Fischer–Hepp rearrangement

In organic chemistry, the Fischer–Hepp rearrangement is a rearrangement reaction in which an aromatic N-nitroso (−N=O) or secondary nitrosamine (>N−N=O) converts to a carbon nitroso compound: This organic reaction was first described by the German chemist Otto Philipp Fischer (1852–1932) and Eduard Hepp (June 11, 1851 – June 18, 1917) in 1886, and is of importance because para-NO secondary anilines cannot be prepared in a direct reaction. The rearrangement reaction takes place by reacting the nitrosamine precursor with hydrochloric acid.

Source: Wikipedia — Fischer–Hepp rearrangement (CC BY-SA 4.0)