Sodium Nitrite → Methyl 5-bromo-6-fluoro-1H-indazole-4-carboxylate

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Reaction Steps

To a solution of methyl 3-amino-6-bromo-5-fluoro-2-methylbenzoate (1.33 g, 5.09 mmol) in acetic acid (25 mL) heated to 50° C. was added a solution of sodium nitrite (369 mg, 5.34 mmol) in water (1 mL), and the mixture was stirred for 1.5 hr and concentrated under reduced pressure. The residue was diluted with ethyl acetate, washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate/hexane=5/95→40/60) to give the title compound (700 mg, yield 52%).

Provenance & Evidence