General procedure for the synthesis of 3-iodo-1H-pyrazolo[3,4-b]pyridine from 1H-pyrazolo[3,4-b]pyridine: 1H-pyrazolo[3,4-b]pyridine (0.50 g, 4.2 mmol), iodine (2.1 g, 8.3 mmol), 3M aqueous NaOH (20 mL) and 1,4-dioxane (20 mL) were added to a reaction flask . The reaction mixture was heated to 55 °C and stirred overnight. Upon completion of the reaction, the organic solvent was evaporated under reduced pressure. Subsequently, acetic acid was added dropwise to the residue and the pH of the solution was adjusted to 5. A yellow solid was precipitated. The precipitate was collected by filtration and dried in air to afford the target product 3-iodo-1H-pyrazolo[3,4-b]pyridine (0.93 g, 90% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3) δ 13.80 (br s, 1H), 8.66 (d, J=4.8 Hz, 1H), 7.88 (d, J=7.2 Hz, 1H), 7.26 (dd, J=7.2, 4.8 Hz, 1H) and MS (ESI) m/z: 246 (M+H)+.
![1H-PYRAZOLO[3,4-B]PYRIDINE](/CAS/GIF/271-73-8.gif)
