N[C:2]1[C:10]2[C:5](=[CH:6][C:7]([C:11]#[N:12])=[CH:8][CH:9]=2)[NH:4][N:3]=1.N([O-])=O.[Na+]>CC(O)=O>[NH:4]1[C:5]2[C:10](=[CH:9][CH:8]=[C:7]([C:11]#[N:12])[CH:6]=2)[CH:2]=[N:3]1To a suspension of 3-amino-1H-indazole-6-carbonitrile (345 mg) in AcOH was slowly added an aqueous NaNO2 solution (301 mg) at 0° C. It was stirred at room temperature for 2.5 days, and the residue was collected by filtration, and washed with cool water. To the residue were added 0.1M HCl and DME, followed by stirring at 80° C. for 2 hours. The reaction mixture was neutralized with a saturated aqueous NaHCO3 solution, and extracted with EtOAc. The organic layer was dried over anhydrous MgSO4, and concentrated. The residue was purified by silica gel column chromatography (n-hexane:EtOAc=80:20 to 50:50) to obtain 1H-indazole-6-carbonitrile (175 mg) as a yellow solid.
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