Process for preparation of N,N{40 -disubstituted-4,4{40 -bipyridylium salt

摘要

A novel process for the preparation of an N,N'-disubstitued-4,4'-bipyridylium salt, characterized in that an N,N'-disubstitued tetrahydro-4,4'-bipyridyl corresponding to the desired salt is treated with at least one aromatic nitro compound in the presence of water. The process of the present invention is more advantageously effected further in the presence of a water-immiscible organic solvent. According to the present invention, the desired product can be obtained with high purity and in high yield.