反应详情

Bis(3-phthalimidopropyl)acetic acid (Step B) (2.5 g, 5.5 mmol), proline tert-butyl ester hydrochloride (0.42 g, 2.0 mmol), and N-methylmorpholine (1.19 g, 5.4 mmol) in 7 mL of DMF are cooled to 0° C. and treated with TBTU (0.64 g, 2.0 mmol). The mixture is then stirred at room temperature for 18 hours. The reaction mixture is poured into 70 mL of saturated sodium bicarbonate solution and extracted with two 50 mL portions of ethyl acetate. The combined organics are washed with 1 M KHSO4, saturated aqueous bicarbonate and brine, and dried over Na2SO4. The volatiles are removed under reduced pressure and the residue is chromatographed over silica gel (4:1 chloroform, ethyl acetate eluent) to give 2.88 g of 1-[Bis(3-phthalimidopropyl)acetyl]-proline tert-butyl ester.

1. extractionextracted with two 50 mL portions of ethyl acetate
2. washThe combined organics are washed with 1 M KHSO4, saturated aqueous bicarbonate and brine
3. dry with materialdried over Na2SO4
4. customThe volatiles are removed under reduced pressure
5. customthe residue is chromatographed over silica gel (4:1 chloroform, ethyl acetate eluent)