Hydrogen Bromide → 1-(2-Bromophenyl)-4-methylpiperazine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 2-(4-methylpiperazin-1-yl)-aniline (23.77 grams, 0.124 mol) in 80 mL of 48% hydrobromic acid was cooled to 20° C. and treated with a solution of sodium nitrite (8.6 grams, 0.124 mol) in 35 mL of water while maintaining a temperature of 20-25° C. To this was added a solution of copper (II) bromide (3.5 grams, 0.024 mol) in 12 mL of 48% HBr. The mixture was heated to 85° C. for approximately 30 minutes, poured over crushed ice in a large beaker and neutralized with dilute aqueous sodium hydroxide. The crude product was extracted into diethyl ether and concentrated in vacuo to a black oil which was chromatographed on silica gel using triethylamine.methanol.methylene chloride (0.5:10:90) as the eluent. The product, 1-bromo-2-(4-methylpiperazin-1-yl)benzene, was obtained as a brown oil 20 grams Mass spectrum: 254 (M+), 256 1H-NMR (CDCl3, 300 MHz) δ 7.55 (1H, d), 7.30 (1H, t), 7.05 (1H, d), 6.9 (1H, t), 3.05 (4H, br s), 2.55 (4H, t), 2.35 (3H, s).

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