反应详情

温度

20 °C

A solution of 29 g of p-fluorobenzyl chloride in 50 g of reagent ethanol was added dropwise to a stirred solution of 34.5 g of piperazine in 150 g of reagent ethanol. A cold water bath was used to maintain the reaction temperature at 20° C. during the addition. The reaction mixture was stirred for an additional 11/2 hours and then added to 2 liters of ether. Precipitated piperazine hydrochloride was filtered off. The filtrate was concentrated to an oil, which was chromatographed on a silica column, the eluant being a mixture of CH2Cl2 /methanol/ammonium hydroxide in the ratio of 45:5:1. After concentration of appropriate fractions, 21.7 g of 1-(4-fluorobenzyl)piperazine were isolated as a colorless liquid (56% of theory).

1. customA cold water bath was used
2. additionduring the addition
3. filtrationPrecipitated piperazine hydrochloride was filtered off
4. concentrationThe filtrate was concentrated to an oil, which
5. customwas chromatographed on a silica column
6. additiona mixture of CH2Cl2 /methanol/ammonium hydroxide in the ratio of 45:5:1