Synthesis
General procedure for the synthesis of 2-piperazine-1-benzaldehyde from piperazine and 2-fluorobenzaldehyde: 2-fluorobenzaldehyde (1.0 g, 8.1 mmol) was dissolved in N,N-dimethylformamide (15 ml) in a 50 ml round bottom flask. Piperazine (836 mg, 9.7 mmol) and potassium carbonate (1.68 g, 12.2 mmol) were then added and the reaction was carried out at 130 °C for 6 hours. After completion of the reaction, it was cooled to room temperature, the reaction mixture was diluted with water and extracted with ethyl acetate. The organic phases were combined and dried over anhydrous sodium sulfate. Purification was carried out by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1; dichloromethane: methanol = 10:1), and the target compound 2-piperazine-1-benzaldehyde (760 mg, 49.4% yield) was obtained after concentration.
