6-Amino-3-chloropyridazine → 3-Amino-4-bromo-6-chloropyridazine

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Reaction Steps

3-Amino-6-chloro pyridazine (7.87 g) was dissolved in methanol (115 ml). Sodium bicarbonate (10.2 g) was added and then bromine (3.1 ml) was added dropwise, and the mixture was stirred at room temperature for 16 hours. The reaction solution was filtered and then diluted with water (500 ml), and the aqueous layer was extracted with ethyl acetate three times. The organic layer was dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure. The resulting residue was purified by silica gel column chromatography (developed with ethyl acetate-hexane) to give the title compound (5.2 g) as a brown solid.

Provenance & Evidence