反应详情

To a solution of (2R)-N-benzyloxycarbonylproline (5 g) in CH2Cl2 (50 ml) were added benzoin (4.5 g), 1-ethyl 3-(3-dimethylaminopropyl)carbodiimide (3.9 ml), and dimethylaminopyridine (2.6 g) at room temperature under N2. After being stirred for 12 hours at room temperature, the solvent was evaporated in vacuo, and the residue was partitioned between ethyl acetate and water. The organic layer was washed with 1N-HCl solution, sat. NaHCO3, and brine, dried over MgSO4, and evaporated in vacuo. The obtained compound and CH3COONH4 (8.2 g) were dissolved in acetic acid (50 ml) and the mixture was stirred for 4 hours at 100° C. After the solvent was removed, the residue was partitioned between ethyl acetate and water. The organic layer was washed with water, sat. NaHCO3 and brine. The dried solvent was evaporated in vacuo and the residue was purified by chromatography on silica gel to give (2R)-1-benzyloxycarbonyl-2-(4,5-diphenyloxazol-2-yl)pyrrolidine (4 g). MS (m/z): 425 (M+ +1) IR (Neat): 1700 cm-1NMR (CDCl3, δ): 1.8-2.4 (4H, m), 3.4-3.8 (2H, m) 4.8-5.3 (3H, m), 7.0-7.7 (15H, m)

1. customthe solvent was evaporated in vacuo
2. customthe residue was partitioned between ethyl acetate and water
3. washThe organic layer was washed with 1N-HCl solution, sat. NaHCO3, and brine
4. dry with materialdried over MgSO4
5. customevaporated in vacuo
6. dissolutionThe obtained compound and CH3COONH4 (8.2 g) were dissolved in acetic acid (50 ml)
7. stirringthe mixture was stirred for 4 hours at 100° C
8. customAfter the solvent was removed
9. customthe residue was partitioned between ethyl acetate and water
10. washThe organic layer was washed with water, sat. NaHCO3 and brine
11. customThe dried solvent was evaporated in vacuo
12. customthe residue was purified by chromatography on silica gel