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

Participants

Reaction Conditions

Reaction Steps

A solution of piperazine-1-carboxylic acid tert-butyl ester (4.0 g, 22 mmol) in methylene chloride (40 mL) at 0° C. was treated with pyridine (2.65 ml, 33 mmol) and triphosgene (3.2 g, 10.8 mmol). The resulting yellow solution was stirred at 25° C. for 1 h. At this time, the reaction mixture was partitioned between methylene chloride (200 mL) and a 1N aqueous hydrochloric acid solution (75 mL). The organics were dried over magnesium sulfate and concentrated in vacuo to afford 4-chlorocarbonyl-piperazine-1-carboxylic acid tert-butyl ester (4.73 g, 89%) as a yellow solid. This material was used in the next step without further purification

Provenance & Evidence