反应详情

A mixture of 2-piperazinecarboxylic acid dihydrochloride (5.06 g, 0.025 mol), ethanol (100 ml) and concentrated sulphuric acid (6.0 ml) was heated at reflux temperature for 6 days. Toluene (10 ml) was added, and the resulting mixture was concentrated in vacuo to 2/3 of its original volume. Cold, saturated aqueous potassium carbonate (80 ml) was added and the mixture was extracted with toluene (3×100 ml). The combined organic extracts were washed with brine (30 ml), dried (MgSO4) and concentrated in vacuo, affording 1.0 g (26%) of 2-piperazinecarboxylic acid ethyl ester as an oil. The oil crystallised upon standing at room temperature.

1. temperaturewas heated
2. temperatureat reflux temperature for 6 days
3. concentrationthe resulting mixture was concentrated in vacuo to 2/3 of its original volume
4. additionCold, saturated aqueous potassium carbonate (80 ml) was added
5. extractionthe mixture was extracted with toluene (3×100 ml)
6. washThe combined organic extracts were washed with brine (30 ml)
7. dry with materialdried (MgSO4)
8. concentrationconcentrated in vacuo