Pyridine → Tert-butyl 4-(chlorocarbonyl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence