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

HRID 2356206Notes

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.[C:14](OC(=O)C)(=[O:16])[CH3:15]>ClCCl>[C:10]([O:9][C:7]([N:1]1[CH2:6][CH2:5][N:4]([C:14](=[O:16])[CH3:15])[CH2:3][CH2:2]1)=[O:8])([CH3:13])([CH3:12])[CH3:11]

Participants

Conditions

Temperature: 0 °C

Procedure

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)+.

Workup

customcompletion of the reaction
customthe volatiles evacuated in vacuo
additionThe residue is treated carefully with NaHCO3 (sat. aq., 50 mL)
stirringstirred vigorously for 30 min
extractionthe resulting mixture extracted with diethyl ether (4×20 mL)
dry with materialThe combined organic extracts are dried (MgSO4)
filtrationfiltered
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-8de8390b71e4411b9fae1fd36cf6be77
Source dataset: uspto-grants-2010_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07759339B2

Reaction notes

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