Sodium Carbonate → 6-(2-Chloropyridin-3-yl)imidazo[1,2-a]pyridine

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6-(2-Chloropyridin-3-yl)imidazo[1,2-a]pyridine was synthesized in the similar to 6-(2-chloropyridin-3-yl)benzo[d]thiazole from 6-iodo-imidazo[1,2-a]pyridine (1.0 g, 4.1 mmol), 2-chloro-3-pyridine boronic acid pinacol ester (1.2 g, 5.0 mmol), Pd(PPh3)4 (250 mg, 0.22 mmol) and 2M aq.Na2CO3 (7 mL, 12 mmol) in 1,4-dioxane (50 mL). Workup of the reaction mixture was carried out by sequential steps of concentrating the reaction mixture, extraction with CH2Cl2, drying over MgSO4/Celite®, filtration and concentration. The crude residue was stirred in 50% EtOAc/hexanes (40 mL). The resulting white precipitate was filtered and dried to provide 6-(2-chloropyridin-3-yl)imidazo[1,2-a]pyridine (0.52 g, 55%). 1H NMR (DMSO-d6): δ 8.73 (dd, 1H, J=0.8 and 1.8 Hz), 8.47 (dd, 1H, J=2.0 and 4.7 Hz), 8.00 (dd, 1H, J=2.0 and 7.6 Hz), 7.98 (s, 1H), 7.64 (d, 1H, J=8.8 Hz), 7.63 (s, 1H), 7.56 (dd, 1H, J=4.7 and 7.6 Hz), 7.33 (dd, 1H, J=1.8 and 8.8 Hz), Hz).LCMS: rt 3.16 min (A), purity 99%, MS (m/e) 230 (MH+).

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