Hydrochloric Acid → (6-Bromo-[1,2,4]triazolo[4,3-a]pyridin-3-yl)(4-(5-fluoro-2-(trifluoromethyl)phenyl)piperidin-1-yl)methanone

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Reaction Steps

To a solution of ethyl 6-bromo-[1,2,4]triazolo[4,3-a]pyridine-3-carboxylate (85 mg, 0.32 mmol) in THF (2.6 mL) was added a solution of LiOH monohydrate (15 mg, 0.35 mmol) in H2O (1.8 mL). The mixture stirred for 20 min and was neutralized with 2 N HCl. The mixture was concentrated under reduced pressure. The obtained residue was diluted in DMF (3.0 mL) under an atmosphere of N2. To this mixture was added 4-(5-fluoro-2-trifluoromethyl)phenylpiperidine hydrochloride (11, 89 mg, 0.32 mmol), benzotriazole-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (280 mg, 0.63 mmol), and diisopropylethylamine (0.17 mL, 0.95 mmol). The mixture was stirred at ambient temperature for 18 h. The resulting mixture was diluted with H2O (20 mL). The solution was extracted with EtOAc (3×20 mL). The combined organic layers were washed with a saturated brine solution (3×20 mL) and concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (Isco CombiFlash Rf unit, 12 g Redisep column, 0% to 50% EtOAc in hexanes) to provide to provide (6-bromo-[1,2,4]triazolo[4,3-a]pyridin-3-yl)(4-(5-fluoro-2-(trifluoromethyl)phenyl)piperidin-1-yl)methanone as a white solid (97 mg, 65%): 1H NMR (500 MHz, DMSO-d6) δ 9.16-9.14 (m, 1H), 7.98 (dd, J=10.0, 1.0 Hz, 1H), 7.77 (dd, J=8.5, 5.5 Hz, 1H), 7.72 (dd, J=9.5, 1.5 Hz, 1H), 7.52 (dd, J=11.0, 3.5 Hz, 1H), 7.29-7.23 (m, 1H), 5.31-5.24 (m, 1H), 4.76-4.70 (m, 1H), 3.42-3.32 (m, 1H), 3.27-3.19 (m, 1H), 3.06-2.96 (m, 1H), 1.98-1.75 (m, 4H).

Provenance & Evidence