Diisopropylethylamine → (1-Piperidin-4-yl)methyl 4-(4-chlorophenyl)piperazine-1-carboxylate

Participants

Reaction Steps

(1-(tert-Butoxycarbonyl)piperidin-4-yl)methyl 4-nitrophenyl carbonate (Intermediate 2; 10.0 g, 26.3 mmol), was dissolved in DMF (50 mL). DIPEA (16.0 mL, 92.0 mmol) and 4-(4-chlorophenyl)piperazine dihydrochloride (7.09 g, 26.3 mmol) were added and the reaction mixture was stirred at room temperature for 24 hours, and the reaction mixture was then concentrated in vacuo. The resulting residue was dissolved in EtOAc (300 mL) and washed with a 1 M aq Na2CO3 solution (6×200 mL), 10% citric acid solution (50 mL), brine (50 mL), dried (MgSO4) and concentrated in vacuo. The residue was dissolved in a mixture of DCM (100 mL) and TFA (20 mL), stirred for 4 hours and then concentrated in vacuo. The residue was dissolved in 1 M aq Na2CO3 solution (220 mL), and extracted with DCM (3×200 mL). The combined organic layers were washed with brine (50 mL), dried (MgSO4) and concentrated in vacuo. The residue was recrystallised from EtOAc to give (1-piperidin-4-yl)methyl 4-(4-chlorophenyl)piperazine-1-carboxylate (4.07 g, 45.7%) as a cream solid.

Provenance & Evidence