反应详情

(3R)-3-Benzylpiperazin-2-one (4.1 g; 21.6 mmol, prepared as described in Example 1) was dissolved in methanol (40 ml). Benzaldehyde (2.3 g; 21.6 mmol) was added followed by 4 Å molsieves (2 g) and the mixture was stirred under an atmosphere of nitrogen for 1/2 h. Acetic acid (1.2 ml) was added and sodium cyanoborohydride (2.0 g; 32.4 mmol) was added portion wise during 20 minutes. The reaction mixture was stirred overnight and the filtered. From the filtrate the solvent was evaporated and the residue was dissolved into ethyl acetate (15 ml) and purified on silica gel using ethyl acetate as eluent. This afforded 2.6 g of (3R)-3,4-dibenzylpiperazin-2-one.

1. stirringThe reaction mixture was stirred overnight
2. customFrom the filtrate the solvent was evaporated
3. dissolutionthe residue was dissolved into ethyl acetate (15 ml)
4. custompurified on silica gel