[Br:1][C:2]1[CH:10]=[C:9]2[C:5]([CH:6]=[N:7][NH:8]2)=[CH:4][CH:3]=1.[H-].[Na+].[CH3:13]I>C1COCC1>[CH3:13][N:8]1[C:9]2[C:5](=[CH:4][CH:3]=[C:2]([Br:1])[CH:10]=2)[CH:6]=[N:7]1.[CH3:13][N:7]1[CH:6]=[C:5]2[C:9]([CH:10]=[C:2]([Br:1])[CH:3]=[CH:4]2)=[N:8]1
To 6-bromoindazole (402A) (5.0 g, 25.4 mmol) in THF (50 mL) was added sodium hydride (95%, 672 mg, 26.6 mmol) with ice bath cooling. The mixture was stirred for 30 minutes. Methyl iodide (6.36 mL, 102 mmol) was added at room temperature. The reaction mixture was quenched with ammonium chloride solution and the layers were separated. The aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with brine, dried over sodium sulfate and concentrated. Purification by column chromatography (SiO2, ethyl acetate/hexane gradient) afforded 1-methyl-6-bromoindazole (402B) (2.71 g, 51%) as a yellow oil and 2-methyl-6-bromoindazole (402C) (2.28 g, 43%) as a yellow crystalline solid.
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