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

HRID 350543Notes

Reaction equation

[N:1]1([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.F[C:15]1[CH:25]=[CH:24][C:18]([C:19]([O:21][CH2:22][CH3:23])=[O:20])=[CH:17][CH:16]=1.C([O-])([O-])=O.[K+].[K+]>CN(C=O)C.CCOC(C)=O>[C:10]([O:9][C:7]([N:1]1[CH2:6][CH2:5][N:4]([C:15]2[CH:25]=[CH:24][C:18]([C:19]([O:21][CH2:22][CH3:23])=[O:20])=[CH:17][CH:16]=2)[CH2:3][CH2:2]1)=[O:8])([CH3:13])([CH3:12])[CH3:11]

Participants

Conditions

Temperature: 120 °C

Procedure

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.

Workup

temperatureAfter cooling
washby washing with brine (2×200 mL)
dry with materialdrying over MgSO4, and evaporation
customThe residue was chromatographed on silica-gel with CHCl3-EtOAc (20:1 to 4:1

Sources & evidence

ORD record: ord-d412922d15134dfeb3cb1e919ce46299
Source dataset: uspto-grants-2007_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07179819B2

Reaction notes

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