How is 2-Bromo-6-chloro-3-nitropyridine (CAS: 91678-23-8) typically synthesized?

2-Bromo-6-chloro-3-nitropyridine is typically synthesized via electrophilic substitution reactions. Common methods include the reaction of 6-chloro-3-nitropyridine with bromine in the presence of a Lewis acid like aluminum bromide. The yield and selectivity can be optimized by adjusting the reaction conditions and solvents. This process is often carried out under mild conditions to avoid overbromination or other unwanted side reactions.