Pyridine → Tert-butyl 4-(chlorocarbonyl)piperazine-1-carboxylate
Reaction equation
[Cl:1][C:2](Cl)([O:4]C(=O)OC(Cl)(Cl)Cl)Cl.[N:13]1([C:19]([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20])[CH2:18][CH2:17][NH:16][CH2:15][CH2:14]1.N1C=CC=CC=1>ClCCl>[Cl:1][C:2]([N:16]1[CH2:17][CH2:18][N:13]([C:19]([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20])[CH2:14][CH2:15]1)=[O:4]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
Triphosgene (25 g, 84.2 mmol) was taken into dichloromethane (200 mL) and the resulting solution cooled to 0° C. A solution of tert-butyl 1-piperazinecarboxylate (40 g, 214.8 mmol) and pyridine (35 mL, 432.7 mmol) in dichloromethane (100 mL) was then added dropwise to the triphosgene solution and the reaction mixture was allowed to warm to room temperature over 30 minutes. The mixture was then quenched by addition of aqueous hydrochloric acid (0.1N, 200 mL) and the aqueous phase washed with dichloromethane (50 mL) followed by drying the combined organic layers over anhydrous magnesium sulfate. Filtration and concentration in vacuo gave tert-butyl 4-chlorocarbonyl-1-piperazinecarboxylate (45.6 g, 85%) as a yellow solid which may be used without further purification. The material can be purified further by crystallization from ethyl ether/hexane.
Workup
- temperatureto warm to room temperature over 30 minutes
- customThe mixture was then quenched by addition of aqueous hydrochloric acid (0.1N, 200 mL)
- washthe aqueous phase washed with dichloromethane (50 mL)
- dry with materialby drying the combined organic layers over anhydrous magnesium sulfate
- filtrationFiltration and concentration in vacuo
Sources & evidence
- ORD record
- ord-606e513eb130421db16798abb51355d3
- Source dataset
- uspto-grants-2000_02
- Patent number
- US06022969
Reaction notes
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