropped to 35° C., and then concentrated. The solid residue was dried by azeotroping with toluene. The solid residue was dissolved in hot ethanol (70 mL), treated with active charcoal (0.5 g), and filtered. Hot water (210 mL) was added with stirring to the hot filtrate. The mixture was cooled in the refrigerator for 3 days. The resulting crystals was collected by filtration, washed with cold EtOH/water (1:3), and dried at 60° C. for 4 hours to give the title compound as colorless crystal. (17.8 g, 76%).

1. customat 60-65° C
2. additionAfter the final addition
3. additiondropped to 35° C.
4. concentrationconcentrated
5. customThe solid residue was dried
6. customby azeotroping with toluene
7. dissolutionThe solid residue was dissolved in hot ethanol (70 mL)
8. additiontreated with active charcoal (0.5 g)
9. filtrationfiltered
10. additionHot water (210 mL) was added
11. stirringwith stirring to the hot filtrate
12. temperatureThe mixture was cooled in the refrigerator for 3 days
13. filtrationThe resulting crystals was collected by filtration
14. washwashed with cold EtOH/water (1:3)
15. customdried at 60° C. for 4 hours