1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → tert-butyl 3-(4-(5-fluoro-2-(trifluoromethyl)phenyl) piperidine-1-carbonyl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate

Participants

Reaction Steps

Step A To a solution of 4-(5-fluoro-2-trifluoromethyl)phenylpiperidine hydrochloride (11, 90 mg, 0.32 mmol), 5-(tert-butoxycarbonyl)-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxylic acid (85 mg, 0.32 mmol), and diisopropylethylamine (0.17 mL, 0.96 mmol) in DMF (5.8 mL) was added EDCI (74 mg, 0.38 mmol) and HOBt (52 mg, 0.38 mmol). The resulting solution was stirred at ambient temperature for 24 h. The reaction mixture was diluted with H2O (10 mL) and extracted with EtOAc (3×30 mL). The combined organic extracts were washed with a saturated brine solution (4×20 mL) and concentrated to dryness under reduced pressure. The obtained residue was chromatographed over silica gel (Isco CombiFlash Rf unit, 12 g Redisep column, 0% to 5% MeOH in CH2Cl2 with 0.1% NH4OH in CH2Cl2) to provide tert-butyl 3-(4-(5-fluoro-2-(trifluoromethyl)phenyl) piperidine-1-carbonyl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate (45) as a white film (120 mg, 80%): 1H NMR (300 MHz, DMSO-d6) δ 12.96 (br s, 1H), 7.76 (dd, J=9.0, 5.7 Hz, 1H), 7.61-7.51 (m, 1H), 7.30-7.18 (m, 1H), 5.34-5.16 (m, 1H), 4.76-4.58 (m, 1H), 4.53-4.38 (m, 2H), 3.65-3.52 (m, 2H), 3.22-3.01 (m, 2H), 2.60-2.43 (m, 3H, overlaps with solvent), 1.83-1.65 (m, 4H), 1.42 (s, 9H); ESI MS m/z 497 [M+H]+.

Provenance & Evidence