Hydrochloric Acid → 1-(3-Chloro-4-nitro-phenyl)-4-(4,6-dimethyl-pyridin-2-yl)-piperazine

Participants

Reaction Steps

50% aqueous hydrochloric acid (30 mL) was chilled to −20° C., 5-[4-(4,6-dimethyl-pyridin-2-yl)-piperazin-1-yl]-2-nitro-phenylamine (1.4 g, 4.28 mmol) was added and the reaction mixture stirred for 15 min. A solution of sodium nitrite (350 mg, 5.14 mmol) in water (8 mL) was added and the reaction mixture stirred for 15 min. This solution was added dropwise to a cooled solution of copper (I) chloride (635 mg, 6.42 mmol) in 50% hydrochloric acid (20 mL) over a period of 20 min and stirred for a further 10 min before basifying with saturated sodium carbonate solution. The mixture was extracted with ethyl acetate then the organic phase was washed with water and brine, dried over anhydrous sodium sulfate and concentrated under vacuum to give a crude residue. Purification by column chromatography over silica gel (100-200 mesh) using 8% ethyl acetate in petroleum ether as eluent afforded 1-(3-chloro-4-nitro-phenyl)-4-(4,6-dimethyl-pyridin-2-yl)-piperazine (800 mg, 54%) as a yellow solid.

Provenance & Evidence