63725-51-9

1093880-37-5

63725-51-9

GENERAL STEPS: To a solution of tetrahydrofuran (THF, 30 mL) containing 6-chloro-2-fluoropyridine-3-carbaldehyde (4.0 g, 25.1 mmol) was added hydrazine hydrate (2.515 g, 56.3 mmol). The reaction mixture was heated at 60 °C with stirring for 5 hours. Upon completion of the reaction, the mixture was concentrated and quenched with ice water. The solid formed was collected by filtration and dried under vacuum to afford 6-chloro-1hydro-pyrazolo[3,4-B]pyridine (3.5 g, 92% yield). The product was characterized by 1H NMR (DMSO-d6, 300 MHz): δ 13.8 (s, 1H), 8.32-8.29 (d, 1H), 8.20 (s, 1H), 7.27-7.24 (d, 1H). the LCMS analysis showed a purity of 89.96%, m/z = 153.9 (M + 1).