How is 2-Chloro-4-iodonicotinonitrile (CAS: 1171919-75-7) typically synthesized?

2-Chloro-4-iodonicotinonitrile is typically synthesized through the reaction of 4-chloronicotinonitrile with iodine in the presence of a suitable base such as potassium carbonate. The process involves the substitution of the chlorine atom with an iodine atom, yielding the desired product with good selectivity. The reaction is carried out under anhydrous conditions to avoid side reactions and is best performed in an inert atmosphere.