Trifluoroacetic acid → (4-(3,4-Difluoro-2-(trifluoromethyl)phenyl)piperidin-1-yl)(4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-3-yl)methanone Trifluoroacetic Acid Salt

Participants

Reaction Steps

To a mixture of tert-butyl 3-(4-(3,4-difluoro-2-(trifluoromethyl)phenyl)piperidine-1-carbonyl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate (35, 41.2 g, 80.0 mmol) and CH2Cl2 (150 mL) was added TFA (70 mL). The mixture was stirred at ambient temperature for 16 h and was concentrated under reduced pressure. The residue was dissolved in CH2Cl2 and the solution washed with saturated NaHCO3, dried over Na2SO4, filtered, and concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (0-20% CH3OH in CH2Cl2) to give (4-(3,4-difluoro-2-(trifluoromethyl)phenyl)piperidin-1-yl)(4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-3-yl)methanone (36) as a white solid (0.052 g, 95%): 1H NMR (300 MHz, CDCl3) δ 7.36-7.27 (m, 1H), 7.14 (m, 1H), 4.92 (m, 2H), 4.04 (s, 2H), 3.27-2.69 (m, 7H), 1.89-1.65 (m, 4H); MS (ESI+) m/z 415 [M+H]+.

Provenance & Evidence