197638-83-8

459-57-4

57260-71-6

197638-83-8

Step 1: Anhydrous potassium carbonate (8.5 g, 62 mmol) was added to a solution of N-methyl-2-pyrrolidinone (NMP, 30 mL) containing p-fluorobenzaldehyde (3.9 g, 31 mmol) and N-BOC-piperazine (6.3 g, 34 mmol) under nitrogen protection. The reaction mixture was stirred at 135 °C for 12 hours. The progress of the reaction was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was slowly poured into ice water (100 mL) and a yellow solid was precipitated. The precipitate was collected by filtration and washed three times (20 mL each) with cold water and dried under vacuum to give 1-BOC-4-(4-formylphenyl)piperazine as a yellow solid (6.4 g, 72% yield).