Reactions
2,4-Dihydroxy-3-nitropyridine could be quickly transformed into 5-bromo-2,4-dihydroxy-3-nitropyridine by the action of a solution of bromine. 3.5 g of 2,4-Dihydroxy-3-nitropyridine were heated with a mixture of 1.15 ml of bromine and 30 ml of acetic acid at 70℃ for 15 minutes. When the reaction mixture was cooled with ice, 3.7 g of 5-bromo-2,4-dihydroxy-3-nitropyridine separated out[1]. Yield: 70 %
References
[1] Kolder, C. R. , and H. J. D. Hertog . Migration of halogen atoms in halogeno-derivatives of 2,4-dihydroxypyridine (II). Recueil des Travaux Chimiques des Pays-Bas 72.10(2010):853-858.