General procedure for the synthesis of 3-bromopyridine-2-carbaldehyde from 2-methyl-3-bromopyridine: 3-bromo-2-methylpyridine (258 mg, 1.5 mmol) was dissolved in dioxane (5 mL), followed by the addition of selenium dioxide (666 mg, 6.0 mmol) under stirring conditions. The reaction mixture was heated to reflux for 48 hours. Upon completion of the reaction, the mixture was allowed to cool to room temperature and the filtrate was collected by filtration. The residue was purified by column chromatography to give a light yellow solid product (175 mg, 63% yield).
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