Triethylamine → 4-nitrophenyl 4-(2,4-difluorophenyl)tetrahydro-1(2H)-pyrazinecarboxylate

Participants

Reaction Conditions

Reaction Steps

1-(2,4-Difluoro-phenyl)-piperazine (3.70 g, 18.9 mmol) and triethylamine (2.8 mL, 19.8 mmol) were dissolved in anhydrous THF (30 mL) under nitrogen and the reaction mixture was cooled to 0° C. 4-Nitrophenyl chloroformate (3.8 g, 18.9 mmol), dissolved in anhydrous THF (25 mL), was added dropwise and the reaction mixture was stirred at room temperature overnight. The solvent was removed in vacuo and the residue triturated with water, and then filtered. The yellow solid was recrystallised from a mixture of hexane and toluene(3:7) using charcoal to give 4-(2,4-difluorophenyl)-piperazine-1-carboxylic acid 4-nitrophenyl ester (4.3 g, 63%) as a yellow crystalline solid.

Provenance & Evidence