1,4-Dioxane hydrochloride → Racemic 4-(4-(benzyloxy)phenyl)-3,3-difluoropiperidine

Participants

Reaction Steps

To a solution of t-butyl 4-(4-(benzyloxy)phenyl)-3,3-difluoropiperidine-1-carboxylate (5.2 g, 12.9 mmol) in MeOH (100 mL) was added 4 M HCl/dioxane (32.2 mL, 130 mmol) and the reaction mixture was stirred at rt for 5 h. The mixture was then evaporated under reduced pressure, and the residue was diluted with a saturated sodium bicarbonate solution and extracted with 200 mL of ethyl acetate. The layers were separated and the organic phase was dried over Na2SO4, filtered, and concentrated under vacuum. The residue was subjected to preparative HPLC (method C) to afford 2.5 grams (63%) of racemic 4-(4-(benzyloxy)phenyl)-3,3-difluoropiperidine. LCMS (method F) RT 2.044 min, m/z 304 (M+H+); 1H NMR (400 MHz, DMSO-d6) δ ppm 7.31-7.48 (m, 5H) 7.21 (d, J=8.53 Hz, 2H) 6.98 (d, J=9.04 Hz, 2H) 5.10 (s, 2H) 3.05-3.20 (m, 2H) 2.98 (d, J=13.05 Hz, 1H) 2.74-2.87 (m, 1H) 2.60 (t, J=11.55 Hz, 1H) 1.88-2.00 (m, 4H) 1.72 (d, J=13.05 Hz, 1H), 19F NMR (377 MHz, DMSO-d6) δ-102.276, -102.900, -115.135, -115.759.

Provenance & Evidence