Hydrochloric Acid → 1-(4-Nitrophenyl)piperazine

Reaction equation

Cl[C:2]1[CH:7]=[CH:6][C:5]([N+:8]([O-:10])=[O:9])=[CH:4][CH:3]=1.[NH:11]1[CH2:16][CH2:15][NH:14][CH2:13][CH2:12]1.Cl>C(O)CCC>[N+:8]([C:5]1[CH:6]=[CH:7][C:2]([N:11]2[CH2:16][CH2:15][NH:14][CH2:13][CH2:12]2)=[CH:3][CH:4]=1)([O-:10])=[O:9]

Participants

Procedure

A solution of 1-chloro-4-nitrobenzene (15 g, 94.5 mmol) in 1-butanol (75 mL) was added over 20-30 minutes to a refluxing solution of anhydrous piperazine (24.4 g, 284 mmol) in 1-butanol (75 mL) and the mixture maintained at reflux overnight. The solvent was removed under reduced pressure to afford a solid, to which was added 2N hydrochloric acid (400 mL). The aqueous layer was washed twice with ethyl acetate, cooled to below 10° C. and basified with a cold solution of 40% sodium hydroxide to pH 10, keeping temperature below 20° C. The mixture was extracted with ethyl acetate (4×200 mL) then the combined organic layers were washed with brine and dried over sodium sulfate. Filtration and concentration under reduced pressure afforded 1-(4-nitro-phenyl)-piperazine (13.7 g, 70%) as a yellow solid.