Diisopropylethylamine → Piperidin-4-ylmethyl 4-(4-methylphenyl)piperazine-1-carboxylate

Beteiligte Stoffe

Reaktionsschritte

(tert-Butoxycarbonyl)piperidin-4-ylmethyl 4-nitrophenyl carbonate (Intermediate 2; 3.80 g, 10.0 mmol) was dissolved in DMF (100 mL). DIPEA (6.10 mL, 35.0 mmol) and 4-(4-methylphenyl)piperazine dihydrochloride (2.49 g, 10.0 mmol) were added. The reaction mixture was stirred at room temperature for 4 hours and 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 (25 mL), stirred for 48 hours and then concentrated in vacuo. The residue was purified by reverse phase column chromatography (gradient eluting with MeOH in water, with 1% formic acid in each solvent, 0-30%). The resulting residue was dissolved in DCM (70 mL) and stirred with solid K2CO3 for 20 minutes, filtered and concentrated in vacuo to give piperidin-4-ylmethyl 4-(4-methylphenyl)piperazine-1-carboxylate (1.60 g, 44.6%) as a pale yellow solid.

Herkunft & Nachweise