反应详情

6-(2-Chloropyridin-3-yl)-1H-pyrazolo[4,3-b]pyridine was synthesized in the similar manner to the preparation of 5-(2-chloropyridin-3-yl)-1H-pyrazolo[3,4-b]pyridine by heating the mixture of tert-butyl 6-bromo-1H-pyrazolo[4,3-b]pyridine-1-carboxylate (2.5 g, 8.4 mmol), 2-chloro-3-pyridine boronic acid pinacol ester (2.2 g, 9.2 mmol), Pd(PPh3)4 (610 mg, 0.52 mmol) and 2M aq.Na2CO3 (12 mL, 24 mmol) in 1,4-dioxane (40 mL). Upon work-up of the reaction mixture similar to 5-(2-chloropyridin-3-yl)-1H-pyrazolo[3,4-b]pyridine provided 6-(2-chloropyridin-3-yl)-1H-pyrazolo[4,3-b]pyridine as an off-white crystalline solid. 1H NMR (DMSO-d6): δ 13.50 (s, 1H), 8.57 (app s, 1H), 8.48 (dd, 1H, J=1.7 and 4.7 Hz), 8.35 (s, 1H), 8.12 (s, 1H), 8.02 (dd, 1H, J=1.7 and 7.6 Hz), 7.60 (dd, 1H, J=4.7 and 7.7 Hz).LCMS: rt 4.50 min (A), purity 94%, MS (m/e) 231 (MH+).

1. temperatureby heating