[Br:1][C:2]1[C:10]([N+:11]([O-])=O)=[CH:9][C:8]2[C:4](=[C:5]([C:21]#[N:22])[N:6]([C:14]3[CH:19]=[CH:18][C:17]([F:20])=[CH:16][CH:15]=3)[N:7]=2)[CH:3]=1.C1COCC1.O.[Cl-].[NH4+]>CO.[Fe]>[NH2:11][C:10]1[C:2]([Br:1])=[CH:3][C:4]2[C:8]([CH:9]=1)=[N:7][N:6]([C:14]1[CH:15]=[CH:16][C:17]([F:20])=[CH:18][CH:19]=1)[C:5]=2[C:21]#[N:22]
To a suspension of 5-bromo-2-(4-fluorophenyl)-6-nitro-2H-indazole-3-carbonitrile (500 mg, 139 mmol) in a mixture of methanol (50 mL), THF (5 mL) and water (2.5 mL) was added ammonium chloride (370 mg, 6.91 mmol) followed by iron powder (386 mg, 6.91 mmol). The mixture was heated to 80° C. and stirred vigorously for 90 min. The resulting suspension was filtered through celite and washed with EtOAc. The filtrate was concentrated, and the residue was suspended in water and extracted with EtOAc. The organic layer was contracted to give 6-amino-5-bromo-2-(4-fluorophenyl)-2H-indazole-3-carbonitrile (310 mg, 68%) as a yellow solid. 1H-NMR (CDCl3, 400 MHz) δ 7.99 (s, 1H), 7.80˜7.82 (m, 2H), 7.23˜7.57 (m, 2H), 7.03 (s, 1H), 4.40 (s, 2H). MS (M+H)+: 331/333.
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