Hydrochloric Acid → 1-[(4-Chlorophenyl)(phenyl)methyl]piperazine--hydrogen chloride (1/2)

Participants

Reaction Conditions

Reaction Steps

To a solution prepared by introducing 7.78 g (213.3 mmol) of hydrogen chloride gas in 45.9 g of ethyl acetate, 176.0 g of a solution containing the obtained (+)-1-[(4-chlorophenyl)phenylmethyl]-4-(tert-butoxycarbonyl)piperazine (optical purity 98.0% ee) was added dropwise at 20° C. over 1 hour. After stirring at that temperature, the mixture was heated up to 60° C. for 30 minutes and was stirred at this temperature for 3 hours. After cooling to 20° C., the crystals formed were collected by filtration and were washed with toluene. The crystals obtained were dried under reduced pressure to yield 8.51 g (23.7 mmol) of (+)-1-[(4-chlorophenyl)phenylmethyl]piperazine dihydrochloride from the (+)-1-[(4-chlorophenyl)phenylmethyl]-4-(tert-butoxycarbonyl)piperazine-2D-(−)-O,O′-dibenzoyltartaric acid salt in a yield of 88.1%. The optical purity of the (+)-1-[(4-chlorophenyl)phenylmethyl]piperazine in the crystals was 98.4% ee.

Provenance & Evidence