Acetic Anhydride → Tert-butyl 4-acetylpiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Tert-Butyl piperazine-1-carboxylate (4.00 g, 21.4 mmol) is dissolved in dichloromethane (40 mL), cooled to 0° C. and treated with acetic anhydride (2.23 mL, 23.6 mmol) over a period of 2 min. The reaction mixture is stirred at 0° C. for 30 min, LCMS analysis used to indicate completion of the reaction and the volatiles evacuated in vacuo. The residue is treated carefully with NaHCO3 (sat. aq., 50 mL), stirred vigorously for 30 min and the resulting mixture extracted with diethyl ether (4×20 mL). The combined organic extracts are dried (MgSO4), filtered and concentrated in vacuo to afford tert-Butyl-4-acetylpiperazine-1-carboxylate as a white solid (4.53 g, 93%). 1H NMR (400 MHz, DMSO-D6) δ ppm 1.39 (s, 9H), 1.99 (s, 3H), 3.22-3.29 (m, 2H), 3.30-3.34 (m, 2H), 3.36-3.41 (m, 4H); ESI-MS: m/z 229.3 (M+H)+.

Provenance & Evidence