Sulfuric Acid → 1-(2-methoxy-5-nitrophenyl)piperazine

Participants

Reaction Steps

2-(Piperazin-1-yl)anisole (5.1 g; 26 mmol) is acidified slowly with 6 ml of sulfuric acid (5N) and then dehydrated by evaporation under reduced pressure. Concentrated sulfuric acid is then added (22 ml) very slowly (25 min) and the reaction medium is stirred until a homogeneous mixture is obtained. Potassium nitrate (3.1 g; 31 mmol) is added portionwise over 35 minutes. The reaction is stirred for 4 hours. The solution is then poured onto ice and neutralized by addition of sodium carbonate (to pH≈7-8). The nitro derivative is extracted from the aqueous phase with ethyl acetate (4×80 ml), dried over magnesium sulfate and purified by flash chromatography with an eluent gradient (2 to 5% methanol in dichloromethane in the presence of 0.5% aqueous ammonia).

Provenance & Evidence