Sodium Sulfate → 1-{3-[4-(2-chloro-6-nitro-phenyl)-piperazin-1-yl]-propyl}-5-methanesulfonyl-3-(4-trifluoromethyl-phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine

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Reaction Steps

To a stirred solution of 3-[5-methanesulfonyl-3-(4-trifluoromethyl-phenyl)-4,5,6,7-tetrahydro-pyrazolo[4,3-c]pyridin-1-yl]-propionaldehyde (0.5 g, 1.25 mmol) and 1-(2-chloro-6-nitrophenyl)-piperazine (0.301 g, 1.25 mmol) in CH2Cl2 (6 mL) was added sodium sulfate (0.354 g, 2.50 mmol) and sodium triacetoxyborohydride (0.396 g, 1.87 mmol). The mixture was allowed to stir at room temperature overnight. The mixture was diluted with CH2Cl2 and washed with water. The CH2Cl2 layer was dried over Na2SO4, and the solvent was removed under reduced pressure. The residue was purified by column chromatography (silica, 10% acetone/CH2Cl2) to afford of 1-{3-[4-(2-chloro-6-nitro-phenyl)-piperazin-1-yl]-propyl}-5-methanesulfonyl-3-(4-trifluoromethyl-phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine (0.380 g, 49%). MS (electrospray): exact mass calculated for C27H30CIF3N6O4S, 626.2; m/z found, 627.2 [M+H]+. 1H NMR (400 MHz, CDCl3): 7.73 (d, J=8.2 Hz, 2H), 7.66 (d, J=8.2 Hz, 2H), 7.54 (dd, J=8.2, 1.2 Hz, 1H), 7.49 (dd, J=8.2,1.2 Hz, 1H), 7.10 (t, J=8.2 Hz, 1H), 4.58 (s, 2H), 4.13 (t, J=6.5 Hz, 2H), 3.71 (t, J=5.9 Hz, 2H), 3.01-3.11 (m, 4H), 2.95 (t, J=5.9 Hz, 2H), 2.92 (s, 3H), 2.42-2.53 (m, 4H), 2.40 (t, J=6.5 Hz, 2H), 2.12 (q, J=6.5 Hz, 2H).

Provenance & Evidence