Ammonium Chloride → Benzyl 2-(7-bromo-6-hydroxy-1H-indazol-1-yl)-1-methylethylcarbamate

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of benzyl 2-(6-hydroxy-1H-indazol-1-yl)-1-methylethylcarbamate (0.90 g, 2.98 mmol) in dichloromethane (10 mL) and tetrahydrofuran (5 mL) was added N-bromosuccinimide (0.59 g, 3.38 mmol) at room temperature. After 16 h, a saturated aqueous solution of ammonium chloride (25 mL) was added and this mixture was extracted with ethyl acetate (3×60 mL). The combined extracts were washed with brine (10 mL), dried (magnesium sulfate), and evaporated. The residue was purified by chromatography (silica, 30% to 50% ethyl acetate in hexane) to give (1.1 g, 91%): 1H NMR (CDCl3) δ 7.86 (1H, d, J=8.8 z), 7.80 (1H, s), 7.37 (6H, m), 6.18 (1H, brs), 5.24 (1H, brs), 4.95 (2H, s), 4.80 (2H, m), 4.34 (1H, m), 1.26 (3H, d, J=6.8 Hz); MS (ES) m/z 404, 406 (M+).

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