Potassium Carbonate → tert-Butyl 4-(2-fluoroethyl)piperazine-1-carboxylate

Participants

Reaction Steps

Potassium carbonate (1.85 g, 13.4 mmol) and 1-bromo-2-fluoroethane (440 μl, 5.9 mmol) were added to a solution of tert-butyl-1-piperazinecarboxylate (1 g, 5.4 mmol) in acetonitrile (12 ml). The reaction mixture was stirred at 65?C for 3.5 hours after which time more 1-bromo-2-fluoroethane (160 μl, 2.1 mmol) was added. The reaction was heated for a further 3 hours then filtered to remove the inorganic solids. The filtrate was concentrated and the crude product was purified using column chromatography eluting with ethyl acetate to give 4-(2-fluoroethyl)-piperazine-1-carboxylic acid tert-butyl ester (714 mg, 57%). NMR Spectrum: (CDCl3) 1.46 (s, 9H); 2.50 (t, 4H); 2.70 (dt, 2H); 3.45 (t, 4H); 3.45 (t, 4H); 4.57 (dt, 2H) MS-ESI: 233 [MH]+

Provenance & Evidence