tert-Butyl piperazine-1-carboxylate → tert-Butyl 4-(2-isocyanoacetyl)piperazine-1-carboxylate
Reaction equation
[N+:1]([CH2:3][C:4]([O:6]C)=O)#[C-:2].[C:8]([O:12][C:13]([N:15]1[CH2:20][CH2:19][NH:18][CH2:17][CH2:16]1)=[O:14])([CH3:11])([CH3:10])[CH3:9]>>[N+:1]([CH2:3][C:4]([N:18]1[CH2:17][CH2:16][N:15]([C:13]([O:12][C:8]([CH3:11])([CH3:10])[CH3:9])=[O:14])[CH2:20][CH2:19]1)=[O:6])#[C-:2]Participants
3
Procedure
Prepared in accordance with Method B with methyl isocyanoacetate (2.51 g, 25.29 mmol) and piperazine-1-carboxylic acid tert-butyl ester (6.28 g, 33.85 mmol. The reaction mixture was stirred 1 h at RT and then concentrated. The residue was dissolved in dichloromethane (50 mL) and the organic layer was washed with 10% aqueous citric acid (2×25 mL), dried over MgSO4, filtered and evaporated. tert-Butyl 4-(2-isocyanoacetyl)piperazine-1-carboxylate SLA 07116C was obtained as a colorless oil (0.41 g, 6.5% yield).
Workup
- concentrationconcentrated
- dissolutionThe residue was dissolved in dichloromethane (50 mL)
- wash