Hydrochloric Acid → 3-(4-Aminophenyl)-4-methylpiperazin-2-one

Participants

Reaction Steps

A 25-mL single-neck round-bottomed flask equipped with a reflux condenser and magnetic stirrer was purged with nitrogen and charged with 104b (210 mg, 0.89 mmol), ethanol (6 mL), iron powder (−325 mesh, 491 mg, 8.93 mmol) and 2N hydrochloric acid (0.70 mL, 1.40 mmol), and the mixture was heated at reflux for 30 min. After this time, the reaction was cooled to room temperature, and powdered potassium carbonate (3.03 g, 22.0 mmol) was added. The resulting suspension was filtered and the filter cake washed with ethanol (4×10 mL). The filtrate was concentrated under reduced pressure to afford 104c in 100% yield (185 mg) as a white solid: mp 153-154° C.; 1H NMR (300 MHz, DMSO-d6) δ 7.74 (d, 1H, J=2.7 Hz), 6.90 (d, 2H, J=8.4 Hz), 6.47 (d, 2H, J=8.4 Hz), 4.95 (bs, 2H), 3.45 (m, 1H), 3.42 (s, 1H), 3.14 (m, 1H), 2.89 (m, 1H), 2.44 (m, 1H), 2.02 (s, 3H); MS (ESI+) m/z 206 (M+H).

Provenance & Evidence