反应详情

To a solution of piperazine-1-carboxylic acid tert-butyl ester (4.00 g, 21.5 mmol) in dry dichloroethane (70 mL) are added 3-chlorobenzaldehyde (2.49 mL, 3.08 g, 21.9 mmol), HOAc (2.58 mL, 2.71 g, 45.1 mmol) and NaBH(OAc)3 (5.46 g, 25.8 mmol) at ambient temperature. After stirring at ambient temperature for 3d, 2N NaOH (40 mL) is added, the layers are separated, and the aqueous layer is extracted with CH2Cl2 (4×50 mL). The combined organic extracts are washed with water (3×50 mL) and brine (80 mL) and dried over MgSO4. The crude material is purified by chromatography on silica gel, eluting with hexane:EtOAc mixtures, yielding 5.83 g (18.8 mmol, 87%) of the title compound as yellow oil. MS (ES): m/z 311.0/313.0 (50/18) [MH+]. tR (method A)=5.0 min.

1. additionis added
2. customthe layers are separated
3. extractionthe aqueous layer is extracted with CH2Cl2 (4×50 mL)
4. washThe combined organic extracts are washed with water (3×50 mL) and brine (80 mL)
5. dry with materialdried over MgSO4
6. customThe crude material is purified by chromatography on silica gel
7. washeluting with hexane