反应详情

To an ice-cold solution of the product of step (a) (6.9 g) and triethylamine (3.64 ml) in dichloromethane (100 ml) was added, with stirring, dropwise over 15 minutes a solution of butanesulphonyl chloride (4.1 g) in dichloromethane (10 ml). The reaction mixture was stirred at low temperature for 2 hours and then at ambient temperature for a further 2 hours. The solvents were removed in vacuo and the residue was partitioned between ethyl acetate (100 ml) and water (100 ml). The organic layer was separated and washed with water, dilute KHSO4 (aq.), dilute NaHCO3 (aq.), brine, dried (MgSO4) and evaporated. The solid residue was collected and washed with hexane containing a small volume of ether to give t-butyl (2S)-2-(n-butylsulphonylamino)-3-(4-nitrophenyl)propionate (6.65 g) as an off-white solid: NMR Spectrum (CDCl3) 0.90 (3H, t), 1.36 (2H, m), 1.45 (9H, s), 1.68 (2H, m), 2.88 (2H, m), 3.18 (2H, m), 4.28 (1H, m), 5.01 (1H, d), 7.43 (2H, d), 8.19 (2H, d).

1. waitat ambient temperature for a further 2 hours
2. customThe solvents were removed in vacuo
3. customthe residue was partitioned between ethyl acetate (100 ml) and water (100 ml)
4. customThe organic layer was separated
5. washwashed with water, dilute KHSO4 (aq.), dilute NaHCO3 (aq.), brine
6. dry with materialdried (MgSO4)
7. customevaporated
8. customThe solid residue was collected
9. washwashed with hexane containing a small volume of ether