反应详情

To an ice-cooled solution of ethyl 4-(piperazin-1-yl)benzoate (2.00 g) and 4-methylcyclohexanone (1.05 ml) in a mixed solvent of methanol (40 ml) and acetic acid (1.47 ml) was added sodium cyanoborohydride (0.59 g) in a stream of nitrogen. The mixture was stirred at this temperature for 1 hour and at room temperature for 17 hours. The reaction mixture was quenched with saturated aqueous sodium hydrogen carbonate solution and the resulting precipitate was collected by filtration, washed thoroughly with water and dried to give a mixture of cis and trans products. This mixture was separated by column chromatography on silica gel eluting with a mixed solvent of methylene chloride-methanol (from 0% to 2% gradient solution) to give ethyl 4-[4-(cis-4-methylcyclohexyl)piperazin-1-yl]benzoate (0.80 g) as a pale green solid and ethyl 4-[4-(trans-4-methylcyclohexyl)piperazin-1-yl]benzoate (0.64 g) as a pale green solid. Trans-product was confirmed by X-ray crystal analysis.

1. customThe reaction mixture was quenched with saturated aqueous sodium hydrogen carbonate solution
2. filtrationthe resulting precipitate was collected by filtration
3. washwashed thoroughly with water
4. customdried
5. customto give
6. additiona mixture of cis and trans products
7. customThis mixture was separated by column chromatography on silica gel eluting with a mixed solvent of methylene chloride-methanol (from 0% to 2% gradient solution)