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

Participants

Reaction Steps

To a solution of 4-(2-chloro-5-fluorophenyl)piperidine hydrochloride (17, 70 mg, 0.28 mmol), 5-(tert-butoxycarbonyl)-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxylic acid (89 mg, 0.34 mmol), and diisopropylethylamine (0.15 mL, 0.84 mmol) in DMF (5.4 mL) was added EDCI (64 mg, 0.34 mmol) and HOBt (45 mg, 0.34 mmol). The resulting solution was stirred at ambient temperature for 24 h. The reaction mixture was diluted with H2O (20 mL) and extracted with EtOAc (4×20 mL). The combined organic extracts were washed with a saturated brine solution (8×20 mL), H2O (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 100% EtOAc in hexanes) to give tert-butyl 3-(4-(2-chloro-5-fluorophenyl)piperidine-1-carbonyl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate (49) as a white solid (78 mg, 60%): 1H NMR (300 MHz, DMSO-d6) δ 12.96 (s, 1H), 7.48 (dd, J=8.7, 5.4 Hz, 1H), 7.34-7.21 (m, 1H), 7.16-7.06 (m, 1H), 5.28-5.11 (m, 1H), 4.77-4.57 (m, 1H), 4.53-4.38 (m, 2H), 3.66-3.52 (m, 2H), 3.30-3.04 (m, 2H, overlaps with H2O), 2.92-2.61 (m, 3H), 1.92-1.74 (m, 2H), 1.69-1.49 (m, 2H), 1.41 (s, 9H); ESI MS m/z 462 [M+H]+.

Provenance & Evidence