Baeyer–Drewson indigo synthesis
The Baeyer–Drewson indigo synthesis is an organic reaction in which indigo is prepared from 2-nitrobenzaldehyde and acetone
The reaction is classified as an aldol condensation. As a practical route to indigo, this method was displaced by routes from aniline.Mechanism
Note
In the English literature this reaction is usually called Baeyer–Drewson reaction, although the author of the original paper was called Drewsen.