Ethyl bromoacetate → tert-Butyl 4-(2-ethoxy-2-oxoethyl)piperazine-1-carboxylate
Reaktionsgleichung
[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][NH:11][CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].C(=O)([O-])[O-].[Cs+].[Cs+].Br[CH2:21][C:22]([O:24][CH2:25][CH3:26])=[O:23]>>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([CH2:21][C:22]([O:24][CH2:25][CH3:26])=[O:23])[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]Komponenten
4
Versuchsvorschrift
Piperazine-1-carboxylic acid tert-butyl ester (2.62 g, 14 mmol), cesium carbonate (5 g, 15 mmol) and ethyl bromoacetate (1.56 ml, 14 mmol) was stirred at room temperature for 1 h. The mixture was partitioned between water (200 ml) and diethyl ether (2×100 ml). The combined organic phases were dried over magnesium sulphate and concentrated to give a yellow oil which crystallised to give 4-ethoxycarbonylmethyl-piperazine-1-carboxylic acid tert-butyl ester as a pale yellow solid (2.6 g)