Bromine → ethyl 3,6-dibromo-1-isopropyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylate
Reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[C:5]2[CH:10]=[N:9][N:8]([CH:11]([CH3:13])[CH3:12])[C:6]=2[N:7]=1.[Br:19]Br>C(O)(=O)C>[Br:19][C:10]1[C:5]2[C:4]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:3][C:2]([Br:1])=[N:7][C:6]=2[N:8]([CH:11]([CH3:13])[CH3:12])[N:9]=1Participants
4
Procedure
To a stirred solution of ethyl 6-bromo-1-isopropyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylate (2 g, 6.43 mmol) in acetic acid (6 mL) was added bromine (5.14 g, 32.15 mmol) at 0° C. Resulting reaction mass was stirred at room temperature for 3 h. Reaction was monitored by TLC. On completion, reaction was quenched with ice, NaHCO3 solution was added to it. Extraction was carried out using ethyl acetate; the combined organic layers were washed with water, brine and dried over anhydrous Na2SO4. Solvent was removed under reduced pressure and residue was purified by silica gel column chromatography to obtain the desired intermediate (1.2 g, 48%).