Hydrochloric Acid → Tert-butyl 4-(4-nitrobenzoyl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 500 ml round bottom flask was loaded with 4-nitrobenzoyl chloride (10.2 g, 53.9 mmol) and dichloromethane (100 ml) and cooled to 0° C. Pyridine (10 ml, 124 mmol) was added, followed by tert-butyl piperazine-1-carboxylate (10.2 g, 54.8 mmol) (solid, in portions) while stirring at 0° C. After the addition was completed, the ice bath was removed and the reaction mixture stirred while allowing the reaction to warm to room temperature overnight. The mixture was poured into a separating funnel loaded with 250 ml ethyl acetate and 250 ml 1N aq. HCl. The layers were separated, the organic layer washed one more time with 1 M aq. HCl, then with sat. aq. NaHCO3 solution (2×), then brine (1×), then dried over MgSO4, filtered and concentrated in vacuum. 12.9 g tert-butyl 4-(4-nitrobenzoyl)piperazine-1-carboxylate were isolated as a white solid. MS (ESI) m/z 280 (M+H—C4H8), 236 (M+H-BOC). 1H NMR (CDCl3) δ ppm 8.28 (d, 2H, J=8.6), 7.57 (d, 2H, J=8.6), 3.76 (bs, 2H), 3.53 (bs, 2H), 3.39 (bs, 2H), 3.33 (bs, 2H), 1.46 (s, 9H).

Provenance & Evidence