反应详情

温度

90 °C

(2R)-1,2-Dibenzyl-4-methanesulfonylpiperazine (2.2 g; 6.4 mmol) was dissolved in dry 1,2-dichloroethane (20 ml) under an atmosphere of nitrogen. The mixture was placed on an ice-bath and a solution of α-chloroethyl chloroformate (1.0 g; 7.04 mmol) in dry 1,2-dichloroethane (10 ml) was added keeping the temperature between 0 and 5° C. When addition is complete stirring is continued for 15 minutes on the ice-bath. The reaction mixture is heated slowly to 90° C. on an oil-bath and heated at reflux temperature for 1 h. The major part of the solvent was allowed to evaporate and the residue was allowed to cool on an ice-bath. Methanol (20 ml) was added and the mixture was heated at reflux temperature for 1 h. The mixture was allowed to cool to ambient temperature, diethyl ether (30 ml) was slowly added and the mixture was stirred for 30 minutes. The solid was isolated by filtration, washed with diethyl ether, and dried to give 0.78 g of (3R)-3-benzyl-1-methanesulfonylpiperazine hydrochloride. M.p. 204-208° C.

1. customThe mixture was placed on an ice-bath
2. customthe temperature between 0 and 5° C
3. additionWhen addition
4. temperatureheated
5. temperatureat reflux temperature for 1 h
6. customto evaporate
7. temperatureto cool on an ice-bath
8. additionMethanol (20 ml) was added
9. temperaturethe mixture was heated
10. temperatureat reflux temperature for 1 h
11. temperatureto cool to ambient temperature
12. additiondiethyl ether (30 ml) was slowly added
13. stirringthe mixture was stirred for 30 minutes
14. customThe solid was isolated by filtration
15. washwashed with diethyl ether
16. customdried