Sodium Carbonate → 5-(2-chloropyridin-3-yl)-1H-indazole

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Analogous to the reaction conditions and work-up procedures used in the preparation of 5-(2-chloropyridin-3-yl)-1H-indazole, 5-(2-chloropyridin-3-yl)-1H-indazole was obtained by heating the mixture of tert-butyl 6-bromo-1H-indazole-carboxylate (7.3 g, 24.6 mmol), 2-chloro-3-pyridine boronic acid pinacol ester (7.0 g, 29.5 mmol), Pd(PPh3)4 (2 g, 1.7 mmol) and aq.Na2CO3 (44 mL, 88 mmol) in 1,4-dioxane (200 mL) under argon atmosphere. The crude concentrate that was obtained after the extractive work-up dissolved in CH2Cl2, adsorbed on to silica gel and dried. Subsequent purification by flash silica gel column chromatography (Combiflash® companion System® with RediSep® silica gel column 120 g, 30-70% EtOAC/hexanes eluting solvent gradient upon dry powder loading) provided 5-(2-chloropyridin-3-yl)-1H-indazole as a white solid (4.2 g, 74%). 1H NMR (DMSO-d6): δ 13.21 (s, 1H), 8.43 (dd, 1H, J=1.7 and 4.7 Hz), 8.12 (s, 1H), 7.93 (dd, 1H, J=1.7 and 7.6 Hz), 7.84 (d, 1H, J=8.5 Hz), 7.59 (s, 1H), 7.52 (dd, 1H, J=4.7 and 7.6 Hz), 7.17 (d, 1H, J=8.5 Hz).LCMS: rt 6.17 min (A), purity 98%, MS (m/e) 230 (MH+).

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