Hydrochloric Acid → (S)-Piperazine-2-carboxylic acid dihydrochloride

Participants

Reaction Conditions

Reaction Steps

The crude tert-butyl (S)-piperazine-2-carboxylate from Example 7 was stirred in 2.9 g of water and 2.1 g (18.4 mmol) of 32 percent hydrochloric acid for 20 minutes at 100° C. The mixture was cooled to 0° C. and stirred for a further 1 hour. The hydrochloride which had precipitated out was filtered off and washed with 10 ml of dichloromethane. The yield of the title compound was 0.24 g (41 percent, based on tert-butyl pyrazinecarboxylate). The ee value was 77.6 percent.

Provenance & Evidence