Under argon protection, 4-(4-nitrophenyl)piperidine (400 mg, 1.942 mmol) was dissolved in methanol (30 mL) and palladium catalyst (144 mg) was added. Argon was replaced with hydrogen and the reaction was stirred at room temperature for 3.5 hours. Upon completion of the reaction, the palladium catalyst was removed by filtration and the solvent was removed by concentration under reduced pressure. The residue was purified by dichloromethane milling to give 4-(piperidin-4-yl)aniline (340 mg, 99% yield) as a white solid.HPLC analysis showed a purity of 95.0% [retention time R = 6.74 min, mobile phase 30% methanol/0.1% trifluoroacetic acid aqueous solution, run time 20 min].1H NMR (400 MHz, methanol-d4) δ 6.99 (d, J = 8.4 Hz, 2H), 6.69 (d, J = 8.4 Hz, 2H), 3.46-3.22 (m, 2H), 2.95 (td, J = 12.8, 3.0 Hz, 2H), 2.70-2.62 (m, 1H), 1.96-1.84 (m, 2H), 1.82-1.70 (m, 2H).LC -MS (ESI+) m/z 177.13808 [M + H]+. HRMS (ESI+) m/z Calculated C11H16N2 [M + H]+ 177.1386, measured 177.1382.
