[Br:1][C:2]1[C:10]([O:11][CH3:12])=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[N:5][NH:6]2.Br[CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16].C(=O)([O-])[O-].[K+].[K+].CN(C)C=O>O>[Br:1][C:2]1[C:10]([O:11][CH3:12])=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[N:5][N:6]2[CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16]A mixture of 4-bromo-5-methoxy-1H-indazole (8.57 g), ethyl bromoacetate (7.56 g), potassium carbonate (6.26 g) and N,N-dimethylformamide (30 mL) was stirred overnight at room temperature. To the reaction mixture was added water, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4), and concentrated. The residue was subjected to silica gel column chromatography to give the title compound (4.65 g, yield 39%) as colorless crystals from the fraction eluted with ethyl acetate-hexane (1:3, volume ratio). melting point 106-107° C. MS: 315 (MH+).
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