Baeyer-Drewson indigo synthesis

What is Baeyer-Drewson indigo synthesis?

The Baeyer-Drewson indigo synthesis is a method primarily used for protecting o-nitrobenzaldehydes. This involves an aldol condensation, where the o-nitrobenzaldehydes are reacted with acetone, pyruvic acid, or acetaldehyde to form indigos.

Baeyer-Drewson Indigo synthesis
Baeyer-Drewson indigo synthesis

While the synthesis has shown to be effective, it is mainly of interest for its role in protecting o-nitrobenzaldehydes.


Baeyer, A. and Drewsen, V. (1882), Darstellung von Indigblau aus Orthonitrobenzaldehyd. [Preparation of indigo blue from orthonitrobenzaldehyde.] Ber. Dtsch. Chem. Ges., 15: 2856-2864.