1. 28.4 g (0.33 mol, 5.5 equiv) of piperazine is dissolved in 50 mL of DMSO. 2. 6.4 mL (60 mmol) of m-fluoronitrobenzene is added to this solution.
2. 6.4 mL (60 mmol) of m-fluoronitrobenzene was added to the above solution.
3. The reaction mixture was heated at 100°C for 60 hours. 4.
4. When the reaction is complete, cool to room temperature and slowly pour the mixture into 530 mL of water.
5. The precipitate formed was collected by filtration and the filtrate was extracted with ether (Et2O). 6.
6. The organic phases were combined, dried over anhydrous magnesium sulfate (MgSO4), and concentrated under reduced pressure.
7. The crude product was purified by column chromatography using a solvent mixture of dichloromethane (CH2Cl2) and methanol (MeOH) (9:1, v/v/v) as eluent.
8. The target component was collected and concentrated under reduced pressure to give 8.04 g of orange oil, which was crystallized as 1-(3-nitrophenyl)piperazine after standing at room temperature in 65% yield.
Compound characterization data.
Molecular formula: C10H13N3O2
Molecular weight: 207.26 g/mol
1H NMR (CDCl3) δ (ppm): 7.70 (t, J = 2 Hz, 1H, H-2'); 7.64 (ddd, J = 8 Hz, 2 Hz, 0.6 Hz, 1H, H-4'); 7.36 (t, J = 8 Hz, 1H, H-5'); 7.17 (ddd, J = 8 Hz, 2 Hz, 0.6 Hz, 1H, H-6') ; 3.30-3.18 (m, 4H, H-3, H-5); 3.09-2.97 (m, 4H, H-2, H-6).
