Sodium borohydride (0.41 g, 10.9 mmol) was added in portions to a stirring suspension of 1-{1-[3-(ethyloxy)-4-nitrophenyl]-4-piperidinyl}-4-(methylsulfonyl)piperazine (1.50 g, 3.64 mmol) and NiCl2.6H2O (0.26 g, 1.1 mmol) in THF (15 mL) and MeOH (30 mL) at rt. The reaction mixture was allowed to stir at rt overnight and then it was concentrated in vacuo. The residue was taken up in DCM and passed through a bed of celite. The resultant filtrate was then concentrated onto silica gel and purified by flash chromatography to afford 2-(ethyloxy)-4-{4-[4-(methylsulfonyl)-1-piperazinyl]-1-piperidinyl}aniline (0.40 g, 30%). 1H NMR (400 MHz, DMSO-d6) δ ppm 6.42-6.56 (m, 2H), 6.29 (dd, J=8.4, 2.3 Hz, 1H), 4.21 (br. s., 2H), 3.96 (q, J=6.9 Hz, 2H), 3.37-3.48 (m, 2H), 3.05-3.12 (m, 4H), 2.86 (s, 3H), 2.56-2.63 (m, 4H), 2.26-2.37 (m, 1H), 1.75-1.85 (m, 2H), 1.42-1.61 (m, 2H), 1.31 (t, J=7.0 Hz, 3H).
