Hydrochloric Acid → Propiophenone, 3-(4-phenyl-1-piperazinyl)-

Participants

Reaction Steps

A well-stirred mixture of acetophenone (17) (3.40 mL, 29.0 mmol), 1-phenylpiperazine hydrochloride (18) (4.48 g, 22.5 mmol), and 0.05 mL of concentrated HCl in absolute ethanol (35 mL) was heated under N2 at reflux conditions. Paraformaldehyde (1.00 g, 33.3 mmol) was added in four equal portions over 40 minutes. The reaction mixture was further refluxed for 6 hours. The solution was then cooled and poured onto crushed ice. The solid was separated by filtration, dried, and re-crystallized using a small amount of aqueous ethanol (<10 mL). The solution was allowed to cool overnight and yielded 5.32 g the desired product 19 (18.1 mmol, 62%) as a white, yellow crystal. 1H-NMR (CDCl3): δ 8.03 (2 H, d, J=7.24 Hz), 7.63 (1 H, t, J=7.37, 7.42 Hz), 7.50 (2H, t, J=7.87, 7.35 Hz), 7.31 (2H, m), 6.97 (3H, m), 3.89 (2H, t, J=6.89, 6.72 Hz), 3.62 (8H, m), 3.10 (2H, m). 13C-NMR (CDCl3): δ 195.99, 149.27, 135.41, 134.24, 129.51, 128.37, 122.00, 117.43, 52.36, 51.97, 46.91, 33.14. Melting Point: 182-185° C.

Provenance & Evidence