Potassium Carbonate → tert-Butyl 4-(4-(ethoxycarbonyl)phenyl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of tert-butyl 1-piperazinecarboxylate (1.00 g, 5.37 mmol), ethyl 4-fluorobenzoate (903 mg, 5.37 mmol), and K2CO3 (1.11 g, 8.06 mmol) in DMF (10 mL) was heated at 120° C. overnight. After cooling, the mixture was diluted with EtOAc (300 mL), followed by washing with brine (2×200 mL), drying over MgSO4, and evaporation. The residue was chromatographed on silica-gel with CHCl3-EtOAc (20:1 to 4:1, v/v) as eluent to give 257 mg (14%) ethyl 4-[4-(tert-butyloxycarbonyl)-1-piperazinyl]benzoate as a pale yellow amorphous solid. IR (KBr) 1701, 1612 cm−1; 1H-NMR (CDCl3) d 1.37 (3 H, t, J=7.3 Hz), 1.49 (9 H, s), 3.30 (4 H, t, J=5.4 Hz), 3.58 (4 H, t, J=5.4 Hz), 4.33(2 H, q, J=7.3 Hz), 6.87(2 H, d, J=8.8 Hz), 7.94 (2 H, dt, J=8.8, 2.4 Hz); MS (FAB) m/z 335 (M++1); Anal. Calcd for C18H26N2O4: C, 64.54; H, 7.84; N, 8.38. Found: C, 64.39; H, 7.89; N, 8.38.

Provenance & Evidence