The directive influence of the N‐oxide group during the nitration of derivatives of pyridine‐N‐oxide

The nitration of some mono‐substituted derivatives of pyridine‐N‐oxide containing a bromine atom, an ethoxy‐ or a methyl‐group in positions 2 or 3, has been investigated. When these compounds are heated With a mixture of fuming nitric acid and sulphuric acid, a nitro‐group is introduced into the 4‐position. It appears that the course of the nitration is not influenced by the presence of the bromine atom, the ethoxy‐ or methyl‐group in the nucleus. A 4‐nitro‐compound is obtained even from 2‐ethoxypyridine‐N‐oxide, the nitro‐group entering the meta‐position with respect to the strongly ortho‐para directing ethoxy‐group.