反应详情

To a suspension of 160 mg (0.74 mmol) of rac-5-amino-2-propylpentanoic acid 1,1-dimethylethyl ester (8) in 1 mL of water and 1 mL of dichloromethane, 153 mg (0.76 mmol) of 4-nitrophenylchloroformate and 267 mg of sodium bicarbonate were added at 0° C. The mixture was stirred at room temperature overnight and then diluted with 50 mL of dichloromethane and 30 mL of water. The organic part was separated. The aqueous part was extracted with 2×50 mL of dichloromethane. The organic parts were combined and washed with 2×50 mL of 5% sodium bicarbonate followed by 50 mL of water, dried over MgSO4 and concentrated. The residue was purified by preparative thin layer chromatography using 1:1 ethyl acetate:hexane as the eluent to yield 185 mg (0.48 mmol, 66%) of rac-5-[[(4-nitrophenoxy)carbonyl]amino]-2-propyl]pentanoic acid 1,1-dimethylethyl ester (9) asan offwhite solid. NMR, IR and MS data confirmed compound identity.

1. additionwere added at 0° C
2. customThe organic part was separated
3. extractionThe aqueous part was extracted with 2×50 mL of dichloromethane
4. washwashed with 2×50 mL of 5% sodium bicarbonate
5. dry with materialdried over MgSO4
6. concentrationconcentrated
7. customThe residue was purified by preparative thin layer chromatography