Diethyl Ether → Tert-butyl 4-(4-amino-3-methoxyphenyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of tert-butyl 4-(3-methoxy-4-nitrophenyl)piperazine-1-carboxylate (I1) (1.90 g, 5.63 mmol) in methanol (20 mL) and ethyl acetate (80 mL) was added 10% Pd/C (0.500 g). The mixture was evacuated and backfilled three times with hydrogen gas then stirred under a hydrogen atmosphere for 18 hours. The crude reaction mixture was filtered through a plug of Celite, washing with ethyl acetate and the filtrate evaporated in vacuo then dried under high vacuum to give a dark red viscous oil. The oil was suspended in a 2:1 solution of diethyl ether and petroleum ether (15 mL) and sonicated for 3 minutes. The resulting mixture was evaporated in vacuo and dried under high vacuum to give the title compound (I2) (1.55 g, 89%) as a dark red solid; 1H NMR (300 MHz, d6-DMSO) δ 1.47 (s, 9H), 2.97 (t, 4H, J=4.7 Hz), 3.57 (t, 4H, J=4.7 Hz), 3.83 (s, 3H), 6.40 (dd, 1H, J=8.3, 2.1 Hz), 6.50 (d, 1H, J=2.0 Hz) and 6.64 (d, 1H, J=8.3 Hz). LCMS Method B: rt 5.02 min; m/z 308.3 [M+H]+.

Provenance & Evidence