[Br:1][C:2]1[C:3]([O:11][CH3:12])=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][N:6]=[CH:5]2.[H-].[Na+].Cl[CH2:16][O:17][CH2:18][CH2:19][Si:20]([CH3:23])([CH3:22])[CH3:21]>C1COCC1>[Br:1][C:2]1[C:3]([O:11][CH3:12])=[C:4]2[C:8](=[CH:9][CH:10]=1)[N:7]([CH2:16][O:17][CH2:18][CH2:19][Si:20]([CH3:23])([CH3:22])[CH3:21])[N:6]=[CH:5]2To a stirred solution of 5-bromo-4-methoxy-1H-indazole (1.33 g, 5.9 mmol) in THF (20 mL) at 0° C., under a nitrogen atmosphere, was added sodium hydride (280 mg, 7 mmol) portionwise. After 5 min, (2-chloromethoxy-ethyl)-trimethylsilane (1.36 mL, 7.7 mmol) was added dropwise. After 3 hours, the reaction mixture was quenched with water (20 mL). The resulting biphasic mixture was separated, extracted with ethyl acetate (2×50 mL) and the combined organic layers were washed with brine (30 mL), dried (Na2SO4), filtered and concentrated in vacuo. The resulting residue was subjected to flash chromatography (SiO2, gradient 10-20% ethyl acetate in cyclohexane) to give the title compound as a yellow oil (1.19 g, 56%). LCMS (Method B): RT=4.91 min, [M+H]+=357.
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