Tert-butyl 4-(3-methoxy-4-nitrophenyl)piperazine-1-carboxylate → 1-(3-Methoxy-4-nitrophenyl)piperazine

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Reaction Steps

1-dimethylethyl 4-[3-(methyloxy)-4-nitrophenyl]-1-piperazinecarboxylate (2.25 g, 6.67 mmol) was dissolved in methylene chloride (50 mL) and trifluoroacetic acid (10 mL). The resulting solution turns immediately dark and was stirred overnight. The solution was concentrated and partitioned between methylene chloride and 2.0N sodium hydroxide. The organic layer was collected and the aqueous layer was saturated by addition of sodium chloride and subsequently backextracted with additional methylene chloride. The combined organic layers were dried over sodium sulfate, filtered, and taken to a residue under reduced pressure to afford analytically pure 1-[3-(methyloxy)-4-nitrophenyl]piperazine as a yellow solid (1.7 g, 7.2 mmol, quant. yield). 1H NMR (400 MHz, DMSO-d6) δ ppm 2.28-2.37 (m, 1 H), 2.76 (q, J=4.64 Hz, 4 H), 3.29-3.34 (m, 4 H), 3.86 (s, 3 H), 6.46 (d, J=2.38 Hz, 1 H), 6.54 (dd, J=9.43, 2.47 Hz, 1 H), 7.84 (d, J=9.34 Hz, 1 H).

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