The invention discloses a preparation method of an amino
pyridine bromide compound, relating to the field of
organic synthesis. The amino
pyridine bromide compound takes
pyridine bromide formamide as
raw material, and is prepared according to the following formula of Hofmann
degradation reaction which comprising the following steps of: (1) dropping liquid
bromine into alkali liquid with the concentration of 2.0-4.0 mol / L at -5-0 DEG C, reacting for 1.0 hour to obtain
sodium hypobromite or
potassium hypobromite, wherein the alkali is
sodium hydroxide,
potassium hydroxide or
sodium methoxide; (2) adding the pyridine bromide
formamide with the general foumula I to the
hypobromite solution at
room temperature for dissolving, raising temperature to 50-80 DEG C, reacting for 0.5-2 hours, decreasing temperature to 0 DEG C for separating out solids, and filtrating to obtain crude products; extracting the filtrate with an
organic solvent, removing the
solvent, and merging the crude products; re-crystallizing by using
petroleum ether, and
drying to obtain amino pyridine bromide. Wherein, the
mole ratio of the general formula I to the alkali is 1:4-8, the
mole ratio of the general formula I to water is 1:80-160, and the
mole ratio of the general formula I to the liquid
bromine is 1:1-2; and the
organic solvent is
dichloromethane,
chloroform or normal
hexane. The invention has the advantages of one-step reaction, simple process, low requirement on equipment, and high product purity, and the yield coefficient is around 50 percent.