2-bromo-6-methyl-1-oxidopyridin-1-ium-3-ol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 2-bromo-3-hydroxy-6-methylpyridine 1-oxide 29 (15 g, 0.075 mol) in TFAA (50 mL, 0.375 mol) and was stirred at 40° C. for 24 h. The solvent was removed under vacuum. The residue was purified by column chromatography (silica gel: EA:Hex, 2:1). Yield: 4.5 g, 30%. 1H NMR (CDCl3): δ 7.32 (d, J=8.0 Hz, 1H), 7.25 (d, J=8.5 Hz, 1H), 4.56 (s, 2H). The solvent was removed under vacuum The residue was purified by column chromatography (silica gel: EA:Hex, 2:1)